What's a good way of cooling down my legs after a long ride? Are pain-relief sprays a good idea?

What I usually do to relieve fatigue on legs after long and/or intense cycling is the following:

at the end of the shower use the shower faucet directly on both your legs for at least 30 seconds with warm-hot water. Then turn the water to cold and again keep the flow for about 30 seconds. (if you are brave enough and you do not suffer form heart diseases you can do the same on your entire body).

The abrupt change in temperature will help your muscle squeeze out of the cells lactic acid and all the other methabolic residuals.

Alternatively, you can soak in a warm bath for some minutes: I did it during my trip in Japan (cycled up to 120 km/day on hilly roads), and the onsen at the end of the day was really a leisure.


What does a cyclocomputer actually measure for calculating the speed of the bike?

The answer is "both, depending." The majority of current bicycle cyclometers use a reed switch and timer, and measure the time between successive triggerings of the switch as a magnet passes by. An advantage of this method is its simplicity and low cost, though if the magnet is ill-positioned or if the rotational speed of the wheel is too high, the reed switch can get fooled since it takes a while for the reed switch to reset itself.

A less common approach (used by the old Avocet line of speedometers, including the venerable and venerated Avocet 50) used an induction coil and magnet ring with 20 small magnets attached around the hub. The induction coil could rapidly count the change in current. You can see the details of this approach in the Avocet patent application for the 50, but its designer discussed some of the idiosyncrasies of that approach in this Usenet post from 1994.

Although these two different methods can be used to collect the data needed to calculate speed, the exact algorithms used may differ from device to device. One can see this in the way that cadence is often calculated. Almost all bike computers that have a cadence sensor use a reed switch, since the rotational speed of the cranks is low enough for reed switches to reset. However, different manufacturers use different averaging periods, time-outs, delays, and triggering events before displaying the result. Speed calculations work similarly, and one can occasionally see the evidence of these choices by examining speed and cadence data from bicycle computers that store these values and allow them to be downloaded after the ride. Here, for example, is a graphic that shows the speed recording from three different devices that were mounted on the same bicycle for the same ride (a PowerTap, a Polar S710, and a SRM Pro -- these are power meters but here we focus only on the recorded speed). Each device was set with the same wheel circumference but the histograms show that each stores and reports slightly different speeds.


Even though the chain is new, you could have a stiff link.  I assume you cut the new chain to get the correct length.  If so I'd start there to make sure you didn't mess up the first remaining link.  Then I'd manually check each link for a stiff one.  If you find a stiff link, you can sometimes loosen it up by bending it a bit side to side.  That is at 90 degrees to plane of the pivot.


Shoe fit and the stiffness of the last are the first things that come to mind.  I'm thinking you have a wide foot and cycling shoes are typically on the narrow side.

I've always had major issues with any shoe that was slightly too narrow for my foot.  I'd get cramping along the outside edge of my foot. It gets worse when the shoe becomes stiffer (It's just hell for me to wear X-country ski boots or hockey skates).  As cycling shoes are meant to be something akin to a block of wood, that means for me I need to be certain the shoe isn't too narrow or I'll be in pain really quick.

For my road shoes, the size is such that I actually have a slight amount of heel slippage which allows my foot to flex a bit more than what typically would be expected.  With my Mtb shoes, I go for the freeride type of shoes which don't give nearly the same amount of energy transfer but my feet are way happier at the end of the day.

I had a pair of Sidi shoes a few years back (Awesome construction) but found that even the Wide width was narrow and caused me pain after a few hours of riding. Specialized seem to fit narrow as well.  I've had to try on many a shoe to find a wide enough fit and usually I'm still left with having to go sockless just for a little bit extra comfort.

Get your foot sized by an expert and go from there.  If it's a width thing you'll know with numbers.  If it's something else then you can start to narrow things down.


Bottom bracket square taper (cartridge) extraction, too tight in one side

I think you'll find that they are actually a different size.  I'm struggling to find any information about it online but I can show you a picture of a tool that should deal with it.  It's hard to say what the difference in size is but there is an obvious difference in thickness of the ends.  You probably just need to find the other size tool and take out the metal end first.


Should I avoid hard-packed crusher dust trails with my hybrid?

You are absolutely fine riding the Trek FX 7.2 with the Bontrager tires on that trail. That gravel surface is not any worse than rough, worn tarmac so go ahead and enjoy those trails.

You don't really need much tire tread (or any) on flat crushed gravel trails, 35mm wide tires have plenty of volume.

Be aware that you will have less grip, both in cornering and braking. Try running slightly lower pressure than you would on the road. Avoid big bumps and potholes. Carry a spare tube, tire levers and CO2 inflator or mini pump in case you get a flat.


Marrakesh w/ Sora STI shifters & Alivio Trekking FD + Crankset 48T

If you look at the Shimano compatibility docs, the Alivio shift levers SL-M4000 are compatible with both the MTB RD/FD-M4000 and trekking RD/FD-T4000 versions of the derailleurs, so there is functionally no difference between the M and T versions.

Compatibility charts are here: https://productinfo.shimano.com/#/com?cid=C-432&acid=C-445

Shimano used a common derailleur actuation ratio for MTB up to 9 speed and road up to 10 speed, so I'm not surprised that the Sora drop bar shifters work with Alivio derailleurs.

if you want to fit Alivio cranks and derailleurs to a frame that is nominally a road bike you have to be aware of crank spacing, bottom bracket shell width and chainline (and what bottom bracket type you have.) The Alivio cranks want a MTB style Hollowtech BB that fits 73mm (or 68mm with spacers) shells, and provides a 50mm chainline.

Specs are here: https://productinfo.shimano.com/#/spec/TREKKING/Front%20Chainwheel


How much energy loss should there be in an internal hub 8-speed?

Anything that has been standing around for 10 years needs some maintainance before it can be used with confidence (especially if it was not maintained before properly). So if there is some extra friction it would not be a total surprise. You should check the manuals provided by Shimano what is recommended for your hub (https://si.shimano.com/#/en/search/Keyword?name=SG-S501&name_web=). There it is shown that you take the hub apart and dip the inside into an oil bath. The maintainance interval mentioned is every two years or 5000 km. The manual also says that the hub is not completely water-proof. So maintainance is the only way to get rid of water possibly present in the hub.

Shimano does not seem to specify a temperature range for the Alfine. So it should be possible to assume that they work well in all temperatures that people ride bikes in. But it is also reasonable to assume that whatever lubricant is in the hub will become more viscous when colder, resulting in less efficient lubrication. And again: the hub is not completely water-proof, and if you have a lot of water, that can definitely freeze.

That said, I reactivated a bike with a Shimano Nexus hub that has been unused for about 5 years for my wife, and it was no problem at all, although I skipped my own recommendation from above.

One personal comment on internally geared hub vs. derailleur gears: I changed from derailleur to hub two weeks ago and to me it is like a dream. But I am lazy with cleaning the drivetrain, so what I usually use is far from being friction-optimized.


How did these pimple/bubble/bump shapes form on my tube?

The culprit is the rim tape. The glue that holds it in place has lost its grip, and when the tube is inflated, the tape is pushed away and lets the tube to extend into spoke hole. Eventually the edge of the spoke hole cuts the tube with the results that you described.

In my experience, this is what cloth rim tapes do. They can be replaced and there are tricks to gluing that may or may not help, but in my opinion the easiest solution is to buy a pair of plastic rim strips and replace the tape with them.


Magura MT7 on Commencal Meta AM V4.2 Race

I got the answer from Commencal customer service :

MT7 with 200mm disc on the front without adapter
MT7 with 200mm disc on the back with +40mm PM/PM adapter. 180mm disc would not fit on the back because there is not enough space in the frame to place the caliber.


Considering purchasing a slightly used Hollandia Evado e-bike... couple minor questions

Is it true that this is a unisex bike?

Step-through frames are indeed considered unisex as they are mostly seen in bikes used as 'way of locomotion' rather than 'sport device': if you are not wearing clothes that are suited for cycling (not only skirts for women, but also tight trousers for men or suits), you gain a lot in comfort by having a step-through frame. They are also popular among people who do not are not "flexible enough" to step in a classical frame (typically older persons).
For other kind of frames, the difference is mostly linked to cultural norms/marketing than physical properties of the bikes. Bikes were introduced in a time where women were required to wear long skirts, so different frames were designed for that reason. Nowadays, if you take a bike of the same size and the same model in men and women version, besides the frame and the colours, at best you'll have a different saddle and smaller handles on the handle bar on the women bike (which are very easy to change).

Is the make and model considered a "hybrid," or, if not, can I at least ride it on pavement as well as the bike trails?

It seems from the pictures (and the name) that it would a bike that would be perfect in a "dutch environment": on a flat environment and paths on a good state. There are several elements that will make it unsafe/uncomfortable on uneven/rough surfaces:

The general geometry is more tuned towards comfort than control.
There are elements that are not designed for rough terrains: frame (not only because it's a step-though, but also because of the sizing of the tubes), the adjustable stem.
The motor in the hub of the wheel is not optimum in rough terrains, and can make punctures repairs more difficult (they are less efficient at low speed, have lower torques as they cannot take advantage of the gearing);
The gearing that might not have enough range for steeper hills
The tires don't have the right profile;
V-brake don't perform well in wet conditions and in sustained brakings;
...


I have a Topeak "Road Morph" mini pump on my bike, and the pressure gauge on that is at best a distraction. The display is a bit of plastic sliding in a tube, so there's a lot of friction and that makes the pressure reading unreliable. It can stick anywhere, but usually it reads low, like yours does. That makes it useless for anything other than "is there air in my tyre", which I can answer more easily by squeezing the tyre.

So it's likely that the reason you're having problems is that your pump is a cheap version of mine, and it works even less well than mine

The effective pressure gauges that I've seen are all dial gauges, and there are not many mini pumps that have those. Normally they're found on floor pumps like this:


Why not place the cleats further back on the foot?

