My rear wheel is bent. How do I know which replacement rim would work?

That link appears to be a dealer-only one, I get a login prompt. It's a flat bar road bike and based on a google search comes with 700c/ISO622 wheels and a 7 speed cassette (7 gears on the right hand shifter). The R23 in the name very probably means the original rim is 23mm wide.

That means any 7 speed narrow rim 700c wheel should work.


Building a traveling bike, frames and components: where to buy in Europe

European prices always include VAT, and US prices are typically announced without sales tax (or customs, if you really intend to order from US). Once you add the sales tax, the prices are closer.

Generally, you will pay extra for a brand that is commonly not available in Europe. In addition to Surly, Thorn is easily available in Europe from UK and cheaper than Salsa.


Practical benefits of expensive jockey wheels?

The advantage of sealed idler cogs is that the bearings stay cleaner and don't (in theory) need lubing.  This keeps the cogs and derailer a bit cleaner, allows you to reduce maintenance slightly, and presumably provides a 0.0001% reduction in drive-train friction.

(I suspect that there was more of an advantage prior to indexed shifters, where considerable sideways force from the cog was needed to help shift the chain.  In that situation wear on the bearings lead to poorer shifting.  With indexed shifters (and the associated profiled sprockets and "climbing" chains) this advantage is somewhat negated.)


If you've managed 200 km without problems you can also ride 300 km. As usual don't ride too fast and keep yourself well fed.
1st big leap is usually between 400 km and 600 km, because after 400 km you will (typically) need to sleep.


'#5 would be 5 mm
10 mm = 1 cm

Most bike shops will have kits / tools with those sizes
Those are very common bicycle sizes

This tool has 4, 5, and 6


Get a clamp-on solution like the SKS Anywhere, Topeak VersaMount or Elite VIP.

As Nate W pointed out in the comments, make sure it doesn’t interfere with your cables.

A quick and dirty solution with cable ties and duct tape can work temporarily as well.

There are also bottle cage mounts which clamp to the saddle’s rails, for example the TacX Saddle Clamp:

I think a disadvantage of this solution is that you can’t slide behind the saddle on descents. They are primarily intended for time trial bikes.


There is an issue with putting anything between a Hollowtech bottom bracket cup and the frame.
A cartridge bottom bracket is not very sensitive to its position being changed relative to the frame shell a little by the chain case mounting bracket. The axle just gets moved slightly towards the drive side.
The hollowtech cups are more sensitive to their position being changed, as they need to be the correct distance apart to match the length of the axle on the crank. If you put something between the cup and frame the cups may be spaces too far apart and you will not be able to fit the non-drive side crank.
However, mountain bike cranks are typically made for 73mm frame shells and MTB bottom brackets are installed on 68mm shells with two 2.5mm spacers. You may find you can omit the drive side spacer to make room for the chain case mounting bracket.
If the bracket it less that 2.5mm in thickness you may need to find thinner spacers to make up the difference and get the correct cup spacing.


How to correctly mount double-lock grips?

Short answer, no!

Almost certainly the entire grip should be on the handlebar.

Then the 2 pieces of steel pushed in by the screws will tighten against the handlebar giving much better security.

The steel pieces should go in the cutouts on the hard plastic inner of the grip.

I'm not sure how well the grips will work now that they are missing some of their structure, but it's worth a try.

FYI, the reason that the hard part is more difficult to get on is that the multi part grips can get away with a looser tolerance under the rest of the grip, but not where they are actually attached to the handlebar.


What you call screws are really axle nuts.  Fortunately your hub appears to contain sealed cartridge bearings, so there are no cups or cones to tweak up.  The axle nuts should be done up close to the bearings and then locked in place against each other.

Your frame has horizontal dropouts so try sliding the axle back a bit to see if that provides enough space for the tyre between the chainstays.
I can't comment on the chain length, never owned or worked on a single-speed bike.

Otherwise, the tyre/tire is too wide for the frame.  Its possible the rims are not original either and the current ones are a bit larger in circumference than the frame was built for.  Sell off your trendy red tyre and go for a rear tyre that is smaller in width by 5 mm.   Or store it away as a replacement for the front tyre.


I dunno about upcoming innovations, but I reject the idea that nothing much has changed in the last 25 years.

Bike lights have improved enormously. I started cycling with the big EverReady-style lights that took two enormous D cells and gave only a few hours of rather weak light (that is, if the bulb didn't fail). If you wanted to ride for moderate distances in the dark then you had to use a dynamo that dragged like a 30kph headwind while you were moving and went out as soon as you stopped.

Now my rear LED light lasts all winter on two AAAs, and my high-power front LED is good enough to ride all night on dark country lanes on four AAs. Dynamos have improved too, with hub dynamos and standlights the norm.

GPS has made a big difference to navigation. No more staring at maps in the dark to figure out where on earth you are and why that junction that you should have reached 5km ago has stubbornly failed to show up yet.

Online mapping makes planning bike rides much easier: a route-planning task that used to involve covering your floor with maps and marker pens can be done in a few minutes on your computer. And you can check out the awkward junctions in Google StreetView so you won't get lost.

Mechanically, the advantage of the upright bike is its simplicity, ease of repair, and standard parts. There can be tinkering around the edges: better materials, cheaper parts, slight improvements to ergonomics (like brake-mounted gear levers). There's nothing much that needs doing to improve the machine. What we can improve is the way we ride.


Generally, bigger sizes of screw heads allow higher torque to be applied to them. This is also often expressed in lengths of wrenches used for them in workshops: typically a 3 mm L-shaped hex key is shorter than a 4 mm one, which in turn is shorter than 5 and 6 mm ones etc. Multitools are exceptions because of size constraints of tool bodies; it is typical to see a 8 mm hex head on a multitool with inadequately short leverage.

An unnecessarily big screw would also mean more "dead" space is needed in the parts such screw connect. These parts are collars of brake levers, derailleur shifters, grips etc. "hugging" the handlebar's tube. Collars interfere with each other, preventing you from finding the most comfortable position of e.g. brake lever. By the way, this is why top-level brake/shifter combinations basically use a single collar and are connected together (Ispec, MatchMaker etc.)

Bigger torque is needed to counteract bigger force × leverage applied to a specific component. For handlebar components, forces are produced by user's hands/palms and have the same order of magnitude regardless of which component is being "touched". The applied force being fixed, it is the leverage (in centimeters) that should decide achievable range of user-supplied torque and thus required screw-supplied counter-torque.

Lock-on handlebar grips tend to have the smallest screws (1.5 - 2.5 mm) because grips sit very tight to the handlebar. Leverage applied to them is defined by their thickness and is an order of 1 cm.
Shifters typically have relatively large paddles sitting far away from the handlebar's axle, let's say 3 cm away. A 4 mm screw would seem to be adequate to hold them securely.
Brake levers have dimensions and leverage comparable to shifters'. Thus, screws of the same size should suffice for them. However, brakes are more critical to rider's safety, and them rotating around the handlebar is even less desirable. As an additional precaution, they are installed with higher torque and thus bigger screws (5 mm).
Fork lockout control is smaller than both shifters and brake levers, but bigger than grips, so I would say it may have a screw somewhere in-between (2.5 - 3 mm).


You say it's bent, but we can't confirm that by the picture. (Your picture is very sharp, but a side view would be helpful) It looks (as someone else commented) like the derailleur may have slipped down the seat tube. If you can't determine exactly what the problem is, you probably should take it to a shop.


