What range of sprockets is useful in a road bike cassette?

Ultimately it's a trade-off between a wider range of gears and bigger jumps between those gears.  There will always be uphills that are too steep for your lowest gear and downhills where you spin out.  If you try to fix both problems with a wider range cassette (your triple already has a great range) you may find that you're never quite in the "right" gear for all of the in-between situations.

I'm using a 11-32 cassette on my road bike (with a MTB derailleur for more capacity).  I have plenty of climbing gears but rarely use the small cogs since I spin at around 90rpm.  Like the Bay Area, there are a lot of hill around here.  But I find the jumps between gears too big (either spins too easily or too hard) so am looking for a narrower range cassette.

If you want just a bit more range for climbing, you'll need to jump up to at least a 28-tooth large cog (you'll barely notice the difference going from 26 to 27) which might require a long-cage derailleur.  On the high end, a 12-tooth cog will be a noticeable difference over your 13.  Since you're used to a compact range you probably don't want to go with a much bigger cassette.

Sheldon Brown has a great gearing calculator that you can play with to see what different combinations will give you.


Studies done by the school of Health at Harvard, and published in Injury Prevention, are showing these to be safer.

http://www.hsph.harvard.edu/news/features/coverage-in-the-media/bicycling-safety-cycle-tracks-lusk/index.html


The showstopper braketrack is a textured finish, with very shallow grooves carved into the surface to make it rough and abrasive. This abrasion is what was grinding the powder off your brake pads originally. Unfortunately the rubber of the brake pads has also been very slowly wearing down the surface of the brake track as you've used the wheels and polishing them to a smoother finish.

To test if this is causing the issue, you would need a second new set of wheels with the same braking surface. You will be able to feel the difference by simply dragging your nail along the brake tracks to see if one is rougher than the other.

As for improving the quality of your braking with the current wheels, you simply need to look at which brake pads perform best on carbon wheels with a traditional smooth brake track. Personally, I always found that the Swissstop Black Prince brake pads worked best for me. In the past few years, I've used carbon wheels by Syncros, Roval, Fulcrum, Campagnolo and Shimano Dura Ace, all of which had a smooth carbon finish. Regardless of manufacturer, I always found that the Swissstop pads worked better in any conditions than the pads supplied by the manufacturer (except the Rovals were supplied with Swissstop pads).


You may be able to find the same frame new from the manufacturer if your bike wasn't too old. Most bike manufacturers sell bare frames, so even if your frame is no longer available, It might be likely you could find a suitable frame new that all or most of your components fit. Without much info on the frame it is hard to get closer to an answer for you, but compatibility checkpoints would be: the head tube/headset style, seat tube diameter, rear dropout and fork end spacing and axle compatibility, bottom bracket shell size, depending on what kind of suspension your frame has, the rear shock pivot type. You may also have to contend with cable mounting issues depending on how different your new frame is. Did I leave anything out?  Those will be the most significant things to look for.
Used frames are a great option, but as you are saying, There is a potential risk that you end up with a frame that is near or beyond tthe end of it's life. It can be difficult to know looking at a carbon frame what kind of damage if any, and warping or fatigue can be hard to spot on steel and Aluminum frames until you've already spent you money and built up you bike and gone riding. I've purchased a few used frames and had good experiences though. I would try to find a new replacement first for sure, and be open to having to also buy a few new components if not all of your old gear is compatible.


You'll need enough spacers to compensate for the width of the cassette and maybe readjust the rear derailleur. Your LBS mechanic will normally have a box of spacers, especially those from discarded 10 and 11 speed cassettes are convenient for fine adjustments.

I run a 6 speed cassette on a Tackx Flux with an early 1980s racebike. It works without any problems. The spacers go on the 'hub' ahead of the cassette. You may have to try out for the correct amount before the locknut sits perfectly.


What does the chainring have to do with SRAM YAW

To quote SRAM on YAW:
"The front derailleur cage rotates to maintain a consistent angular relationship with the chain. Yaw technology eliminates the need for shifter trim. As a result, shifts feel more direct, more precise, and combined with the new Red crankset and chainrings, delivers an unmatched performance advantage in front shifting."
According to Velonews, you can use the chainring* with a Shimano setup, but you might get some chain rub (scroll down to compatibility grades). If you are not running a SRAM Yaw FD, I'd probably just avoid these rings and get normal ones.

See the "Swapping chainrings" section of the same article on issues with the small ring.


How many times to patch a tube before dumping?

My rule of thumb is the following:

Never patch a patch: when a puncture is too close to another patch so that the patches would overlap or almost, then I toss the tube
Never patch too close to the valve: the valve makes is a structural anomaly in the butyl that makes the tube, so is a more sensitive area, not to mention all the air input comes from there so it is a less stable area.
Toss a tube that has more than 8 patches... it is an arbitrary number but it is the one I set. Most of the times, when you reach that many patches, you will bump into one of the first two points,...

Of course, when in trouble, when you have no spare tube, and you have a flat, patch it no matter what. That is a no-brainer.

A properly patched area might be stronger than the intact area since it fixes the hole, but apart from the hole, it adds some thickness to the tube so puncture resistance.

You will (almost) never puncture a patched area: the patch might fail, but you will not puncture the patch.

That downside of the patch is that it does not expand (or just very little) compared to the intact tube (try to inflate a patched tube outside of the tire, you will see the diameter is smaller in patched areas). So an overly patched tube will be less expandable in the tire than an intact one.

This causes the whole physics of the tube inside a tire to be less perfect than it is conceived for; which is why you must not over-patch a tube (and solves the apparent contradiction).


Setup for heavy rider and DB 29" overdrive

Manufacturer weight limits on bikes are a little nebulous in that they're not totally meaningless but they tend towards estimation, liability protection, and a fair line for the warranty department to take when a bike eventually breaks under a heavier load then they designed for. Going above it is an at your own risk thing because forks, wheels, and frames failing are all real and dangerous things that are only going to be at greater risk of happening as a result. In practical terms though, those kinds of worst case scenarios don't happen very much as a result of exceeding weight limits on non-exotic mountain bikes by this much.

What is at pretty good likelihood of happening is the wheels not really holding up over time. The usual case is for heavier MTB riders that ride a lot to burn through the stock wheels pretty quickly and then get something with a heavier weight rim, ideally handbuilt and with 36 spokes. If you want to, it could be reasonable to skip the step of tacoing the rims that came on it or dealing with them going out of true repeatedly and just upgrade now.

As for the flats, you don't say what's causing them, which suggests some odds that it's one of the common causes of repeat flats and not related to weight. The really common ones are a rim strip that's not doing its job, something lodged in the tire, or tires/tubes that aren't puncture resistant enough for where you're riding.

If you're pinch flatting, the main remedy is more pressure, and failing that more width.


What causes rim failure where spokes pull it apart?

If there are several spokes showing this failure, it's not because of a single impact.

I think it's safe to say that the rim was simply overloaded and has suffered metal fatigue from stress cycles imposed by the differing forces on the spoke as the  wheel rotates.

Can't say if the failure is because of overloading beyond what the wheel was designed for, or poor design or a manufacturing problem.


What do I do if my brakes keep squeaking when I press on them? Do I use lubricant or what?

Answer: NO

NEVER lubricate the friction surfaces of your brake system under any circumstances.  There is NO time where this makes sense, ever.

Do check the duplicate question for answers on how to reduce squeal.

Or embrace it - I had some canti brakes that would make hideously loud noises under hard braking, but under gentle braking they were silent.  After a while I realised that is really a feature, cos hard braking squeals is like a car horn and alerts people to a possible danger.


how to reassemble mountain bike rear wheel hub and bearings

While not necessary, it will probably be easier to understand what is happening if you lift the cassette off. The ring at the front of your photo (C) is the nut that holds the cassette on, so right now you should be able to lift the cogs off the freewheel. That will leave you with the splined body of the freewheel exposed and you'll have one less distraction.

The parts labelled are :

A: cone locknut (the last thing to go on)

B: seal, probably from the drive side

C: cassette nut/lockring that holds the cassette together and onto the freewheel

D: spacer/washer that goes between A and E

E: cone with seal attached

F: seal from the axle and cone labelled H

G: seal from the non-drive side

H: axle with cone attached.

I: there is no I

J: washer. I have no idea where this goes.

K: quick release axle.

Ignoring the bearings for a minute, the order things go back in from the non-drive side (underneath, in the photo) of the wheel is likely to be: Put the seal F back on H from the long side - it probably should not go all the way to the washer. Push H up into the wheel screw E down onto it then add D, screw A down and lock it off. Push G over the non-drive side cone assembly to seal that side. Push B into the drive side if it fits (I'm not sure it will, I haven't seen a seal like that or in there for a very long time). Put the cassette cogs back on, then add C to lock them in place.

Before doing this you will have cleaned the old grease off the cones in the hub (careful with solvents, you don't want to wash the grease out of the rest of the freewheel), then put in new grease and pushed new bearings into it (the grease holds the bearings in place while you reassemble).


Are fixed or floating SPD-SL cleats most suitable for a long commute?

Fixed position cleats, or 0 degree float cleats, require far greater precision about cleat setup on the shoe. Failure to get the setup right will mean pain, and can mean injury.

That is also true of floating cleats. Most pedals come with cleats that have between 4.5 and 9 degrees of float built in. I don't know of any pedal which has a 0 degree cleat, stock. You would have to buy it separately.

For your purpose, there is no benefit to a fixed position cleat. They are primarily used for track racing and for sprinting specialists in racing.

Given that, floating cleats are most suitable for a commuter's bike.


How to select gear on internally geared hub with broken shifter

From the image I'd guess your bike has Shimano Nexus 7 hub gear, though I'm not sure.

Anyway, the gear probably defaults to 1st gear when there's no tension in the shifter cable. So, riding your bike is very light probably because you are riding on the 1st gear.

What this means is that the hub gear might still be ok. It might've been stuck in the 6th gear earlier because either the cable or the shifter was stuck. Try attaching a cable back to the gear (it attaches to the bolt that is pointed by arrow in pic), pull it and see if the gear works.