First off, i question why anyone thinks the calf muscle is not suited for endurance. Its a very active component of running, biking, jumping and so on.

The ball of your foot can take hours of running, biking and other activity with high pressure. The arch of your foot is soft, and where tendons stretch across. A cleat in your arch would cause massive pain over time.

Additionally, the clipped in pedal motion for ideal power is a triangle. Push down, scrape back. This backward pull would be difficult from the arch, and not very fluid feeling. Also likely causing other injuries.

I am not a doctor, medical professional or trained in physical therapies. Just an avid cyclist that pushes 4500 miles a year, 2 - 3 centuries on a road bike and several other mountain bike events annually.


Ultegra 6700 Left Side Crank with SRAM Red

Speaking under correction, because I don't know the exact model, but have owned Shimano & SRAM in the last few years.  The two systems aren't compatible to the point that you can just swap the left side crank.

But, you will be able to swap both sides.  In other words, once you've taken the left side off, the right side, with chainrings and all should just slide out.  You can then put the whole shebang onto the other bike.  As long as the chainrings are the same size (i.e. 53x39) you won't need to move the front deraileur to accommodate the change.


Brand New bike, chain slips into spokes on first gear

Normally this would be a simple "take it back to the bike shop" situation, as the bike has not been assembled correctly. But unfortunately you probably have a bicycle shaped object (BSO) that you bought in a box (or was assembled by the proverbial "moron in a hurry"). It's likely that even a BSO can be made to work after a fashion. However you may find that a bike shop will refuse to work on your BSO because they are of such low quality that the shop will be unable to offer warranty on its work.

The easiest problem is that the limit screw on the rear derailleur is not set correctly. This is slightly tricky to explain so if this doesn't help try Sheldon Brown's detailed explaination. Basically, there are two "limit adjustment screws" (one for each limit of the travel) and the one that sets the limit towards the wheel needs to be screwed in a little:

 and

Shift to the largest cog at the back, then without spinning the pedals move the gear shift (twist grip) all the way (to the point where the chain normally falls into the wheel). Now turn the screw until the derailleur pulley lines up with the largest cog on the freewheel. If the derailleur doesn't move when you turn the screw, you're either turning the wrong screw (put it back!) or you're turning it the wrong way (reverse!)

Note on the left hand diagram above there's a line from the pulley to the right hand side of the smallest cog. You're trying to get the mirror image of that line - from the derailler puller to the left-most cog and probably a little to the left of the cog if you want to be really fussy about it.

If you're unlucky this is not the problem at all, and instead you're mounted the derailleur wrong (but normally they're already mounted inside the box), or something has been bent or broken in transit. Maybe use Google image search to look at pictures to make sure it's not something obvious in how it's attached. If it's bent things get tricky, as there are tools to help re-align it and doing that by eye is unlikely to work well (and could break something).

First, try setting the limit screws.

If that works, you might find the adjust rear derailleur answer helps with the next step.


Which gears combinations shouldn't be used?

This is an old chestnut from the days of 5 speed freewheels and chainrings without shifting ramps. With modern hyperglide cogs and the relatively slinky thin modern chains, cross chaining is simply no longer an issue. While there are very few studies on this, the one I've seen suggests that there is no loss in mechanical efficiency for cross chaining at the angles typical of most bikes.

In general for a given gear ratio, big/big is more mechanically efficient than
small/small. So the only science out there suggests that cross chaining on the big
chainwheel is actually more efficient.

http://www.jhu.edu/news_info/news/home99/aug99/bike.html

Use the gears you like, check your chain wear and replace your chain often and the expensive bits of your drive train will last a long time.


One of the advantages of a coaster brake is young children typically have stronger legs than hands. They can apply more brake pressure with the legs than the hands. Many children however have difficulty squeezing the lever with enough force to stop the bike confidently. In my experience the lower the bike quality the more effort required to actuate the hand brake. Some of this can be alleviated by proper adjustment of the lever movement by use of the lever stop screw. This adjustment brings the lever closer to the grip so smaller hands can get a stronger pull on the lever. Many entry level brake levers lack this feature. The disadvantage to the coaster brake is it requires that the crank be rotated backwards to actuate the brake. Most people have a dominant leg similar to be left or right handed. In a panic situation the pedal may be out of braking position delaying braking. Another disadvantage of coater brakes is they are totally ineffective if the chain falls off or breaks. I would teach your son to ride using the hand brakes. Practice stopping drills on a level surface. Perhaps draw a chalk in the drive-way and see how close he can come to line without going over it. With my children as we rode along the local rail-trail I would occasionally tell them to "Stop Now" so they would gain confidence in stopping quickly.


There may be some confusion with terminology here. A power meter measures power, usually by measuring the strain in some drivetrain component (i.e. how much it flexes when pedaling). You need to physically attach strain gauges to the component. This is usually a crankarm or pedal spindle, but strain gauges have also been mounted to bottom bracket spindles or inside rear hubs. The Fenix 6 is a watch, and it's nowhere near the drivetrain, so it can't be a power meter. It can track heart rate by itself, and heart rate can also be used to pace a workout. (see footnote)
Power meters then broadcast the torque measurements to a head unit, usually a cycling computer we put on our handlebars (or, if you are a track cyclist where they are banned, you put them on the back of your seatpost). They usually broadcast over two protocols, ANT+ and Bluetooth (older meters may only use ANT+). In any case, the Fenix 6 appears to have ANT+ compatibility, as do a few other sport-specific smart watches. Generic smart watches like the Apple Watch do not have ANT+, so you can't use them as head units capable of displaying power (although most should be able to pair to a Bluetooth-capable heart rate strap). The ANT+ page for the Fenix 6 Solar, European model lists many power meters, including power pedals by Garmin and Favero, crank-based power meters from Quarq, Shimano, Rotor, and Easton, and, as an aside, One Giant Leap's Kayak Power Meter (to emphasize, this is for kayaks, as in the ones you use on water). Thus, you can use your Fenix 6 as a head unit if you don't want to buy a dedicated one. It should be able to pair to power meters in general.
Occasionally with technology, the devil is in the details. One Reddit post claimed that their Fenix failed to display the cycling dynamics (an advanced metric) from their Favero power meter pedals. There may be other relatively minor issues like this with other manufacturers. As a different example, Garmin's Varia rear facing radar warning system transmits over ANT+, and requires a specific software protocol. Wahoo very recently implemented the protocol, so now I can see the traffic warnings on my head unit, but Wahoo failed to let users see the battery's state of charge or the light's flashing mode. It could be that the Fenix lacks some implementation of one of the features on some power meters, but the core features (it will need both torque and cadence) would likely be present.
The OP asked if the watch could be used as a power meter if they connected it to unspecified Garmin bike sensors. The Fenix 6 is an impressive unit. However, as explained above, it can't read power by itself. Unless one of the other Garmin sensors was a power meter (e.g. the Garmin vector power meter pedals), the answer must be no. If you want to use your Fenix 6 as a cycling head unit, you would want to get a bike mount. If you are primarily a cyclist, I would normally recommend just getting a cycling-specific head unit, which will have a larger screen and cost less (perhaps a lot less) than the Fenix 6. However, the OP already has a Fenix 6 watch, and it would obviously be fine to reuse it as a head unit.
Footnote: other ways to measure power
It's possible to estimate power from air resistance, e.g. the Notio Konnect or the Power Pod. This requires a device with a pitot tube at the front of the bike. It's also possible to estimate power from chain tension. No active power meters do this, but Polar once made such a unit. In any case, the Fenix lacks any functionality that would get at either of these methods.


What can be done to make a trainer work quieter?

Baffling - place it on carpet or a rug (and several towels), this will both stop vibration through the floor and catch the drips of sweat.


What do you do when the bus bike rack is full?

There's a couple options you can take in this case.

Ask the bus driver really nicely if you can get on the bus with your bike. I've done this a few times, not because the rack was full, but because there was no rack where there should have been one.  If the bus is quite empty, you can often use the wheelchair accessible seats as a place to put your bike.  Don't be surprised if the driver doesn't let you.  There is no way you can do this during rush hour unless your route isn't used very much.
Go on the train/subway. Depending on the rules in your locality, it's often allowed to take your bike on the train.  Even if you have to go out of your way to get to the train, it can be better then waiting for the bus only to find out the racks are empty. Again, maybe not possible during rush hour.
Cycle to a location that's before where the majority of people board the bus. Take the following scenario.  Assuming you are downtown, and want to travel home, Travel in the reverse direction along your bus route to a location before the bus gets downtown, or to the first stop if the bus starts downtown. This will give you a better chance of getting to use the rack.
If you work at a place that lets you have flexible work hours, adjust your schedule so it isn't during rush hour.
Look for a different bus route.  You might have to cycle a bit further to get to the other route, and take a slower bus  (more stops, residential roads, non-direct route) .
Plan a completely different route, and avoid the bus altogether. For a short time I had a 25 km bike ride to work. I would take the bus in the morning as I could get on at the beginning of the route and almost always got a spot on the rack. However in the evening, after a week or so of waiting upwards of half an hour and sometimes giving up at getting a rack spot, I decided it would just be quicker to bike all the way home. Got in really good shape that summer.


Is it important to have a road bike shoes and pedals or it won't make a difference?

First, note that if you're new to clip/clipless systems, it takes a while to get used to it.

A lot of non-racers prefer mountain bike clipless pedals (e.g. Shimano SPD) since you can clip in on both sides of the pedal and the shoes often allow the cleats to be recessed (so you can walk around). Mountain marketed shoes generally tend to be more comfortable as well.
An example SPD pedal is:

Note that some SPD pedals also double as platform pedals, so you can use regular shoes.