No, as offered by @NoCo, is the correct answer. This merely offers some additional information.
When you're talking about "normal tires," you mean clincher tires with tubes. These will require new wheels. Unfortunately, if you bought a 1980s bike, you may have an older standard rear wheel - current bikes are 130mm in the rear dropouts, as are current rear hubs for rim brakes.
You could likely get a new front clincher wheel for cheap on eBay or through local classified ads, since rim brake wheels are not the most current technology. You may be able to find a rear wheel to match the rear spacing, but that might take some searching. This is the best route to take. I would measure the dropout spacing with a ruler. See this page for more information.
You could also keep those tubular wheels and change the tires...
If you talk to tubular aficionados, they may state that tubulars aren't that hard to glue to rims. This is true, but you have to learn how, and the logistics chain is quite different from clincher wheels. You'll need glue or glue tape, and you'll ideally want to carry a pre-glued spare tire to deal with flats. You'll ideally want an unused wheel to stretch new tubular tires on before mounting. Furthermore, if you don't glue your tires properly, your  tire could roll off while cornering and you will crash.
You may want to remove some old glue first. With wet glue, you'll definitely have to apply several coats of glue to your rims and new tires, letting the glue dry between coats, and you have to guide the tire onto the rim. If you stick with tubular wheels, tubular tape alone will be easier, but this leaves open the question of what to do if you flat - you'll still want to prepare your spare with wet glue, as a taped spare would stick to itself.
If you stick with the tubular rims, you should be able to find training tubulars for relatively cheap if you look. Most of the tubular tire users are professional road and cyclocross racers, and some weird aficionados. Actually, it so happens that I'm one of them - I have a pair of tubular cyclocross wheels, although I use clinchers on all my other bikes. Nevertheless, you are likely to mainly be seeing very expensive racing tubulars when you search.
There are relatively cheap ones, you just have to keep searching. Just as one example, the Continental Giro training tubular is selling for $40 per tire at this online store. You could get a bike store to help you mount tubular tires as well. However, this may be a lot more hassle than you're willing to put up with, and I don't blame you - I get a store I trust to mount my tubulars, and in my experience, not all the mechanics at bike stores are going to be experienced with mounting tubulars.
Why on earth do people still use tubies?
This is just for information and is tangential to your question. In the past, clincher technology was clearly behind tubulars. Until perhaps the mid 2000s, tubulars had lower rolling resistance and a better ride than clinchers in general. In addition, if you puncture, tubular tires are more controllable than clinchers. You can actually ride a flat tubular tire, albeit carefully, for some distance, whereas a clincher tire (tubed or tubeless) is liable to come off the rim. For example, Abraham Olano (Spain) won the 1995 men's World Championship road race despite a flat in the last kilometer. This article doesn't explicitly say that he was on tubulars, but tubies were de riguer for all pros then. If you doubt me, you're invited to keep Google searching.
In cyclocross, very low pressure (15-20 PSI) can help with tire traction on loose surfaces. At that pressure, tubed clinchers will pinch flat. Some tubeless clincher tires are liable to burp (that is, the bead may come partly off the rim, and you will lose air) at that pressure. To my knowledge, although tubeless clincher use among pro CX racers is rising, tubulars are regarded as the optimal equipment.
On the road, best current standard clinchers with latex tubes and the best tubeless clinchers have lower rolling resistance than the best current tubular tires. Pro road cyclists seem to be relatively slow to change their practices, and they have many mechanics who are trained in tubular tire mounting, plus they still desire the safety factor if they flat. Nevertheless, the use of tubed and tubeless clinchers is rising among pro roadies.


You need a +40mm post to post adapter. The Magura one is their part number QM42. Usually these kinds of adapters interchange between brands, but just getting the Magura one plus a Magura or Shimano 203mm rotor should set you up.


Just noticed this old question and I thought I'd try to close it out. I finally took the bike in and the tech tinkered a bit and ended up replacing one of the bearings. It's entirely possible that I had, in fact, installed it incorrectly, which wouldn't be too surprising considering I'm still learning.

Thanks to everyone for their comments!


The 'arch' is actually an arrow - look at the right hand end.

I believe it means there is a junction between the carriageways that allows you to make a right turn and travel along the opposite side.

There's another sign on the other side of the carriageway, and a corresponding u-turn junction.


Modern bike security, a lock with GPS and SIM card?

Sophisticated bicycle GPS trackers have been on the market for a while now. You can even get some that can be hidden in the seatpost or handlebars and the battery life will be different on different trackers and how regular you want the  GPS reporting.
Smart locks do exist, but having a conventional lock, one that isn't permenantly fixed to the bike, is not much use (IMO) in the event of a theft, thiefs rarely take the broken locks with them, and by the time you get to the location of the theft, they will likely be gone.
A bike lock such as the I lock IT might be something to consider, although without knowing the bike you plan to protect, I can't advise on compatibility.
I don't know of any conventional bike locks with SIM and GPS functionalities, there are some with bluetooth-like alert systems, but you would have to be within Bluetooth distance of the bike.
You can also consider GPS tracking bicycle lights. Although, if you live in a place with bike light theft is high, this might not be an option.
Personally, I would invest in good bicycle insurance (and Gold Standard lock) before looking for any GPS systems. Bare in mind that difference insurers will have differe policies on claiming for bike theft, triple check all the small details required before thinking you are covered. This might include what lock you use, what you lock the bike too and where on the bike you place the lock.


How much displacement are we talking about.  A mm or two?

I've never heard of the wheel moving along the axle.  Is the 15QR skewer (the axle) tight?  There is a rotatable nut with numbers on the opposite side which you can adjust to move the final angle at which the skewer lever handle sits.

One thing I would try is to remove the caliper completely (two bolts to the fork) and see if the rim and or the rotor wobbles when turned.  Also check to see if the wheel itself is loose and moves "along the axle" or rattles / has loose play.  The front wheel on my Nerve AL 8.9 is centered, as far as I can tell.

It's possible that the caliper position changed during a crash.  There is slop in the two mounting bolts on purpose so that you can center the caliper pads onto the disk.  But before you try that, you should probably make sure the disks aren't warped as well.


We're all adults here.
When wearing well-fitting bib shorts, a male should feel "cupped"  The legs of the bib shorts should touch the skin all the way up the thighs, through the "curve at the top of the leg to scrotum"  and around the whole area.
Your old-fella should be pointing forward, slightly cupped by the cloth so it points up towards your belly button.
One way to get a good fit is to pull the shorts on, and wearing nothing more, lie on your back on a bed.  Pull one knee up to your chin and leave the other leg more horizontal.  This will help get the cloth up to the aforementioned curve.  Swap legs and repeat.  You should be able to do this without cloth sliding past your skin, and without any large air pockets/spaces being formed beside the legs/scrotum.
One  possibility is the cuffs of your bibs may be too low down your leg/thighs.  You should pull the legs upward to free material for the crotch area.
Also, if you stop for a toilet break, this will disrupt the lay.  So do your best to reestablish the cloth up to the curved area.
The padding should be inside the shorts, not on the outside where its visible to the world.
Chamois cream can be helpful too, but I only wear it for long rides of over 100 km.  This also goes on the skin, or sometimes on the padding.
Lastly, nothing else goes between padding and skin, so no underwear.  The bottom of your T shirt or baselayer is fine to be in the area, but shouldn't be long enough to get that low into your bibs.

There's got to be a better name for "that curved bit between inner thigh and nutsack"


Why does my road bike come with only one valve adapter?

Because you only fill one tire at a time.  The adapter screws off and can be used on either tire if needed.  It can also be easily stored with your patch kit, so it doesn't need to be on the bike.  I only keep one around in case I get stuck with only a schraeder pump at my disposal.


Front tire skidding, resulted in a crash, any advice?

I currently ride on Rubino Pro Slick tires, and have used various Vittoria tires for decades.

The Vittoria Rubino tires you are using have similar wet grip to what I use (dry grip will be the same). The pressures you quote are good.

I get the impression that both incidents occurred in the same corner. If that is the case then I would strongly suspect oil on the road.

When cornering with under inflated tires, they give a characteristic sickening lurch to the side, usually accompanied by a scrubbing noise, and then they let go. This kind of crash can rob your confidence. Just take it easy, be extremely careful on that corner (or avoid it), and get well soon.


I think you need to start from the point where you say that any lock is breakable, if the thief is sufficiently determined. But I do think your insurance arrangements will have a bearing on what lock to buy.

So, rather than asking "what lock should I get to prevent my bike being stolen?", I think it makes more sense to ask "what lock do I need to get so that if my bike gets stolen, the insurance co will cough up?"

So essentially rather than asking your question on here, it might be more useful just to contact your insurance company and ask them for a list of approved locks. You don't say where in the world you live, but in the UK there is a "sold secure" scheme which I think a lot of insurers use, with different levels (bronze, silver, gold) required depending on the value of the bike.

Its also worth noting that the lock on its own is most likely only part of the story - my own policy places restrictions on what I can lock the bike to (must be immovable) and where and for how long I can leave the bike unattended.

On the Sold Secure scheme itself, I've spoken to people who say that it is all a marketing ploy to get you to buy certain locks over others, and their rating of a particular lock has no bearing on how good the lock is. This may or may not be the case, but again I'd stress that its not about preventing the bike from being stolen, its about the insurance company paying out.

I'm making an assumption that your bike is insured. If it isn't, you're really taking a punt when you buy a lock. It might be worth going over to the "Sold Secure" web site (or seeing if there is an equivalent scheme in your country) but as I say it is questionable just how objective these schemes are.


Using Direct Mount brakes on braze on frame

I don't believe there is one. I found one image on Google that appears to look like it would adapt a standard frame/fork to take direct mount brakes, but I wasn't able to find a link to any manufacturer. There is an exceedingly brief discussion in this forum post.
Because direct mount rim brakes are a niche item, I wouldn't hold out much hope for an adaptor. In fact, the link is mainly sarcastic commentary.


I ride a steel frame fixed gear nearly daily in tropical conditions, and near the sea. It really puts the frame through its paces. As far as my experience goes, there's nothing that can be totally rust proofed.

Using any sort of metal lubricant on the inside of the tubes will certainly help prolong the life of your steel frame. Some may insist on using the tried and proven J.P. Weigle's Frame Saver. The seat tube and bottom bracket are where rust forms the quickest, as moisture gets to them easily. Always remember to lube them, especially after wet rides, as the lubricants can be easily washed away by tire spray and water seeping between the crevices.

