There are several different types of power meter on the market and each measures something slightly different in order to make their estimates. In addition, the way that they measure what they measure has implications for their accuracy. Below I discuss what the major models measure, how they measure it, and the implications for accuracy.

Power is the rate of work (so you need to know the amount of work and the span of time over which that work is done), and work is a force exerted over a distance, so each power meter has a different way to measure those forces and, because of patents, each has chosen to measure them in a different "location."

With the exception of the iBike, most power meters measure the forces somewhere along the drivetrain: working from the back to the front, the PowerTap (and the old Look MaxOne) measures at the rear hub, the older Polar systems measured along the chain, the Quarq, SRM, Rotor, and Power2Max measure at the spider of the front chain ring, the new Look/Polar and Garmin Metrigear (thus far, announced but unreleased) measure at the pedal spindle, the (announced but unreleased) Brim Brothers measures at the shoe cleat, the Ergomo measured at the bottom bracket, and the Stages measures at the left crank. The iBike measures in a completely different way, discussed below. One consequence of measuring at various points along the drivetrain is that drivetrain losses will (or won't) be accounted for to a different degree; for example, a PowerTap will usually read lower than a SRM since one is "upstream" of most drivetrain losses while the other is "downstream." This difference is more of a definitional issue than a strict "accuracy" issue (in the sense of, "is gross income or net income a more 'accurate' measure of income?" Unless you have a specific use in mind, it's hard to say which is more "accurate").

Most of the power meters on the market use strain gages, which are small thin foil strips whose electrical conductance and resistance varies as they are deformed. Strain gages are used in lots of applications (like, bridges) and their properties are well-understood. In general, strain gages are combined in a "rosette" or "Wheatstone bridge" in order to produce more accuracy and precision (more strain gages usually produce better results), and, when operating properly the Power Tap, Quarq, and SRM are usually accurate to within a couple percent (and, just as importantly, with high precision); this has been verified both statically (using known weights hung from the crank) and also dynamically (using a large powered rolling drum in a lab). The forces are then combined with a measurement of angular velocity or speed to get power. A virtue of strain gages is that the change in resistance can be measured even when the device is stationary so the cyclist can measure the accuracy of the strain-gage-based power meters at home by hanging weights of a known mass from the crank. A common problem with the strain gage approach, however, is that they can be sensitive to changes in temperature and so need to be "re-zeroed" prior to (and sometimes, during) rides. The old Look MaxOne's achilles heel was waterproofness, not the strain gages or method of measurement. For example, the original Power2Max (and the old discontinued SRM "Amateur" model) uses fewer strain gages than the current PowerTap, Quarq, or SRM models and reports from users (subsequently admitted to by the manufacturer) showed that it was more sensitive to temperature drift during a ride than those others. The Power2Max was redesigned and updated in late 2012 and reports are that the temperature problem has been largely addressed. A claimed feature of the Stages is that it is designed around automatic temperature compensation — as of early 2013 this claim is still being evaluated by users and it is too early to know if their approach does what it claims.

The old Polar power meter measured the force transmitted along the chain by chain tension, and included a chain speed sensor to get total work. In a chain higher force transmitted along the chain results in higher tension, and tension can be measured by the resonant frequency of the object (for example, plucking a highly-tensioned spoke with your fingernail produces a high frequency tone while plucking a loose spoke produces a low tone). As an historical aside, the proof-of-concept prototype for the Polar chain tension sensor was the pickup from an electric guitar. The chain speed sensor fit on one of the derailleur jockey wheels and could count the "pulses" in the magnetic field as the chain rivets passed; since chain rivets are a known distance apart, chain speed was easily calculated. As for accuracy, when the Polar was operating well, it was very good; however, when it wasn't it was very naughty indeed. Worse, it was often hard to tell when it was being naughty. The downfall of the old Polar power meter was three-fold: 1) the chain tension sensor needed to be close to the chain, which was hard to achieve since the chain sometimes had to be in the large or small chain ring or the large or small rear cog; 2) the chainspeed sensor sometimes got overwhelmed and gave false speed readings; and 3) incomplete weatherproofness in part due to exposed wires and a poorly sealed "pod."

The Ergomo bottom-bracket based power meter used an optical sensor and a series of "peek holes" to measure torsion in the bottom bracket. An odd characteristic of this design is that it could only measure the (torsional) force traveling through the bottom bracket; thus, it only measured the power contributed by the left leg: to get total power it doubled the left-leg contribution. In conjunction with the difficulty in installing and calibrating the Ergomo (it had to be installed just exactly so), this dependence on bilateral symmetry between the legs was the death knell for the Ergomo. The Stages power meter similarly measures force by deformation in the left crank, and doubles the "left" to arrive at an estimate of total power. Research with instrumented force pedals shows that bilateral asymmetry in power production between the right and left legs is the norm — worse, the research shows that the asymmetry can change with the level of effort. However, some riders are willing to accept this inherent inaccuracy and imprecision.

Because neither the old Polar nor Ergomo power meters used strain gages, their accuracy and precision could not be statically checked in the field by the cyclist; they could only be checked dynamically (or against anotheher known-calibrated power meter).

The unreleased Garmin Metrigear and Brim Brothers pedal or pedal cleat power meters are rumored to use piezoelectric sensors and solid state accelerometers rather than foil strain gages but until they reach the market all claims about accuracy or precision should be taken with grains of salt. An interesting problem in the design of a pedal- or cleat-based power meter is that the direction of force and the position of the pedal spindle must be known: for example, if you add downward force at the bottom of the pedal stroke, that is wasted force since it does not aid in moving the crank in the correct direction; likewise, if you press down (however slightly) on the upstroke, that will cancel out some of the force exerted by the other leg on its downstroke. Keeping track of the various force vectors is therefore key to getting reliable accuracy and precision. To some extent, the Stage power meter can also occasionally be susceptible to a related problem: the Stages uses a solid-state accelerometer in the pedal (similar to the solid-state accelerometers one can find in smart phones) to determine its position. Early production models of the Stages were plagued by imprecise measurements of pedal position, so pedal speed was also imprecise — and this had repercussions for the precision of the final power estimates.

The recently released (as of January 2012) Look/Polar power meter uses strain gages arrayed along the pedal spindle, and each pedal must be carefully installed so the pedals know which direction the forces are being applied -- a special tool is supplied with the pedals to help with the orientation. To simplify the conversion of measured forces to torque values, the Look/Polar pedal allows the use of only four different crank lengths: 170mm, 172.5mm, 175mm, and 177.5mm. Cranks shorter than 170mm are currently not supported. One pedal is the "master" and the other is the "slave"; the slave pedal transmits information to the master which then bundles data from both pedals and forwards it to the head unit. At the moment, the Look/Polar pedal uses its own transmission protocol and no other manufacturer has yet signed on to provide compatible head units. Early reports on the new Look pedals confirm that the orientation of the pedals is critical: because the spindle of a pedal is small, a small absolute error in alignment can be a large relative error in its angular orientation.

The iBike takes a completely different approach: it calculates power indirectly. That is, you need a certain amount of power to overcome changes in potential energy (climbing or descending), for changes in kinetic energy (accelerating or decelerating), to overcome aerodynamic drag (including the wind) and drag from rolling resistance so if you know ground speed, gradient, wind speed, your total mass (you plus bike and all equipment) then combined with estimates of the coefficients of rolling resistance (Crr) and of aero drag and front surface area (CdA or drag area) you can calculate the overall power (see, for example, here). In essence, the other power meters on the market focus on the "supply side equation" by measuring power supplied by the rider somewhere along the drivetrain; the iBike focuses on the "demand side" by measuring power demanded to move the bike against wind, gradient, and other drag forces. Under normal conditions, this can be quite (perhaps even surprisingly) accurate, though the precision of the power estimated in this way is not as good -- the iBike assumes that the aerodynamic drag area (aka CdA) is constant, so if the rider changes position (say, moving from the drops to the bar tops) or if the wind speed differs because the yaw angle changes, the power estimate will be off. In general, the iBike has been shown to be quite accurate for hill climbs; less so for rolling courses or riding in a pack, so the overall accuracy will depend on the exact mix of riding done and the variability in the direction of the wind. As with the non-strain gage based old Polar and Ergomo, the iBike cannot be statically checked for accuracy or precision; worse, nor can it be checked on a dynamic rig in a lab since it depends on gradient and wind speed. Checks of the iBike have been performed in the field when riders have mounted another power meter on the same bike and compared the two data streams.

There have been a few "simultaneous" comparisons of power meter accuracy where one rider mounted two or more power meters on the bike and went on structured or unstructured rides. You can see one such "Rosetta Stone" comparison here and here.

In general, all of the commercially released power meters have been accurate (and sometimes precise) when newly-adjusted and performing under ideal conditions. However, conditions are not always ideal and parts get damaged, dirty, and deteriorate. If accuracy and precision are important then the "design" accuracy (whether based on strain gages, optical sensors, magnetic sensors, or wind speed sensors) is only half the battle: equally important is the ability to verify a power meter at home so you can tell when they're off.


what are good training program for offroad racing?

If you new to XC (cross-country) you will need to develop three different components:

Technical Skill - This can include descending, switchbacks, riding drops (even hucking the odd drop - I have had to resort to this in many a race and even in a cyclocross race or two (a good way to get cheers from the crowd is launching yourself into a sand pit!).  You should also work at carrying speed through corners and over flat rough terrain. The more momentum you can carry the faster you will be for a given fitness level.
Endurance - Being an endurance sport, this is a critical component. Believe it or not it will help you with (1).  It is very hard to concentrate on technical sections if you are coughing up a lung and bleeding from the eyes.
Short term power - This is used to get up short steep climbs, to surge through technical sections and get you up those difficult step-up climbs.