If that's the case, you might be able to get a fully functional bike for a little money or effort - new shifters are not that expensive, especially if the gear is Nexus 7. It's a very common type and spare parts should be easy to find.


Heart rate during a ~1 hour individual time trial?

This is absolutely specific on the heart rate zones of each individual. Each person has a different heart rate at their functional threshold (FTHR). Professional cyclists are able to cycle for a long time (most of the road race) almost at their functional threshold but the actual heart rate is completely individual. Even the percentage of the functional threshold heart rate to some "maximum" heart rate will be individual. All these values must be determined by an appropriate physiological stress test to be reasonably accurate.

See, for example, https://cyklopedia.cc/cycling-tips/what-is-ftp-in-cycling/#1

When it comes to the maximum heart rate, that is not a very reliable value (may vary strongly for different activities) and it is much better to start all you zones and comparisons from your FTHR than some percentage of some maximum.

As a good source of example pro-cyclist heart rates you can use https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6572307/ although it uses a longer race.

  The HR during the race was 158.9 ± 10.6 bpm (86.4 ± 2.2% HRmax), and
  exercise intensity is categorized as vigorous intensity.

As you can see, the variance for the heart rate is higher (more individual) than the variance of the maximum percentage.


Any fix for a schrader valve that won't open?

Sounds like the valve has stuck shut, this can happen if the rubber seal at the base of the valve swells up. If the valve core is replaceable just get the appropriate valve tool and a replacement core,  both are really cheap.

Otherwise its likely to require a replacement tube.


Surprisingly this is enough info to give a lead.

http://bmxmuseum.com/forums/viewtopic.php?id=1493 says

"Mongoose used the M on the drop outs of their frames in the early-mid 90's"
"Mosh stamps their frames with an old english "m"."

So your next step is to start browsing through http://bmxmuseum.com/bikes/mosh/ and  http://bmxmuseum.com/bikes/mongoose/ looking for a match.  There are over 5000 bike photos to compare - good luck!

Mosh logo on Downtube - can't find a photo of one on a dropout though.


I personally would not ride that bike. The top tube is severely compromised now, it will get worse as cracks develop from the ends of the cuts.

No-one plans to crash so you can't resolve to always ride it 'gently', You do not want to ride over a pothole or off a curb and have the top tube buckle up into your face, neck or chest.

Your proposed fix of clamping a sheet of aluminium over the tube would not be sufficient, neither will JB weld. There is no safe solution for $30.

Unfortunately, a proper welding job will probably cost more than you paid for the bike.


Have not seen 27 x 1/2 tires before but the old 27 x 1 1/4 rim probably will not care if the width is greater.  One question is whether the wider tire will clear your frame.


Minor but persistent saddle sore - Safe to continue riding?

I'd perhaps look at your saddle again.  Padding isn't everything and there is a lot to be said for fit/sit bone width.  Consider getting measured/fitted.  I know what width fits me in the brand I buy.  Personally, I think every serious cyclist should know their saddle size as well as their frame sizing.  Keep in mind that all your riding up to this point (before saddle change) developed extra padding/tissue/internal callus (whichever) on the contact points of your old saddle.  Moving those contact points just a slight bit by getting a new saddle can make quite a bit of difference.

Not to be rude, but what is your hygiene like?  I would recommend making sure to always wash after a ride (commutes included).  Always ride in clean shorts.  Toward that goal, if you haven't cleaned/showered/bathed recently and go for a ride, you really aren't riding in clean shorts (your skin isn't clean, even though the shorts are).  Consider washing before and after a ride.  Are you using a chamois cream of some sort?  Part of the problem can be caused just by friction.  A good chamois cream can help.  Some have various antibacterial/anti-infective "stuff" rolled in and can help on multiple fronts.

If you are going to look for less padding in your seat, you may look for more in your shorts.  Seven hours for most folks goes past stage type training and into endurance riding/training.  Ultra light sometimes gets sacrificed for comfort.  You may look for touring or thicker winter padded shorts/bibs and opt away from ultra light race padded shorts/bibs.

I have done a fair amount of winter endurance riding (100 miles on snow) and sometimes you just forget your prep and end up with a sore.  I've lanced my own in the past to speed healing, but that's not for everyone.  Once you have one (I have my own set and recurring spots), it's kind of always a preventative fight while you are trying to train.  In the end, if all your equipment is properly fitted, proper hygiene and prep (wash before/after, clean shorts and chamois cream) just become a regular part of your training like bike maintenance and proper nutrition.


After reading that blog post and some forum threads about this issue, the cause seems pretty obvious to me.

At the time, the local traffic light crew had 4-light groups on hand, and didn't have 3-light groups.

This 4-light group was probably originally designed for car traffic, with one of the lights being a turn light.

If having an extra red was an improvement of any kind, it would be much more common (and likely mandatory).


Help identify BMX please - possibly 80s or early 90s

PMX Clubmaster from bmxmuseum.com

bmxmuseum has PMX bikes from 1982 to 1984 named "Clubmaster" or just "Club"

The bike pictured does not have original parts.

According to this link the PMX Club is a steel frame bike from Germany


There's two ways to adjust the toe in. The metal pad holders that are the other half of the brake pad assembly should have some semispherical washers in them, allowing you a few degrees of adjustment. Loosen the bolt that holds it on, jiggle it to free up all the pads, then squeeze the brake lever to pull the pad against the rim and get the alignment right. Using a wee bit of cardboard or something between pad and rim at the back to set the toe in, of course.

The other method is to carefully bend the caliper/brake arm. Obviously it's much better to use the previous method, but if that's not an option, set an adjustable wrench so that it fits tightly onto the slotted part of the arm (just above the brake pad), and twist the arm to a better position. Careful is the word - much better to have to tweak it three or four times than have to bend it back if you go too far.


Is it possible to fit a chain guard to a bike with derailleur gears?

SKS Germany - a company that make great bike products, including the fenders that I put on two of my bikes, make a product called the Chainboard - a chain guard designed to accommodate front derailleurs.

I don't have one, but you can google SKS Chainboard and find several reviews.


Which e-bike kit should I choose? Hub vs chain driven (hilly terrain)

For hill climbing without the ability to change the gear the motor is in you're going to have to pick a lower gear than it was designed with, somehow, and accept that it won't help much on the flat.

The "chain driven" kit you're looking at will only work while you're pedalling, as it requires you to keep the chain tight against the motor sprocket. Despite the bike being shown with gears, the motor will only work in one gear, otherwise the chain won't hit the sprocket on the motor. If you're lucky you will be able to choose the gear, and you can choose a fairly low one to go up hills in. If you're even more lucky the other gears will still be usable without the motor.I suggest you ask the seller those questions before buying. They say:

  This kit is designed for normal bike, not for the bike that can shift gears. However, you can install the kit on the left hand side if your bike is 18speed/24speed

Note that that kit does not come with a battery or charger.

The hub motor kits normally are easier to install, especially if they come built in to a wheel already (I suggest you do this, the extra shipping is usually cheaper than the cost of getting a wheel built). Since the hub motor is already set up to drive the wheel, you don't have to adjust anything that's got a lot of force or power going through it, so it's less critical that you get it exactly right. With a hub motor you only have to get the anti-rotation setup fixed properly. The usual problems are getting the wiring to work - cheap kits will almost always work, for a while, in the workshop. Getting them to work reliably in all weather while riding the bike can be a challenge. It will help if you're willing to solder connectors in place, and you should definitely plan on buying an extra hundred cable ties to hold everything onto the bike.

I think your budget is optimistic. Normally when you find a product that's much cheaper than the competition it's because it's junk. Either it's going to fail much sooner, it doesn't work as well, or it's missing key things you assume are required. In this case I think you'll find that it's both unreliable and less than you expect - the motor will be less powerful and the battery smaller (it will go less distance per charge). It will all fall apart within a few months.

Make sure that you have a reasonable workshop and a collection of bike brackets and stuff that you can use to assemble and install the kit. Those kits either come with a huge bag of brackets and bits that you won't use for your bike because they come with every bracket you might need for any bike, or they come with one set of parts and inevitably you need a different set. Cheap kits will always be the latter type, so you will need to put their brackets in a vice and hammer/bend them to fit your bike. Or add a stack of washers and use longer bolts to get the thing to sit right. You many also end up needing to add more bracing. With the kit you're looking at, note that they mention "spot weld the sprocket"... you will also need a welder.

I have a friend who has spent a lot of time on this, and eventually built a business around importing electric bike kits and bikes from China and Taiwan. His experience has been that since he's legally required to offer a minimum one year warranty, he has to use kits that cost him at least $500 and realistically more like $1000 (because people look at the "100 watts for 30 minutes" kit you get for $500 and don't see the point).


This is obviously (from the images) a suspension fork, and a very low-end one. Suspension forks are heavier than their rigid counterparts, but the trade-off is that they absorb shocks. These rust spots MUST MEAN the fork has long ago COMPLETELY LOST its ability to work properly as a suspension. As a result, you are carrying useless extra-weight, are not getting a suspension effect, are risking some worse failure along the way, and are risking some crash/injury.

The surface presenting the rust is the surface where sliding occurs (the "telescopes"). This surface must be perfectly smooth and shiny, and the rust shown necessarily means it is not, and never will be, as new again. Grinding will remove dust, but will not make the surface smooth nor prevent more rust to build-up afterwards.

My suggestion: sell the fork for metal recycling, and buy either a new suspension fork, or a rigid fork.

Hope this helps.


Don't know about India, but assembling from parts in my end of the world costs a lot more than a new bike. I know of many instances where people buy a "donor" bike for good new parts at a reasonable price. If you can get parts at the right price, it may be worth it, but problems with compatibility between components can lead to a  lot of blood, sweat and tears, as well as expense, especially for a beginner. It seems every year has at least one small but significant change that is incompatible with last years model.... Something as simple as seat posts - One post recently someone counted 39 different sizes -size increments are 0.1mm - measuring the hole that accurately is not possible for most of us.