Apart from the inside of the frame, do note that the quality of the paint/clear coat has a great impact on how "rust-proof" the frame is. If the paintwork is chipped, which can easily happen if you ride often, there's a chance that the frame will start rusting from the chip.

Do care for your steel frame as you did with the aluminum frame. It may be prone to more visible wear and tear, but as long as you take care of it, it's bound to last a lifetime. Steel frames are durable and great to ride on. It's worth the time to take care and maintain them.

As an extra precaution, I remove almost all the components, except for the crankset/bottom bracket, and give them a thorough wipe down and re-lube once every two months.


Very narrow gap between pad and brake rotor

Its unclear to me what the actual problem is, apart from your feeling the pads are too close.
If they are not pulling back far enough and rubbing the disc all the time, it could be
stiffness just from being new and unused. Install them and ride...
You could try to lube the piston and seals (remove pads, squeeze out pistons and drip oil on them then work them in and out a few times a few times. Personally I would not bother unless I had a few miles on them and still had problems.
The issue of winter grime between the disc and pads will not go away or get better with a bigger gap.


Are Ultegra brifters compatible with 10-speed XT Dyna-Sys derailleurs?

In a word, no. Different cable pull ratio on both systems. You can check out this question if you want a slightly more verbose answer.


You should not have to replace the entire crank-set. In general, a 'mid-compact' 52/36 crank will have a 110mm BCD spider, which allows 50 and 34 tooth rings to be installed.

The Ultegra FC-R8000 crank on the Canyon comes in 53-39, 52-36 and 50-34 versions, so you will be able to get the smaller rings for that specific crank.

The front derailleur may need to be dropped down slightly to adjust for the slightly smaller rings.

Front derailleurs have a 'max capacity' spec which is the difference in tooth counts between the rings - typically 16 for a road group-set. Obviously this is not changed between 52/36 and 50/34 so the derailleur does not have to be replaced.

Updates:

As mentioned in comments the chain may need shortening.

You might need to remove the crank to get the small ring off, but no special tools are required with Shimano 2-piece cranks - just a couple of bolts on the non-drive side arm.


Cyclocross Frames and Disc Brake Compatibility?

There are two (ignoring flat mount for the moment...) main standards in use for disk brake mounting systems, IS 51mm and 74mm Post Mount (Disk Brake Mounting Standards - Bikeman). Both of the linked frames appear to be using 74mm Post Mount on both the frame and fork since the brake mounting lugs are parallel with the plane of the wheel. TRP Spyre calipers default to post mount, so your calipers would bolt up fine on those mounts (on either frame) barring any manufacturing defects.

The main disadvantage of having a brake mount on the seat stay (outside the rear triangle) is that the caliper will interfere with standard racks, necessitating the purchase of disk brake compatible racks that are usually slightly more expensive. Moving the mounts to the chainstay (bringing the caliper inside the rear triangle) makes the frame compatible with a wider variety of racks if that is something you're interested in.


What does self-support mean during touring?

Self-Supported Touring

I do most of the obvious things - I have a hammock, stove, basic first aid and bike repair equiment, carry food and water etc. As I often tour in places where there are no shops and that motor vehicles can't go this is necessary. I do get food parcels and other necessities posted to me and pick those up along my route. Having a cellphone/internet device makes it easier to arrange those drops. I use a digital camera rather than film, but that's become the norm.

Extra or unusual things I do:

carry a small solar charger to recharge my phone and music player
eat roadkill from time to time (it's free and environmentally friendly). In NZ where it's legal I've also carried a slingshot to kill pest species and eat those too.
use a hammock rather than a tent because it's more flexible and less obvious, so it's easier to free camp
wear long sleeved shirts and pants rather than using sunscreen (personal preference, but also more sustainable/self-supporting)
use a liquid fuelled stove (in NZ) or fires (in Australia) rather than disposable gas cartridges to get more cooking per kg of carried weight. It often hard to find fuel for a cooking fire in NZ even when it's legal to use one.
I use public transport to get to and from tours. Or I just ride from where I live. Since I don't own a car that's easy for me, but I meet a lot of people whose "cycle tour" involves driving further than they ride.
shop mostly at supermarkets rather than tourist shops or corner shops to save money. In Australia especially it can be 1Mm or more between supermarkets. So I often carry food for a week or more between shopping expeditions.

My experience is limited to countries where I already speak the language and have citizenship rights so I haven't faced any of those issues. But my tendency is to learn the language etc anyway, and since I'm a geek citizenship has not been especially hard to get. When you're young a "working holiday" visa is often easy enough to get and is worthwhile (since it lets you work legally).

I do cycle tour as a holiday, I regard it as a break from my normal life. I usually quit my job, stop renting somewhere to live, give away or sell my spare possessions, and go ride my bike for a few months. I've worked hard to get into a position where that's possible.

I don't usually prepare physically for a tour, I just pile up the stuff I need and go. The first week is slow and hard, after that I get fitter and start riding further and faster. Usually I lose ~5%-10% of my bodyweight while touring and come back with more muscle as well. I suspect that means I'm fat and lazy...


Is there a way to know if someone is drafting behind without turning your head back or trying to hear the noises?

A group riding together and cooperating will ride to a set speed, so you'll be surging if you exceed that speed for long.   A simple wheel-magnet speedo and bike computer helps show this on your bars without being big or expensive.

An ad-hoc group will ride with varying speeds depending on who's in the front and whether they are trying to make a break away or if they're just sick of waiting for the rest of the group to cycle through the paceline.

Some riders need short pulls and some can cope with long pulls at the front.  Separately some people need short rests out of the wind, and some people require quite long periods behind someone else to regain their pace.

The best groups work together for the end goal which is a good training ride.

In racing, your team is your group and the other teams are NOT your friends so they're working for themselves.  A race peloton is therefore an adhoc group of teams who are not working together.

If you face some decent climbs in your route, then groups tend to fall apart as everyone climbs at their own pace.  For training and bunch rides, stop at the top and let everyone get there, then rest till the last arrival is ready to carry on.

Otherwise the first arrivals are rested while the last people are shattered and the group breaks up or is held back.

Same goes for downhill - strava segments work on segment time, not first-down time :)

More thoughts - A shoulder check every half minute should show you if the rest of the paceline is there still.

If you don't have a speedo, riding to a set cadence might be enough.  Try and memorise the speed of your feet while in the paceline, and simply maintain that rhythm when you hit the front of the line.  Sing a song in your head of the right speed, or count off like marching if that works for you.

Getting expensive - there are race-radios like the pros wear.  They are essentially Personal Shortrange UHF radios with an earpiece and a small transceiver in a pocket.  The aerial/headphone cable runs up the back and is often taped on.  Some new ones are small enough to work with the helmet.  These talk to each other in the team and to team car, who then relays messages onwards with a second radio or maybe a cellular phone.   Some are even bluetooth based and just associate with one~four other units.   Motorcycle riders might wear these under their full face helmets.


Is the Park Tool Allen Wrench going to strip out bolts?

I have never had a problem with Allen keys rounding. Using the correct size, using them correctly (Inserting them fully and not letting them slip out the bolt) and not using too much torque for the bolt size means even cheap Allen keys will last a lifetime.

If the bolt head has rusted or has gunk in it, you sometimes cannot easily get the Allen key in all the way. In this case cleaning the hole is required. Abusing the bolt/allen key by only inserting it part way is the most likely cause of problems. Workshop quality tools will survive abuse such as this (although it's more likely the bolt won't).

If you are having problems rounding the Allen keys, workshop quality tools to likely just move this problem to the bolt, making it a much bigger problem.


My first clue was from the serial number which started with a J. The French derailleur also pointed me to this direction: I took a guess and searched for pictures of Jeunet frames.

Then, browsing a bit I saw this forum which shows many pictures of similar models where the lugs are exactly the same, similar dropouts and forks chromed. My guess; it is a Jeunet 620 or a very similar model.

Edit:

Well, I looked a bit more and found this catalogue. If you look at the course (racing) section, their top of the line model for that year is called 570-10 (10-speed 570). The marking on the dropout might be just that, the model number. Identifying the year, now, that's something else.


My e-bike wiring is damaged and I don't know where to begin

First thing to do is check all the parts are present.  Without knowing your specific bike, you will probably have

A bike - thing with two wheels, etc.
Built into the bike will be a motor, probably in the middle of one wheel, but some designs have the motor between the pedals.  Rarely, some use a rubbing roller to push the wheel, but these are uncommon.
Battery - it should be fairly obvious.
Charger - lack of a charger is a strong indicator that the bike might be stolen.
Optional head unit / control panel - If the bike has one, it will likely be on the handlebars, and have some buttons and possibly a display or at least some LEDs for charge remaining.

Either in the battery pack or in the head unit will be a DC to AC converter.  Many ebikes have a 24 or 36 volt DC battery, but the motor itself is probably an AC unit for efficiency.

If you're looking at resistances, expect megaohms across the motor, and that it has 3 or 4 wires going to it.   You can't just connect the battery to the motor and have it go.

Make sure the battery is charged fully, then connect it, and turn on the bike.  You may need a key or card to do this, and lack of this is another indicator of a stolen bike.