1. Technical skill

If you are relatively new to off-road riding you should really focus on component (1).  This is your foundation, if you cannot efficiently navigate the terrain you cannot compete effectively.  Here getting out and simply riding is a great approach.  Try and deconstruct how you approach trail obstacles.  Experimenting with lines, body position on the bike (e.g., how you weight the wheels in turns, over drops and jumps) and attack strategy (e.g., maintaining speed or scrubbing speed for different obstacles.

Depending on the terrain of where you compete/live the amount of time you will need to dedicate will differ from area to area.  (For comparison I used to live and train on North Vancouver Canada, which have some of the most technically challenging trails in the world - so I spent a lot of time honing my technical skills).

Have a look through the SE questions for tips on riding techniques or ask around within your local community.

2. Endurance

Some dedicated mountain bikers may shudder at this suggestion, but the best way to build endurance is on the road on a road bike.  The environment is very consistent so you can pace much better than on the trails which tend to have a lot of periods of rest or inconsistent power output.  For me personally, I went from lower categories to begin reasonably competitive in Pro/Elite once I started putting significant time in the saddle on a road bike.

A quick search on SE will uncover lots of questions and answers about training on a road bike

3. Short Term Bursts of Power

While you could train this on the road, the trail is best for this component as you often need to be able to put down huge power while gingerly maintaining your balance and traction.  Training these components together is only possible off road.

Find some difficult off-road climbs and practice on them so you can climb them without putting a foot down.  My personal favourite was a steep 20% climb that had five large step-ups (each one as 2-2.5 feet high) in sequence. (Most rode down that trail, I preferred to ride up!)

It helped me to hone my focus and concentration, develop explosive power and develop determination to clear these obstacles. I first practiced after resting so I was at my best, then as I got more proficient I would ride harder and harder up to this section until I was basically full out the entire time with my heart in my throat.

Remember you can always breath on the descent (maybe)!


Thanks for posting this problem. I have exactly the same with my Cannondale Synapse alloy 2009 (Tiagra triple). During every ride I have to tighten the micro-adjuster. After renewing cables, housings, bottom bracket guide etc several times I have finally reached the conclusion it's the barrel adjuster itself.


That is a Direct Mount derailleur.  The hanger there is a separate part that is part of the frame.  When companies call them Hanger Mount or hanger style, the hanger is built into the derailleur and not removable.  To replace it, order the Direct Mount one.


Common wisdom is that upper body length, true inseam and riding style are important to bike fit, as is where/what you will be riding.

Riding offroad needs more frame/rider clearance than street or park riding.  You should have 4 inches/10 cm for true off-road mountain biking, and 1-2 inches (2.5-5 cm) for road or commuter riding.

One of the better bike fit sites: http://www.competitivecyclist.com/Store/catalog/fitCalculatorBike.jsp


It's not the hub's fault unless somehow its axle hardware is put together wrong or it's otherwise not putting the rotor in the right spot, but that would be a weird problem, whereas forks and frames with the issue you're having are an unfortunately common one. Step one could be downloading the IS disc mount standard and confirming it's the fork's fault.

It appears the fork tabs are unfaced. It's possible that simple facing, or even just sanding off the powder/paint, could buy you the space to make it work.

If not, the main option to make this physical combination of parts work, presuming there's adequate material for it, is file off some material from the tabs and then finish by facing it again (don't try to do it all with a facer). Either that, messing around with filing the washers (might actually be a better approach if they're what's seeming to invariably hit first), or a different brake that might have marginally better clearance, or get them to send a less borderline defective fork.


Replace old square taper bottom bracket / ISO or JIS?

First, very nice drawings and measurements. This makes answering easy.

According to the Sheldon Brown link, for JIS "The standard width across the flats at the end of the axle is 12.65 mm", which is very close match to your measurement. ISO would be narrower at 12.33 mm.

Many European manufacturers switched to JIS square taper before two piece cranksets arrived, so it is not that implausible that Nervar did it too. Of course, there is the possibility that an original ISO axle was already replaced with JIS at some point. If this is the case, the end of the axle should be very deep in the crank hole.

Product recommendations are not appreciated on this site, but in my experience basic Shimano bottom brackets are fine.


quads feel over used while in an aero position

You likely need a bike fit. The body position for using aero should be quite different than riding on hoods. Unfortunately, there really isn't a good compromise between a road and a TT/aero position.

I recommend getting a professional bike fit. I'm including the "quick fit" below, but there are too many factors in play and millimeters matter. If possible, go to a shop that specializes in setting up Triathlon athletes (road fit != TT fit).

The "quick fit" for aero is to slam your saddle forward and then adjust height and reach. Your forearms should be on the pads, not your elbows. You should be able to reach all controls (brakes/shifting) without having to move your body (arms yes, body no)...if you can't, then you likely can't reach controls fast enough to be safe.

Happy Riding.


How can I determine whether rust has made my bike unsafe?

Sounds like you have only surface rust. The frame would have to rust through to cause any integrity problems and that would take many years of damp conditions. The creaking you hear when shifting your weight to the bars may be the headset.

It may be worth getting it serviced. As its likely the grease has escaped/become clogged with dirt causing the creaking. It would be wise to check all the joints and welds for signs of fatigue or cracks. Ensure they are all solid.


I would go with something in the 26x2.25 range with the Double-Defense protection.  The 2.25 will give you nice volume to allow lower pressures while still being narrow enough to fit most frames (you might have to go narrower if your frame won't allow the 2.25).

Double defense will give you the maximum protection, it weighs more, but I doubt you would notice unless racing.

Unless you are well versed in running tubeless, I would just stick with tubes.

Hope this helps.


Racks generally do not come paired with panniers, although there are some exceptions. Waterproof panniers are widely available. There are some high-vis panniers out there, and some that have reflective patches.

We generally avoid specific product recommendations here on bicycles.se, but Ortlieb is a standby pannier maker.


If you are not sure what you need, take it to the bike shop. Front derailleurs are complicated! You need the derailleur that fits your bike design and the gears that are installed on that bike.

There are five things to look at: attaching it to the bike, how many chainrings it needs to handle, the space it has to maneuver, whether the front shifter is indexed (sometimes it was only the rear) and how the FD is connected to the shifter.

The attachment for MTBs is just 2 ways, an E-type (which is the fairly rare bottom bracket mount) or a band clamp around the seat tube. You need the right band size (the clamp) for your seat tube - old steel frame MTBs usually had 28.6, or if it's aluminum, it's usually a 34.9. This number is the diameter of the seat tube, in millimeters - you need to measure.

Most of the older MTBs were built with triple chainrings, so most MTB front derailleurs will support that (you don't want a narrow cage double or one destined for the road, though it would probably fit the space).

If the shifter is not indexed you will have a much easier time, if it is indexed, then you will need to be more particular in picking a FD - one that matches your front shifter.

Now it gets complicated...there are top swing and bottom swing FDs. You need to be able to clamp the derailleur to the seat tube at the right height above the chainrings, but it can't be so low that it hits the chainstay when it swings to move the chain. This is the complicated part. Depending on the frame, and the size of your chainrings, either could fit. Older MTBs usually had bottom swing FDs. But there were interfering bottle bosses and weird high chainstays...who knows.

You have already said that the cable goes under the BB shell, so you will need a bottom pull FD. If it went under the top tube, then you would need a top pull FD. Shimano make a dual pull, so it could do both (very handy for cyclocross bikes!), but if you had one, you still need to choose how it swings.

Given the info you have provided, I would expect you to look for a Shimano 28.6, bottom swing, bottom pull...something like the FD-M650, which is a 90s era Deore DX. But I could easily be wrong :)

Good luck!


Do brakes provide full power when used from the hoods?

most mid level and up brakes / levers will offer 75% or better power from the hoods. Max brake power from the drops.

The handle bar position is critical on long rides to offer 3 or so different hand positions. Start with the hoods level, to just above level and move around from there. I tend to micro adjust them as i get comfortable on a new bike. Seat height, frame size, stem length all play a factor in finding that sweat spot.


How brake pad dust/residue affect braking and rim life?

Cleaning the wheels regularly will probably help the life if the brakes, but most likely only modestly. The most important reason to clean the wheels is to remove the road dirt/grime that builds up and can wear on the pads faster, but the brake dust most likely isn't causing undue wear.

Cleaning the rims shouldn't adversely affect the life of the rim if you are doing it correctly and making sure that the rims are dry after cleaning.


If the clicking stops when you stand up, the first suspects are the parts you sit on: saddle and seat post.


Combining flat bar and aerobar: Double stem setup or alternatives?

A previous question regard rim and disc brakes had this link....

Essentially use a long steerer tube and mount two handle bars on the bike. Mount disc and rim brakes so you also have brakes on both handle bars (although you could one set of brakes off two levers.)

Edit: (The original Link now broken so I have now linked to a Sheldon page (which still has the the broken link) in hope they restore it.) and attached the pic (although too small to be really useful)


Caliper position effect on braking or suspension?

So long as the caliper attachment point is rigidly connected to the axle, precisely where along the circumference of the rotor (or wheel, for rim brakes) the caliper sits is of no consequence (other than to the designer, who must consider stresses on the "rigid" components).  Braking force and forces applied to suspension components do not change based on the location of the caliper.

Note that position will, to a significant degree, affect such factors as the torque put on the "tine" of the front fork, which may in turn result in such things as a slight twist in the caliper position while braking, but these effects can only occur to the extent that the "rigid" components aren't, quite.


Please help me identify this bike (Staiger MTB)

Initial answer:  Google says that Staiger is a German bike company.  http://www.staiger-fahrrad.de/

Curiously, none of their current range has any resemblance to your frame shape - that weird shortened toptube is quite unusual.


Recumbent, diamond-frame or trailer to move heavy things?

I would go with a four-wheel recumbent for carrying a big load any distance, just because it's comfortable and controllable. I have one, after building and trying a wide variety of load carrying bikes. It will carry 120kg in a 60x80x50cm bin (220l), and with a bit of plywood instead has carried a chest freezer and a washing machine (separately). With a trailer that has a similar bin I can carry 250kg of soil or other bulk material. It has a Rohloff hub and disk brakes on all four wheels, which makes 250kg loads relatively controllable.