I don't know about India. but where I live you can get great secondhand bikes for good prices, if you do homework and take care. My 14 year old neighbor just got a "new condition" second hand bike for $850 -  a new one with equivalent components would have been $2.5K. The previous owner was obviously a fanatic on maintenance and all of the important bits look anything more than a few 100km old. It's not risk free, but its the best way to ride a better bike than you would otherwise be able to.

The other option is end of season and last years bikes - often 1/2 retail price just because the color changed. This is a good way to get into a new bike cheaply.


cold setting 3-speed road frame to 7 8 speed cassette

Cold setting a 114mm to 130mm is significant. Usually the rule of thumb for cold setting is you can go up one step, such as from a 126mm to 130mm or 120mm to 126mm. A three speed freewheel bicycle is extremely rare and I'd personally leave it alone, it's just too valuable to risk destroying the frame.


Why do current, entry-level shimano rear derailers have large-diameter pulleys?

There are 2 versions of derailleurs which come with extra large pulleys.

The first, which is what is being discussed here, are the low end mega-range compatible derailleurs.  A mega-range freewheel has one distinct characteristic which requires compatible derailleurs to have very large cogs.

As seen in the image below, there is a large tooth count difference between the second to largest cog and the largest cog.

This large difference in size requires a large derailleur pulley, to make sure that the chain has cleared the teeth on the last cog, in order to shift into this gear.

If you use a smaller pulley on the derailleur, you may be able to get it to shift, but it will be clunky and loud at best.  At worst, it will trap the chain against the side of the largest cog, and refuse to shift into that gear at all.

The second type of large pulley derailleur is decidedly not low end.

The Berner Carbon Fiber derailleur upgrades are designed to reduce resistance on the drive-train by decreasing the severe chain bends associated with smaller cogs. While expensive, my experience has been an average 10 watt reduction in energy used by the cyclist, with no apparent loss of efficiency in shifting, or in anything else other than the cyclist's wallet.


In what sense are UCI Pro teams 'national' teams?

The association is based on where the license holder of the team is located. Garmin Sharp is listed as USA since they are based in the US. Omega-Pharma (OPQS) has their license held by Esperanza bvba, which is based out of Belgium so the team is listed as being from Belgium, etc.


Today, the major part of city masks were made to avoid breathing dust as @mgb said, you need more than a simple mask to stop micro particles. Anyway try http://www.u2sportmask.com/ (for example).


It could be:

The pedal itself (even if it moves freely)
The other pedal
The bottom bracket
The saddle
Loose crank

Try to isolate each one of these by taking the weight off each in turn.

I was recently convinced my saddle was creaking as it only happened when sitting down but it turned out to be the left pedal!


Assuming nothing is wrong with your frame, your bottom bracket probably needs to be properly greased up and re-tightened to the right torque specification.

Frankly, unless you're interested in rolling up your sleeves, buckling down and familiarizing yourself with bicycle mechanics and purchasing all the necessary tools, just take it to your local bicycle shop and have them tighten things up for you.


You most probably damaged the rear light and are risking damage the voltage regulator on the front, too, since the huge majority of generator hubs provides 6 Volts.

If the regulator on the front is sophisticated enough, perhaps it is using just enough current and voltage to feed the light, but I think most circuits use a Zener diode, that actually make the excess voltage to "leak". This is not big issue with generators, whose alternating current waveforms just go above 6V during very short fractions of a wave, but with a battery, it's possible that it is working a bit like "short circuited". If the front light is over-heating, that most probably might be happening.

As for the back light, the light-emitting elements of leds are very sensitive to higher-than-normal voltages, and tend to "burn" due to overheating and chemical/physical damage.

I advise you to check the current voltage of your system, and switch back to a lower voltage if that is the case.

Hope that helps!


flat tyre even after replacing the tube?

Start by replacing your tyre.  If you can see any part of the fibres at all, then it is long overdue replacing!  Buy a new tube too.

Then, inspect the rim and rimtape, if anything looks like it may chafe or cause an issue, then repair / replace it.

Tubes go flat if left for a long time in any case. If you buy a decent tube, they will keep their pressure for longer. I only buy Schwalbes for my roadie and easily pay more than $10 a tube, but I ride competitively, and I know that they will keep their pressure for at least a month before needing topping up.


How should the brakes on a child's bike be adjusted?

With young children is very rare for them to have the hand strength to cause a problem with brake strength. Their hands are small and weak, giving small reach hence low level action in the brake handle. Children bikes are built using cheap components (Even the components on the best children bike rate just above BSO adult bike components)

The bikes for my boys (now 11 and 7) were always adjusted with both brakes giving maximum possible braking. I would be very surprised if a front brake being too tight would cause a crash, unless it was grabbing and not braking progressively.

Further - the kind of crash needs to be considered. I would rather my boy went over the handle bars through too much brake force than under a car though not enough.....


The point of the National Bike Registry, and similar schemes, isn't so much to prevent theft as it is to make it (sometimes) possible to recover a bike after it's been stolen.  Police departments do recover a lot of bikes; but, since it's usually impossible to trace ownership, most of them end up in police auctions.  The bike registries help to solve this problem, so that if your bike winds up in the hands of the police, there's at least a fair chance they'll be able to get it back to you.  If the tag is still on the bike, the cops (or a bike shop) won't have to look in five or six different databases.  They'll know which one to check.  But I agree it would be much better to have a single national (or better yet, worldwide) database.

I have a nice bike, and I know that there's no single way to prevent losing it to the creeps who go around stealing bikes.  But the more I do, the better my chances are.


CDF touring build with mtb crankset and road shifters

What you're describing is a "mullet drivetrain", that is, road shifters with mountain derailleurs & gears. There are a lot of variations on this. Here's a guide. Note that some   of these require third-party adapters to make them work.
Some of these permutations offer a lower gear than you might need or want. Another alternative would be a gravel drivetrain. Shimano's 2x11 GRX, for example, could be used with a 30x46 low gear, which is very low for riding on pavement, even fully loaded.


Alternative to Cane Creek 200TT Brake Levers

There are other options out there, just one i came across are these Origin 8's that are 99% silver, they have black endcaps but wouldn't break the bank.
Tektro's version below them.

Soma Urban Pursuits are pretty sweet:

(source: singlespeedshop.com)


Can Di2 only be tested as a complete setup?

Okay problem solved. Apparently the NOS cable set that I bought came with an SM-EW90-A with really old firmware. After installing E-Tube Project v3.4.5 and restarting my laptop, I was able to update the junction box using SM-BCR2. The RD works without the FD mounted and I was able to make initial adjustment while waiting for the FD.
Thank you for all your comments and hopefully we learn something new everyday!


What is the safest and most courteous way to ride on a two-lane road?

I use the method in your 3rd picture - I take the middle of the lane when there are no bike lanes. I am helped in these cases by the fact that these roads in my city usually specify the right-most lane as a shared car and bike lane.

Besides the speed issue you state when riding on the sidewalk, it is also hazardous for both the cyclist and pedestrians.

I feel that riding far to the right, while still in the lane, just invites cars to pass you even when there isn't enough room.

Taking the middle of the lane is my way of encouraging them to overtake the proper way by fully moving into the left lane.


What are the key components to compare and contrast when deciding between hardtail mountain bikes?

Before outnumbering some key points I usually look when I want to buy a bike, I will tell you this: Ride them both. Form an opinion for each one and buy the one you think that comes better to you.

Compare their peripherials (suspension, drivetrain, brakes etc). Check what their manufacturer made them for and the warranty provided. If you have two bikes having drivetrain from the same manufacturer, it is wise you choose the one that might have a better series on (why get sram x9 if you can have xx for example).
What is the frame warranty from the manufacturer?
Make sure you know what are you spending your money to. Both bikes you are looking at are expensive xc bikes with some top peripherials. What discipline do you really want to ride? Do you need something that expensive? Are you a competitor, or just a fan of mtb?
What is your experience level? Beginner or pro? Spending a huge amount of money on a bike as a beginner is wrong. Learning and evolving on a reliable, yet not top of the class bike, will make you a better rider.

I suppose you are a beginner. If you are not oriented to racing xc, get a cheaper bike. Once you have learned technical stuff and have concluded to the ride discipline you prefer, get a serious bike.


For cycling, there are only a few reasons to shave:

Massage - feels better without all the hair tugging.
Taping/bandaging - In the event of a crash, taping and bandaging is easier without hair. Additionally, wounds in general are cleaner when incurred without hair.
Vanity - Hair tends to cast shadows and blur the edges of well defined muscle.
Cooling - Hair is an insulator, so especially hairy individuals will shave for the cooling effect.

There are some sports where shaving is done for performance purposes (chiefly swimming), but anyone that tells you that in cycling is fooling themselves. My personal experience is that crash scars heal better and are less visible when shaved, but that may be an individual thing.


The tire on the wheel you are metering decides it.


Sounds like the bearing has the wrong dust shield.  Sizing lines up closer to an imperial(inches) sizing, 1/2"x1 1/8" x 3/8"ish.  The inside and outside diameters are close, the width is less important than the ID and OD as you typically have a preload adjustment on the axle.  Try a 1616-2RS (9.5mm wide) or a R8-2RS (8mm) bearing.

Alternatively, If the bearing is simply feeling rough, you can remove the dust cover with a knife, clean out the bearing with alcohol and repack with a marine grade grease.  This may improve the smoothness if the races are not too pitted/corroded and add a bit more life to the bearing.


Tubulars would be a bad idea, because you need to glue new ones on and most shops don't handle tubulars so getting spare parts when necessary is hard.

Most people will run a standard clincher for touring on roads, since there isn't much benefit for running a tubeless system for riding on the road and most wheels for road bikes are not tubeless ready (especially for high spoke strong wheels you'd fit on a touring bike). Everyone knows how to handle tubes and the tubes+tires are available almost everywhere if you choose an appropriate wheel size (you'll be able to find 26" wheels almost everywhere, 700c many places, 650b less so in the US, for example).