Road pedals (e.g. Look/ Shimano SPD-SL) have larger support for the shoe but only allow you to clip in on one side of the pedal. An example of SPD-SL is:

However, at the end of the day, the pedal-shoe combination is completely up to you. You could use road platforms, toe clips, mountain bike clipless, road clipless, etc. - do what makes you most happy.

See this excellent question as well for comparison of pedal-shoe systems.


I have bike tires that read 26 x 1.95. Does that mean I need a 26-inch tube?

Did you inflate the tube off the rim or without a tyre?  they stretch when inflated naked.

Read the tube side it might be a 27.5 in the wrong box.


Effective 'equipment minimal' leg strength training for cycling?'

There's been a number of questions about how to improve once you've plateaued with your current training regime. None of them specifically deal with weight training but they are all about improving strength and endurance on the bike.

The commonly accepted answers (and usually championed by wdypdx22) is Interval Training.

  Interval Training.

  It's a type of workout where you alternate bursts of energy with
  periods of recovery. There are many variations of interval training.
  If you want cycling specific intervals, you could try "The Time
  Crunched Cyclist" by Chris Charmichael. The book is primarily about
  training for Centuries or racing, but if you follow the methods,
  you'll get into great condition. Interval training is an excellent
  cardo workout and a great alternative to jogging.

  One popular method of interval training is the "Tabata" method. This
  uses 20 seconds of ultra-intense exercise (at an intensity of about
  170% of VO2max or 90 - 95% of your max heart rate) followed by 10
  seconds of rest, repeated continuously for 4 minutes (8 cycles).
  Typically, this is done 3 or 4 days a week and not on consecutive
  days.


What is ideal for long distance road bike rides 23mm or 25mm tires?

A 25mm tyre can be run at a lower pressure with the same rolling resistance, thus giving you a slightly more comfortable ride, and slightly better grip in wet conditions or on a dirty surface.  If you take that reduction in pressure too far, you'll get more pinch flats, but you'll be very comfortable just before you stop to fix that flat. :-)

However, if you inflate to the appropriate pressure then you'll get a better ride, better grip, with minimal difference in rolling resistance - the downside being weight, and possibly an increase in frontal area causing a little more drag.    So why don't the pro teams use a 25mm if there are all those advantages?  There's some indication that they have been starting to over the last few years:

http://www.cyclingweekly.co.uk/news/latest-news/are-wider-tyres-really-faster-160403
http://www.competitivecyclist.com/learn/25-vs-23
http://velonews.competitor.com/2012/05/news/giro-tech-rise-of-the-25c-tire_218011
http://cyclingtips.com.au/2014/04/tyre-trends-what-the-teams-are-using-for-paris-roubaix/

So what is the right pressure? Here's how to work it out: a 25mm tyre is about 8.7% wider than a 23mm, so round that to 10% for easier calculations which means that you can run about 10% less air pressure in a 25mm as compared to a 23mm.  E.g. if you typically run a 23mm at 100PSI, then run your 25mm at 90PSI.

Note - I have never had a pinch flat in a road tyre in 15 years of riding road bikes, so if that is your concern, the you may be running your tyres at too low pressure for your weight (or your local roads are much rougher than mine).  The thing about the weight is not meant to be an insult - I'm just reminding you that your tyre pressure needs to be in proportion with the weight that's being supported: made up of your bike, you, and your luggage.

If you're riding on gravel/dirt often, consider a 28mm - but first check that it will fit in your frame (1 of my bikes can fit a 28mm on the front, but only a 25mm on the back - which is a bit annoying).


The raw pedal force or torque data are difficult to work with but you can extract some information from them. First, note that Stages mounts the strain gages (or gauges) permanently to the crank, so the crank length is constant and they know what it is; that means that there is a one-to-one relationship between the kgf and torque columns. In this case, it appears from the given kgf and Nm data that your left crank is 170mm long.

Stages say the data are sent at 64 Hz but note that the timestamps are not all equally-spaced; there are some gaps in the timestamps. In any event, to make things simple, here is a plot of the first 128 kgf samples from your data set (if the data density were truly 64 Hz, these first 128 samples would represent exactly 2 seconds of data):

The data are not stamped with the crank position or crank angle but all is not lost: we can calculate the elapsed time between the peaks of the data. For those same interpeak intervals we can calculate the mean force or mean torque. Dividing the mean torque (in Nm) over each revolution of the cranks by the elapsed time over each crank revolution (in seconds) gives us the average power over each revolution in watts, since a Nm/s is a watt. Note that this will differ from the data usually reported since that is power over a second of time rather than power over a crank revolution. However, note that this is exactly how most power meters currently on the market calculate power: they average torque over a complete crank revolution, then divide it by the elapsed time for a revolution. Most (but not all) power meters currently on the market use a reed switch to determine when the crank passes by a fixed point. Thus, they know the elapsed time between closings of the reed switch and the position of the crank only once per revolution. In addition, although most power meters transmit data to the receiving head unit either once per second or sometimes at a nominal 4 Hz, they generally report the average power over the last completed crank revolution before the scheduled data transmission.

How do we know that this is a valid approach? Below is a plot of torque and crank angle from Kautz's classic study of pedal force and crank torque. From this plot it is clear that the torque peaks only once per crank revolution. Note, by the way, that the Kautz data were collected from an instrumented pedal on only one crank, so the torque is measured only on one side, just as Stages collects only on one side. These data show that the assumption that the torque peaks observed in the data here also only occur once per crank revolution, even though we are plotting against time rather than crank angle. Importantly for this analysis, maximum torque is more easily identifiable than minimum torque. If you look at the first plot above, you can see that maximum torque is (in this sample) single-peaked but minimum torque can sometimes have a "blip" or other anomaly that makes identifying the peak-to-peak interval easier to find than identifying the trough-to-trough interval.

Below I have plotted your data file with the x-axis converted from "Timestamp" to seconds of elapsed time and with torque (in Nm) on the y-axis. For each crank revolution I have done as described above and calculated the mean power in watts between torque peaks, presumably equivalent to crank revolutions. The average power between peaks is shown in red. Note that over one of the intervals the average torque as measured by the left crank was negative -- I have not suppressed or cleaned up the data so that shows up as -20 watts for the period from roughly 14 to 22 seconds on the plot (presumably, your right leg was generating positive torque at that point but we cannot see it). A slightly larger version of the plot below can be seen here.

Note that other power meters (including the Garmin Vector, the Power2Max, and the new Pioneer, among others) use a combination of force-sensing strain gages and acclerometers just as the Stages does to determine force patterns and thus power. In fact, the Power Tap uses only strain gages and elsewhere I have shown that its "virtual cadence" estimated by variations in torque measured at the hub provide a reasonably good estimate of cadence as measured by a dedicated reed switch on the crank. Once again, this supports the approach taken here of using torque or force patterns as a way to determine time taken for a full crank revolution.

Since we calculated the elapsed time for each crank revolution, we can also calculate the cadence (in terms of revolutions per minute). I had calculated 28 values for the power over the 28 interpeak intervals in the plot above. The plot below shows the cadence and average torque for each revolution corresponding to those 28 values, with the cadence and average torque pairs sequentially identified by a number from 1 to 28, indicating which crank revolution is shown (thus, the first combination of cadence and torque is labeled "1", the second by "2" and so on; the point with negative average torque is off the bottom of the plot). The dotted red lines are isopower contours at 100, 150, 200, and 250 watts. As can be seen from the plot, for the first 16 or so peaks, cadence was higher and torque lower than for the final few pedal strokes. That is consistent with the first plot above of torque against time-stamp: you can see that the pedal strokes are farther apart and the torque peaks are higher.

Thus, you can see that even without nominal crank angle, it is possible to reconstruct reasonable estimates of power and cadence from these data, tedious though the effort may be. If your data sample were longer you might want to pass the torque data through a filter to strengthen the "signal" and suppress the "noise," then difference the filtered torque values and look for records where the difference passes zero from above; this will identify a torque peak (this method is essentially the same as examining the first derivative of a function to identify transition points and then examining the second derivative to determine whether the transition point was a maximum or a minimum). Then you can calculate the elapsed time and average torque between peaks as described above to derive power and cadence.

Is there a way to check that the cadence values derived in this way are correct? Not with only these data alone. However, almost all usual Stages data sets will include wheel speed. Wheel speed is typically measured by a reed switch (see this bicycles.stackexchange answer for a description of how speed is measured) and it is possible to use measured speed and estimated cadence to calculate the implied gear ratio. Except for the rare bicycles with continuously variable transmissions, gear ratios are discrete. That means that if you plot the putative gear ratio based on speed and cadence over time, they should fall into easily recognizable discrete rows rather than into a random scatterplot. As an example, below you can see calculated gear ratios based on speed and cadence from a ride. Unfortunately in this plot you cannot see the speed but the measured cadence is shown in the top panel, and you can verify that it is not constant but rather varies up and down. The bottom panel shows the calculated gear ratios and, as expected, they fall into discrete and easily identifiable rows. If the cadences estimated for the Stages high-frequency data were correct, the gear ratios derived from them would both fall into discrete rows and also would coincide with the gear ratios defined by the actual chain rings and cogs on the rider's bicycle. That would provide a check and validation of the method of estimating cadence from the peak-to-peak intervals.

In summary, these data are not easy to work with but, evidently surprisingly to many, it is still possible to glean some information from them. In combination with other information that will probably be available from the usual Stages data files (speed and power) you could verify that this approach produced the correct high-frequency torque values to be consistent with the 1-second data. Then you could use the torque values to examine application of power around the pedal stroke with some amount of confidence that the data were complete and consistent.


What you are thinking of goes by several names:

Front-loader
Long john
Bakfiets

There are a variety of manufacturers of these style bikes available in the USA. Some of the big names are imported from Europe such as Bakfiets, Babboe, Riese & Müller, Urban Arrow, but there is an American brand Yuba that manufacturs them too. There are many other smaller manufacturers as well.

If you expand to trikes with a basket in front, those come in even more names, and even more manufacturers.