When it starts, read the display, look at the LEDs, listen for beeps, and any bad messages should be referenced with the manufacturer's info.  This will be unique to the system, not necessarily the bike brand.

Modern ebikes tend to be "pedelec" meaning they give the rider an assist when pedalling motion is detected.  Older bikes tend to be throttle based, where you have a rheostat or a simple button for "add power"   Buttons are easy to troubleshoot, sensors are much less straightforward.

Other than that, its all getting very specific to your bike's electric system.  More details could help.


Thule Helium Pro hanging bike rack - assembling problem

It looks like a defect in manufacturing to me.   Appears to be a daggy piece of metal left over from the drilling process, aka swarf that is still connected. I'd suggest putting a bolt in and then tapping it firmly with a hammer to dislodge or shear off the flake.  Maybe use another piece of metal to avoid damaging the bolt.  You might be able to grab it with some needlenosed pliers and twist it off.
If the obstruction is thick then you may need to drill it with a drill bit that is the right size for the bolt.
Either way, add some paint or grease to protect both the bolt and the frame from the elements.  Having removed some paint will allow rust to form there.
You could try sending the whole thing back for replacement or refund, but to me its a minor annoyance that will be fine once drilled.    It is disappointing to see this quality-control, and wonder whether other parts on the rack are similar.
Whether this voids any warranty, that's another question that only the manufacturer could answer.


is it possible to go and install a suspension onto a bike that dosen't have any suspension?

You could add a suspension fork (this bike seems to come with a very low quality one) or suspension seatpost or suspension stem.

On such a low end bike though, only the suspension seatpost would make sense -- for the other options, you're more likely better off getting a new bike.

Another option is to get the biggest tires that fit and run them at a low pressure, which should provide some shock absorption. But this bike wasn't intended for use off-road really -- just to be ridden a few miles on road.


The key property is hardness. For uniform materials (like cogs), hardness directly affects wear resistance. The harder the metal the longer it will last.

Some digging around wikipedia suggests that typical Brinell hardness values are:

pure aluminium 15HB,
6061-T6 aluminium (heat treated) 95 HB
mild steel 120HB,
4130 CroMo steel 183-217 HB (90-96 Rockwell)

It seems likely that most aluminium cogs will be 6061 or closely related alloys, so you're looking at the steel being about twice as hard as the aluminium ones. So it should last about twice as long.

Since people generally replace the entire cassette because the smallest cog is worn, by using an aftermarket one you're prolonging the life of the rest of the cassette by only changing it when the second smallest cog is worn.

Sorry for all the links, I couldn't find a single page with all the info on it.


I'll declare an interest in that my company is the senior (Main) Technical, Service and Warranty Centre for Campagnolo in the UK - but having said that. the Service Centre work that we do for Campagnolo is not all of what we do - we supply general technical training to the industry across the board and I am also part owner and Technical Director of a business that looks after Services de Courses activity for races and spotifs here & in Europe (www.servicecorps.eu), so I have seen the best and the worst of all the electronic and mechanical systems out there.

There are some urban myths around electronic - wet weather performance being one. This is not an issue for any of the systems in the market if they are properly installed. Shimano has slightly greater vulnerability because there are more breaks in the wiring loom than with Campagnolo but if it's assembled to Shimano specs this is not a problem.

Battery life - Di2 and Campagnolo are both around the same - both will give from a full 4 hour charge, something around 1200 km of normal use - it depends how much you shift and how the split is between F and R shifting. F shifting is more power consumptive in both systems. If the battery fails, Shimano defaults to the inside chainring. Campagnolo allows you to manually position the RD under any lower (easier) gear than the one you were in when the battery failed but you can't manually move the FD. In our experience, most people with electronic shift are so paranoid about this that in real life it's never a problem.

Electronic shift won't make you go any faster in and of itself ... it is more accurate though and once correctly installed, it will remain as accurate as it was the day it was installed, unless the user changes something, chain, cassette and chairing wear of course needing to be accounted for. The accuracy of shift remains, however tired the rider. In competition, this can matter.

Cost and cost of ownership - Shimano Ultegra Di2 is at a killer initial price point - the system is robust, spare parts are widely available and expertise likewise. Problems though, can be a headache to diagnose and the diagnostic software also requires (at the moment, anyway) connection through a relatively expensive interface to a PC. Campagnolo Chorus is comparatively expensive but offers a higher-spec, carbon crank set and on-board basic diagnostics. In my general (and genuine) experience, chainring and cassette life is better than Shimano, chain life can be better and I have never seen a correctly fitted Campagnolo chain fail - I have seen one or two instances with Shimano chain that I can't account for by fitting (but maintenance and use play into this and there is also a lot more Shimano "around" so that might also account for it on simple probability rules.

If the cost and availability issues are not the decision makers, then in terms of functionality, there is very little to choose - both shift, shift relaibly and well.

Some users prefer the ergonomics of one over the other, especially when wearing gloves - Campagnolo use a thumb lever to shift one way, a lever behind the brake lever to shift the other way so you are never in doubt which way you are going to shift - that's not always the case with Shimano with their closely-located shift buttons. Campagnolo place the feet closer together on all their crank designs than Shimano - this gives more options for bike fitting (if that is a consideration) and could be said to be inherently more "aero" FWIW.

Most of the choice, costs aside, are going to come down to aesthetics and ergonomics. There is very little bad product from Shimano or Campagnolo in the market now, design and execution from both makers is excellent. IME if SRAM could sort out some of their build-quality issues, they'd be up there as well but conversation with bike mechanics will tell you where their preferences lie and it's not as often with SRAM as with Shimano or Campagnolo - having said that a lot of mechanics are more wary of Campagnolo because they don't see it so often and equate doing things differently, with doing things worse. Not the case - but you do have to know how to set it up & that's not the same was as Shimano.


Tacx Flow Smart trainer calibration issues with 700x35c tyre

After listening to advice from @Carel, I warmed the tyres up for 20 minutes, a lot more than I would have envisaged, and I finally got consistent results being able to calibrate more than once.

After a bit of slackening, I managed to calibrate to the centre of the green zone. I can't wait to re-do the whole process after my training tyre arrives!

A quick thank you to @AndrewHenle and @DanielRHicks for their time and help also :-)


Do I have too much chafer strip showing after fixing a puncture?

The visible strip sticking out from the top of the rim and inside the line is in fact the Chafer strip. This is on the tire to prevent the bead hook on the rim from cutting into the tire.

The bead is the wire or in the case of folding tire such as the x'plor ush Kevlar ring on the edge of each tire. When seating the tire the bead is place inside the bead hook on the rim with a tube inside.

Rims have a few different standards and many proprietary designs so do not have a consistent inner sidewall height. The tire bead when seated actually sits at the bottom of the rim rather than on the hook, so the amount of Chafer strip shown is dependent on the depth of the rim.

The amount of Chafer strip showing would not be a cause of your tube exploding and there are many answers that address punctures  but my thought would be something loose in the tire.


Looks like you need a 1in threaded fork. You'll also want to measure the night of the threaded tube to match it as closely as possible in length and make sure that you get one for a caliper type brake rather than post mount.


Without pictures or a better description, it's hard to know if it was a failure of the cable or the brake lever. If the brake lever has broken and can no longer grasp on to the end of the cable, you'll need to replace the lever itself. However, a more likely scenario is that either the nub on the end of the cable that the lever holds on to has come off. You may also have a lever where the nub can pop off of if there's no tension in the cable, which can happen if there's too much friction in the cable housings. This may also be caused by the cable having become detached from the brake: you're pulling the lever, but it's not attached to anything.

The quickest and easiest thing to do is try to simply re-cable the bike. This can be done quickly (time: 15m) and cheaply (cost: $10), and in doing so will also help diagnose if the problem is deeper. You should also go ahead and re-cable the other brake lever and the shifters as well — if this was caused by a failure in the cable, the other cables may be ready to fail as well.

To get the cable out of the brake lever, pull the brake lever until you can see the cable, or where it should be. Find where the cable comes out of the other end of the housing and push it through until it comes out through the handle. To replace it, just thread the new cable back through and clamp it on the brake. It should look like this:

If you feel a lot of friction pulling the cable out or installing the new one, you should replace the housings. This will take a little bit more time (45m) and some more money (housings: $10, bar tape: $15), but is still pretty easy to do. Unwrap your handlebars and re-insert the brake cable, replacing the old housings as you go. Wrap the handlebars back up, and you should be all set.

If the nub end of the brake cable isn't being gripped by the brake lever, or the piece to do so is missing, you will have to reinstall a new brake lever. This will be a good bit more expensive, and will also require that you re-wrap the handlebar tape.

Best of luck!


Preventing downtube cable stops from sliding out of place

That calls for a shim. Cut a narrow strip from a drinks can, about 3-5cm long and lay it under the cable stop before re-tightening the screw. Make sure all the surfaces are clean and degreased. The soft aluminium of the shim will 'absorb' the remaining roughness of the tubes and the cable-stop and make slipping more difficult. (I've solved the problem of the brake lever rotating around a steel handlebar in this fashion.)