If you want to run tubeless, you can (which would be a preferable starting point for off road touring) since you can always throw a tube in a tire or put a tube+new tire on if necessary (if you find a shop, note that it might not be equipped for tubeless). Note that you are carrying some extra kit with tubeless such as an extra valve, sealant, less tubes than you would carry with a tube system, plugs, and what not versus say a patch kit, some boots, some tubes.


Chain Waxing - Strainer / Colander / Other?

Once you have fully de-greased and waxed the chain, most suggest that you can simply re-dip the chain in melted paraffin  to re-wax, but as you have found out this can leave small particles in the bottom of the slow cooker.

Personally, I just keep a small circular mesh steel plate at the bottom of the slow cooker to keep the chain out of the debris when re-waxing. Then every so often I like to remove the debris from the wax.

Removing debris from the wax

While the wax is liquid in the slow cooker I will pour off wax into a container (usually old yogurt container that has been cleaned). Because it takes time for wax to cool and harden, typically the debris first settle to the bottom prior to the wax hardening.

Once the wax has hardened I will heat up the outside of the container (e.g., boiling water) to loosen the adhesion of the solid wax to the container so I can get the wax out as one solid chunk. The debris will then be at one end of solid wax piece, making it easy to cut off the wax with the debris.

With the debris removed, I will remelt the remainder of the wax and reuse.

Cleaning chains before re-waxing

Once a chain has been de-greased and waxed, it is much easier to clean than a regular chain that has been lubed with oil. As such, cleaning the chain before re-waxing can ensure you wax stays cleaner for longer before having to deal with debris build up.

There are two main approaches that I know about:

Soak the dirty chain in boiling water, the heat will liquefy the paraffin.  Agitate the chain to loosen debris, then wipe the chain with a clean rag.  This typically gets the chain very clean before re-waxing.
Ultrasonic cleaner. Molten speed wax has a good tutorial on this approach.  I haven't tried this so I can't comment.

Both approaches are water based (i.e., aqueous) cleaning solutions as such please ensure your chain has had time to dry before attempting to re-wax.  When dealing with boiling water, ensure you use heavy duty gloves to prevent burns.


How to store a bicycle for an extended period of time?

Doesn't really matter.  Just try to avoid really wet places.  I have left bikes in the garage for years.  Or for months at a time between rides.  (Road bike during the winter, while I ride my MTB to work, and vica versa).

I have left them standing on the floor.  Hanging from both wheels in the ceiling.  I recall a thread on hanging from just the front wheel and consensus was it did not matter.


Shimano Nexus 3 — what anti-rotation washer to use?

From your photo, it looks like you're fine. The load from the hub is being taken on the anti-rotation arm that you've attached to the lateral tubes of your mixte. So the anti-rotation washer (I'm presuming you're talking about the orange washer) is not being loaded.

Also, as described in the responses to your previous question, your dropout is just horizontal enough that you can get about 1-2 cm of movement - enough to tension your chain if you can shorten it, so that you don't need a derailleur.


What are the advantages of a building an electric bike from a kit vs. prebuilt

First, check your local laws. As others have mentionend, in some countries (EU), maximum power for an electric bike is 250W. Go beyond that and the vehicle will be considered a moped and will need license, insurance and and license plates. Your local laws might also require an assist-only option for your bike to be considered an e-bike. That means usually a pedal sensor, and those can be difficult to install especially with exotic or outdated bottom brackets.

Selecting a kit is not necessarily easy. If you're going to front mounted motor, check that brake type is compatible (disc or v-brake) with the kit and that fork spacing is suitable. E-bike kit should come with brake levers with a cut-off switch so the motor stops pushing immediately when braking (problem with some e-bikes).

Kits can be had cheap, but installing them takes time, effort and experience with bike mechanics. If you got all three, go for it. If you need to get up and running quickly, an entry-level e-bike is probably better option.


Do higher speed crashes result in less serious injuries.

In "Epidemiology of bicycle injuries and risk factors for serious injury" by Frederick P Rivara, Diane C Thompson, and Robert S Thompson, the authors gave a questionnaire to 3,390 bicycle riders who had attended a hospital emergency department in the Seattle area.

They found that cyclists involved in a crash at a speed greater than 15 miles per hour were 1.4 times as likely to have a "severe" injury (defined as an injury severity score greater than 8) as cyclists involved in a crash at a speed of 15 miles per hour or less. The 95% confidence interval was 1.0 to 1.9.

(Caveats: 1. It seems strange to me that the authors only reported odds ratios, when they apparently had the data to compute effect sizes too. 2. The fast cyclists differ systematically from the slower cyclists: the odds ratio fell to 1.2 when other factors in the study were controlled for. 3. It's Rivara, Thompson and Thompson.)


It depends entirely on what your are trying to accomplish and what your expectations are.  Many RAAM riders opt for a TT style setup, so don't let the long distance dissuade based on "it's not done" that way, because it is (by some riders).

A large consideration may be parts and maintenance.  Most traditional touring bikes opt for simpler parts that are easy to repair or find replacements for.  I saw a guy attempt a similar thing on a TT bike starting up north on the Haul Road and planning to finish in South America.  He crashed soon into his ride and needed a new derailleur hanger and bar end shifter for his fancy bike.  Since the hanger wasn't available in town (direct from manufacturer part) our mechanic had to fabricate him a hanger out of scrap.  For the shifter, nothing (within reasonable expense) could be done.  He was forced to call ahead to a shop in Canada and hope they could get one ordered and available by the time he got there, then ride without it for several hundred miles.

Also, from commentary from links on another answer, tire selection may be impacted.  Depending on the rear tolerances on your TT bike, your selection of tires may be limited to less than desirable tires for touring.

The point being that TT bikes tend toward extreme specialization and part styles that aren't often carried in stock.  As long as you are aware, careful, bring your own second TT bike, or comfortable with the possible delays (or some combination of the 4) it may be fine.


Yes - mixing sealants will either make no difference, or both will interfere and neither will work.
Start by checking the SDS (aka the MSDS)
Stans: https://www.notubes.com/pub/media/wysiwyg/GIS-004_R3_Stans_Tire_Sealant_SDS_GHS.pdf
Finish Line: http://www.finishlineusa.com/files/Tubeless%20Tire%20Sealant_EU%20SDS_UK%20English_6%20November%202017.pdf
Both are based on Propylene Glycol with Latex embedded as the solid.  So there's similarity in their basic makeup - its not like one is oil and the other is water based.  However I still would not mix them; Similar in this case means you don't need to dispose of the new tyres.

I would unmount both tyres, pour out the existing sealant and dispose safely.
Then wipe them out with a cloth rag or paper towels. Also wipe down the rims.
Leave to sit open over night to let anything remaining evaporate.
Then reassemble your tyres onto the rim and add you preferred sealant brand as per the instructions.

And consider doing this yourself - no need to pay a bike shop for a simple tyre swap.
Based on that, you may choose to try a couple more months on the original sealant, and go through this process after ~5 months because by then it would need a topup anyway.


securing disk brakes against theft in a low-visibility locked bike room

Realistically there's nothing you can do to stop a thief who has regular, unsupervised access to your bike from stealing parts of it. You can only have nothing he wants to steal, or not put your bike there. But you can make it more annoying for him (at the risk of vandalism, either accidentally when trying to steal stuff, or deliberately out of frustration).

There is a whole world of "secure" bolts out there, and a matching world of drivers for those bolts. At best it's "security through obscurity" but in reality someone who wants to steal your bike parts can buy a $20 set of "200 different security drivers" and remove 99% of those very easily. We've had a question about those closed as too broad, which really translates to "impossible to answer".

Most of the solutions I've seen just add time and tools to the removal process, which doesn't really help when the thief can check up on what you do then come back a few days later with different tools. Using ball bearings in the heads, or hose clamps over them, is unlikely to work for that reason.

One fairly easy approach is to buy a roll of stainless steel wire and a crimping tool. They're not too expensive and the wire is lightweight. Once you have one they turn out to be quite useful, and with ~2mm wire you can tie components to your bike. It's relatively easy to cut the wire with decent side-cutters or cable cutters, but hard to cut with bolt cutters because it's too thin. It's also harder for a thief caught in the act or on camera to argue that it's their bike they're working on... because if everything is tied on, where is their replacement wire and crimping tool?

 (both via SWR.com)

One problem is that you don't know whether it was a one-off theft by someone who wanted the brakes for themselves, or a theft for sale. If the latter I'd expect more stuff to go missing on an ongoing basis, which means you reporting the theft is important. The sooner building management know there's a problem the sooner they can act.


What should I use to wash cycling clothes?

For cycling clothing made of synthetic materials (lycra, spandex, etc), a modern, high efficiency washing machine, or even a normal machine on a gentle cycle, is the way to go:

Cold water mild detergent or "athletic" clothing detergent.
Gentle cycle and cold water. Optional, pre-rinse with 1/2 cup white vinegar.
Hang to dry.

For expensive wool:

Prior to having a high efficiency machine, I hand-washed with a wool specific detergent.
My current machine has a wool/gentle cycle. I use that now with an appropriate detergent.
Lay flat to dry.

  Well, how exactly do I know if its "delicate?"

The detergents are usually labelled as such. Generally, detergents labeled, "cold water" will be fine. The bike shop guys will say that you need to use "special" detergents. Nah. Any cold water detergent will be fine.

FWIW - I have 10+ year old jerseys that are perfectly fine. The shorts and bibs don't last so long, and I figure it's the wear and tear.


Pressure range conflict between tire and rim

The answer from Maxxis support is about what I expected.  I am impressed that they responded and withing about a day.

Maxxis Support Team:

  The suggested pressure range is 30-60psi for most applications but you may find
  your particular setup to be different. Rim internal width, rider weight, and
  riding style determine the correct pressure. I would experiment with different
  pressures to achieve the tire characteristics that work for you.