GC leaders are generally not out in the wind by themselves or taking many pulls on the front. They often put time on the field on climbs and in individual events like TT (which use bikes focused on aerodynamics).   As such, in pack riding GC leader will likely favour a bike that focuses on climbing (light and stiff) and handling (note, aero road bikes are improving here), rather than raw aerodynamics.  GC leaders are also more likely to be conservative with gear selection because they are in it for the long run and can't afford any technical issues.

That said, aerodynamics still plays an important role within the pack while drafting. As aero road bikes continue to improve (e.g., less weight penalty) and continue to prove themselves in competition you may very well see GC leaders riding them soon.


Is WTB Tubeless Compatible System rim incompatible with clinchers?

All tubeless compatible (aka "tubeless ready" or just "tubeless") rims and tires can be used with tubes. It would be impractical even for bike industry standards to disallow people from putting in a tube when something goes wrong, or even buy a modern wheel/rim if they weren't interested in tubeless.

The main special thing about the TCS rims compared to many others is, as their ad copy points out, they have a certified UST standard bead seat. The idea there, not to give an opinion either way, is that in conjunction with a UST tire the bead interface meets a designed standard and can have greater security than the alternative of just using parts that are more arbitrarily designated as "tubeless compatible," in other words every non-UST MTB tire and rim on the market. You can still use whatever tires on TCS rims, tubeless or not.


Replacing disk brake pads with multi-tool only

Some models of Shimano calipers do use a pad retaining bolt so what you've pictured should be viable. I would make sure the bolt's diameter is small enough so it has a little play in when through the pad and caliper holes. The pads shouldn't move around at this point, but like with a pin, a thinner bolt will allow some play which maybe necessary for proper function. If they bind, it may prevent their return to the ready position, the spring may not open normally and rub the rotor, etc. Leave a little play like the system is designed with.
There are few designs of pins that may work well, even a safety/diaper pin of sufficient size.  This design of retaining pin is made to remove by hand, or you could use an Allen key from your multi-tool through the loop of the pin to generate more pulling power.  It will have to have sufficient length so that the secondary arches will fit over the raised area of the caliper that has the hole the pin goes thru.

Here's something designed to hold parts or fasteners in the event they've come loose.

Here's a link to this product and description.
I don't feel using the Shimano provided, common cotter pin is absolutely necessary and options exist that will work just as well.


Experience biking with child trailer during winter?

I strongly suggest you put a studded tyre on the bike (ideally 2, but certainly the back in your case).  I run Schwalbe winters for occasional icy patches (overkill round here, except when they aren't).  This will be important for stopping as well as going. Spinning the back wheel with a trailer is no fun.  The trailer tyres don't matter nearly so much.  They don't really need traction (though side-slipping isn't good). You can get marathon winter tyres in 20×1.6" which will fit both your bike and your trailer.

The trailer will get cold inside in sub-zero temperatures.  But it will do a good job of keeping the wind off, so your kids should be fine wrapped up warm.  Makes sure the to start with short journeys, as you won't be able to hear the kids easily (especially if you fit studded tyres) and you want to know before too long if they get cold. I know on a rear seat even above 0°C kids can get quite cold despite gloves and warm clothes, but that's only sheltered by my body.  Some form of hat or even a (thin) balaclava under their helmets would be a good idea.  Lining the seat with a blanket you can tuck round them might also be good if you've got room.

Visibility is important, including visual signs of the width of the trailer. Drivers need all the help they can get to see your trailer in dirty, dark conditions.  Little blinking LEDs as wide as possible on the trailer frame show up well.  I've got 2 of those plus a big steady rear light, as well as extra reflectors and lights on the wheels.  And that's just on the trailer.

Bikes and accessories get dirty in winter.  Mudguards won't help much on somethign so low to the ground, and every trailer is different when it comes to fitting accessories (as I found when fitting parking brakes to mine).  Folding makes accessories really tricky. Overall you'd almost certainly have to make mudguard brackets of some sort, and remove them for folding.  A rear mudguard on the bike would be a very good idea though, and one with a low, soft mudflap on the bottom.


Daniel is right - it sounds like the mechanism in the back that allows coasting, has failed.    This means the chain is driving the cogs forward, but there's no connection between the cogs and the hub of the rear wheel.

There are no good fixes short of replacing the rear freewheel or freehub, depending on what the bike has now.   A deep clean and relube can help, but it may not, and even if things improve they soon deteriorate again.

To test this, take the back wheel out of the bike, and rotate the cogs by hand.  Yours will probably turn both ways, when they should only turn anti-clockwise.  When you try to spin the cogs clockwise, they should not move at all.

The replacement you need will depend on what you have.  Either show us a photo of the cogs when the wheel is out of the bike, or just take it to a LBS and ask for a new freewheel.  Its not a big job to fit to your wheel, but does take one or two special tools.

This is fixable.


Could a road bike be used for cyclocross?

Depends on your road bike, but for the most part no.

Reasons against

Many road bikes are limited to tire width of 25 or 28mm.  Because cycle cross is off-road you need to find tires with knobbies. This really isn't possible for such small tire sizes as most knobby tires available start at around 32mm or large. Even if you could find knobby tires this small, The tight tolerance between the tire and the brake caliper will mean any mud would clog and slow the wheel from moving.  Finally, most rode bikes have a much lower bottom bracket and twitcher handling. The lower bottom bracket will mean a lot a pedal strikes especially on off camber sections and the faster steering will make this type of road bikes harder to hold a line in rough sections. Cyclocross bikes also tend to have lower gearing, a much slacker front geometry and longer wheel base so that the bike hold the line better. The higher BB not only reduces pedal strikes but also makes it easier to initiate change in directions by shifting weight, despite the slower steering.

Reasons for

Some road bikes slacker geometries and more tire clearance (e.g.,older, endurance and adventure road). I had one steel bike that could clear 35 mm tires, this one could have been used on dry courses. The bottom bracket will still be too low and the handling likely a little too twitchy, but these would be much more suitable than what most manufacturers  currently sell as race road bikes at the moment.

Note that many cyclocross series do not follow UCI regulations and are happy to let you race whatever bike you bring.


As we've discussed earlier, its fine to have a disc brake hub to work with a rim brake rim, but most disc wheels aren't built with rims that can use rim brakes (you need a rim brake track to use rim brakes safely; I don't know of any higher end wheels which are shipped this way, so if you buy a complete bike later, you may end up with better wheels on the complete bike).

One thing you may run into later is that your hub uses a different disc brake standard than the rotors you want to run (but this is an easy enough problem to deal with). Another thing you might run into is different types of hub compatibility needed (e.g. if your next bike has a thru axle or something; unlikely on a commuter though, I suppose, or width as Jamie A points out in the comments).


How to mark pins that were once extracted on a chain?

You're overthinking this

There are 100-114 links in a chain.  Even blind shooting you have a 3.5% chance of getting the same pin twice out of 5 selections on 114 links.  Even if you did get one twice, it should be perfectly happy to be pressed out again.

Otherwise use a $2 quick link, which are good for several dozen join/parts.  If you use the proper curved pliers, it will be dead-easy to undo.

When I'm out on the road I don't carry the right tool for quicklinks, so I end up using either a length of brake cable inner that is in my toolkit, or some generic leatherman needlenose pliers, which takes a bit of effort.


Redmond bikers: Can you ride all year long?

...just speaking up for the Local Bike Shop - if you are moving to Redmond permanently then it may make sense to have a bike with a warranty and the support of the LBS for when/if it goes wrong.

Also consider the mudguards situation - I know they are unfashionable but they are handy for the commute. Since Specialized bikes are designed for sunny California where nobody could ever imagine needing mudguards, you may want to also post a question on what people recommend.

You will only be cold if you get clothing that is not up to the job. You know the drill - baselayers, as many layers as you need on top and a breathable jacket. Overshoes and neoprene gloves optional...


Is it possible to add another chainring to Cannondale Trail SL 3?

There seems to be a place to mount a front derailleur on the seat tube of the bicycle. It also seems to have unused ports in the down tube for routing of another cable.

Picture source: https://www.cannondale.com/en/bikes/mountain/trail-bikes/trail/29-m-trail-sl-3
It is possible that the same frame design is used in different bicycle configurations which come with 2 front chainrings.
Given that your bicycle currently has a drivetrain with quite large rear 12-speed cassette range (from 11 to 51 teeth), there is a better solution.
Replace the front chainring with one that has bigger number of teeth. Currently the bike comes with 30 teeth at the front, so you should go with 32 or 34 teeth. There seems to be enough clearance between the ring and the chainstay to fit a slightly larger chainring.
Replacing just the chainring is definitely easier and cheaper than adding a front derailleur, front shifter, routing all the cables, another chainring and possibly swapping the crankset as the current one may be single-ring-specific.


How do I know if there is water in my fork

The XCRs are very simple forks and unless specified don't have an oil or air damper so very user friendly.

It is possible that water has got below the dust wipers but this is generally unlikely.

The mechanism for a XCR is a sealed lock out unit and a coil. You should simply be able to drop the lowers off the fork without disrupting anything else to check them out for water and to ensure there's plenty of grease to protect the spring and other internals.

The 'whum' could be the stanchions being a bit sticky moving through the wipers but not much else I can think off.


Can I change a 26" to a 24" tire on a Huntington Schinn Women's tire?

Your 26" tires sit on wheel rims, whose diameter is probably 559 mm. 24" tires will not fit onto these rims; to use 24" "junior" tires you actually need smaller wheels, of a 507 mm diameter. These smaller wheels require a different frame.

Smaller rims require a different frame mainly because hardware related to the wheel which is mounted to the larger frame is at the wrong location for the smaller wheel diameter: this hardware includes mounting bosses for rim brakes and fenders. Also, on smaller wheels, the existing pedals will have less ground clearance; you might strike the ground when pedaling through turns.