24" MTB Crankset Truvativ E300 3.0, 42/32/22 Right arm replacement?

Fitting a helicoil or thread-replacement is the correct fix, or the whole crankset needs replacing.  From your photo, the right-side crank arm and spider are one part, and it may be rivetted onto the chainrings.
Sadly, thanks to some poor historical choices, the thread of a pedal is a weird combination of 9/16" diameter, and 20 TPI, where the common industry standard is 18 TPI.  Thus, the taps and coils are specialist to the bicycle industry and are therefore very expensive.   And additionally, the left-side pedal is left-hand thread, so the tap and inserts are all duplicated.
I'd bet that your tool library tap set won't have the required items unless its a specialist bike set.
Even having the 20TPI parts isn't enough - making the pedal thread bore at right angles to the bike is also critical, and the accuracy required is too much for a bench vise and a hand drill.  You'd need a vertical mill ideally, or at the very least a rigid pillar drill/drill press.

Your cheapest option might be to look for a donor bike.


Knobs and pavement don't go together. At all. Knobs are made to dig into loose riding surfaces to optimize traction. They can't do that on pavement and, among other reasons, that's why road tires don't have knobs.

What you're likely feeling with the higher profile knob is more warning before the tire cuts loose. The lower profile knobs on the Land Cruiser almost certainly grip pavement better, but offer less warning before they let loose.

The best tire for grip on pavement is a slick. Slicks offer the most rubber in contact with the pavement and the least deformation under side load. The flip side to that coin is that when they're ready to cut loose they offer virtually no warning, and when they're gone they're gone- your chances of recovering traction are nearly zero.

To kind of answer your bonus question, cornering techniques don't differ so much by tire, but by riding type. There are differing cornering techniques for road vs mountain bike riding. I would say that cornering on dirt is much more dynamic than on pavement.

EDIT: in response to your question in the comments:

  So basically my question was "[Your third paragraph] - is that normal?" and the answer is "Yup, deal with it."?

In terms of your tire cutting loose, the answer is partially yes, but not entirely. Proper cornering technique and weighting of your bike, especially your front tire, will help you maintain traction. Keep in mind that it's different for road than it is for mountain, but that's a different question.

A set of tires specifically designed for pavement would make a huge difference. You're not limited to narrow road slicks either. The Specialized Electrak is very wide for a slick, and Schwalbe has several very wide mostly slick tires that can be run at very low pressures (as in, 20-30psi) which equals a lot of rubber on the road and a lot of traction.

In the end though, when you lose the front end on the road it is going to be harder to recover for a variety of reasons. It's not the same as temporarily losing traction in the dirt because you hit an especially loose corner. Traction on the pavement is typically pretty consistent, and you're usually going significantly faster, so when the front tire lets go, it will be very hard to regain traction and stand the bike back up. The tips above will help with the problem but not eliminate it.


Some things to check and I'm assuming you're running V-brakes:

My first guess is that the brake cable inside the brake cable housing is sticking. Some light oil on the cable could help. (WD40 is a solvent, do not use it on cabling or chains and do not use it where you want to maintain lubrication on parts. Look for some light oil like TriFlow, or whatever your LBS sells.) If the brake cable does not travel smoothly, I would suggest a new brake cable.
If you unhook the brake cable at the front brake arms, the arms should travel smoothly and you should feel some spring action that will resist squeezing. If the brake arms have no spring to them, that's a problem.
With the brake cable unhooked, the brake hand lever should move freely. If it doesn't then oil it. Light oil should penetrate any rust, and that might take 20 minutes of sitting before it works in.

Keeping the brakes in good condition is worthwhile and important. If you don't feel confident about how they feel, seek some help. Having a front wheel misbehave can be quite dangerous. Best of luck!


"Top swing" versus "bottom swing" is defined by the position of the derailleur cage in relation to the clamp. There are indeed two completely different versions of direct mounts: high direct mount is for bottom swing derailleurs (since the derailleur is below the clamp), and low direct mount is for top swing. The two versions are not compatible.

Bottom swing is in general preferred unless there is a compelling reason to need the more compact size of a top swing; typically this is only the case on full-suspension bikes.

This is not to be confused with "top pull" and "bottom pull", which only reflects the direction of the cable entering the derailleur - from above or below. Both top pull and bottom pull (as well as dual pull which supports either) mechanisms can be found in both types of derailleur mounts.


what is this hole for on a B&M Luxos U light?

I now suspect this is a vestigial hole.
I took apart the older version of the same light and found that on that one (which has a 2-conductor cable leading out from the hole), the wires inside are actually soldered onto the back of the main board. I could not determine where the current went along the board from that point, as I was only looking at the back side through a tiny slit.
Clearly they were there, factory installed, for some purpose in prior versions -- maybe a pigtail end for directly wiring the power or tail light. That doesn't seem to make sense since there are spade connectors for those, but maybe that was an option earlier.
I think they are no longer attaching anything to the board inside, and the hole is there because that's how the light lower shell is manufactured, though that still doesn't make a ton of sense to me since it seems like making that hole might involve an extra step after molding. (It sure is clean and precise.)
I'll put a dab of silicone on that hole before I finish the install since there's no point in having extra place for potential water ingress.
EDIT: I took apart one of the newer lights and got a better look at the solder pads to which that terminated wire is attached in a prior light. You can clearly see they've got some kind of connection down around the board to where the main AC / hub power connectors usually attach, so presumably this was a way to wire the light if one chose to solder on a wire or connect up to a factory-soldered lead (I don't know which, but suspect the latter since why would an OEM solder leads then not use them when crimping spade connectors takes 2 minutes?)


They're build QC tolerance numbers for side to side (lateral), up and down (radial), and offset (dish).


Carbon Fibre Frame Paint Chip from Stuck chain

To literally answer your question, Yes the carbon is damaged.

Considering it's exposed and because carbon consist of many filaments bonded together, you can also say it's integrity has been affected. The degree of damage however, is not easily determined by visual only inspection.

Sealing it with epoxy is a good idea to stop any contaminants and further fiber damage, but not a good fix for integrity.

When you get to proper damage assessment, you start looking at ultrasound and x-ray and a lot of $. Carbon has the tendency to 'flare' out on the inside on the tube. Consider the impact on the outside as a force and that would transfer through and push the fibers out on the inside. This is the bit you can't see and the dangerous part of carbon damage.

If you really want to know what the condition is like, you will need to get it to a proper carbon repairer. I say proper because there are many on the market that will 'fix' it by simply repainting and clearcoating it so it looks fixed. It's pretty cheap, but you need to understand what you pay for and how much you value your face IF the repair fails.


Can I change my tyre size from a 20x2.20 to a 20x2.30 with out changing my rims

As long as you have wider rims it should be okay, but it really depends on the inner rim width. An inner width of 19 - 20mm will support a 2.30 tire just fine. If your rim has an inner width of 16 or 17 i wouldn't go any bigger, not that it would be catastrophic, but you increase your chances of a blowout on a big bump or curb.

To find this measurement either look up the rims on google or measure it yourself, you're looking for the distance between the two bead hooks.

With that small of a jump though i imagine you will be just fine. Tube-wise you should be okay as well as they are made to handle a range of sizes rather than one specific size. One thing to consider is the more you pump a tube up the thinner it gets and the easier it will pinch flat and puncture. So without knowing what size tube you are running right now it's kind of hard to say. But many tubes are sold as a 20 x 2.00-2.40 so assuming these are what your running there should be no problem. If you have a 20 x 1.50-1.95 in there and it is already stretched past is usable range it may go boom.

So with the assumption you have ample frame clearance (Check your brakes too) and that your are running the correct equipment to begin with you should have no problems.


Should I wipe my suspension fork stanchions with a wet or dry cloth after rides?

A damp cloth is probably the best option, but a simple paper towel is more than adequate. You don’t need to thoroughly scrub the entire stanchion. Just wipe away the ring of muck around the seals and anything on the stanchions that may remain. Be gentle; you don’t want to prematurely wear out your stanchions by overly aggressive wiping.


Need to choose crankset for 135mm rear hub of MTB

You can look up the specs of Shimano cranks here: https://productinfo.shimano.com/#/spec/MTB/Front%20Chainwheel.

The tables give the OLD (over locknut distance) aka rear hub spacing for each crank. Most are for 142 or 148mm.

Many cranks for 142mm rear spacing have a chainline of 48.8mm, which is just over the old standard of 47.5.mm for triple cranks on 135mm spacing, so any of those should be fine. You just want to avoid cranks with chainline of 50mm or or more.


Bought a Genesis bicycle for £100 and wanted to know if it was worth it since I can't quite identify the exact model

It looks like a moderately modern road bike that has been refitted with MTB flat bars to make it a rigid hybrid commuter.

Modern threadless steerer and a cartridge BB suggests its within the last decade or so.