The classic "long john" bike is a good compromise - they can carry 60-80kg bulk loads quite easily and are as fast and nearly as maneuverable as a similar weight diamond frame bike. But, of course, the load is in one piece, low down in front of you. Especially when carrying kids, the advantage of being able to see your load is significant. A long john can often also take a rear rack for added capacity (but you're back to breaking the load up and putting it in panniers).

If you can split the load, a Surly Big Dummy (or XtraCycle) works well, they're easier to ride than a long john but the split load makes them less flexible.

For short trips an upright trike based on a rickshaw works well, but riding slightly canted over (from road camber) is a very odd sensation that takes a bit of getting used to. I've seen one of those with a wheelchair strapped to the platform which was quite cool.

Trailers work well for loads up to about 100kg, but more than that is getting quite dangerous - if your bike falls over the trailer will not stop, it will run you over. For long loads a "jinker trailer" where you attach the load to your bike then the trailer to the back of the load can work really well. I've carried 6m lengths of bamboo and timber behind an upright bike this way. A cheap trailer is often a good start but they are usually poorly made and fall apart if used regularly. Expect to spend $500 or more for a trailer that will carry its rated load 5Mm or more.

My "big trailer" is 1m wide by 2.4m long with four wheels and inertia braks on the front wheels. It's only safe to tow behind the quad but will take ~500kg. It's more a question of how much I can pull.


Sounds like you have moisture in there somewhere and its frozen.  Try pouring warm (not boiling) water on it from a jug.

When you get it open, take it inside, dry it,  and store in a hot water cylinder cupboard to drive out moisture.  If you don't have a HWC then 30 minutes in a normal oven on super-low temperature would do.  Or even putting the open lock in a sunlit window for a whole day.

Once its dry you need to keep the moisture out - I'd use a lot of grease like White Lithium.

You also want to check the seals and perhaps arrange the lock with the keyhole facing down, and the curved part of the D would be lower.  That way rain water won't run into the lock along the sides of the D.


What can I do to fix or replace this broken axle?

You've broken your bottom bracket's axle.
There is no way to safely reattach, so you're up for a replacement bottom bracket.  Ideally you'd install a cartridge BB that duplicates what you have.
The crank arm (in your hand)  is probably okay to reuse, though have a good clean and a close inspection before doing so.  Dings are fine, chips maybe, and cracks are not.  You need a crank puller to get the sheared-off stub out of the crank arm.
I'm not sure if your bike uses a square taper or one of the newer standards - the broken bit could be square or round.  So your new BB has to match what the cranks fit onto, otherwise you'd need new cranks too and that's getting expensive.
Tools should be mostly common hand tools (ie a big spanner), and you will need a BB tool to fit the splines visible in your photo, and a crank extractor to push the nubbin out of the crank arm.   That last might be possible using a press or a hammer and brass drift, but only because its already off the bike.

A follow-on thought - to break a bike like this means either a very hard impact or a lack of maintenance on your part.
Based on the corrosion I can see in the photo, there's a part which was already cracked and exposed to the elements for long enough for rust to start.
Upshot - there was a fairly hard impact, and this was focused on pre-existing damage that you hadn't noticed.  I'd strongly recommend a good clean and de-grease of your entire bike, and go over it looking for other looming damage.  Or ask someone else to help with this - its easy to miss things.


Suspension not compressing on Rockrider ST520

There are many factors affecting the behavior of a suspension fork that may be in play. Let me describe those that I can recall and which can explain the difference between the two identical bikes (one older, one newer).

Many (if not all) suspension forks have a "break-in" period in the beginning of their service. During that period of riding, the fork gradually "loosens" as its internals start to play with each other. I definitely felt such a break-in on my new fork. Some manufacturers list the length of the break-in to be as long as 50 hours, which I think is an overestimation.

The bicycle in question is at the lower end of price and quality ranges, and so is its fork. It may happen that characteristics of such forks simply vary wildly across the production batches. By a pure (bad) luck, your friend got a softer fork, you got a stiffer one.

While such entry level forks are not very configurable, there may still be some adjustments that affect the feel and dynamics of the fork. In this case, these two forks are simply set up in a different manner, and it should be possible to try doing some adjustments. More advanced forks typically have a few tuning knobs that allow to configure air pressure, compression and rebound.

You and your friend are in fact built differently (weight, height), and so are the seemingly identical bikes (frame size, frame geometry etc.). Same named bike models, if they have different model years or are from different production batches, may in fact have different components. Two forks looking identical on the outside may have different internals.

Finally, a fork that is slower to compress does not mean a worse fork. A suspension that compresses too easily can result in the front end of the bike being lower more of the time, which is not optimal. The tune of the fork depends on the riding circumstances and rider preferences. Many pros run their suspension very stiff because of the terrain and speeds they deal with.

My advice would be to continue using the bike with the fork for a while (a couple of dozens hours of riding). If you are content with the feel it gives you after that, just keep it as is. Otherwise, you may play with the tuning it has, but be sure not to wreck it in the process (do not unscrew things all the way out!). It is unlikely to make any difference however, I am afraid to predict, but I may be wrong.
If you are still not content with it, your best option would be to look for a better fork, or a better bike. In the urban setting and without any tricks involved, I do not think that you'll be at a disadvantage with your current whip.


What causes a tube to become deflated on its own?

Sometimes the puncture in an inner tube is very small and the air leaks out very slowly.  This is called a slow puncture.  The classic technique for finding a slow puncture is to immerse the partially inflated inner tube in water and watch for the appearance of any bubbles.

In my experience even the slowest punctures usually get bigger somehow - I don't know how but I prefer not to wait until this happens so I'll usually fix the tube or replace it.


Should I be able to 'manually' rotate the headset?

Most likely you are describing a spacer, but it is not clear.

The spacers should not spin. If they do, it's a sign that the bearings have little or no pre-load and the head set will be loose.
Couple possible causes

The pinch bolts were not loose when the top cap was tightened.

You are missing a spacer.
If you want to lower the bar, you move a spacer from below to above. Someone may have removed a spacer to lower the bar without replacing it above the stem.

Internal view of head assembly

Note: There must be a gap between the top of the steerer tube (fork) and the top cap. If not, the cap bolt cannot pre-load the bearings and a spacer needs to be added. It can be added above the stem if desired. Alternately the steerer can be cut shorter.
How to fix:
(Should take no more than a few minutes)

Back off the cap bolt a couple of turns. Loosen the pinch bolts on the stem until it can easily rotate.
Tighten the top cap bolt (not too much). This sets the bearing pre-load.
Tighten the pinch bolts.

If this does not work

Leave the pinch bolts tight and remove the top cap.
Check for a gap between the top of the stem/top spacer and the top of the steerer.

If there's no gap, go to your LBS and get a spacer or two (a few dollars at most).

If there is a gap, and the spacers below the stem are still turning, something is very wrong. Check that the threads on the bolt and star nut are not the problem.

Refer to this wikibook for instructions.


From the information available your bike uses a 1-1/8" quill style adjustable stem. The only other pertinent  variable is handlebar diameter. While you most likely have 25.4mm (1 inch) bars you could have 31.8mm bars. Locating replacement bolts will likely be difficult as the pinch bolts of pivoting stems are typically brand specific in terms of length of the shoulder and diameter of the head.


Where can I find a compact/ultra 7 speed freewheel?

Found a few sources by searching on "compact 7-speed freewheel" – here is what Sheldon Brown / Harris Cyclery has. The claim is that they will work, perhaps with the addition of a thin washer or two if the clearance is tight around your dropouts. The appear to have new (or maybe NOS) Sunrace FW760 (13-25), and Shimano FW722 (13-28), and a FW723 (14-34) freewheels in stock.

Nashbar has a 13-24 and a 13-32. It appears that Amazon has some sellers with some as well.

Hillary Stone in the UK also has some, both NOS and used.


Replacing front chainring on my old bike

Chainring replacement is pretty easy. It's easier if you take the crank out of the bike but you may be able to get the rings over the spider and crank arm without removing the crank.
You can find instruction videos for pretty much every bike wrenching task. Here is one for chainrings.Note you will need a special chainring bolt tool to fit in the long thin slot on the back of the chainring bolts.
Just get a replacement chainring from a known 3rd party manufacturer, these are not hard to find in the major online bike component stores. You obviously need a ring that has the correct bolt circle diameter (BCD) and bolt pattern.
If you have 53/39 chainrings and you should replace them with the same size. 50 tooth rings are designed to be used on compact chainrings with a 34 tooth small ring. If you fit a 50 tooth you'll have a large reduction in gear ratios on the big ring and a smaller ratio gap between the big and small rings. Older cranks with 130mm BCD won't take small rings smaller than 39 teeth.
Sprocket and chainring wear is accelerated by worn chain 'stretch' (the bushings wear allowing each link to move slightly further apart from its neighbors). If you have worn you chainring out chances are your chain and sprockets are worn too. It's a good idea to replace the freewheel, both rings and chain all together. A worn chain on new sprockets or rings has a tendency to slip over the teeth.


What adjustments can you do to prevent psoas tightness in an aggresive postion on a road or track bike?

When they say activate the core, they mean you should also actively use the muscles on the front of your belly and inside. Not just your back. It definitely does not mean you should be overstressing your rectus femoris or psoas.

Something has to hold your posture. Hands do some of the work, but also cannot take too much, because then they become tired and numb. So than the spine and the muscles around it take a lot of stress. Mobilizing the core means taking some of this load from the back muscles.

I recommend this one where the topic is discussed on an actual bike saddle in the other half of the video.

One has to use the abdominals to held the position, not just leave everything on the back muscles. The context of the video is the pressure on the saddle. But when you watch the pelvis and the lower back when he loosens the abdominals, you can also imagine the stress on the psoas.

There are many articles and videos about core exercise specifically directed to (road) cyclists. For example:

Getting those muscles stronger will enable using them for holding the posture and relieve some other parts. If you only look for stretches, it may not be enough for you.