I rode the tire at about 28 psi this weekend and it felt good.  Old tire still had tread but was hemorrhaging Stan's from the sidewalls and I could not longer keep up with it.


Adjusting TRP RG957 deep drop rim brakes

Yes I have had these brakes for about 4 years. Turning the adjuster anticlockwise no problem (I have to do this to remove the wheel), but to adjust the brake for wear, you are right, it won't turn clockwise UNLESS I first pull up on the cable to relieve the pressure.


Ultimately, you're comparing two entry level bikes.  The differences are small and mostly irrelevant.  The one thing that really matters is how they fit you - ride both and figure which one is more comfortable to you.  So bare minimum is to get a leg over each one and ride it around.
Most bike shops will let you pedal around, which is enough to rank them in immediate comfort.  If you're buying online, then you're stuck and have to make the best guess you can.  This is one reason for buying from a real LBS and not a boxmover.

This question is pure shopping and is off-topic for Stackexchange, because there's virtually no chance of this question being useful to anyone else.  For example, neither of these bike brands exist in my area.
The transmissions are Tourney grade, which is shimano's second bottom groupset in terms of cost or quality.  It will work fine, but comparing variants is like comparing pebbles in a stream - in detail there are differences but up close, they're all much the same.
And no, if you were asking about expensive top-end bike comparisons, that would still be off-topic.


Can I mix LOOK pedals+cleats with SPD-SL shoes?

Whilst the shoes are marketed for SPD-SL cleats because that is the Shimano system and you have Shimano shoes, this is really referring to what we call a 'three-bolt' pattern. Both SPD-SL and the look cleats are a 3 bolt pattern so the cleats are compatible with the shoes.

See how there are another two bolt holes in the middle of the three-bolt pattern - in the same manner, those are compatible with any two-bolt cleats, i.e. mountain bike cleats like Shimano SPD, but not limited to one brand of cleat.

You must use the right cleats for the pedals, which is fine because your cleats came with the pedals. Shimano ones look quite alike but aren't the same.

Cleat adapters are indeed for helping you to walk with more grip, as well as to stop the cleats from scuffing and wearing down, but the SM-SH40 are for 2-bolt mtb cleats fitted to a 'road' shoe where they are not recessed. These metal cleats are particularly slippy to walk on if exposed like that.

There is another product, removable covers for plastic 3-bolt cleats, which protect the cleat when you walk around off the bike, but you have everything you need to ride in the photo. Not a whole lot of people even own covers, sometimes I take my shoes off if I want to preserve the cleats and have to walk any distance.


Why are my wrists the first part of my body to start aching during a long ride?

As @Daniel has commented, and I agreed, you probably have a bike fit problem. We cannot be sure; the only way to find out for sure is to get a professional fitting done. Having said that there are still a few things you can try.

  While you say you try to adjust my hand positions, what positions do you use most?
  ...
  The Allez handlebar setup is one I just would not be comfortable with: not enough drop, the straight section of the drop is too low an angle, and the hoods are too low.
  ...
  @andy256 mostly on the hoods, I don't tend to use drops very often - only for variety.

There are several different ways of riding on the hoods. Try them out if you haven't already:

With the thumbs only on the hoods, palms vertical, fingers pointing forward touching the brifter.
You can easily operate brakes from this position.
With the thumbs only on the hoods, palms vertical, wrists high, two fingers wrapped under the hoods, similar to sprinting on the hoods.
You can operate brakes from this position, but not so easily.
With the base of the thumb on the hoods, palms near 45°, one or two fingers touching the brifter.
This is a common position, but it IMO it is the one that causes such problems.
You can easily operate brakes from this position.
Palms further back, with some fingers either side of the "horn" of the brifter.
You can not easily operate brakes from this position.
Good for variety. Can alleviate discomfort.
Palms further forward, resting on the "horn". Fingers forward, just dangling, palm horizontal.
You can not easily operate brakes from this position.
Good for variety, and gives more stretch.

The last two are clearly just for variety. They have obvious dangers.

There are other positions you can use for variety.

Hands at the end of the drops, arms almost straight. Your body position is not much different from having your hands on the hoods. You can't reach the brakes.
Hands further forward on the drops, just touching the upward curve. This requires a different wrist position, but may be worse for you. Some people can reach the brakes, but on the Allez I don't think you will.
Hands on the tops with elbows bent and tucked back beside your body. This can be uncomfortable at first but may grow on you. Your body position is still low.
Again, you're not anywhere near you brakes.
Sitting up more, with hands on the tops. Your hands can be close to the middle or wider to the corners. You'll find each position puts your wrist in a slightly different position.
Again, sitting up more, with hands on the corners. You can have your fingers pointing forward and to the inside, or have your thumbs on the bars with fingers underneath. These have very different wrist positions.
And finally, if you're really into relaxed positions and don't mind a little less control, rest your wrists on the tops, with hands dangling.
There are obvious dangers in this position.

These positions are not for everybody. Some don't work on a given bike, or with a given person's body. Bikes and people are all different. Try some of them and see if they help.

As with any on bike experiments, do it in a safe location.

I have not mentioned adjusting the brifter position. On many bikes I'd try that, but I don't think that would work on the Allez. But you could rotate the bars slightly to make the hoods angle up more. 5 to 10° should be enough to have an effect. I think changing the angle is more important than lifting them (everybody has their theory).

Finally, try taking one hand off the bars and shake it from time to time, then do it with the other hand.


When pedaling forward my bike suddenly disingages and goes limp

From your description it sounds like a freehub failure, where the pawls of the ratchet in the rear gears are sticky or broken.  It's a replaceable part.  Any bicycle repair shop should be able to provide it.


Sounds like your gears need adjusting. How to do so would depend on the type of the gears you have exactly.

But if you're getting the clicking and jumping gears, then your gears are out of index.


Bike won't shift into 2 largest rear cogs (lowest gears)

I didn't see the video but if your talking about the last 2 lower gears you may need to loose the tension cable. if its the top 2 big gears then you may need to tighten.

make sure you derailleur is installed correctly. make sure the last pulley lines up at all cogs especially the biggest one, using your hand and pushing this up and down the cassette, make sure it clears.

try to unbolt the cable, back out on the gears with shifter and back out the fine tune barrel adjuster located on cable/derailleur. pedal, then chain should drop to last small cog. then pull cable hand tight and screw bolt back on cable. make any fine tuning with the barrel adjuster when shifting up.

those are some tips from what I would assume...maybe others can help :)


I've ridden many different tires on my cyclocross bike, and I've found that a 32 mm is the comfortable on the road.

The most fun I've had though is on 40mm Clements, especially if there's any off road involved, if you can fit them on your cross bike.

https://www.biketiresdirect.com/product/clement-xplor-mso-60-tpi-adventure-tire


Mount additional water bottle on bike frame with only one water bottle mount

Get yourself two hose clamps that'll fit around the tube and some rubber strips to put under then so they don't scratch the paint up too badly. They'll hold a bottle cage on just fine.

If you can see under the dirt and grime, that's exactly how the bottle cage in this picture is mounted:

Edit: Here's another picture of a bottle cage mounted with hose clamps (not mine).


Can I run a SRAM road rear derailleur with downtube shifters?

If you set the downtube shifter to friction mode then you can run any rear derailleur you want. If you're looking for indexed downtube shifting with a SRAM rear derailleur, the answer as of the date of this posting is no. Cable pull for SRAM is different than it is for Shimano and others, which is why mixing different brands of shifters and derailleurs is not advisable.


Almost always the H limit screw is on the outside and the L limit screw is on the inside.


You can just spring in the dropouts. Its only 3mm on each side, a steel frame will easily bend that much. Just put the wheel in place, then tighten up the nuts on each side.


One way to get tears around the valve stem is by not supporting the pump head and stem while you're pumping up the tire with a frame pump (the kind where you are pushing on the stem as you pump up the tire, like in the photo below).

Notice the way the person's left hand is holding the pump and the rim. The idea is to stabilize the head of the pump so that no stress is placed on the valve stem.


How much does bike price correspond with maintenance needs?

The cheaper bike will probably require you to adjust the brakes and gears plus lube the chain every week or two, and a bike shop to replace the brake pads, chain and cassette every 3-20Mm. For you, that's probably twice in the winter, once in the summer. With rim brakes you will also need new rims/wheels every couple of years, more often if the roads are gritty. But a lot depends on your riding style and the enthusiasm you have for maintenance (hence the 3-20 range). If "lube the chain every week" actually means "the bike shop does that every month or two", they'll probably be putting on a new chain. Count a monthly service at ~$50 and the chain/cassette/pads as $200 and that's $1000/year in maintenance, or $600 if you do the monthly service yourself.

It's important to note that you can skimp on all of this and it just means slightly more expensive fixes and a slightly worse riding experience (gears that skip under power, more resistance from damaged bearings, cables or chains the break, brakes that don't really work). When I was a mechanic I saw bikes where basically everything needed to be replaced, but people were still riding them (and just wanted a puncture fixed or a new basket or something). The bad riding experience means an hour for your 18km commute instead of 40 minutes.

With hub gears and disk brakes, especially with a full chain case, you'll lube the chain every couple of months, put new brake pads in every year or two, and I expect that replacing tyres will become your main dirty maintenance task. With a single-cable hub (Shimano, SRAM) you'll have to adjust the gears after a couple of months (the free service) then again a few months before you need a new gear cable. If you run Marathons or some other puncture-resistant tyre you should wear the tyre out without getting a puncture (a puncture is often the thing that makes you look at the tyre and go "need a new one". I run a Marathon Plus on the rear and have only had one puncture in at least 20Mm. I did get a 3" nail through one though (with no puncture!)

Those numbers are why people often end up with a dedicated commuter bike that costs a fortune up front. New Rohloff Oil every year at $20 compared to a new Shimano hub every three years at $800 makes the $2000 up front cost of a Rohloff seem cheap (a Rohloff will last 100,000 kilometres or more... no-one really knows because there aren't many hubs that have done that distance yet, Rohloff only started about 10 years ago).