(That's okay, because since for your height, you will probably benefit from shorter cranks anyway: see this crank length versus body height table on the Sugino website, according to which, a 152 cm person should consider pedal crank arms of 155-160mm.)

Luckily, your Schwinn Huntington Cruiser itself comes in a girls' size with 24" wheels. If the Schwinn Huntington Cruiser is your dream bike, all you have to do is exchange the adult 26" one for the youth 24" and you're set.

Though I strongly suspect you would be comfortable on the 24" version of the bike, is that really necessary? Smaller wheels will not help with balancing; that is, not with balancing the bicycle while in motion. I suspect that what you mean by balancing is that, while seated, you have trouble reaching the ground. However, this is okay; shorter people should not expect to be able to reach the ground from a bicycle seat.  For that matter, taller riders on a large bike should not either. If your feet can easily reach the ground while you're seated, it means your knee is too bent at the bottom of the pedal stroke, which means your seat is too low.

The proper bicycle technique is to get up out of the seat when you come to a stop and stand over the top tube, not over the seat. Then when you get moving again, get the bike in motion while briefly standing on the pedals, straddling the top tube. As soon as it is moving, get into the saddle. Your cruiser bike makes it easy to straddle the top tube because that top tube curves radically downward. This video demonstrates the techniques. Practice this starting and stopping technique until it is second nature, and you're not bothered by difficulty reaching the ground out of the seat.

A useful technique not shown in the video is to come to a stop to a raised object, such as a curb, where you can plant one foot without getting out of the saddle. When you start moving again, you give a good push with that foot, and push down on the opposite pedal with the other foot.

Even if you had the 24" version of the bike, you'd still want to adjust your seat so that you can barely touch the ground with extended toes out of the saddle, if at all.  I am 6'1" tall and actually used a 24" bike for quite some time! I used it for daily commuting, and even did a 200 km road trip with an overnight stay. Of course, I had to get an extra long seat tube for it. And, guess what, I could barely reach the ground with my toes from the saddle! That's what it takes for a proper fit. If the seat had been any lower, pedaling would have become inefficient. The leg has to be almost fully extended at the bottom of the pedal stroke. And since the bottom of the pedal stroke is still quite a ways from the ground due to the necessary ground clearance, that means the ground is hard to reach out of the saddle, regardless of how tall you are or what size bike you're trying to fit.


Do kits that allow me to add lockout to my shock exist?

Lockouts are performed internally within the shock, often by closing out part of the dampener circuit. This would make it nearly impossible to create a general upgrade kit as shocks can have very different internals (even from the same brand).

The only possibility would be a lower end shock that shares its shock body with a higher end version that has a lockout feature. In this case you might be able to purchase the internals of the higher end version. Even then you may be missing components such as the lock out lever, plus the lower end version may be missing ports for the lockout lever.

Purchasing new rear shocks is another possibility, but it can be quite expensive and there are a lot of measurements to get correct (e.g., eyelet to eyelet length).

In short I don’t see any easy upgrade path.


What's this part of the bike, and is it safe to alter it?

What he hammered down is the star nut.  It's a gription (yes I made that word up) device that serves as an anchor point in the steer tube to allow the top cap to properly compress the headset during a headset adjustment.  Old or damaged star nuts are often driven all the way through the steer tube to remove them (that's why your steer tube is open at the bottom).  They are generally only hammered in a short ways because being longer serves no purpose.  In this case, so long as that GPS unit is as stiff as a steel bolt and allows for proper compression during an adjustment, it should be fine.


It is possible but quite uncommon. The trainer holds the bike upright while you throw your weight around, and the frame is not really designed for that. Bike fames are very strong with regard to vertical forces but nowhere near as strong for sideways forces. Twisting the bike between the rear axle and the handlebars is kind of ok (because it's designed to take a twist between the handlebars and bottom bracket) but it's something to minimise. You're more likely to see a fatigue failure than a simple overload.

If you are moving your upper body as you pedal you should try to learn not to do that. Wind trainers are all about sitting still and pedalling, not about practicing sprints. You should avoid getting out of the saddle, and try to minimise upper body movement. Or you may need to go with rollers rather than a trainer.

You definitely shouldn't bolt the trainer down - having it free to move almost guarantees you won't break your frame. The break I've seen was from one bolted to a concrete floor and the rider was out of the saddle when it broke.

As Billy said, your rear skewer will suffer cosmetic damage. Trainers often come with a cheap steel skewer for this reason.


Replace chain at 0.5% wear, or 0.75% wear?

Its up to personal preference at the end of the day, but a general recommendation is to replace at (or before) the 0.5% point for 11 speed and 0.75% for 10 speed or lower. You can also see if theres something in the chain manual or chain wear gauge's manual.

The multiple indicators are there because some people will want to change at 0.5%, others at 0.75% and so on. For a more expensive drivetrain, it makes sense to change earlier given the insane costs associated with all the other parts (whereas with a cheap drivetrain, you can run longer).


Citizen folding bike 3 speed - pedal slipping

Does the chain make a ratcheting sound when you "slip" or is the sound coming from the hub?

My best guess if it isn't the chain is that either the ratcheting pawls in the hub are worn or some of the planetary gears in the internally geared hub are worn or maladjusted.

The first thing you should do is check chain tension. If that's good, then I'd take it to your bike shop. They can quickly:

Diagnose if the shifter is shifting properly and make sure you're not between gears when it's slipping.
Make sure the rear freewheel is working properly.
Check the internal geared hub.

The first problem is super cheap - a simple adjustment. The second and third are more expensive, especially if the hub needs an overhaul or replacement.


Can I use a SRAM Force BB30 Crankset?

Unfortunately, you will not be able to use the BB30 on your bicycle. You will need to search for a Sram Force GXP Crankset. You will also need to verify if your particular Bianchi is Italian threaded or not as not all Bianchi are.


Is there a collective name for the non-groupset parts?

I don't think there is an 'easy' way so it will require a bit of leg work and study to get a good reference. It is unlikely that any manufacturer will offer any of these parts at a higher spec level than that of the groupset. So I would:

Choose a few bikes at different spec levels (based on groupset, Acera, Alivio, Deore, SLX, XT and XTR (or equivalent SRAM models)).
Jump on to BikePedia and note down what parts each bike has.
Use Wiggle or Chain Reaction or similar to price the parts.

This will give you some reference as to the price of all the other parts on any bike you are looking at by the groupset.

It's also worth noting that:

under SLX level most bikes will have generic parts so take an estimate at quality based on materials.
bike companies are buying thousands of these items so with economies of scale will actually be paying very little.
unless you are buying factory wheels separately you will have to pay for building.
bikes cost more to build than buy complete but you get to choose what you want.


You don't need a Dahon specific wheel to upgrade from 6 speeds to 8. Bicycle wheels (like practically all bicycle components) are very standardized.

What you need is any wheel with:

The correct rim diameter
Acceptable rim width for the tires you want to use
Correct hub width/dropout spacing
8/9/10 speed freehub (slightly wider than those used for 7 speeds and below)

A difficulty I can foresee is that Dahon 6 speed bikes might use an older style 120 or 126mm wide hub rather than the now standard 130 or 135mm. An 8/9/10 speed hub that takes a cassette  will not be available in that width. Dropout spacing is very easy to measure with a ruler so you should check what you bike has.


My rear MTB tire keeps rubbing on this thing that holds the front derailleur whenever the rear shocks are compressed to a certain amount

I am far from convinced the bike is stock, I would be surprised if any bike manufacturer or seller would ship a bike in this condition, even a cheap BSO. The rear tire is definitely not new, so its probably not a new bike.  What little I can see of the shock it looks out of place (Aircan shock on a cheap looking frame).  I therefore suspect the shock has incorrect stroke - e.g. 210 shock comes in both 50 and 55mm stroke.  A 55mm stoke where a 50mm is require would do exactly this, have the wheel foul on frame components when at full compression. The difference between 50 and 55mm stoke is often an internal spacer so it can hard to tell if the shock is correct just by looking at it.
Ideally find the bike make/model/year, look up the specifications and compare to the shock you have on the bike. If the shock has no measurements, let the air out and measure its length uncompressed and fully compressed to determine its stroke.
If you cannot confirm the requirements for the frame from make/model etc, and the shock is length is a common size with the longer of two common strokes, a shorter stoke will stop the tire rubbing when you bottom out.
If the shock is the correct size, then look at the wheel - its possible the frame is designed for 26" wheels and has had 27.5" fitted (maybe from new). This increases the diameter and would cause the interference you are seeing. You could install a 26" on the rear (Presuming disc brakes) which will most likely solve the problem.
Hacking the frame should be a last resort - however will almost certainly be cheaper than a new shock or new wheel(s).


Can I use a Sora rear derailleur with my 7 speed shifter?

Yes, despite being from a 9 speed road groupset it will theoretically work. If fact any Shimano road or MTB shifter for 9 speeds or below would theoretically work. The reason is that for 9 speed and below derailleurs, Shimano used the same cable actuation ratio - the ratio of cable length pulled to cage movement.


Will the same lock ring fit 11T or 12T ring, SRAM cassette?

Yes, you need an 11T specific lock ring.

The outer diameter of the 11T lockring is definitely smaller, a 12T lockring won't let the chain sit properly on an 11T cog. The threaded section is the same size.


If a slime tube hardens when exposed to air, why doesn't it harden when I pump it?

For the same reason a salt-water solution in a closed half-filled bottle will not evaporate - even though it is in contact with some air.

Open the lid - and eventually the water evaporates to leave just salt.

The slime solution is in a "balance" with the air in the tube - since it is a "closed" system. When the tube is punctured the slime flowing out of the puncture is no longer in a "closed" system and evaporates / dries in the open air.