I often experienced lower back pain during and after rides on my roadie. Stretching helped me significantly. Try regularly stretching the muscles below, above and around your hip / bum, perhaps using hip-focussed yoga poses.


Yes, as long as they are not different.

It makes sense that the actuated side wears more as it does most of the work.

Just bear in mind that some pads are directional, but you haven't posted which pads you're usring.

One thing you should think about though, is how far the static pad can be pushed. Some cheaper mechanical brakes only have a limited amount of movement and if you bottom that out, then actuated side won't be able to push far enough to hold it. Again, this is a general statement as I don't know which calipers you are using.

Edit

You can physically swap the sides from Tektro A10.11 pads. Everything else from above still applies, ie about brake caliper limits.


Is it normal Allen keys are loose fitting?

They all have some play in the fit. The target outside dimensions for the most common bike hex wrench sizes (4, 5, and 6mm) are all around .1mm less than the bores they fit in, which match the nominal sizes with a tolerance of I think +/-0.05mm-ish. That shouldn't lead you to feel they're "very" loose, but they typically aren't exactly snug. Very loose suggests using imperial aka fractional/SAE wrenches, whereas virtually all Allen bolts on bikes are metric. The only exceptions I've encountered are certain 90s BMX stems.

That it's Chinese is here nor there.


Take the new bike to the bike shop where you purchased it and ask for the brake pads to be adjusted. They may need some break in time/miles, but usually an adjustment of the brake pads so that the front of the pad makes contact with the wheel first, will keep the pads from squealing when used. We're talking millimeters in difference...hardly noticeable at all with the front of the brake pad being closer to the wheel. This reduces the vibration you're hearing.


What are these diagonal marks on my innertube?

Those are scuff marks from running the tire flat (or nearly so), and/or from a tire whose sidewall is breaking down.

One suspects that underinflation played a significant role in this tire failure. If you can see "ripples" in the side of the tire while you ride it, it's way under-inflated.  One wall of the tire will tend to fail before the other, based on the rotation and the diagonal cord alignment. The spacing corresponds to where the tire rippled as you rode it -- it repeats in the same location on each rotation since the sidewall gets softer and softer there.


Why would someone steal my rear derailleur and hanger?

Some thieves will intentionally disable a bike so that it can’t be ridden home. Then they’ll come later in the day or evening with the appropriate tools to finish the job.

Often they’ll steal a wheel or your seat or handlebars. But if you had those secured with security bolts then the derailleur might be the next easiest thing to steal that would totally disable your bike — and on many bikes you just need a hex wrench to take it off. And you can put it back on just as easily when you’ve taken the rest of the bike.

Otherwise, no clue. It may have been done by the same thieves who stole an inner tube from a bike here on SE while leaving the tire and rim.


A friction shifter allows you to continuously move the derailleur. The point of this on a front shifter (the left) is to trim the front derailleur. Trimming the front derailleur is when you tweak the position of the front derailleur to account for the change in chain angle with shifting, e.g. eliminate the chain rubbing on the cage of the derailleur.

There isn't a "best" setting -- you'll adjust it depending on which gear combination you're in.


Expanding the range of capabilities of a gravel bike

To me, gravel bikes seem mostly like cross bikes with a bit more money they can take from your wallet.

1) Road and mountain shifters and derailleurs don't play nice with each other at 11 speed, so this question is moot. If you want to check a particular crankset on the bike, look at the width and the type of BB setup. I don't see why you'd want to switch to a mountain drivetrain in the first place.

2) If a wheel is 700c, you can technically mount any tire on it thats 700c (though you'll have problems if too narrow or too wide). If you look at the width compatibility chart from Sheldon Brown, you'd want a rim with a smaller width. Since you're upgrading, may as well buy the right width. By running this, you increase the risk of pinch flats/rim damage over a more well matched width.


How do I measure a fork for suitability?

The overwhelming majority of modern road forks are designed for 10mm axles and 100mm-width hubs. (Since the hub width is the important measurement, it's the inside measurement between the dropouts which should concern you).

After you've ensured that the wheel sizes are the same (700c), the largest concerns are the axle-to-crown measurement; or very nearly what you're measuring as "the dropouts to the brake point", the steerer length, and the fork's rake.

Axle-to-crown. As you've surmised, changing this will modify the angles of the bike. Increasing it will rotate the bike back, slackening the head and seat tube angles.  Reducing it will steepen them.  Unless you've got a particular desire to change the handling of your bike and are willing to work out the geometry (see Damon Rinard's article for starters), it's advisable to keep it as close to "as-designed" as possible.  3-4mm is a minor change. 20mm is significant. It will also reduce the range of tire sizes you can run and most likely require new brake calipers, as they typically have only 20mm of total adjustment.  I don't actually see the axle-to-crown measurement on the fork you have linked.
Steerer length. This is the amount of steerer tube from the top of the fork crown.  On the fork you linked, the steerer length is listed as 250mm, with the top 130mm threaded (leaving 120mm unthreaded).  You'll want to remove your current fork and measure the steerer tube.  If it is longer than about 220mm (rather long) it probably won't have enough room for you to install the headset and get everything threaded on - you'll need a longer fork.  If it's less than 150mm (rather short) you may not have threads far enough down the tube to tighten everything, so you'll need to get more threads cut at a local shop.
Fork rake. This is the distance that the axle is offset from the centerline of the fork.  Changing this dramatically will also change the handling of the bike, so try to stay close to what you have now unless you want to work out the maths. You can measure it by having a friend hold the old fork vertically and then sighting down the steerer:

There are lots of resources to learn more about how fork rake affects handling, Dave Moulton has a good introduction.  The fork you have linked doesn't show a rake measurement.


You mean larger right side flange. Making the left side larger on a derailer wheel would exacerbate the tension disparity, not equalize it.

There are companies that do it. The reason it's not more common is that the difference has to be pretty radical (i.e. a way more expensive shell to produce) before the tension disparity is affected much, and at the same time, it doesn't take much difference at all before lacing the hub gets difficult using conventional j-bend spokes.

On 6-bolt hubs, the left side already has to be around 58mm, so making the right side much larger means starting with just a really big piece of al, and I believe that's why it's seldom done.

The only tall left side mountain hub I know of is the DMR Revolver. I have no idea why they did it that way. But if you want equal spoke tensions, don't buy that hub.


Rebound is close to b in your equations above. The guides I've seen and used recommend the following procedure for setting rear shock rebound.

Ride over a sidewalk curb ( ie. 4-5 inch drop ) and adjust the rebound until you have only one bounce. I.e. you want the shock to be able to absorb a hit, but not keep rebounding to cause you to lose control.

Setting the rebound on the front fork is similar, but not as straight forward. Find a short bumpy descent and keep doing it until you feel like you've got the best control. It's a balance between absorbing the hit and keeping control of the front wheel. If the front shock is "bouncing" more than once after the hit you are don't have control during the up phase.

If you set the rebound too high, the shock won't be able to function as designed to absorb the terrain. If you think of it as a wave form, you want the rebound to not significantly damp out the initial height of the wave, but to damp out the oscillations as quickly as possible.

As you get better and faster you will likely need to tweak the rebound. The trick is to always find that balance between absorbing the hit and sustaining the hit through oscillations.


Can I use a narrowide chainring on a double rings crankset?

There would be a 50% chance for a narrow chain link to sit onto a wide tooth during a transition from the small ring to the big ring. This would result in chain misplacement and imminent failure under load [thanks to @mattnz for figuring that out].

Narrow-wide is all about chain retention, while what one needs in a front double by definition is chain derailing easily and reliably.

My suggestion is to have a proper double chainrings. Given that you'll be touring, you'll need to consider possibility of repairs, and finding a new regular chainring would be much easier than a fancy narrow-wide one.

You can also have two front chainrings but no front derailleur. In this case, gear switching happens by hand: stop, throw the chain from one ring to another, and move on. Provided that you do not plan to use the granny gear often, it may turn out to be a viable option.


Clipless makes it hard to bail out when you're in trouble, which is why most DH riders use flats.

A quality pair of flats + decent shoes are going to be just as expensive as clipless pedals and shoes.

Unless you're doing serious downhill (and crashing a good bit), I would go straight to clipless.


Is there a recommended way to center your handlebars?

It sounds as though you have drop bars, and one of your measurements is to the brake hoods. Since those are independently attached to the handlebars, that measurement only tells you that something is off, not what it is (you have two measurements and three unknowns - the bar position in the stem, the left brake level position on the bar and the right brake lever position on the bar).

I assume there are no markings on the bar, and no bulge where the bar thickens to 25mm from 22mm, otherwise you wouldn't be asking?

I suggest loosening the stem off and making a mark on the centre point of the bars, measuring from a point that has a sharp edge. If the bars are new the end of the drops is good, but on old bars one or both end is often bent a little. Even 5mm makes a noticeable difference here. If the bars have been taped the tape will also affect the measurement, which is why the bar end points are good.

But regardless, the next best way to measure is from the inside of the forward-swept part of the bars. Get a ruler that's longer than the width of the bars and place it on top of the bars, at 90° to the bike's long axis (across the handlebars). Line it up parallel to the bars, so that it's just in front of the cross part. and the same distance forward on both sides. I find that lining up the forward edge of the bars and the back edge of the ruler works well. Then measure off the forward edge of the ruler, since that's on the straight parts of the bars.

Here's a quick top view:

Ideally your bars will not curve this much, or you'll use a wider ruler :)

This lets you measure the exact width of the bars. Halve that, and measure in that far from one side. That's the centre :) Now make a mark there, or better still, mark the ruler and centre the bars in the stem with it in place. A couple of rubber bands can be used to hold the ruler in place while you do this - put them on the rule, put the ruler on the bars, pull a band under the bars and over the end of the rule. Repeat for other side. Now wiggle the bars in to position. Test ride, and make sure it feels right.