Not sure what you mean by 'stance' of the bike, but rear wheel will not be moved relative to the bottom bracket by a perceptible amount. No change in handling will result.

Similarly, shift cable will not be affected, but can be adjusted anyway.


What is the stopping force of your average road bike?

Beck Forensics have figures (pdf), peaking at about 0.5g for a MTB on flat concrete. I used this search to find that paper and some of the other results look relevant.

The number that springs to my mind is 0.3g, but that may be for cars. Bicycling Science or Human Power are where I would go for well-researched answers. Human Power doesn't seem to have anything, although it may just be missing from the index.

A great deal depends on the geometry of the bicycle, since that's the limiting factor (most bikes can throw the rider by overenthusiastic braking). A little thought experiment might help. Assume the CoG of the rider is in the hips, so about 10cm above the seat. A line from there through the front contact patch will be roughly 45 degrees above horizontal (give or take, say 15 degrees), so an upper limit of 1g is likely.

To further Feynman it, 10m/s is 36km/hr, so 1g would stop you from 36km/hr in one second. During which time you'd travel about 1/2at^2 or 5m (I cheated by making t=1). One simple test would therefore to sprint to 35kph then hit the brakes at a marked point and see what your stopping distance is.

On reflection, 1G or 10m/s/s sounds more plausible as an upper limit.


I would say it is most likely oil moving through the valves. If you are concerned about more water getting into the fork you could clean out your fork seals with a piece of old camera film.

Given the year of the fork, I suggest taking it to your local bike shop. It cannot hurt to service your fork and support the people that support riding in your area!


Friction in newly installed bottom bracket

Sounds like a spacing issue, the cranks shouldn't bind at all.  They may have some resistance with new bearings, but not enough to noticeably feel in most cases. Check that you don't have excess spacers on the spindle and are just using the wavy washer.

The crank arm bolt should pretty much bottom out on install and the cranks should be easy to turn. (there is a black alloy spacer that is used for BB86 shells included with most SRAM gxp cranks/bb and is not needed on the BB92 install).

If that looks correct, have a visual check in the BB.  It uses a plastic shell and sometimes this can be damaged when pressing in and contact the crank spindle on install.  Next check that the bearing cups are not deformed where they meet the frame on the outside (ie pressed in too hard) which can cause the bearings to run out of alignment, again a plastic shell issue and can happen when using larger headset presses.

Worst case, replace the BB with something like a Wheels Manufacturing or Hope BB that use alloy parts throughout; these are much more reliable for press fit applications as they do not deform like the plastic ones.


You state in the comments that the (pinch) bolts on the left crank had come loose (Ultegra Hollowtech 2). So you’ve solved the problem by tightening the bolts.

I saw another bike (I think Ultegra cranks) do this yesterday, again it was a very new bike, it was on its first serious outing and the left arm had worked loose.

I found the question with a relevant Shimano publication extract: How to tighten the Hollowtech II (on R2000 Claris) cranks?

In short, any time you install these bolts, tighten/torque check them again after 20 km, much like checking the wheel nuts on a car, a short time after it’s been in for a service.


Got a new cassette and chain, freewheel not working correctly

You're on the right track with your Googling; the mechanism which disengages the drive when you pedal backwards (or coast) is plainly not working as it should. That is independent of the newness of the cassette or chain.

If you don't want to get into dismantling the freehub to clean and lube the pawls just yet, you could try your new parts with a known good wheel and see whether the problem goes away. If the problem disappears then you know it is worthwhile to overhaul your freehub.


What is this hook near the cantilever brakes?

This is a cable-catcher, but using the brake in the picture it doesn´t work, as the cable coming from the handlebar goes straight to the brake body. If the cable breaks, the whole system will snap open, with loose cables, not interfering with the tires.

A cable catcher is useful if you have a brake that uses the configuration shown in the picture below. In the event of the main cable snapping, the cable that goes accross the break arms stays in the hook, not interfering with the tires. At speed, with no cable catcher, this could cause quite a crash.


The pages you linked to both say "700/900 Alloy Frame", and they look identical in geometry and tube sizes, so they are very likely functionally the same.

I notice the higher spec bike has internal cable routing though.

Update: after a closer look at the pictures of the bikes, several small differences can easily be seen, in addition to the internal cable routing.


How often should one service headset bearings?

Probably never -- headsets can easily last the life of a bicycle for most people without needing an overhaul.

If you ride in the wet, it is advisable to have a front fender, though (to reduce the likelihood of needing an overhaul even further).


I have a hybrid bike which the frame is too big, is there any modifications I can make to make it more comfortable?

You have a couple of options, lowering the seat and changing the stem, or some combination of both. One other option would be to find someone that has a similar quality bicycle that is slightly small for them and trade! Local co-ops or bike clubs would be a place to start for this.

As for changing the components you may consider an adjustable stem so that you can do the fine tuning your self, rather than buying a 70mm reach stem and realizing it didn't really help.

You will have to decide what needs to change based on what part of your body is uncomfortable. If you feel stretched out like your reaching to far forward a shorter stem will bring your handlebars in a little.

If you legs are being over extended drop the seat post a little and see how it feels.

One other option would be to show up at your local bike shop with a 12 pack and ask for advice. They will charge for a proper fit, but with beer they should be fine with giving some advice and options free of charge. If they are not, find a new shop.

This site has some good information to explain it to beginners.

As does REI


What tool do I need to remove this bottom bracket?

Three-hooked spanner is not necessary, but it would improve the engagement and decrease chance of stripping a notch on the BB lockring. Parktool makes the  HCW-5 spanner, which combines both a three-hook and a single hook. Here's a relevant quote:

  One side is a single hook, the other is a hook spanner with 3 notches
  for better engagement in the lockrings.


One possibility is to mount the tail light on your bike's seat stays. As an example here are a couple pictures of my preferred tail light (the cygolite hotshot) mounted to the seat stay of a cross bike:

There are a bunch of options out there for this sort of mounting, from lights specifically designed to be mounted on a seat stay to ones that come with seat stay mounts in addition to the normal seat post mount.

A few things you want to keep in mind when choosing/using a seat post mounted tail light:

Make sure the light's mount has enough adjustability so you'll be able to correctly aim it.
Make sure the light's mount will fit properly on your bike's seat stay. For instance, the seat stay mount for the cygolite hotshot I use won't fit on the extra skinny seat stays on either of my road bikes but fits fine on my hybrid and CX bikes.
When mounting the light, make sure it is extra secure, you don't want to risk the light getting knocked into the bike's wheel because it was installed too loose.

Another possibility is a rack mounted light. Again like the seat stay mounted tail lights, there are lights specifically designed for rack mounting as well as mounts for that allow other tail lights to be used with racks. In the example of the cygolite tail light I use, there is an optional rack mount available, although I was actually able to adapt an old rear reflector mount to serve in this capacity.


What is the typical angle between the derailleur post (seat tube) and top of chain?

There is not a fixed angle between the front derailleur and the chain, because the angle of the chain relative to the bike changes depending in what front and rear sprocket it's on.

Chain stay angle range is a parameter specified for front derailleurs. As an example, see this Shimano specifications page for road groupsets. Chain stay angle is the angle between a line drawn from the bottom bracket axle center and the rear wheel axle center, and the seat tube (or a line from the BB axle center to wherever the front derailleur is mounted if there is no traditional seat tube).

If you place your front derailleur on a line at that makes an angle to the chain stay line in the specified range, you know the chain will be at an acceptable angle to the cage in any gear combination.


Most likely the problem is not with the actual brakes, but cables and brake pads. Replacing these is very likely to fix your problems.

If you want to replace everything and keep everything in official Shimano spec, it seems that there aren't non-shifter brake levers. The options are to install the expensive and useless shift levers, non-Shimano brakes or use a non Super SLR lever that results in slightly mushier feel.


Looks a lot like a Specialized Crux cyclo cross bike / frame. There are various versions around.
Here is one in a different colour:
http://www.rutlandcycling.com/314372/products/2016-specialized-crux-e5-cyclocross-frameset-cyan-pink-yellow.aspx
Has the extra piece in the rear triangle near the left dropout:

Also:


The photos look like you had the saddle clamped at the very rear end of the rails. This, especially if you sit at the tip of the saddle like time trialists often do, puts unusually high torque on the seat rails and clamp. In your case, the rails were stronger than seat clamp bolt.
Since there are four options for mounting the seat clamp, try to choose the seat clamp position so that it is close to center of the saddle rails to avoid unnecessary stress on the seat clamp.


Saddle started to hurt after years of riding

Whether we like it or not, we all change every moment. Because we are alive. The differences are slight, but they are cumulative. Any change in activity, diet, lifestyle, etc. changes our body. Saddles are only getting old.
Pain isn't just an inconvenience - it's your body's way of talking to you:

constant little pain when you get tired of translating: 'enough for now, I'll fix minor problems',
increasing pain: 'stop, at least slow down, I need more time to fix myself'
muscle pain the day after training: 'you did it wrong, don't force it anymore'
sharp pain: 'STOP !! Never do that again'

If your lifestyle has changed to be less active:

you have smaller muscles and you sit differently
you slouch - your spine is overloaded and you sit differently

If you have lost weight:

you have too little weight to use the suspension perfectly
Your skin is not sufficiently isolated from the bones
Your skin may be too dry to deal with it
you have a different weight distribution
you sit differently because your body is different

If you have gained weight

you have a different weight distribution
you sit differently because your body is different

Check the saddle - even a 1 degree incline can make a difference, it's a long saddle.
Check your ... body - take 2 mirrors and look at them - you may have a new sign (no it's not cancer, cancer is vicious because it doesn't hurt until it's too late). If you find anything unexpected, go to MD and have it removed / healed.
All of the above can occur together.


What are the reasons for these two very different post mount adapter designs?

While I can't find anything from Shimano themselves, this description is used in regards to the second one on a number of websites selling them (so perhaps it is in Shimano's sales literature?):

  2nd version of adaptor, lighter and better hose routing

Since this is the best I can find, I'm posting it here as an answer, but by all means if someone else finds more details post that up.