As for value - if you needed a bike and could afford it out of pocket, then you're doing fine financially.  Now just ride it and enjoy not paying for operating costs of a motor vehicle, or per-ride costs of public transport.


What is typically the best bolt to hold Park BBT-22 on to square-taper spindle?

There’s actually a tool made specifically for this purpose. For example, here’s a link to the Pedro’s version:

https://pedros.com/products/tools/pedal-crank-and-bottom-bracket/bb-socket-holder-ii/

They call it a “bottom bracket socket holder” so try that as a search term for others.


What to do with scratched top tube on carbon fiber frame with no structural damage?

There doesn't appear to be any cracking, and its hard to tell from the photo/video, but it also doesn't seem that deep, so that rules out the need for epoxy for either bonding or to act as a filler.

I'd start with nail polish - i've had fairly good results with it although not on such a large area.

Tape as a last resort as its ugly.


Are CO₂ tire cartridges reusable for multiple tires?

CO2 cartridges are fine if you use them in the intended way: Roadside emergency. Otherwise they are a terrible waste of energy, resources and money. Normally a single cartridge is just enough for one tyre. You will also lack means to control the pressure that you put into the tyre. Which is OK in an emergency where you just need to have it inflated and eventually be able to move on and get home

In this case, you better invest into a decent track pump with a pressure gauge that you will get for a dozen or so cartridges plus applicator.

Note: a cartridge is for one-time use only. If you inflate the tyre and store the cartridge in your saddlebag because there is still some CO2 left, which is difficult to estimate anyway, the cartridge will empty completely within the next few hours. The system isn't that well sealed against leaks of the remaining gas.


How to increase the brake force of my drum brakes

As bicycle mechanic in the Netherlands, I see a lot of these brakes. The drum shoes can become harder due to wear or age or something. They can also become a bit uneven.

Remove the brake
Use a good metal file to remove a very thin piece of the drum shoe
Make sure the entire drum shoe has a 'new' surface, and make sure this surface is even
Clean the drum with brake-cleaner or some other de-greasing stuff
Re-assemble and enjoy your quality retro bike

If the drum is to worn out, you can easily replace it.


How to choose the right hydration pack for me

Rule of Thumb: a water bottle an hour

That rule of thumb slides from person to person... me I am more like a 1/2 bottle per hour a little more if it is hot and a little less if I am mountain biking with my dog just joying being outside.

On a 3-4 hour road ride with no water stops available along the way I would take two bottles... if it was exceptionally hot I may add a small bottle to my jersey pocket.  On a similar time duration mountain bike ride (sans dog) I would use a hydration pack.

So, things to consider:

Do you just want the pack for hydration or do you want to carry stuff in the pack as well (e.g. Tools, pump, jacket, food, etc..)
After gauging your consumption rate (only you can do this) and considering  a bottle is 22-26 oz determine the bladder size you need/feel confident will provide the amount of hydration required for your targeted activities.

Once you answer those questions I am pretty sure you will be able to look at your selections and make all the little personal preferences relative to style and selection necessary to wind up with a hydration pack that works for your needs.


Unfortunately, the best thing to do is to change the frame.
As the builder is no longer in the biz, I guess it will be more difficult to find someone who can fix your frame properly.

You can still ride your bike even with the crack, BUT, the frame is now fragile because of this crack. The crack can grow bigger and bigger with vibrations and at some point, the frame will break on an impact. So you better avoid this case by changing your frame.


Minimum mountain bike trekking/touring equipment

The answer to your question depends heavily on the infrastructure that is available to you, and the highest level of mechanical ability in your party.

As another pointed out, you will want at least two pumps, multi-tools, etc.
  My wife and I do pretty challenging mtb tours with BOB trailers. We generally bring the following (subject to modification depending on how present bike shops might be).

for disk brakes, at least one set of extra brake pads for each type used (e.g. my wife as avid, I have deore xt, so we bring one pair each).  When riding with extra weight, it's shocking how fast brakes can wear away.
two spare spokes for each size used.  These can be taped to your bicycle frames, so they won't affect your packing at all.  Breaking a spoke can end a trip if you don't have a spare.  At least learn the theory of how to do a field repair.  It doesn't have to be perfectly true, but you want to be able to at least roll into a repair.
at least one spare tube of each size in use (you want patches too, but you may need the spare for a big cut).
duct tape. You'd be amazed how this can help you. I've fixed panniers, packs, rain-gear, sleeping bags, and patched a ripped tire.  This can save a trip.  Make a small roll for yourself, you don't have to take a gigantic one.
Consider your water needs.  Water purification can be a life saver.  My wife and I use a steri-pen, which we love.  What you need depends on where you are going. When we rode across Albania, my wife and I brought a ten litre sack of water with us, which may very well have saved our lives on a couple of occasions.  In the alps we just brought 2 litre camel-backs and filled them up at the many opportunities.
bike lights are a good tip and will be useful at camp time.
Unless you are sleeping indoors, you must bring bed rolls.  Depending on the weather you might be able to do without a sleeping bag, but an insulating layer between you and the ground is vital.  I can't stress this enough.  Therma-rest makes small, light and highly packable bedrolls.  Cheap foam rolls are an alternative, and are light but  bulky.  On the plus side however they are virtually indestructible.  You can roll them up and strap them to the outside of your backpack.  At a bare minimum bring enough for your core (neck to thighs).  You'll sleep for crap if you don't bring something to put between you and the ground.
A first aid kit.  REI sells nice, small, packable, reasonably well fitted kits for a reasonable price.  At the very least, bring some bandaids (for blisters), some sunscreen, some painkillers, and some antiseptic.
I highly recommend bringing some kind of emergency contact gear.  If you are somewhere with cell reception, a cell phone is enough.  If not you should consider bringing flares or some such.
Saddle cream.  Unless you are routinely doing that kind of mileage now, you'll be really happy to have this.


Which bike computer is best purely for navigation?

Your phone would be great for navigation, but not so much for working with sensors. I have had good luck with Garmin (1030 - I figured if I was spending that kind of money, do it once vs. getting a cheaper model that I may want to upgrade later) head units, but I do not primarily use it to navigate. I like the metrics it provides.
I usually plan my route using google maps and memorize it. If I get really lost, sure GPS helps and also I usually have my phone in my saddle bag so I can navigate a route if I need to on the fly.
Regarding speed GPS will always be less accurate than a on bike sensor and because I use a on bike sensor, I do not rely on the GPS speed so cannot speak on its accuracy.
As Chris mentions above, bike computers do involve a lot of personal preferences too.
Also, if you are new to biking, it may be prudent to hold off on expensive head unit purchases until you really feel it is worth it. For me I waited several months before buying my Garmin unit and before that used a cheap $69.00 bike computer for basic speed/cadence. Again, I planned my route on google maps, memorized it, and used my phone for backup if I got lost or made a wrong turn, which occasionally has happened.


Fork Failure on Vintage Steel Tandem Bikes - Any insights?

I'm not saying I don't believe them, but surely they have legal and financial incentives to recommend I err on the safest side.

Yes, but now that you've asked them and they've instructed you to buy a new fork, if it fails on you and you try to sue them, they'll laugh you out of court. So they've covered that base already.

  you've got to figure that a tandem would have been ridden less over 30 years than a solo

Perhaps, but they recommend replacement after 10 years.

  Just how risky is riding on this 30-year-old steel fork (which seems to be performing well)?

If you read the page linked to above by Daniel R Hicks, you'll see that A) the point of failure is hidden inside the head tube, and B) "Tandem fork failures nearly always cause an accident which puts both riders in an Emergency Room."

  I'm trying not to be an idiot and risk a catastrophy out in the wild.

Then don't rely on equipment that the manufacturer has told you is prone to catastrophic failure.


What is the recommended procedure for adjusting the fit of my bike?

There's quite a lot of discussion on the subject of fit, and some folks have considerably different ideas in this regard.
I use the old-school methods to get close, then try to "dial in" things according to what my body tells me.

Seat height should be such that you can easily pedal "circles" without rocking or stretching, nor by over-flexing the knee.  It's hard to describe...Essentially the leg should not be fully extended at the bottom of the stroke.  Just short of being fully extended.
The thigh should be more-or-less level at the top of the stroke.

The fore-and-aft measurement is often neglected or even ignored.   Again, the classic measurement is that with the pedals level (3 and 9 o'clock) a plumb line dropped from the bony process just below your kneecap should intersect the pedal's shaft.
That's assuming you're sitting on the saddle properly, with your "sit bones" on the heavily-padded portion of the saddle.
Saddle attitude is one of personal preference; I prefer just a few points nose-down from dead level.
"Reach" is somewhat dependent on the type of bike.   On roadsters, you want the reach to the hoods such that you can ride with a relaxed upper body at a reasonable angle.  Some authorities advise such-and-such a percentage of weight on the hands, and such-and-such on the seat.  You don't want to be totally supporting your upper body with your arms.
I've seen folks who maintain that these things are "all wrong", and propose all sorts of ideas for getting the perfect position.    I know I can ride comfortably and without hurting anything using these methods....