Mark with a permanent marker both sides of the stem so you can line it up easily next time.

Also, now if you repeat your measurement to the brake hoods you can twist one or both on the bars to get them symmetrical. If you prefer them that way.

This also works for most other curly bars.


Yes, should be fine. Those 19mm BBs are available for replacement though.


I am having trouble identifying the manufacturer of this bike

The headbadge says K2. Here is the K2 website


20.5" is way to big. You likely want something more around 18.5".

There are a number of bmx bike sizing charts out on the net to help guide you. Two examples are:

https://www.usabmx.com/tracks/1709/pages/492
https://www.danscomp.com/serve/products%7Ccharts/riderchart.htm

Other items you'll want to consider changing in addition to the frame size are going to be crank length, stem length, bar rise and bar width. Assuming you bought a pre-built bike, likely they are all oversized (for you) on your current bike. You may even be better off with a different wheel size.

If you were to get a smaller frame and move parts over you would want to make sure the new frame used all the same sized parts. Specifically you would want to make sure the new frame used the same type/size of bottom bracket, headset, seat post, dropout and wheel.

Do you have access to a local bike shop that has someone knowledgeable about BMX racing on staff? If so it might be worth stopping by and having a conversation with them.


Cost aside, a carbon framebuilder or repairer could likely figure out a good way of doing it.
If tire clearance considerations allow, a simple way would be removing the existing hanger and building up the needed area to 31.8 or 34.9, then doing a hanger adapter. (If by some chance it's both a round tube and a standard diameter, you might not even need to build it up, but one or both of those probably isn't the case.) This would be a fabrication-minimal way. Or they might just bond on a new hanger. Or they might feel comfortable just relocating the holes for the existing hanger.
I would look askance at filing it unless it was clear that a good amount of material would remain. Weakening that spot too much could make terrible things happen. That said, if you tried it and it didn't work, you will almost certainly have outs, either from a third party or from Cannondale. I've known them to replace SuperX FD hangers as a paid repair and I assume they're able to do this frame as well.


If I change my cassette to a different range do I need to change my chain?

Theoretically, you could shorten your chain to accommodate the smaller (largest gear) cassette.  However, I never install a new cassette unless I install a new chain as well.  Cassettes and chains tend to "wear" to one another and one can sometimes encounter difficulty if you don't.

That "could" be the issue with your new chain.  If the old chain was run past it's proper service life and damaged the cassette, no new chain is going to work well with it.  Depending how many miles/hours you put on the new chain, if you put a new cassette on your rig and leave the "new" chain, it could be fine.

However, there are many other issues that could cause slippage.  A stiff link in the new chain if it was twisted/damaged during installation would be a prime example.


Shimano 105 RD-5501 on a six speed freewheel?

Friction shifters do not care what kind of derailleur is at the other end and do not care about the number of speeds on your cassette or freewheel; they just pull the cable. So long as the shifter can pull enough cable to move the derailleur the appropriate range, everything is fine between the shifter and derailleur.

So there's no compatibility issue with the shifter and the derailleur to be concerned about.

The derailleur just needs to be able to move the range of the cassette/freewheel and clear it (depends on the maximum number of teeth, also how much chain it needs to take up depending on which chainrings/cogs you're in). A 6 speed freewheel should be fine; if you are to buy a new freewheel, in most cases a 7 speed freewheel would be the way to go; you may have to put a washer on for it to fit (but if you find a new 6 speed freewheel and want it for some reason, that's your choice).

Edit: As Nathan points out in the comments, make sure to use a 9 speed chain (which should work with a 7 speed freewheel); the derailleur cage narrows as the # of speeds goes up, so you need a narrow enough chain.


How to install pre bled brakes with internally routed frame

Usually what you do is disconnect it at the lever, install the lever to the bar, and run the hose up from the caliper end. Because it's sealed on the other end, no more than a few drops of fluid will escape. Then once it's through you can size the hose by turning the bars as far as they go while holding the hose up to the lever and finding the length where the hose can't get accidentally kinked. Cut it at the lever end and put on the spare barb and olive that come with the brake.

Once you have the system reconnected, in many cases you'll find there's no need to even re-bleed the brake. Since you're cutting the hose, usually the fluid will be essentially flush with the cut. Only a marginal amount of air gets introduced, and Shimano brake reservoirs are able to absorb it. (That air floats up to the reservoir in the lever and won't be in the system during braking.)

If you do want to bleed it, usually only a "gravity bleed" is all that's needed, where you skip the step of shooting oil up from the caliper and just drain it down from the cup at the lever end into the collection bag or bottle at the caliper. (Basically this is taking Shimano's written procedure and eliminating the whole first half.) The concept here is that you've only introduced air in the hose, which the gravity bleed will be well able to eliminate.

As for whether it's really better for brakes to come pre-bled, it's probably kind of a concession to giving people something they can just put on their bike and ride without needing a bleed kit or the ability to use it, etc. It's not necessarily the best way of doing things.


Before you commit to putting money and effort into a build ask yourself is this really the bike you want? Doing your own bike build can be fun and fulfilling but you want to end up with a bike you actually want and will enjoy riding

Is the frame actually the right size for you. You obviously can't sit on it do try it out in its current condition. What size is it and how tall are you? How tall is your neighbor? Look on Scott's web site for size guidance perhaps. Is the cockpit geometry right for you? The CR1 probably has a fairly aggressive low handlebar position. I note that the steerer is cut so you cannot raise the stem. What I would do in your position is measure the CR1's stack and reach geometry, then compare that with some other road bikes that you can test ride at local bike stores. That's not really an option during the current situation.

You also need to address safety issues. If the bike was owned by a pro it probably has done a lot of miles. There may be a reason it ended up in the trash (carbon is cracked) or perhaps your neighbor is getting a new bike for free or for a good deal an could not be bothered to sell this frame and get a couple of hundred bucks (if that) for it. Check the frame and fork carefully all over for signs of damage, impacts, paint cracks etc. Same for the seatpost, stem, handlebar. Take the fork out and inspect the steerer tube as well.

Check the wheels are true, check spoke tension by pinching pairs of spokes together - you are looking for ones that are loose. Check the wear on the brake track (there should be a wear indicator groove. Check the rims for dings or scrapes.

if the bike has lot of miles the the bearings may be worn out. Turn the bars and check for play, excessive friction, roughness or 'notchiness', do the same with the wheel axles. Put a finger in the BB bearings and turn them them looking for the same issues.

Next step is to do your homework and start learning all about bike components and compatibility and how to install everything properly and all the tools you'll need. There are lots of resources online that are not hard to find with Google. My personal favourite is Park Tool which as has tons of great repair articles and videos. You should be able to find some full bike build up videos on YouTube which will get you started. If you have a particular problem or issue look for existing questions with answers on this site. Be aware that in component installation and adjustment details are really important. Do stuff right, don't take shortcuts.

The good news is that road bikes are pretty standardized. A Shimano rim brake groupset will probably bolt right on. There are only a few options to deal with such as the front derailleur mount type and the bottom bracket type.

There are many online bike component stores the are easy to find via Google. I'd go with a bike specific store rather than Amazon etc. as you get better guidance and access to specs and data. Ebay is great for used parts but you do have to know what you are looking for.


In the US, you generally expect bicycles to get cheaper towards October/November, rather than May/June/July.

Everyone wants to buy a bicycle when Spring gets nice and Summer. Then, they'll ride a few days in the fall and put the bike away in winter. So, sales tend to decline in the Fall/Winter (and the deals come out), so looking in Fall is probably the best.

As for tricks to get bicycles at cheaper prices, you could look at shops in different areas which may have different costs (locally, some bikes here are more expensive than going to one of the cities a few hours away; however, some manufacturers may have price control) or look used (but it seems like you're looking at relatively high end bikes in this case, so you may not have as much luck with it). You may also get a good deal on accessories with a bicycle (a certain amount of free kit in some places), so you could hawk those on eBay or something to recover some money.


How to prevent my front derailleur from rubbing on my back tire?

So after tinkering with derailleur position some more, I still couldn't get it to stop rubbing, that's when I had the bright idea to move the clamp bolt to the other side of the derailleur. Now I've got enough clearance that it doesn't rub against the tire and the chain doesn't rub against the cage. There's not a groove for the wire on the other side, but it seems to work just fine in the time I've tested it. It was a stupid idea, but I guess it works for now.


Is it a good idea to lift the front wheel to go through small bumps?

Potential for damage to wheels depends on sharpness of the bump, speed, bike and rider weight, tire volume and pressure, and how tough the wheels are.

Moving your weight back or pulling up on the bars will lessen the impact to the front wheel but will increase impact on the rear.

Large or sharp bumps are best avoided altogether. Standing on the pedals with bent knees and lifting your butt off the seat a little will allow the bike to move underneath you and absorb the impact.

You can also move your weight back as the front wheel goes over the bump then move weight forward as the back wheel goes over, but this gets harder to do as speed increases.


How to prepare oneself for riding in the snow?

Studded tires are a must on ice. They are expensive, but well worth it! A couple of points to consider that have not been mentioned:

Footwear: Winter specific riding shoes or boots. For mountain biking and cross, I ride with Lake boots. On the road, I use an older pair of road shoes that have been stretched to accommodate thick wool socks and neoprene shoe covers.

Head-wear: I typically ride with a helmet cover all winter. I also bring along a couple different varieties of skull caps on ride ranging in thickness, ear/face coverage etc... yes to balaclavas!!!

Depth of snow: whether you are running studs or not, my experience is that if the snow is deeper than 4-5 inches, it is not ride-able. In this case, it is best to wait until either the cross country skiers, hikers or plows(in the case of roads) have cleared or packed down the snow.

Body Temperature: Many cyclists new to riding in colder weather tend to over dress. The trick that works for me is twofold, first absolutely dress in layers and second I want to be cold, not freezing, but cold as I go outside and get my bike ready or at the very start of the ride. If I am warm at that point, I will be sweat soaked in the matter of minutes and wetness is something you want avoid!