Takes me back to Chemistry and reaction kinetics (yuck) .. but anyway that's my take on it.


practical pro and contra for Nuvinci CVT especially for hilly terrain

The NuVinci system is fantastic in principle and one day all bikes might come with it, but we aren't there yet. As the system stands there are a few matters that might not make it the answer to your prayers of an easier time going up hills:

For hilly terrain you need gears - it goes without saying. The steeper the hills the bigger range of gears - going up you may need a 'granny gear' and going down the hill you need a big gear (unless you don't like speed and coast).
This is the potential problem area with your intended application. The NuVinci hub has a range of 350% - exactly what that relates to depends on your spocket/chainring choice. Meanwhile, with a Rohlhoff or basic derailleur setup you are going to get a range of around 530%. Touring bikes and XC-MTB's usually come with an even greater range, however, do you use the 'granny ring'?
Note that early adopters of the NuVinci hub seem to be primarily in Denmark and the Netherlands, where the terrain is flatter than the North Sea.
There is also the small matter of efficiency. With a derailleur gear setup you can get an amazing 98% efficiency when on the middle ring and middle sprocket, marginally less for other 'sensible' gear combinations, even if you have not 'lubed' in a while. (The problem with studies on this is that they also include 'silly' gear combinations such as small sprocket and small chainring where the hideous chainline makes for an inefficient system, giving a wider efficiency range than is realistic). No hub gear system can improve on derailleur efficiency levels and the NuVinci FAQ side-steps giving any useful figures, preferring to make comparisons with existing hub gear systems, for which 92% is roughly ball-park. Personally I could contend with that on rides through town where gears are for getting up to speed but not for sustained hill climbing where 5% loss would mean 5% slower.
Weight is another area where the derailleur rules supreme. At the moment the NuVinci hub is relatively heavy - I think the latest systems are 1.5Kg heavier than an average derailleur setup. In my opinion weight really does matter on hills in a way that it does not if riding on the flat. I frequently pick up 2 litres of milk at the bottom of the hill where I live and it does make an appreciable, albeit not show-stopping difference to how I attack the hill.
Variable range gears. Personally I have no problem shifting gears on a 9 speed sprocket, thanks to the wonders of 'Hyperglide'. I also find that there are enough of them and I have no need for gears in between the gears that I have. For me an infinite amount of gears sounds good, but in practice I think the 'need' is over-hyped. I don't find myself changing up/down to find myself spinning furiously or plunging away completely out of sensible cadence. However, I can see how the NuVinci would help those that don't change gears that cleanly, i.e. not anticipating the need for the middle ring at the base of a hill.
Maintenance. Not a lot is needed for the NuVinci system because it is a hub gear. If you are running bullet proof tyres you won't even need to get the wheel out for punctures. However, if you did have a problem and needed to take it to the shop then they would be stumped.

To conclude, you will have extra weight, lower efficiency and a reduced range of gears. Despite the benefits of CVT with smoother shifting, reduced maintenance and not having to match your cadence to available gears, you are not going to get round the fundamentals of weight/efficiency/range.

My recommendation is that you try an electric assist bike such as one of the models made by Giant. Although they weigh a lot they are amazingly nimble and you can pedal as much as you want to on one.


Secure front fork when mounting on roof rack

I take it you are talking about the process of loading the bike, not when the bike is up there and the car is in movement (since most bike racks have a kind of trough that keeps the front wheel aligned).

What I have done on occasion is to loosen the handlebar and turn it backwards about 75 degrees relative to the fork. The handlebar is then more or less aligned with the front wheel. Re-tighten the handlebar in this position. Then a bungee or other elastic material can be used to fix the handlebar to the horizontal frame bar.

This does mean using an Allen key in most cases, but I figure it is worth getting the key out.


How can I get a snapped gear cable out of my Shimano brifter?

Use the small lever as if you were moving to the small chain ring or smallest rear cog. This unwinds the cable as far as possible, though it might not have a huge effect depending on how frayed the stub is.

Then, traditional advice is to start poking around with tweezers, needle-nose pliers and anything else that's small enough to get into the little hole the cable feeds into.  If you can grab the frayed end with pliers and pull firmly (not hard) on it while you use the small lever, that might help it unwind more.  You're trying to get it into a position where you can see the cable's end block, so you can push it out.

However, don't try that for more than a minute or two. Replace the rubber cover on the hood and then peel it off from the front, like this (sorry, didn't think to take photos until I'd already replaced the cable):

On the underside of the hood, close to where it meets the bar, there is a screw ('scuse my big ol' thumb):

Undo that screw and you can remove a cover from over the shifter mechanism (this is why you need to peel the rubber cover off in the opposite way to usual). That will give you full access to the shifter mechanism and you can usually remove the cable stub in seconds.

Thanks to YouTube user cycling stuff for this technique.

Comments under the video say that it won't work for Ultegra 6600, but that's nearly 15 years old, now.


In the world of professional cycling, the 'Monument' races are five of the oldest and widely considered most prestigious one-day races held each year. They are:

Milan – San Remo (Italy)
Tour of Flanders (Belgium)
Paris–Roubaix (France)
Liège–Bastogne–Liège (Belgium)
Giro di Lombardia (Italy)

More information can be found on each race, and the "Classics" in general in the Wikipedia article Classic Cycle Races.

A key factor in the argument that Eddy Merckx is the greatest competitive cyclist ever is that he won 19 Monuments - the next rider on the list won 11.


Should I use a road bike or track bike on my rollers or trainer?

The bike to use will depend on the reason for using the trainer. If your use of the trainer is for off season track training use the track bike, road racing  use the triple,etc. If you just want some saddle time, the triple will simulate all of them to an extent, you can select the gearing of the track bike,the fixie or the single and leave it there.


Installing flat pedals (with pins) on a MTB for rainy/wintry conditions?

I agree that a decent-quality plastic platform pedal like yours shouldn't crack in Boston conditions (which are not as bad as Wisconsin or Alaska!). However, if you haven't used metal-pin platform pedals before, be careful of your shins -- the pins will do a number on any flesh they dig into if your foot slips off the pedal or you put your foot down on the ground.
I've switched to platform pedals with molded plastic "pins" to avoid the shin damage, but I don't ride in frozen areas.


Maxxis DH or Freeride tubes.  They're not light but I've only ever once punctured the DH model - a 6inch nail through both side walls, so I won't hold it against them!


Is it possible to get distance travelled without gps

Yes, it is possible, and bike computers have had sensors like yours before GPS existed. Either your sensor is broken, in which case you can have it replaced, or you have installed it wrong.


Novatec Hub D041SB and Novatec Hub D042SB What's the difference?

I'm a little worried I might be missing something, but 41 is a front and 42 is a rear.


Try it out! For long distances it helps me personally to remind myself that anybody can cycle 100 km when I only have 100 km or so left. It may hurt, but really, any cyclist could do that. This turns your ride into 240 km, which is only 40 km more than what you seem to be comfortable with. And of course anybody can do 40 km ;-)

It all happens in your head, especially when you leave your comfort zone...

Planning/scheduling also helps me a lot when covering long distances more-or-less non-stop. Make a conservative schedule, e.g. based on 21 km/h (or whatever is "quite slow" for you) and taking planned longer rests (one or two?) into account. Based on that figure out your scheduled time for each 20 km and write it somewhere accessible while riding. If you planned conservatively, you will be able to stay ahead of your schedule. Then you can stay calm, and just ride with the feeling that you will manage. Use some of the "buffer" for smaller breaks.


Is it OK to have a single front chainring paired with 7 speed at the back?

Without taking into account whether it's a good idea or not; yes it's possible, with a few caveats.

You have two issues:

Chain line i.e., alignment between the front rings and rear cassette.

The single ring needs to be aligned with the center of the cassette so you minimize the lateral deflection on the chain and avoid excessive wear on the chain and sprockets.

With a 7 speed rear its likely that you have a triple set of rings. If so just us the middle position for the single front ring as it's aligned with the middle of the cassette. If you have a double, things are trickier but you may be able mount the ring on the inboard side of the spider.

Dropping the chain

The front derailleur helps to keep the chain on the front rings. Outer rings help keep the chain on inner rings. With an unaided single front ring there is a greater chance of dropping the chain from it.

1x11 setups feature a narrow-wide chainring that have alternating narrow and wide teeth that fit between the inner and outer chain connecting plates to more firmly hold on to the chain. If you are looking to do this conversion as cheaply as possible you probably don't want to get a new chainring. Leave the front derailleur in place to act as a chainguide.

You don't say whether you are saving for a whole 1x11 bike, or or planning to replace the drivetrain on you current bike. In either case this article may be of use to you. If the latter, bear in mind you will need to check compatibility between your freehub body and an 11 speed cassette.


On what surfaces can I safely use my hybrid bike?

28mm wide tires are perfectly suitable for riding hard-packed fine gravel trail surfaces. You do have to be more careful when braking and cornering than on tarmac as the top surface is loose. Larger rocks and potholes should be avoided of course.

As the size of the gravel particles gets larger or the depth of the loose gravel top surface gets deeper the less suitable 28mm tires will become.

I personally will ride 28mm tires on deeper, coarser gravel for short sections, but I would not want to do it for 50 miles. As well as increased likelihood of punctures ad discomfort, narrow tires take more power to push through deeper gravel as then tend to sink in rather than floating over the top.

Note that on flat hard-pack fine gravel you can decrease your tire pressure for better grip and comfort, but on deeper coarse gravel higher pressures are needed to avoid  pinch-flats.

Update

  [The surface] is fairly level and smooth but covered in a mixture of compacted soil, gravel and stone chippings and grass in some areas.

You'll be better off with your original 35mm tires. With the larger tires you will not have to worry about what you will encounter, and you will be able to run lower pressure for better comfort.


How about the rolling resistance from terrymorse.com. Its the top link from a google search on "bicycle tyre rolling resistance".