If your bottom bracket is a sealed cartridge unit it's less important.  If you're using a bottom bracket that has loose ball bearings and a spindle it's very important.  Mostly the same advice goes for headsets.  All this is less important than back in the day when all BBs and headsets had exposed and floating bearings inside.


Are taller carbon fork expander plugs available?

The critical thing here is how much steerer tube length the stem is clamping. The expander plug does not add any structural strength and the cap must be of slightly less diameter than the steerer otherwise it would prevent the stem clamping it.

If the stem overhangs the end of the steerer tub by more than a few mm, then the stem is mounted to high and could possible stress the steerer tube too much.

If you need to raise the bar consider flipping the stem so it’s angled up rather than down.


What should I do at, and what should I know about, bike shows?

Ok. It's basically a trade show and exhibition. According to your link it appears to be typical of trade shows/exhibitions.

1. What should I do? Walk around. Explore. Watch events. Shop for products of interest. Ogle bikes and collect brochures. And also, talk with manufacturers about things you find of interest.

2. What should I know about? It's not a test, so you probably don't need to know anything in particular. You might "know" about products that you're considering, but other than that...

Otherwise, you'll get to see new bikes, new bicycling technologies, and new accessories. And, it appears that you'll get to watch some bmx and mtn bike events.

Last thing... Bring along a friend who is vacillating about taking up bicycling. There's nothing like pretty gizmos to get someone started. ;~) And things like this are usually way more fun when you have a friend along.


How can you tell how far apart your chainrings are?

It's possible that you just need to adjust your front derailleur a bit to accommodate your new setup. There are many threads here and videos online about how to do this.

The crank may not be the exact same distance from the frame as your old one, but that doesn't mean it doesn't work.


I'll start by saying that finding solid data on wheel aerodynamics is tricky at best.  Some of the better sources are worth taking the time to read in full, and provide much more information than I can provide here.  For example, see the article from Tour Magazine [1] that covered the Mavic Cosmic Carbone SLR (similar, but not the same as what you asked about).  Also see the testing done by Roues Artisanales [2] where he reviews many wheels including some older Mavic Ksyrium models.  Of course, tests such as these are expensive and time consuming, so we typically can't find wide ranging, scientific test data across all of the current model wheels.

Having said this, there is also a lot of rider data that can guide you as to the ride-ability of these wheels.  For example, on the weight weenie forums [3] SpinnerTim said that the Mavic CCs "have strictly traditional deep-rim stability issues in cross winds. These ride the way deep rims like mid-decade 404s or Lightweight Standards rode when V-sections were the rule...".  In short, the CC SLE will provide some aero benefits from the front, but isn't the best in cross winds.

The Ksyrium is kind of the opposite.  It isn't a particularly aero wheel, but will also have pretty normal / average performance with cross winds because there isn't much there to catch the wind anyway.

For improved aerodynamics at various wind angles, I would encourage you to look at some of the more modern wheel shapes.  Things like the Smart ENVE System or the Zipp Firecrest.  Even the Mavic CC 40C is likely to provide better cross wind handling than the SLE [4,5].

[1] http://www.tour-magazin.de/services/qtr/epaper_4_2011/page67.html#/96

[2] http://www.rouesartisanales.com/article-15505311.html

[3] http://weightweenies.starbike.com/forum/viewtopic.php?f=3&t=109139

[4] http://cyclecraft.wordpress.com/2013/05/23/tested-mavic-cc40-carbon-clincher-wheelset/

[5] http://www.bikerumor.com/2013/05/06/first-impressions-early-miles-on-the-mavic-cosmic-carbone-40-c/


Changing Campy index downtube shifters to 'only' do friction shifting

I'm not familiar with those shifters but perhaps this will be of assistance: Campy Syncro 2 shifters

The left/front shifter is a standard friction shifter.
To convert (the right one) to pure friction, you can actually just remove the springs and optionally the boss collar -- the springs are all that is required to (re)move.


Shimano Claris FH-2400 Rear Hub Dimensions

Details found here: http://productinfo.shimano.com/specifications.html

Spoke Hole P.C.D. Left/Right (mm) 45
Flange distance (mm) 57.9
Dish (mm) 8.4

Based on these figures, I would calculate the following values for your chosen Spoke Length Calculator:

Centreline to Left flange: 37.35mm
Centreline to Right flange: 20.55

Spoke hole diameter is not given.


How to get a replacement crankset gear for Dahon P8?

Any chainring that has the same bolt circle diameter (BCD) and the same number of bolts as your crank is compatible with your crank. The ever helpful Sheldon Brown has a page describing how to measure your BCD.  The way you do it is dependent on how many bolts you have so I won't go into the details here.

While a chainring may be compatible with your crank, there are other problems you can run into...

Depending on your chain, you may or may not be able to use a chainring that was designed for a different chain, e.g., a 9-speed chainring with an 8-speed chain. Many people do this with success while many others have problems. It's probably easiest to just get one that you're sure matches.

You also may have problems going bigger or smaller than your current chainring. Whether or not this is the case depends on your front derailleur and the amount of clearance you have on your frame. Derailleurs have a minimum and maximum number of teeth they can accommodate. Check the specs on your derailleur to find out what these are. The frame clearance is a bit more guesswork. It's kind of hard for me to tell from the picture how much of an issue it would be, but if you're going to go bigger you just want to be sure that nothing's rubbing when the chain is on the ring. If you're dead set on a bigger ring, you might be able to get a little wiggle room through spacers or a longer bottom bracket spindle but it's usually not enough to be worth the hassle.

As Benzo points out in the comments, the chain guides also limit the size of chainring that you can use. Consult with your manual and/or an experienced technician to determine what sizes yours will accommodate. Or plan on replacing those as well.


BB and Crank compatibility with Pressfit 86.5

Pressfit 86.5 is really PF86.

As outlined in this BikeRadar guide (or this from Problem Solvers), your crank options are: "Standard 24mm external-type (Shimano Hollowtech II, SRAM/Truvativ GXP, Campagnolo Ultra-Torque, FSA MegaExo, Race Face X-Type, etc), BB386 EVO".

The bottom bracket options are corresponding BB86 sized options.

You can't use a BB30 crankset/BB.


I want to tell you you have a classic old bike with original components and you should preserve it that way, but I'll provide some guidance.

Be aware there may be many things that need fixing in order to make the bike truly usable. If you just want a bike that works better for everyday riding an option is to sell the Italvega and buy a used modern bike.

If you want to get the drivetrain working better, you may not actually need to replace the derailleurs or crank. A new chain and freewheel may be enough. You likely have an Italian standard thread size on the hub which is a little different from the modern standard thread size, but according to this page a modern freewheel will actually fit.

Replacing the brake and shifter cables and their housings will also make a big difference.

If you need to replace the derailleur the easiest thing to do is get a low-end Shimano Tourney level derailleur that will work just fine with the analog shift levers.

Replacing the crank is a slightly trickier proposition as you very likely have an Italian threaded bottom bracket, which is different from the modern standard. However, I believe Italian threaded square taper axle bottom brackets are available which would allow you to fit an inexpensive new crank.

I'd also want to check out the wheel bearings, head (steering) bearings, and service and regrease them. You may also find that you crank just needs a bearing service if the rings are not too worn.


Can an 8 speed chain fit inside an 11 speed Shimano 105 (RD-R7000 ) rear derailleur?

The internal width of the chain will be fine, as this has not changed in decades, so it will roll over the cogs and jockey wheels. The problem will be the external width of the chain.  It will probably not fit though the 11 Speed derailleur cage, and if it does is likely to rub in some gear combinations. According to Park Tools, 11speed is 5.5mm and 8 speed is 7mm.
On balance it is one of those things that might work, might not, where 'work' is something you define. If it works, mixing and matching components like this is as likely to end up with Claris performance at 105 prices as anything.


This handy chart shows the recommended pressure for different rider weights.
Sadly it doesn't help you or me, both our weights are off the chart.

My road bike has 700x25 tyres, so I picked 100 PSI and aim for just over that when inflating.  The tyres are rated to 120 but that feels harsh and I get a lot more flats at those pressures.

Added: Since your tyres say maximum pressure of 90 PSI, you shouldn't go much over that.  Kenda's specs say 90 psi is the maximum for the "kenda street black mocha" so while they will survive more, the question is how much more.  Instead, consider replacing them with tyres that are suitable for higher pressures.

Note: This chart is purely referencing road tyre pressures.  If you have a MTB the pressures drop off really quickly.

Answer: I wouldn't go much over 90 PSI, but others have routinely put 100 PSI in Kenda tyres without issue.  Your weight suggests that a higher max-pressure tyre would be the best solution, aim for 120 PSI capable tyres in 28 width.


Difference of bottom bracket cup materials: resin, plastic, metal

You have the pros and cons pretty much down. I'll add a couple:

Metal cups are stiffer.
Plastic/resin cups are less expensive.

I am not familiar with resin, but I would suppose it has similar characteristics to plastic.

From what I've seen, all the higher-end bbs use metal. Probably meaning that the only reason plastic is used is to reduce costs.