Fender: Clearly, if the snow is dry, it is not necessary, but my experience is it is better to have one as a precaution than go without!

Heat Packs: At extreme temperatures, I have successfully used heat packs in the tips of my shoes and palms of my gloves. I am not a huge fan of use in the palms, I very rarely and if i do it is usually just a temporary fix.

Use of Car Heater: If I am driving to the ride, I preheat my shoes and as much clothing as possible using my car heater on the way to the ride.

If you get yourself set up with studs, I would highly recommend finding a frozen lake or pond to ride on! The experience is phenomenal! If you can time the lake ride with 1-2 inches of fresh snow it will be that much better!

I ride road, mountain and cross year round outside. Hope this helps!


Padded seats tend to have more padding than used at any given time. This pushes the other 'extra' padding into the soft tissues. This causes numbness and discomfort over time.

So slim hard seats are actually more comfortable over time, if they are the right size. You need to make sure your sit bones (ischial tuberosity) are well situated. The sit bones of your hips are designed to support weight for long periods of time, where a plush seat disperses your weight to muscles and other areas.


Which 9 speed Shimano Cassette should I get?

You can use a crankset thats market for 8 speed with a 9 speed group. Im assuming the 8 speed 105 cranks are already on the bike so thats one job done.
Personal preference. Hilly means different things to different people. Note the derailleur will provide some constraints due to its chain capacity and maximum cog size. But for hills, you want lower gearing (larger cogs).

Go to your local bike shop and see what they sell the most for commuters in the area.


Why do my disc brake calipers fall out of alignment?

There could be a few possible issues here:
1: You’re not tightening the bolts enough. Take the bike to a bike shop, or even a car garage, and have them torque the bolts down properly with a torque wrench. Additionally, make sure to use threadlocker on the bolts, which is a special type of glue that prevents them from loosening due to vibrations.
2: Your bike’s caliper mounts are not faced properly, meaning that they are not flat and square. This is a more complex issue that can be resolved either by getting the bike warrantied, or having a bike shop machine the mounts down to get them flat. See Weiwen’s comment for details.
3: Your rotor isn’t true. Realigning the caliper won’t fix this. To diagnose this issue, watch the gap between the rotors and brake pads as the wheel spins. If it pulsates or the rotor briefly rubs, then the rotor is not true. Carefully use a clean adjustable wrench to bend it straight again, a little at a time.
4: Your brake piston seals are dirty, and one or both pistons is not operating as it should. This can be remedied by extending the pistons and cleaning them with alcohol.

5: As mentioned by Nathan in the comments, if your bike uses quick release hubs, your wheels may twist and reposition themselves under hard braking if your QR skewer is inadequately clamping on the fork/frame. Make sure you are properly tightening the QR skewer, that it is fully closed and not contacting part of the frame, and that you are indeed flipping it and not just using it as a wrench. If the problem persists, consider switching to an internal cam skewer.
If you have thru axles instead, make sure the axles are properly fastened. The exact procedure depends on the axle system your bike uses.


https://www.parktool.com/blog/repair-help/hub-overhaul-and-adjustment might be worth a read.

The cones do not look too bad.  Hard to see from the photo what the hub is like - are the hub cups pitted? This is what will require replacement. If the cups are not replaceable, the free-hub body might be. However, it boils down to cost and parts availability. Chances are a new wheel will be cheaper than replacing the hub if the hub cannot be rebuilt.

If the cups are not too bad, I would go with new bearings and cones as these are cheap.

From the shops point of view, if they try to service the hub and it fails after a short time, they are on the hook and their reputation is toast. As big chunk of the cost of servicing is labor so it's more cost effective to replace rather than repair. If you are prepared to do it yourself it costs a small amount of money to gets a bit more life from the hub, making a service worth while.


Is it rude to take the lane, then filter when encountering congestion?

In general, yes it is rude. But there can be times when it's acceptable.

I'm sure we all understand that you are trying to maximize your own safety. It is a tricky balance to achieve. Especially since how you ride depends on the local driver and cyclist cultures, and local laws.

In many places we cyclists struggle for respect and acceptance by the motoring majority. There are multiple overlapping factors / factions involved:

The might is right faction. For whatever reason: permanent inferiority complex, transient anger, whatever. Logic will never prevail here, but don't give them a reason to target you.
The cyclists don't obey the rules faction. Reinforced every time a driver sees a cyclist run a red light, ride on the footpath, or in many cases / places - split lanes, take up a whole lane, ride without a helmet, ride with no hands (on the handlebars), pop a mono, have fun, you name it. To them, if a cyclist does anything they as a driver can't do then it should be banned: the rules are written and unwritten.
The cyclists are unpredictable faction. These people may appreciate that every cyclist is freeing up road space, but cyclists vary in experience and predictability. And in peak inner-city traffic it can be hard to know where we are: "Did I pass him yet? I can't see him; did he turn off? I don't want to hit him ...".

In summary: obey the local rules.

For example, I ride in 4 different conditions, when I'm not in a bike lane or on a bike path:

Inner city, generally with heavy and congested (0-40kph) traffic. The drivers generally see lots of bikes, and have learned to accommodate. Because their max speed and mine match, I take a full lane when it's available. At lights, there are "bike boxes" painted on the road in front of the stopped traffic. Bikes are expected to start from there, so that they are visible to the traffic behind. So bikes often filter through the lanes when the traffic is stopped. This example supports taking a lane, but it is a limited case.
Inner city, traffic dominated by recreational and fitness cyclists (Kew Boulevard, for those who know it). The speed limit is 50kph, so on the downhills we usually take the whole lane. Elsewhere, we mostly use the bike lane, unless there is too much bike traffic to fit.
Outer city (the 'burbs). While the traffic here has greatly improved in the last decade, taking a lane is putting your life in their hands. Some drivers are very bike aware, completely changing lanes to overtake. When other drivers see that behavior, they often copy it. But some drivers can look you in the eye and just not see you. Taking a lane is dangerous because to these drivers you simply don't exist. It only takes one to take you out.
Outer city on regular cycling routes, with no bike lanes. If alone, I ride about a meter out from the curb, to avoid all the broken pavement and any rubbish. The local law says vehicles must drive "as near as practicable" to the side of the road. I only take a lane when it would only be for a short distance, and the motorists are aware of me, and safety depends on it. If in a bunch, we would take a whole lane unless it was unsafe.

The third example sounds more like your case. The other examples show how the local conditions and expectations can change things.


Ultegra BR 6800's; Increase the reach to 53mm-54mm?

I increased the reach of my front 6800 by about 1 mm with a Dremel tool because the tops of the pads were extremely close to the tire mounted on my dynamo-hub rim when the front light was mounted. I don't recommend modifying the brakes in this way. No doubt it will void any warranty. I didn't have time to replace the brake with one with a longer reach before I left for a bike trip. I've ridden more than 2500k since the change and don't notice any difference in function. However, I believe my 1 mm modification was about 1/3 of what you're suggesting.


What cause and cure for tense or cramped stomach muscles?

Of course, as with any exercise, stretching is worthwhile. Mostly a few slow warm up laps around a short course, or taking it a bit easy the first few trips out, as you get used to riding a bike again. Mostly, try riding 2 or 3 days a week, with a rest day between, until you get fit enough to ride comfortably.


Why are my disk brakes rubbing when wet and not dry?

I have notice the same phenomenon. If you keep washing with clean water the rubbing noise should go away.  My best guess is that the water coming off the tires and falling into the brakes brings a fine road grit into the system.  This coats the pads/rotors reducing tolerances, causing rubbing to be more noticeable.

If it is really wet for a long time, the rubbing will accelerate pad wear (which I found out during an insanely wet Dec last year).


Areas that you need to check and consider are:

Bottom bracket size and type - the bottom bracket shell on a frame can vary in overall width, and in the type of bottom bracket that it is machined for.
Headset diameter - different frames can have different headset diameters. I think the common ones around at the moment are 1 1/16", 1 1/8", 1 1/4" and een 1 1/2". Some frames have different sizes at the top and bottom.
Length of head tube - important if you are swapping the fork over and have trimmed the steerer tube to length on the original bike.
Brake mounting type - obviously cantilevers have a different mounting type to calipers and disc brakes. Additionally, there are a number of different disk brake mounts out there (although this is much more standardised these days).
Seat tube diameter - these can be different between bikes and will affect whether you can transfer the seat post across.
Drop out spacing - this differs between road and mountain bike frames (120mm and 135mm if I recall correctly), but should matter if you are keeping to the same style of bike.
Length of cable runs - depending upon how each frame routes the brake and gear cables, you may need new cables and/or outers. I'd suggest replacing these anyway as they are pretty cheap, the replacement will improve your shifting and braking performance and you can get the outer lengths just right for the new frame.
Front derailleur mounting and pull direction - does it clamp to the seat tube, or to a braze-on on the seat tube? Is it a top pull or a bottom pull derailleur?


Purpose of partially filled in rear drop out

What you more often see is that the derailer hanger is a separate piece that bolts into what is the filled-in space in your picture.

But this is for frames that are designed for the axle to fit only that far back.  Generally these are less than top quality frames where having both dropouts match exactly would make it obvious that the frame wasn't quite true (since the wheel would not center with the axle all the way back).

So with one side filled in you are forced to tighten that side, then slide the other side forward or back until the wheel is centered.  They make it look like a "feature" that facilitates alignment.


1949 - 1950 JC Higgins built by Murray.  The serial number is stamped into the bottom bracket.  Time and rust will make it difficult to read.  Keep scrubbing.  MOS is the prefix for Murray of Ohio for Sears.  L, M, N, O, P will indicate the year.

This bike is missing the tank.

Here's a picture of one complete with tank and rear rack. Some models had painted tanks rather than the exhaust ports. Some had painted rims, some had chrome rims


Upgrading cassette from 11-28T to 11-32T?

Frame size doesn't really matter.