Once possibility is a rusty cable/housing.  When the cable or cable housing gets rusty it can be the case that the spring of the derailleur can't provide enough force to overcome the friction of the cable moving through the housing.  You can test this by disconnecting the cable from the derailleur and seeing if it is difficult it is to pull the cable manually (after you've switched the gear down).  If this is the problem, the solution for this is to replace the gear cable.


Is UK National Cycle Network Route 20 fully open?

While the sustrans website can get a little behind, they're normally pretty prompt to announce route openings.  And they say it isn't yet.  But you should be able to plan a route to link the sections that are open -- after all, much of it is planned to be on road anyway.

Even with a signposted route it's unwise to rely on the signs, especially in urban areas. The signs are small and easily missed if you're concentrating on the traffic. I've been caught out by this on NCR4. So I suggest spending some time with maps first (cyclestreets, Google, or paper). Cyclestreets shows gaps in the route, and doesn't use all of what does exist; this is based on openstreetmap data which I would expect to be reasonably up to date on a major bike route.


Unidentifiable metal bracket part I received with my tandem bicycle which didn't come with instructions.

It's a rear derailleur guard.

Their effectiveness is often discussed on here.


New to Drop bar Road Bike, severe upper back/neck pains

You should try a professional bike fit.

Just because you are 179 cm doesn't mean a 56 is right for you (the sizing of a bike with a given number varies on the type of bike and manufacturer and model). Normally, when you switch to drop bars, you will be sore (but pain is different, and should be alarming, though going for a 40 minute ride while just starting out may be a bit much). The geometry of the bike can also cause problems - racers may cause more pain than touring bikes due to their more aggressive geometry, for example.

Here are some tips from sheldon brown on pain, and what to do about it.


How's this for ultimate lounging - you could add a projector that projects onto the sail, not only could you read ebooks while you cycle, but also watch the occasional movie! very nice ergonomics, no need to strain your neck.


converting a nine speed hybrid disc to a seven speed drop bar, is it possible?

The Coda's freehub body can take a 7-speed cassette with the addition of a 4.5mm conversion spacer to take up the extra room, which is a common bike shop item.

There are two stumbling blocks though.

First, if the Coda's current left shifter and front derailer come from a Shimano mountain group, which they probably do, then they won't work correctly with STI because the actuation ratio is different between mountain and road. It can be made to work badly but will never be right. So if this is what you have (as opposed to a flat bar road shifter and a road derailer), you'll need a road derailer, and then there's the question of getting one that either plays nice with the existing crank or getting a crank to match it. If you don't want to have to mess with changing cranks, you may look at the IRD Alpina FD, because it's just about the only one out there that has a cage profiled for mountain/hybrid/trekking/etc triples and takes road cable pull.

Second, you probably have normal v-brake-lever-compatible brake calipers, whereas your STIs have road/sidepull/canti cable pull. They don't work together, at all. So you need either road calipers or a cable pull conversion device such as Travel Agents.


There are no thru axle FH-6800 or WH-6800 versions. The next/new Ultegra will have some, but as of now I don't think think any thru axle hubs or wheels that say Ultegra on them are really out in the wild at all.

This bikes uses the SCS dropout/hub/axle system. Long story short, in the past couple years it was unclear what road thru axle standard was going to become dominant and manufacturers had to make decisions with incomplete information to ship bikes on time. 12mm road thru axles with spacing of 142mm in back and 100mm in front have more or less won out, for now. SCS was a competing standard whose history you can find read more about here and here (this page also offers the rundown of wheel compatibility options, which is complicated but basically you can either use one of the few SCS wheelsets/hubs out there or use adapter dropouts, which can have issues with cassette clearance, and which may have already been done on this bike if it's got some kind of Shimano wheelset).

If it is a Shimano wheelset or hub, the situation is the same as with any other Shimano hub. They can be overhauled, ideally on a preventative schedule, and if done faithfully they can last a long, long time. If it's not done, or done too late, they can pick up damage to the non-replaceable or expensive to replace parts, making perfect adjustment impossible and starting the internal condition of the hubs on a downward spiral because of it. When you overhaul Shimano hubs, you have the option of whether to replace the individual ball bearings with new ones. Many of us do it by default but some find that just re-using them, especially on the high-end ones and only in a situation where no damage to anything is apparent, is fine. To replace the ones on the DA, Ultegra, etc hubs that use a plastic retainer, usually the convenient thing is to gently pop new ones into the retainer and re-use it, after cleaning it thoroughly.

A random seller recommending to replace the bearings on a Shimano hub could also be a veiled way of saying that the bearings feel gritty/notchy, in which case the hub internals are likely already damaged.

If they're trying to say the bike is having actual freehub issues (the freehub body itself is acting funny, i.e. getting stuck or not freewheeling at all), the options are usually either replace it, which is expensive for the higher end Shimano hubs, give it some flush/lube type attention, or go to the extreme of actually dismantling, inspecting, and overhauling the freehub body, which is an arcane thing that almost nobody does and requires some special tools.


Bottom Bracket on a Trek CrossRip Elite 2015?

There are two measurements you need: shell width and axle length.

Shell width is very easily determined - you can just measure it. The standard for road bikes with threaded bottom bracket shells is 68mm but some gravel bikes use 73 so it's worth checking.

The axle length can also be measured but you need to at least pull the cranks off to do so.

Different model cranks require different axle lengths to get the correct chainline. Shimano publishes detailed specifications going back to 2005 that will tell you what BB you need for any of their square taper cranks, but as you have an FSA crank that does not help. FSA does publish some documentation if you dig for it a bit. The manual for the current version of the Vero crank is here. It gives a FSA BB part number, the notes say '110.5 for Chainline 44' - i.e. 110.5mm axle for 44mm chainline - which is correct for a road double drivetrain.

Looks like you are correct and a 68x110 BB will be fine.


mtb deraileur for 1998 s-works (8 speed)

If the derailleur is correctly adjusted at one spot in the gear range, but not throughout the full range of movement, this can indicate the gear hanger is no longer aligned properly.

If the hanger is bent towards the wheel, each step in the derailleur's movement will be too wide and its path will be shallower (it may hold the upper jockey wheel closer to the large sprockets than it should, or if the B-screw has been adjusted to keep it away from the large sprockets, the jockey wheel would be further away from the small spockets than it should.
If the hanger is bent away from the wheel (only really happens when someone "overcorrects" a bend towards the wheel, or an impact occurs when the rear wheel is not present), the derailleur won't move far enough for each step and the path will be steeper (closer to small sprockets but far from large sprockets).

If you get correct shifting at the low and high gears but not in the middle, your derailleur is probably configured correctly and your gear hanger undamaged, but your cassette is probably worn out in the gears you use most often. You will experience more problems with new chains on old sprockets.

A common rule of thumb suggests the service life of a cassette is about 3 chains, assuming you don't delay replacing worn chains and make reasonably even use of each sprocket.

Chain wear gauges are readily available, costing about the same as a cheap chain. They often look like a capital I (or very wide H, depending on your point of view). Usually, one side is calibrated for +0.5%, the other +0.75%. On each side, one "finger" will be hooked, the other straight. On a tensioned chain, place the hooked end into one of the chain gaps. If the straight finger drops into another gap easily, the chain has worn such that each pin is that percentage further from its neighbours than spec.

+0.75%: Replace the chain immediately
+0.5%: Replace soon.

The teeth of the sprockets, chainrings and jockeywheels are worn more quickly when the distance between chain pins is over spec, so for a cassette's "3-chain" life, it's better to change the first chain early, whereas the third chain can be run slightly longer since the rest of the drivetrain is approaching end-of-life.


Which is the strongest lacing pattern for 32 and 36 spokes

3x is the standard lacing pattern, because it is strongest. Radially spoked wheel will be slightly lighter and stiffer but can not handle torque at all.

There are two reasons why 3x is strongest for 32 and 36h: First, the spokes are connected to the hub tangentially, so braking and pedaling forces go directly to spoke tension without any sideways forces. Second, for every spoke there is a spoke pulling against it in the next hole, so they are less likely to tear apart the hub flange.


Let’s quickly review how your bike shifts. Your front derailleur rests in the small ring position. When you move your left shifter to the big ring position, you pull cable, and that pulls your FD to the outside position. The same principle applies to the rear derailleur, which rests on the smallest cog, and gets pulled to the big cog. There's a ratchet inside each shifter that controls the amount of cable it pulls per shift.

The thing with cables is that they stretch over time. So, there may be a bit of slack in the cable, and your shifter isn't pulling as much cable as it should. This means your front derailleur doesn't move as far outward as it should. This happens with new bikes - I distinctly remember this happening on my first bike, and I was having trouble shifting both front and rear. The same issue will probably happen to your rear derailleur.

If this is a new bike, chances are the bike store asked you to come in after a few weeks for a free tune up - they’d adjust your cables. You can take them up on it. Alternatively, you can adjust your bike yourself. It likely seems complex at first, but the mechanisms are fairly simple once you understand them. Park Tools has a nice post explaining how to do this, and the post also has an embedded YouTube video. If it’s just cable stretch, you will only need to twist the cable barrel adjuster, and you can skip the bits about setting the limit screws.

Basically, righty tighty (I.e. turn clockwise to tighten) on almost all bolts on the bike. When you turn the cable adjuster clockwise, you push the barrel further in, which slackens the cable. Turn it anti-clockwise instead to tighten the cable.

If you have gone and adjusted your limit screws, you’ll need to re-adjust them carefully. The symptoms you describe can be explained by new bike and cable stretch, so I will not describe the limit screws right now.

(A previous version of this answer wrongly described what to do for just the rear derailleur. The title of the post initially said "cog", which is standard terminology for the gears in the back. We would say "chainring" to mean the rings on the crank, i.e. the front. The principle is the same, it's just that cable stretch affects each derailleur in a different direction.)


First off, the number one cause of broken spokes is not enough tension. When spokes aren't tight enough they load and unload with each revolution of the wheel – basically they are getting bent back and forth each time they go around. Over time they break, just like bending a paperclip. The most likely place for the spokes to break are at the bend at the hub.