They are not any less secure than the old style where they are built into the frame. Even if you were to undo the screws, they would still be a solid ring around your wheel, and would prevent the bike from being ridden as it would come into contact with the seat stays, chain stays, and ground as the wheel went around.  However, in general, these types of locks aren't very secure as they are highly susceptible to the "pick it up and walk/drive away" method of theft. Once the thief has the bike in their own garage, the lock can easily be cut with basic tools like a hacksaw or a grinder/dremel with a cut-off disk


There are commercial kits that do exactly this, such as the Problem Solvers ones:

To be clear, a wheel adapted this way offers none of the advantages of Boost, since the flange spacing remains the same.
While these kits are being sold without any such compunction, it's worth pointing out that they put extra leverage on the hub rotor mounting holes and on the axle. Personally I wouldn't be surprised if there's a scenario where you could get a hub or axle to fail because of this - if you look at some hubs, Hope is what I'm thinking of, you can see there's a very minimal amount of material around the rotor mount. So I'm dubious how universal of a solution these kits really are in that sense.


Safe and proper (or vice versa) left turn in traffic

The proper and safest option is to 'claim' the lane and act as if you were a car by sitting in the turning lane. This ensures that you are visible to motorists and if you follow the road rules you are more likely to gain respect of those around you.

In a number of countries there are cyclist boxes in controlled intersections which offer even more security when sitting in front of traffic. In these instances you move to the front of the traffic during the red light phase.

There are some motorists who dislike this however and you need to be watchful (and mindful) of irrational drivers who may take offence.


How to cut a counterbore for chainring bolts with simple tools

What I did in the end was this:

The new chainring was a black Dimension with a pretty generously thick tab section. I actually went with an unramped one, but running it flipped wouldn't work because of its offset. Running it without a counterbore for the nut caused the chain to get stuck on the nuts when in the inner ring.
I used a countersink drill bit in a hand drill to cut away at the holes on the non-factory-counterbored side until the hole on the top surface was enlarged to the diameter needed to clear the nuts.
For grins, I tried stopping there and mounting the ring that way to see if force from the nut/bolt would be enough to squish down the material sufficiently to give the chain clearance. It didn't work.
To create the counterbore, I decided to get risky, and used my Dremel freehand with the baby endmill looking bit that came with it, which I think is a Dremel 196 bit. I carefully cut from the inside of each hole out to the major diameter, then went in a circle from there. The countersink bit took away half of the material that was in the way of me making this circle, whereas the bit going off course into where I didn't want to cut would require a lot more force, as would driving the bit deeper, so I was able to use tactile feedback to stay pretty much on course.
After getting it most of the way there, I cleaned it all up with alcohol, and colored the cut areas with a Sharpie. Having it all black again let me observe any irregularities and touch up those spots to better keep the surface for the nuts to bear against flat. I also tested that the nuts were sitting neatly just below the surface of the ring.
I mounted it all up and the counterbores worked perfectly. Because the crank in question is strange, I had to play with spacers under the small ring to work out issues with chain rub on the new large ring in more gear combos than I liked.


Does ProPedal on FOX RP2 rear shock wear out when on during downhill?

While shocks are certainly meant to be locked out and ridden, even over semi-rough terrain, there are probably some limits to the design. I'm not a fork/shock mechanic, but what I know about fluid dynamics tells me that you shouldn't do this too often!

When you lock out your fork/shock it limits that compression of the fluids inside or prevents compression at all by preventing other parts from moving.

Scenario 1: The fluid isn't allowed to move through the damper. You could cause high pressure build up on a seal or damper and cause it to blow, or even rupture the canister.

Scenario 2: The parts are prevented from moving. The forces exerted on the locked parts could be more than they were designed for and could cause premature wear to the point of failure.

Again, I'm not a professional, but I wouldn't recommend riding like this regularly. Perhaps a quick email to Fox might be more helpful, as they may have actually done testing to see what happens when a rider rides the rough stuff with a locked-out shock.


Safety of taking a bicycle to a country where they drive on the other side of the road?

In my opinion it is actually safer to bring the setup you are used to even if it theoretically might be less optimal on the other side of the road. Such a difference is very small. Sometimes you have to indicate to the left and sometimes to the right anyway.
When I lived in the UK for 2 years I had problems getting used to the reversed brakes and I was more or less only able to brake with both levers in the same way. I would suggest to bring your own bike instead if you do not remain in the new place for very long.
As far as I know there are no legal requirements to which brake is which. The bicycle just needs to have the brakes it is required (often two independent brakes, some countries or states may allow just one).


How can I adjust index shifter so it doesn't skip the second chainring?

You went at it backwards.  First thing to do (after backing off the limit adjustments a bit) is to adjust the barrel adjuster so that you can hit middle gear, then adjust the upper and lower limits so that you hit the outer two without going too far.  Then you can "tweak" the barrel adjuster slightly so that you minimize chain rub at the rear without upsetting clean shifting to the middle gear at the front (then "tweak" the limits again).


How do I lock out the front fork on my RST Neon shock?

The RST Neon comes both with a lockout and without a lockout.  If your unit has a lockout, it can be found on the right hand side.  By looking at the image of the top right fork it appears that you do not have the model with the lockout.

You can see an example of what the lockout looks like here: http://rstsuspension.com/en/forks/city-trekking/neon


Difficulty & Value of replacing suspension forks w disk brakes (for Touring)

The wheel should attach to the new fork with the current hub.

You just need to match the tube diameter and height.

You need to match the height for a bike designed for shock.  Like look at a Salsa Vaya compared to Fargo.  The Fargo comes with solid but can take a suspension.

You did not post the size of the wheel or fork but this is an example of fixed fork that replaces a suspension. OrgeFork

You need to match brakes.  Often they will support more than 1 brake type.  That Orge supports disc I think - most 29" most do.

And checked used.  Most people go the other direction (solid to shock).

You also posted a question on mounting a rack. Look for fork with mounts for fender and rack.  Why did you decide to not put a rack on the suspension?

As for if you are on a budget should you go ahead and put a rack on shock?
I would say yes use the shock and put the money into a nicer rack and/or nicer bags.
A decent set of bags is $100.
Put your lighter stuff up front.
A mountain bike with shocks for a road touring is not ideal but that is where you are.
As for a point of failure I would not worry about that unless you have an indication you shocks are failing.
If you can find a used solid fork with rack mount for $40 and can install it yourself then I would do it.  There is a Salsa Fargo fork on ebay right now that multiple attachment points.  If it fits your bike it would be nice.  I don't know how much of a budget you are on.


It happens, especially if you remove the pump head not perfectly vertically or you move the pump head while pumping.

You can avoid this by using a bit of hose on the mini pump like on this mini pump

or bracing the head of the pump while pumping.

Its not the end of the world if the valve core is bent -- I've run tubes for years with slightly bent valve cores. Note that at some point it may break (and you'd need to get a new tube then). The presta valve only lets out air when you press down on the valve core, which you can't do once you tighten down the nut (even if it doesn't sit flush with the rest of the valve and hits the stem at the angle, you can't push the nut down anyway to let out air).


Is it possible to service Specialized Brain suspension systems at home?

I've serviced the brain on my 2006 sworks stumpy several times over the past few years, mostly because of the crummy turnaround times from spesh, and the fact that it never makes it through more than half a season before losing lockout etc.  And the fact that I'm a mechanical engineer and stupidly tear into anything that breaks thinking I can handle it (half the time I can't).

I have to admit it took me about a year to get good at rebuilding it, the critical thing is you have to make sure there are absolutely NO air bubbles in the system when you refill it.  Air bubbles getting into the hydraulic fluid seems to be what makes them fail.

There are a few threads out there that are helpful, and there's a rockshox monarch repair video that's similar enough to give you some good ideas.  There are also schematics available on the net that are a huge help and also tell you what size o-rings etc you'll need (and make sure you replace them every time, at the least the standard ones which are easy to get from the internet or in my case my friendly neighbourhood hydraulic component shop), they're cheap and if you don't you have a good chance of failure.  Note that some of them are Vitron (teflon impregnated), unless you have absolutely no choice replace vitron with vitron of the same color (durometer).

I had the schematics saved somewhere but haven't found them yet, that's how I ended up here, I'll try to remember to check back once I find them, and if anyone wants let me know and I'll pass them on.

I don't bother with nitrogen, I think the main reason they use it is the convenience of a high pressure cylinder of nitrogen versus using a hand pump or a high pressure compressor (you want to charge the brain side to 350-400psi).  Some shocks do just use air.  I put a schraeder valve on my brain and use a suspension pump to fill it, I can get about 350 psi into it.  If you wanted nitrogen you could probably go to a motorcycle service shop and get them to charge the system for you.

To refill it I have used Fox fluid, but it's just rebranded motorcycle fork fluid marked up about five times as much.  I've used Belray motorcycle fork fluid with success (It's available in a variety of weights so you can experiment a bit, I think I used 7 wt).  I've also tried transmission fluid at someones suggestion, it works fine but smells terrible, I doubt I'll use it again.  Whatever you use you need a lot because you need to have a bath of it you can fully emerge the whole system in while you reassemble to make sure you don't get bubbles, for me I need about a gallon minimum.

There's probably no reason to take apart the shim stack, but if you do be very careful and methodical, take your time and take LOTs of pictures.  If you dont get it back together exactly the way it was it probably won't work, and I've only found shim stack diagrams for one or two models of brain.

Good luck!


A picture of the damage would tell for sure but 90% of the time tearing a valve - presta or schrader - is due to under inflation.
Low inflation pressure allows the tire to slip (during acceleration and/or braking on the rear, braking on the front) on the rim. The slipping tire rotates the tube. As the tube moves the valve is torn off as it moves against the valve hole in the rim.
It is possible to have a faulty tube. Usually defects (imperfections in molding etc.)look very different than forcibly tearing or cutting the valve on a tube.