11-32 does make a substantial difference; remember its the ratio of the front gear to the rear gear that matters. Your lowest gear will be 12.5% lower. Also, you'll get a wider (and likely more useful) spacing in gearing between changes.

You will need a new chain as well, but it should be fine to install. Putting a bigger cassette on is a good starting point.

Of course, you have to shift appropriately -- if you're running 50/11 all the time, you're going to be tired regardless of what the biggest cog is. A 11 small cog is not very useful all the time.

Finally, "extremely steep" has a different meaning to everyone and their abilities (and the type of biking they're doing). For example, a touring bike in the mountains might be using a chainring in the 20's of teeth and some huge cassette to get the gearing needed to comfortably ride up the mountains. Most racing bikes aren't really built with that kind of riding in mind remotely.

Also, if you're using a 47 cm frame and it has 700c wheels, you can also get a reduction in gearing (and height) by switching to 650b wheels (easy if you have disc brakes; bit more work if you have rim brakes, but might be possible). My personal view is people below 5'5" ish shouldn't be riding 700c wheels.


52/15 fixed gear ratio - what should I change to?

Different from the other answer, I read the question as OP wanting to change to lower gear ratio without changing chain length. 52/15 is an extremely high ratio.

For all practical purposes, if you want to keep the chain length same, the sum of numbers of teeth in cog and ring should stay the same.

The changing geometry does affect the result a bit, but the difference it will make is less than a half link's length. The exact math is a bit hairy, since you have to take into account that the part of chain that wraps around cog is not actually part of circle, but N-gon that has its angles at chain pins.

My recommendation would be to bite the bullet and get a chain tool and not try to optimize cog sizes. You will need one anyway later, and if the old cogs and chain were worn, it's best to replace the chain at the same time. A normal sized chainring will give you more options to play with ratios later, and prime numbers 41, 43 and 47 would let you use any cog without thinking about skid patches.

With lower ratio you might need to take the skid points into account.


What accommodations might be made for riding a frame 4'' too large?

Because of the era of production, the length of the bike is actually fine, and it's just the hight that is off.

Where is the problem then? Saddle too high even when lowered as far as possible? The wheel size is completly irrelevant for that problem. Or are you unable to stand on the ground without your privates hitting the top tube?


How to safely clean up spilled chain oil

Getting the oil into either a container or solid material like paper towel or cloth will prevent it from spreading. It should then be treated as "household hazardous waste". It is toxic to many creatures (like us if swallowed!) and so it is actually illegal to put it down the drain in most places in the US at least.
Bigger cities/counties in the US usually have household hazardous waste disposal centers/procedures for safely disposing things like paint, oil, solvents and other chemicals, batteries and so forth. They will have instructions on how to "package" it, label it, and where to bring it or set it out for pickup.


What's the safest way to turn left from a right-side bike lane?

The Oregon Bicyclists Manual explains this very well, and with good diagrams, so I'm going to pretty much copy them verbatim here:

There are several ways to make a left turn on a bicycle:
As a Vehicle
As you approach the intersection, look over your left shoulder for
traffic  and, when clear, signal your turn, move over to the left side
of the lane  on a two-lane road (1), or into the left lane or the
center turn lane when  available. You should be  positioned so cars
going  straight through can’t pass  you on the left. Yield to oncoming
cars before turning.  if you are riding in a bike  lane, or on a road
with  several lanes, you need to  look and signal each time  you
change lanes. Never make a left turn from the  right side of the
road, even  if you’re in a bike lane.
“Box-style”
Proceed straight through  the intersection on the  right. Then stop,
and either  cross as a pedestrian in  the crosswalk (2), or make  a 90
degree left turn and  proceed as if you were  coming from the right
(3).  If there is a signal, wait for  the green or walk signal  before
crossing. Yield to  pedestrians in crosswalk.

In your particular case, I would suggest method 2. Cross the intersection, then pull off to the side and orient yourself to cross with the crosswalk. Then wait until there's a break in traffic, and head across that way. If you eventually become more comfortable biking in traffic, you may choose to use method 1. I find that cars almost always slow down and let me in if I clearly signal that I'm making a left turn, but it depends on how fast traffic is, how confident of a cyclist you are, and what the road conditions are like.


If you are having pain and riding a lot of volume, it makes sense to get a fitting. Your other options are to

continue to experience the pain, possibly doing long term damage to your health.
reduce your volume of riding
get a different style bicycle with a more relaxed and upright geometry. Your fitter may recommend this anyways.


Your options for temporary hair removal are:

Razor Blade: Pros - cheap, easy to do for most areas. Cons - you won't stay smooth for long, regrowth is stubbly, you can cut yourself.
Electric Razor: Pros - very cheap, very easy to do for most areas. Cons - you won't stay smooth for long, regrowth is stubbly.
Depilatory Cream: Pros - fairly cheap, fairly easy to do for most areas, reasonable results, stays smooth for a reasonable length of time. Cons - smells,  potential for chemical burns if you get it wrong.
Waxing: Pros - good results, stays smooth for a long time (probably a few weeks). Cons - can be painful, difficult to do yourself, expensive (and possibly embarrassing) to get it done professionally.
Epilator: Pros - very cheap, easy to do for most areas, good results, stays smooth for a long time. Cons - hurts like hell.


I wear a Bern Brentwood with a winter liner in cold weather. It's a certified bike helmet, but designed more like a ski helmet. The winter liner does a great job of keeping my ears warm without wearing any other protection, but doesn't block traffic noise. It is vented, but not well enough that it makes my head cold. It also has a clip in the back for ski goggles if you're using them. With the summer liner it works well for fall and spring, too.


How to nonverbaly signal a drafting proposition to fellow cyclist?

Yes.

There are a number of different ways to initiate a paceline via hand signals, but the most common one I've seen and used is to make a circle with an upwards pointed finger.

Watch Peter Sagan (white jersey, yellow/red helmet) do this in the following video.

He's joking in this situation, but note that his fellow sprinters all know that he's referring to starting a paceline, which is why Greipel (green jersey) checks the gap to the rest of the peloton.


When to change winter tires for bicycles

The cost of burning through studded tires can start to add up. I find it more efficient to keep a pair of studded tires installed and ready to go on an older pair of wheels, and I can just throw them on if it looks like it's going to be an icy day.


Bike Fit for 5'3" (1.60m) woman, 47 or 51 cm?

The bike shop is correct. This will depend on what model of Cervelo you have but looking at the Classic Road geometry here,

48cm: stack 505mm, reach 560mm

52cm: stack 530mm, reach 569mm

That's annoying but kind-of does make sense. At the small size extreme of frame geometry it's hard to reduce the length of the bike and leave enough space between the wheels, because the wheels are the same diameter as larger frame sizes. This is why some small frame road bikes are built around 584mm (650b) wheels instead of 622mm (700c) wheels.

It's possible that 0.9cm reduction in reach is enough, and you can raise the bars up a couple of cm with a different stem.

If you are thinking about buying a whole new frame and transferring wheels and components over, you should probably think about a whole new bike of a different model/brand that fits you better. If you sell your current Cervelo the overall cost may be comparable to buying a frame.


Does the nukeproof horizon mtb rim have a brake track?

Zooming in on the image shows decals, stickers, appliques all the way to the edge of the rim. It also lacks a machined brake surface. So the appearance is that of a disc brake only wheel.


The levers in the first post that you linked to appear to be Cane Creek Crosstop (interrupter) levers. Tektro, Paul, and probably others as well, also make levers like this. They usually work by pressing on the cable housing (effectively making it longer), which is split at the lever. It looks like the levers in the photo are being used as conventional levers and are pulling on the cable itself – the cable appears to dead ends in the barrel adjuster of the levers rather than passing through as it would in a conventional interrupter lever setup.


Shimano Tiagra - Install smaller front chainring

The Trek Checkpoint ALR4 has a Tiagra 4720 series groupset. The FC-4700 crank as a bolt-center-diameter of 110mm which will not support a small ring below 34 teeth, so yes you are looking at a whole new crank to get smaller rings.

The RD-4700 derailleur will not work directly with an 11-42 cassette, although 11-36 will probably work OK.

You should be able to keep the front derailleur - 48-32 or 46-30 sub-compact cranks have the same tooth count difference between the rings. You would just need to drop the derailleur on the seat tube a little. From the pictures on the page you linked to the derailleur appears to be a band-clamp type so there should no problem moving it (some braze-on style brackets prevent the derailleur from being dropped to accommodate smaller rings).


How does a mountain racing team work together?

Each type of racing is able to take advantage of certain team dynamics, and a few things are common across all disciplines.

Specifics:

DH/Super D: Downhill "teams" are more associated by sponsors and bikes than by riding together during a race. Since each run is done one at a time there's no drafting or anything like that. However, during track walks and practice teammates can help each other with line choice and bike setup suggestions.
XC/Marathon/Cyclocross: Cross country teams sometimes act more like a road team with drafting happening on straights and doubletrack sections. Teammates can also help pace each other through longer races. With teams that have riders across multiple levels of competition or age groups, some team members may act as support during another member's race (hand ups, mechanical, etc.).
Enduro: Though relatively new as a competition (in some parts of the world), Enduro takes facets from both XC and DH. Typical Enduro races are one at a time affairs where each rider is on his own, but might benefit from teammates during practice like a DH race. However, in races like the Megavalanche with a mass start, teammates can help to protect each other or advance a rider through a pack.
Other: 4X is pretty similar to BMX and DH in that practice usually assists the teammate more than during the race. Trials is the same. Short track is closer to road and XC in team dynamics, but more like a Criterium in pace and tactics.