Any good wheel builder knows this and will take great care to get the spokes uniformly tensioned. Once the spokes are tight enough they don't load and unload on each revolution and they will last a good long time.

Here's what you need to know to order a new wheel:

The size of the wheel: 700 C on your bike.
The rear dropout spacing: you can measure this by taking out the rear wheel and measuring the distance between the dropouts (the part of the frame where the wheel attaches) in millimeters. Odds are good it will be 135 mm, although 130 mm is also likely. They need to know this to choose the right hub width.

Beyond that the wheel builder should be telling you (or at least making recommendations). I think the bike shop questions were being asked to learn about how you ride and care for your bike.

Unless you've been riding hard (jumping curbs, bouncing through pot holes, etc.) I'm very suspicious that your spokes were too loose. Really, you're not "too big" for a decent bike. Trek, for example, says their road bikes are good for riders up to 300 pounds, and mountain bikes are good for 275 (if I recall correctly). I'd guess that the mountain bikes are lower due to the rough service they are likely to get.

Some things I'd expect your wheel builder to recommend:

Don't use heavier spokes, use more. I'd go with more (at least 36 or even 40). On our tandem our wheels are built with 40 14-gauge double butted spokes. They are holding up just fine, and our team weight is 360 pounds, with the bike and bags the load is up around 425 pounds. We're using nice sturdy rims, but the big thing is that I built them with good tension on the spokes.
Use the biggest tires that will fit and run them with relatively low pressure. This will enable the tire to absorb road shock, and being big it let you run a lower pressure without risk of "snakebite" punctures in your tubes.
Consider using an asymmetrical rim in the rear. Asymmetric rims offset the spokes to the left a bit to help equalize the bracing angles of the spokes (on a symmetric rim the drive side (right) spokes are much tighter because they are at a steeper angle. This is because the flange of the hub is moved to the right to make room for the cassette.


Your hub is a SACHS Maillard 'New Success'. Don't pin me down on the date, but it's got to be from the late 80s - a couple of years before the branch was acquired by SRAM.


The best way to connect aerobars with Di2-shifters to bike w/ Ultegra 8000 Di2 and the junction box in the bar end?

Yes, you can. You can have as many SM-JC41s as you like. It's basically just a 'dumb' connection box.

Each shifter has 3 ports, so are you really in need of more ports?
I think your current setup is:

Left shifter => EW-JC130 => right shifter
EW-JC130 => Junction A (EW-RS910)

That would mean you still have 4 ports available, right? (2 per shifter)

A climbing shifter usually only takes up one port, but I suppose if you want to add sprint shifters you might need two free ports.

Note that you can have only one of the Junction A boxes (EW-RS910, SM-EW90-A/B) as the Shimano compatibility charts state: https://e-tubeproject.shimano.com/pdf/en/HM-CC.3.4.0-00-EN.pdf

Also note: max 6 shifters.

The B junction is not mentioned(just like EW-JC130 and EW-JC200) because they're just connectors and you can have as many as you like ;)

I'm not sure what the best setup would be, but think that is your only option if you want to connect that many devices.


Attach bottle cage to frame w/o mount screws

Yes, it is possible to install a set of water bottle "braze-ons" on a frame which was not originally supplied with them.

It requires a very specific set of tools and parts.

The video below shows how a Rivnut works.

The second video wexpolains how to install a set in a bicycle frame.


Why do racing cyclists wobble when furiously pedalling?

Not a stupid question. The simple answer is that they are throwing every ounce of leverage, weight, and power into the pedals and that much movement side to side is the visible result of trying that hard to move forward.

If you could stay absolutely still, and input the same amount of force to the pedal, then more of that energy would go to moving forward, but you can't. It's a matter of balance and leverage.


Clicking sound coming from pedals/pedal spindle/crank

Papuass is correct - take it back to the shop as it is under warranty and they may have offered you a free service anyway.

Here is the complete checklist for future reference...

I believe that you have a Shimano Altus chainset - a pressed steel number with no chainring bolts to come undone.

As for diagnosis, you are not getting the click when you are freewheeling - that is normally a simple check to do first.

Next, try different chainring - does the click only happen in the outer ring? This can be due to the front mech touching the crank. Also check the mech clears the outer ring with the cage staying away from the teeth.

Now try the granny ring - this will not be using the same 'chainring bolts' and will identify if the problem is there - this I do not suspect in your case due to the construction of the chainset.

Now try and pedal out of the saddle - do you still get the click? Sometimes the seat post can creak as you pedal and you need to check that is not it.

Stiff link? If the click on each power stroke then it is unlikely to be the stiff link going through the chainset as this will be  different each time.

Now for checking the pedals. There should be a smidgen of grease on the pedals and inside the crank arms. With a 15mm spanner you can take them off, check the grease and put them back in again. The pedals should be in really tight, you may want to wear a tough glove whilst putting your pedals in/taking them out. This is because you can mangle your hand on the chainset quite easily doing this. Remember that the left hand pedal has a left hand thread and the right hand pedal has a right hand thread - it is important you turn the right way.

Now for the bottom bracket. Get a socket set - 15mm and check the crank arms are on massively tight.

Check the pedals for wear/general condition and decide whether you need to tighten up the bolts holding the cages onto the bodies. There should be some play with affordable pedals - the bearings do not have to be great - but if there is too much play consider tightening them up with the socket set, or, better still, just get a new set of pedals, maybe upgrading yourself to Shimano SPD/Time ATAC.

If that has not cured it then check the bottom bracket is inserted properly. The chances are that you will need brand specific specialist tools for this, including a crank removal tool. Again you will have left hand thread on one side and right hand side on the other side. Make sure you are not doing up when you think you are trying to take off the bottom bracket.

With modern 'cartridge' bearing bottom bracket sets (you have one of these with octalink) it is unlikely to be penetrated with dirt/grime (giving rise to noise) but older square-peg bottom brackets can have problems with ball bearing cages falling to pieces and making quite a racket. Usually these can be repacked with new balls and grease, however, you might want to put in a new b/b - this will need to be the correct outer shell length and axle length - see your existing b/b for numbers.

There is an outside chance that there may be something up with the frame, older cr/mo frames sometimes have a really basic tube for a bottom bracket that can make itself ovaloid over time. This you can only determine with the b/b fully stripped out and when you try to put it in again.

With fairly accessible tools you can get most of the bolts tight, this may cure it and save you the 'trek' to the bike shop. Given your warranty situation you can return it to the shop and let them make a decision on how much they want to strip the bike down.


The short answer is no.

The SPD-SL 3 bolt pattern is larger by several centimeters.

An SPD shoe has tread to make it easier to walk in the show off-road and a smaller, 2 bolt cleat mounting pattern. The tread would be in the way of mounting the SPD-SL cleat.


(Apparent) chain slippage causes on new bike - usual culprits already eliminated

If everything is shifting smoothly and the hanger is aligned, it's very likely the freehub body slipping intermittently, which feels much like the chain slipping. Usually it takes a visual to be sure it's the freehub and not the chain.

Different freehub designs call for different procedures to fix and investigate this. The root cause could either be overly viscous/gummy lubrication causing the freehub pawls (or other engagement element depending on the design) to not spring back rapidly enough, causing incomplete engagement, or an issue such as a broken, mangled, or out of place pawl spring. I've seen both on new and new-ish bikes. Ideally at this point one would put their eyes on the freehub internals themselves to check for damage, which can occur from skipping with partial engagement, often in the form of a pawl tooth getting blunted or torn. Some designs make such a check easy, i.e. many cartridge bearing hubs, but others make it impractical, like generic OEM cup and cone hubs where freehub disassembly isn't really intended to be possible.

The good news is that usually it's just some overly thick lubrication at the pawls and fixing it is often as simple as getting some light oil worked in to reduce the overall viscosity. Usually Tri-flow or similar. If it's a "closed" design freehub it can just be dripped in at the crack, sometimes by temporarily pulling a seal first.

By taking the cassette off the wheel and turning the freehub by hand, experienced mechanics can take a pretty good guess whether there's something wrong inside. Not 100% accurate but there have been many times where I've done this and found it to be obviously rough or felt something jangle inside, implying a spring issue.


Is an old mtb with replaced gear safe to buy?

With a mountain bike parts do wear out. I would be more cautious of a 10 year old bike with original parts unless it had original tires and I could still see the manufacturer 'tags' (i.e. like new) showing it had been ridden only once or twice and been a garage ornament for all but the first 2 weeks of its life.

If the bike has been ridden regularly you will be wanting a well maintained one. This means parts replaced as they wear out or get damaged.

I have bough several second hand MTB's - you get a better bike for you money than new. The ones I have always ended up buying have had many parts replaced, as its these bikes that the riders are using regularity and keeping well tuned and maintained.

With respect to the edits - a leaking front fork could simply need a new seal or it could be a new fork - its a deal breaker for me.


Looks like you may not be closing your Quick Releases quite tight enough, and they are causing the wear.  Here's a Park Tool blog post about it:

Wheel installation


Rear derailleur shifting poorly, skipping gears

A tune-up fundamental SHOULD be the proper alignment of the rear derailleur hanger. If the shop doesn't use a Park Tool DAG-1 [derailleur hanger alignment gauge], or some other manufacturer's, to inspect, verify, and correct the relation of the hanger to 3 different points on rim of rear wheel at 180 and 45 degrees apart it is throwing parts at a bike. As the hanger should hold the rear derailleur in direct line with each cassette chain ring, any deviation -- inward or away from the cassette -- induces erratic shifting and skipping that mimics cassette and chain wear.  (Misalignment is difficult to "see" without this tool but may be suspected if the bike has been bumped in a rack, dropped, or fallen, on the drive side.)  The tool at $65 to $75 will be used for diagnosis by a careful shop but is unlikely to be worthwhile for an occasional home wrench.