Where to buy dust cap for bottom bracket for an old bicycle?

I highly doubt you would be able to find replacement for a bottom bracket dust cap on a bicycle which looks that old.
The economics for such parts do not make sense in general.
Something you could do, however, is 3D print it. It is a fun little project to redesign a part in 3D. You can use something like SketchUp to do it.
It will be a bit expensive though to have it printed (~tens of $), but you get to pick between different polymers.
FYI It is something I did to salvage a 1960s chest of drawers I have, where the plastic bits holding it together had become completely brittle.


Can I use Shimano 105's brakes with vintage bike?

For many years, all brake levers had a cable pull for either traditional sidepull/canti/u-brake brakes or linear pull/mechanical disc brakes. There were small differences between levers but essentially every lever across all bike genres in one camp would work with every brake in that camp. When Shimano came out with their under-tape shift housing routing STIs, they changed their brake lever pull to a higher number, putting it pretty much in between the two existing classes. These levers and brakes are designated Super SLR and they include most of the current Shimano brakes.

It's more cable pull. What that means is if you pair Super SLR levers with conventional sidepull brakes, you'll have more rapid arm movement and nice crisp brake feel but less leverage and less power. If you pair Super SLR brakes with conventional levers you'll have the opposite: more leverage but mushy feel and less arm movement, forcing you to have the starting position of the pads very close to the rim if you're going to avoid running out of lever travel.

I don't really recommend doing either. The danger of the former is inadequate braking power, and of the latter it's that it can be easy to run out of lever travel, which is also a safety issue, plus the lever feel is poor.


BikeCalculator attempts to quantify these different positions. I find it tends to overestimate speeds a bit (probably thinks all roads surfaces are smooth/good).
In my experience you gain about 0.5mph for each of these position shifts:
Flatbar -> Tops of drop bar (narrower hands) -> hoods -> drops -> aero hoods (flat forearms) -> puppy paws (forearms on the tops)


Scott S30 road bike 11speed with 10 speed compatibility

New 105 5800 crankset is compatible with older components, according to numerous posts in this thread.

Yes, you can use the same cassette.
Even if you use short cage rear derailleur now, it should have enough capacity for 28 teeth sprocket.
11 speed Shimano chains have the same internal width, so these should be compatible with older 10 speed systems. Given that you have limited budget, 10s might be a better choice.
Yes, that cable set will be fine.


Should I put my wider tire in front or in back?

Generally on a road bike it is considered better to run tires of equal size.

There are a few newer tires which are designed to run different sizes front and rear, but they are usually within 2 mm of each other. (Like the Continental Attack/Force combination)

I would consider a jump from 28c to 23c somewhat large.

That said, run the larger on the rear. The higher air volume will make for a more comfortable ride, and the narrower front tire will steer quicker, which makes for more reactive handling, and has a better aero profile, (which may or may not matter to you).

The comfort part will matter though, and I'd say that's a trump card.


Specialized Allez - Upgrade to Carbon Seatpost for Long Distance Comfort?

There are a lot of more potentially useful avenues to investigate first, because you feel that chamois pad quality is not the culprit next most obvious choice is the saddle:

Stock saddles are often not very high quality.  They are also typically too soft (aka not supportive) which will cause problems on longer longer rides. Adding to this, if you still have the original saddle, it is 4 years old now.  The padding may have simply become compacted and unsupportive. Being a heavier rider you would likely benefit from a saddle that uses more dense/supportive foam, as well as one that has a stiffer body to better support weight.
Is the saddle angled correctly.  The Allez should have come stock with a Specialized body geometry saddle. It should have explicit instructions on how to angle it correctly.  If the saddle is not tilted correctly, your pelvis will not be angled correctly and you may not be distributing your weight as evenly across the saddle as it could be.  This can cause hot spots, and other problems
How is your position on the saddle?  Saddles are often designed for a particular body angle.  Some are designed for a more upright posture, while others are designed for a more aggressive body position.  This affects pelvis position/tilt and how you interface with the saddle.  For example, a saddle designed for more aggressive body positions may be too narrow for a more upright riding position which can cause hot spots and discomfort.
How is your pelvis position?  Ideally, your pelvis should be rolling forwards like a pitcher pouring water (especially for endurance riding).  Many riders due to bike fit issues find themselves rotating the opposite direction (sometimes to protect the prostate, due to a poor saddle) which can change how you bear weight on your sit bones and cause high pressure areas and discomfort.
Is the saddle the correct width for you?  Saddles are like shoes, one size does not fit all.  There are tools to measure the width of your sit bones in order to ensure that you are matched to the correct width of saddle.  Too narrow and you will not be supported properly, too wide and it can interfere with pedalling and cause chafing and hotspots.

Expanding on (4) pelvis position (@gaurwraith)

This passage from "Bike Fit" by Phil Burt (lead physiotherapist for British Cycling and a consultant physio for Team Sky) describes pelvis position.

  POSTURE

  Posture is the maintenance of a certain body position and requires appropriate joint mobility, joint/muscle coordination and muscular endurance.  Limits in any of these elements can result in postural irregularities.  Good posture on the bike required good flexibility through the hamstrings and the glutei muscles:  this allows the pelvis to roll forward, keeping the back in a straight position while reaching the handlebars.

  One major factor limiting the back's ability to remain relatively straight while on a bicycle is thoracic immobility: lack of movement in the middle of the spine normally results in the spine flexing too much.  Excessive spinal flexion while on a bicycle will limit breathing and compromise your ability to stabilise your spine for torque production to the pedals

I personally when through a episode of mid-to-upper back pain caused in part by the issues described above.  I was posteriorly rotating my pelvis (rolling towards the back rather than forward), which also affected how I sat on the saddle.  My Brooks saddle developed very deep sit bone impressions and modern saddles quickly became uncomfortable.  As I regained my back flexibility, I noticed I could roll my pelvis much farther forward evening out sit bone pressure on modern saddles, which made them comfortable again.


To what extent is grease interchangeable?

Some greases really are special. But in other cases the grease doesn't really matter. Since so many companies just say to use their approved grease, it can be hard to tell apart which applications are really special and which ones don't really matter.
There are some applications where you should only use the approved grease and using the wrong grease really will cause a problem. This includes roller brake grease. This is critical to use the exact grease specified, and unsafe to substitute anything else.
Also, some frame couplers specify special fluoro-compound grease, and it's best to follow the instructions or potentially ruin your frame from thread galling.
Any carbon parts like carbon seatposts should use grease recommended by the manufacturer or for the application.
Internal gear hubs usually use oil, but it's important to use the correct lubricant. Some hubs like the NuVinci hub literally are designed around the special oil they use. For other hub types, the grease doesn't usually matter.
On the other hand there are a lot of applications where the grease doesn't matter that much. In that case I use boat trailer bearing grease, or if something lighter or cleaner is needed, white lithium grease. These include things like most steel threads including pedal threads, steel seatposts and quill stems, brake pivots, wheel and headset bearings, crank splines, cassette splines, etc.


I'm betting that you need to install a brand new chain and a brand new freewheel / cassette, at the same time, and out of an abundance of caution, make sure they're the same brand. I doubt your friend actually ruined anything, the more likely scenario is that the chain is old and stretched, causing it to slip ( or it's the wrong length as Daniel mentioned ). This isn't all that unusual.


Is there a do-it-yourself way to tow a kid's bike?

If the child's bike has a quick release front wheel, you could also use a universal fork mount bolted to a rear bike rack. Then just hang the front wheel on the kids bike with a bungee cord.


Why do full suspension bikes seem to be on average £1000 more expensive than hardtails?

I don't think you are matching like for like and actually the price differential is quite small.

The only fair way to compare two bikes is by looking at the frame only price. In this case I've been unable to find the frame only price for the Codeine (SingleTrack forum suggested £599 with Monarch R vs £225 for 456) so have used Santa Cruz instead:

The frame only price for:

The hardtail Highball is $750USD RRP
The full suspension Superlight 29 is $1,099USD RRP with a Fox CTD

Both are XC bikes, 29" and alloy.

So the price difference between the two bikes is $349, this would include:

the shock
the pivot bearings bolts etc
additional welds for the FS
additional strengthening for the FS
more complex manufacturing of the pivots
additional design costs

There are other factors that influence the price of a complete bike that may explain the difference between the 456 and the Codeine. The £899 45650B is an intermediate level specification whilst everything I have seen on the Codeine indicate it will have a high performance build. The differences from what I've seen include:

the 45650B has a Deore groupset, a XT or X9 groupset would be £300 cheaper but the Codeine prototype had an XX1 groupset which would be at least £500 more.
the Codeine may come with a dropper post which would be £200 more.
the 45650B has a Sektor fork vs the Revelation on the Codeine which would be £100 - £200

Comparing the two bikes side by side there would be more examples where the specification levels are different and would justify additional costs (brakes, wheels, tyres, bars, saddle etc.).


8 speed drivetrain stronger than 9 speed?

My guess is in reality no statistically measurable difference between 8,9 and even 10 speed setups. 8 Speed these days is low cost components, meaning you are fitting out a bike with low cost gear. Even 9 speed is lowish cost. 10 is geting into quite fine tolerances but has been around long enough to be well understood. 11 and 12 speed setups might be a concern, but I would not fit them because of concern over strength.

More important though is "Strong enough" - once the gear is "strong enough", does it matter if one is stronger than the other. And setup built with components of good enough quality to be used where reliability is a concern is strong enough.

The disadvantages of more gears is finer tolerances meaning wear is a bigger issue. Wear is a different concern to strength as it affects everything but is predictable, and easily managed with normal maintenance. (Cost is another discussion)

There might be reasons for not going to higher gears - availability of components in remote places in the event of a break down. However going 9 speed over 8 speed has little disadvantage here. Most components are interchangeable between these, and if needed you would as easily get you bike up and running on the off the shelf components at the most basic bike shop  with 9 speed as 8 speed.

As eluded to earlier, cost might be a reason to stay on 8 speed - but that is a different question (and I have my doubts it is significant).