Shared:

Training(Bike): Most teams have at least a few training sessions as a whole team. Obviously this can be difficult logistically if team members are further apart (other side of the country/world/state). Sometimes this takes the form of special trips, such as to an area of high altitude, for working on specific training. Other times it's just regular rides or skills work.
Training(Other): Large teams have associations with gyms an trainers to provide their athletes with good off-bike training as well. Team workouts happen along with individual workouts tailored for the rider's needs.
Nutrition: Again, larger teams usually benefit more here with a dedicated health person who will work with the athletes on their nutrition and food intake.
Race support: Mechanics, cheering, pits and everything else that happens on race day is supported by everyone on the team. Whether that's a teammate on the sidelines cheering you on up a grueling climb, or your mechanic making that last minute suspension change before your finals run.

Ultimately, a team is what you make of it. I know guys who ride for a team, but are pretty solitary and keep to themselves. There are other teams that seem more like a traveling party, but they know when to train and when to have fun!


Brake Cable Ends - Barrel and Pear Nipples

Original MTB brake lever designs did not include a rotating barrel inside the lever
to account for the change in angle as you apply the brake, so the wire end needed to be round to accommodate this.

Road bike brakes have had the interior rotating barrel for a very long time.

If the wire end does not rotate, the brake wire will be flexed in a "coat hanger"
way and break in a relatively short time.

They are two different solutions to the same engineering problem.


Reinstalling tire after replacing inner tube, how important is it that tire bead is even along rim?

An uneven bead can indicate the tube is trapped under the bead. This can cause blowouts or pinch flats. Let the air almost all out of the tube until you can push the tire back away from the bead, then push the tire back from the bead and look all the way around on both sides to ensure the tube is not under the bead, but instead all the way inside the tire. If it isn't, work the tube back into the tire all the way around on both sides. Once you're satisfied the tube is fully inside the tire, reinflate. Also, ensure the tire is the right size for this rim.


Construction hints for a sociable dicycle?

Some thoughts - but not really an answer.

Fundamentally its a RWD tricycle with no front wheel.

Drive  shaft drive.
I'd be exploring a driveshaft that runs horizontally under both seats, and using a tricycle-style open differential in the middle.

There is a shorter jackstaff drive axle that runs from the rear diff up/forward to the half-shafts through a closed differential. Otherwise this would not be rideable solo.

Drive  chain drive.
For this you'd have a chain from a front pedal axle to the rear axle.  This would allow conventional bike components to be used for chainrings and rear cassette, and even deraileur gearing.  However you'd want to incorporate two more freewheels out by the wheels themselves, to allow for skid steering

In this case both riders will pedal at the same cadence, and the spare cranks will rotate when riding solo.

Some excellent concepts of "chain drive to two wheels" show up in this answer https://bicycles.stackexchange.com/a/38875/19705

Final drive
To get drive up from the under-seat cross axle up to the wheel hub, you're probably looking at another chain on each side.  Good thing about this is the gearing could be swapped out as required.

Steering
Steering would be achieved by skid-steer, braking the inside wheel on the turn so the outside wheel drives around.  Ideal turning circle would be twice the horizontal wheelbase or width.  Brakes would be best as disks attached to the wheel hub, outside of all the chains.  That way any drive failure will not stop you from braking.

Brakes
I'd contemplate a pair of motorcycle-sized disk brakes, one per side.  Possibly use two bicycle calipers per disk, and connect each pair to each seating position.  That will give a redundant braking solution.

Visibility
Too much framework and it will be difficult to see around.

Roll-around
Gerbilling will always be an issue, so put in a pair of three point racecar harnesses in case you end up inverted.   Likewise, racecar seats would be appropriate rather than bike saddles.

Off road gerbilling would be awfully dangerous - even flat-land there could still be an obstruction that catches part of the frame, or part of a rider.

Safety
You might want to consider drag rails at the back in case of "wheelie" when taking off, and possibly a front outrigger too (Though this would need a wheel or a skid/ski to prevent digging in)

You require wheels to be larger than the maximum "size" of any rider so that no part of the riders comes outside the "can" shape.

Other
The passenger's hands will be bored.  Consider adding a cupholder.

Side slope - most roads have a degree of slope to assist water running off.  Even pathways and sportsball courts are generally not completely flat.  So your ride will be canted in one or the other directions almost all the time.  Whether its worth allowing the seats to rotate or not may be over-engineering.


As usual Sheldon has the answer. However you can also find a great range of second hand parts such as derailleurs from your local bicycle shed.

There's little point replacing the entire groupset, however if you want to move up to 9-speed then there's no problem replacing the rear derailleur, cassette and shifters. If you're replacing your cassette, replace your chain.

Sheldon writes:

  In general, all Shimano Cassette Freehubs will work with all Shimano
  cassettes, any number of speeds.

Your crankset, front derailleur and bottom bracket can remain as they are (matched groupsets are a lie sold to everyone by Shimano). If you do decide for a lighter crankset, you can still leave the front derailleur alone so long as it suits your chainring choice. Similarly you can reuse the bottom bracket if it has the right interface and spindle length.


Can cars legally drive in the bike lane down the street?

No. In California, a car can only drive in a bike lane 200 feet before making a turn from that side of the road or when entering or exiting the road.

California Vehicle Code 21209


What kind of jersey for summer heat and sun?

This is a matter of personal preference. I live in a hot climate. I've worn everything from sleeveless jerseys with perforated backs to long-sleeved jerseys in hot weather. My current preference is for long-sleeved jerseys, in order to get the added sun protection. There aren't a lot of lightweight long-sleeved jerseys, but there are some, and some advertise their SPF ratings.
Some clothing manufacturers advertise "coldblack" jerseys (black, but intended for hot weather). I've never tried one, and I'll admit I'm skeptical they'd be comfortable. I always wear lighter colors.
Jerseys are designed to wick sweat and breathe well. Modern performance textiles are pretty amazing.


Inflating airspring fork with Topeak products

A floor pump like Joe Blow has a massive piston, and the problem I can see is not about reading the pressure, but actually pumping such small amounts of air for this to be accurate (although the manometer may also not be too precise...). Technically you can use this, but as you mentioned it will not be accurate and there's not much you can do about it.

You don't have to buy a specialist shock pump, however I'd recommend it. Hand pumps may be good enough, but you have to choose the right one, i.e. the one that can fit around the valve (there's often not much space around them), and that can stand high pressures, especially in case of rear shocks may be over 200psi (screw-on heads are preferable).

There are also three features that put a shock pump in advantage, based on my experience with a few:

They are thin and it's easy to pump up accurately even very small air chambers.
Most of these pumps have a button that allows to release small amounts of air if we pumped a bit too much.
This button also prevents air from leaking from the valve while unscrewing the pump head.


Cyclist vs Van. Who is wrong in this scenario?

The cyclist is clearly in the wrong.

A turning vehicle must indicate some distance or time (depending on the jurisdiction) before changing lanes or making a turn. There are no exceptions for bicycles, or keeping hands on the bars.

I think the driver has done well to avoid the danger created by the cyclist.

See also Best ways to avoid getting hit by cars?

And How to get over anger at inconsiderate drivers


Spoke tension is way off but wheel is true, How do I fix this

For reference, I used to work for Velomax Wheels, and Easton Wheels.

You may want to back all of the spokes off an equal amount, say 5 or 10 turns.  This will give you a little bit of room for adjustment, without having to completely detention the entire wheel.

There is a book called "the Bicycle Wheel", by Jobst Brandt, that does a great job of walking you through the process of truing.

Another way to tell if the spokes are of equal tension is to pluck them like guitar strings.  Since they are all of the same length and same thickness, equal tone means equal tension.  (We used to attach an electronic "pick up" to our truing stands, and wear headphones so we could better hear the differences when we plucked the spokes.  This shouldn't be necessary say, in your garage where there is a lot less ambient noise.)

A couple tips for truing (though you may know these already):
- Be sure to back off any adjustment that you make on a singular nipple. This will eliminate any possible spoke 'wind-up" caused by the twisting of the nipple.  (example - if you want to make a 1/4 turn adjustment, turn the nipple a 1/2 turn and then back off 1/4.)
- Be sure to give adjacent spokes a soft squeeze to help the spokes and nipples settle.
- check for cracked nipples and cracks at or near holes in rims.

Once it is true, then you can bring all spokes back up to tension (the 5 or 10 turns that you originally made.)

Truing stands are very helpful in holding the wheel in the right position to make your adjustments.  (Rather than trying to do it in your hands or in the bicycle frame/fork.)  they also typically have a measurement pin or finger that helps show where (and to what degree) the wheel is out of true.

Tensiometers are okay devices.  Here are a couple of their downfalls: 1-no two are the same and they come out of calibration quite easily. 2-several factors, such as how you hold the tensio on the spoke and where you place the tensio on the spoke, influence the gauge reading.

Hope this helps.


Basically the only real way to get better at going up hills is to get fitter - which you can do by repeatedly riding the hill :-)

Some tips:

Stay sitting down
Use low gears and a fairly high pedaling cadence
Use good gear management, shift down progressively as you start the hill and keep pedaling cadence up.

The main point is you want to avoid using your anaerobic system and exhaust your legs. Pedaling too slowly and too hard will make you go anaerobic. Low gears and faster pedaling will keep you aerobic longer.


How do you spot the left side pedal on egg beater pedals?

This is from the Crank Brothers pdf available on their site or in the package:

  Eggbeater pedals have either a 6mm Hex, an 8mm Hex, and/or 15mm wrench flats.  Note that the right pedal has a
  standard right-handed thread and the left pedal has a left-handed thread.  For identification, left pedal has a small
  “L” on the spindle or a small groove around the spindle flange.  The right pedal has a small "R" stamped in the
  spindle or no special markings.

In my case there was no "L" on the spindle, but there is a small groove around  the left spindle flange.

The link: http://www.crankbrothers.com/support/product_documentation/instructions_eggbeater.pdf


Grip shifters not opening on a Mongoose Terrex (trying to remove the shifting cable)

If you still need help, or someone else needs this, I just got one open. Take it off the bar. Take out the grub screw and separate the silver ring it goes in from the body. Looking down the hole from where the ring was, you’ll see locking fins (?) that hold the body together. You can use a screw driver to pop the fins off from the inside and it all comes apart.