As a competent mechanic who has changed many bbs, I would favor metal. I'm not worried about cross-threading, and greasing the threads removes the potential for corrosion.


9/10 it’s a tiny sharp object like a sliver of wire stuck in the tire. Take the tube out of the tire, pump it up really big, run the tube through your hand until you feel where the air is coming out. Then look at the tire in that spot and find the thing that poked a hole in the tube.

Alternatively, switch to tubeless and don’t worry about small punctures anymore.


Tubeless conversion on schrader valve rims

I mean, put enough Stans in to the wheels, and you can run tubeless on just about any rim setup.

If you have non-tubeless tires, you may run in to an issue with the tires themselves being too porous, and that is hard to get around.  But I imagine that the combination of rim-tape, grommet, and Stans will be fine.  The rubber wedge/plug thing on the base of the Stans valve stems is pretty wide, I bet it would work even without the grommet.


Need Advice with upgrading Chainrings / Crankset

Because you say you have Apex rings and the specs list the S150 crank, it's not clear which crank you have, Apex or S150. Either could have the rings swapped to 52/36 just by getting new rings. If you were to do that, the simplest path would be getting the SRAM 10spd 110x52 and 110x36 that are still available, although you may have to hunt around for them a little. If you were to use another brand or 11spd SRAM rings, you could probably get it working fine, but it wouldn't necessarily "just work" as easily, may require thin spacers with the 11spd, etc.

If you have any Apex GXP crank you could switch to any other GXP road crank without having to mess with the BB. If you have the S150 that means you've got a Powerspline BB, which can only go on other Powerspline cranks if you wanted to re-use it.

Depending on prior chain sizing choices you may (probably) need a new chain to accommodate the 52. Even if not, it's still a good idea to pair new rings with a new chain. If your cassette is fairly worn it's good to replace that at the same time. Don't worry about it if it's pretty fresh. If it's somewhere in the middle it's a judgment call, but depending on how $$$ of a cassette you go with it can easily be the more economical choice in terms of saving chainring wear.


New Trek 1.5 wheels need to be trued after 2 rides, normal?

I'd say it can be normal because there are many factors can stress a wheel and depends on the quality of the wheels, they might need to be trued again. There's an article about how they build wheels at Bontrager: Inside Bontrager Wheel Factory.

tldr;

Expensive wheels are trued, stressed, trued, and stressed again, trued again. Your wheels were trued in the factory (maybe only once), then you stressed them and now somebody needs to true them again.


I suggest cutting the broken loop off and using a cable ("zip") tie through the big triangular loop.  Two cable ties chained together may help it lie flatter.  As an alternative a short loop of bungee cord would also do the trick (available from camping shops).

Thats actually nicer than most lock holders, and seems worth saving.

Edit:Picture:


I have around 1 year touring experience in South America. Mostly remote dirt roads and trails.

I would never ever purposely run tubes again.

As long as you are confident in your tubeless setup flats should be almost nonexistent. I only carry one tube for emergency that has never been used. A small bottle of spare sealant is pretty essential to top off if you start to get small air leaks. Needle and thread to sew small cuts, as well as tire plugs. A few patches if you are forced to use a tube.

All decently large size cities in Chile and Argentina should be fairly well supplied with bike parts (somewhat less so in other countries in my experience). If not, then it is usually easy to travel by bus somewhere bigger. If you are in big cities (especially capital cities) can be good to stock up or change parts, especially if you are headed to remote areas.

Tubeless sealant is becoming more and more ubiquitous, especially in MTB communities. Usually these guys are not running tubeless specific tires, and they make it work. 650b mountain bike tires will be easier to find than road or gravel tires (could be an issue, not sure what tire clearance a kona rove has?).

SRAM parts can be much trickier to find than Shimano. Old shimano standards are king. Dub and GXP bottom brackets/chainrings could be difficult (especially 1x). I believe Peru only recently has an official SRAM importer.

I would carry plenty of extra brake pads, they are light and depending on your brake model could be difficult to find.

Generally just keep an eye on parts. Be religious about cleaning and oiling your chain. Have a good idea for what is wearing and when you might need to replace it, and plan ahead.


Preload on Haro mountain bike fork not working

Lockout
Looking up the HL CH-389 fork shows that it can have a lockout lever, which will stop the fork being able to compress if it is on. I can't see a lockout lever in the specs or pictures of the Haro Flightline One but I may not be looking at your exact version/year.
So my first step would be to check on top of the other fork leg to see if you have a lockout lever, and if you do have one then make sure it's not in the lockout position. If you are unsure if it has lockout then post a picture of the top of the other fork leg.
Fork Problem
The other reason the fork may not compress easily could be it needs a service or the fork is faulty or damaged. But a bike shop should be able tell you if the fork is performing as it should just by trying it.
Preload
Often preload adjusters do not click, so I would not worry if it doesn't click when you turn it. Damping adjusters (rebound for example) will usually click but they are a different adjuster for a different purpose.
At the moment you don't know what the preload is currently set to so you can't be sure if it's already set to maximum or minimum.
To check if the adjuster is working and see if you are at either end of the limits you should try turning it both directions and see which direction(s) it will turn in. If it will turn only in one direction or is a lot easier to turn in one direction from where it is now then it's likely you are at one end of the adjustment limit.
It should turn relatively easily when not at either end of its range, especially when turned anti-clockwise as reducing preload is easier than adding preload (when adding preload you are compressing the spring which makes it harder to turn).
If you get it turning, you can then work out what the maximum and minimum are, most preload adjusters will have a range that's multiple full turns, something like 3-5 turns from min to max.
If it's very stiff to turn in both directions and does not get easier at all then the adjuster may be the problem. This can be serviced as per Jeff's instructions or replaced if the part is available.
Preload adjustment is fine-tuning and may not dramatically change how hard/soft a fork is. If you need more adjustment than the preload provides you would need to look at changing the spring weight in the fork.


If the frames are being designed on a computer, CAD tools may help but these are high tech. Companies spend a lot of money on doing detailed analysis for durability and strength of frames. I don't know what design tools people did other than force diagrams and other mechanical engineering things before computers (which use a lot of finite element methods) in the bicycle industry, but a simple civil engineering stress visualization method was building models out of a photoelastic material and seeing where the stresses built up.

Several articles have been written on doing (multiple links) tests for bicycles, normally with some applied stress then measuring deflection. You can try to mimic them on a unicycle to some extent, but they don't have all the same parts that a bicycle has, and testing for trick ability is even harder. They can also build a few frames and run them until they break in stress testing (which would be hard to do if people are building these bamboo unicycles by hand).

Unfortunately, the low tech way to test this will likely be just taking the thing out for a spin (and likely getting injured [especially if the people making these frames don't have experience designing unicycle frames and/or don't understand the properties of bamboo  (for example, how do you join 2 bamboo pieces appropriately?)]). There are companies which make bicycles out of bamboo, so you may want to look up some bamboo bicycle builders and try to talk to them about it (since they're botique manufacturers, they will likely not have as much if any testing going on; however, they've likely trained as regular frame builders before so have some intuition on how to design the bikes).

I should add that there are likely legal liability issues which will come up in this challenge - everything stated in this post is at your own risk, obviously. I'd think its non-trivial to make half decent unicycle without having the ability to do tricks to begin with, though.


It looks like the T822. But I don't think you necessarily need an exact replacement. Shimano, Campagnolo, and other companies have made bottom-bracket direct-mounted brakes as well, and any of them would probably be a drop-in replacement, although clearance could be tight. I think the T850 would also work.


I can remove crank arms without a crank puller, is this a problem? I'm worried the crankarms might be loose

If you are able to seat the crank arm onto the axle such that it hits the green area you marked (i.e., it will slide all the way down the taper), then the crank arm is "worn out." The taper on the crank has been enlarged by wear or over tightening to the point where it can no longer form a solid connection to the axle. The "right" fix would be a new crank arm, but it seems like you could try the ideas suggested in the comments above. Do check the condition described by @mikes, if the axle is sticking out beyond the crank arm then grinding will not work, but then you are also likely to have quite a bit of room for a shim :-).

If you're game to experiment, my biggest concern would be that there might be cracks starting to develop in the corners of the crank arm socket from the stresses of the arm trying to rotate on the axle. Eventually those could lead to the crank arm failing at the socket.


How to remove the broken ball end of a small hex key that is now stuck inside the socket

Chances are you were turning it clockwise when it broke. By tapping it anti-clockwise with a small drift or cold chisel, it may unjam it, when a magnet along with gravity and tapping should release it.


What is the correct way to close roll-down Ortlieb panniers?

If you rolled it to the front it would not look like that picture.  Yes you roll it to the back.  I have some Front Roller - not making this up.


Shimano 8/9/10 speed freehub conversion to 11 speed does not appear possible due to changed spline pattern

There is no remotely practical way of doing it. It's possible that could change in the future as 11 trickles down more, but probably not likely given that the interface is also different on the standard axle, less expensive 11-speed road hubs they've already made.

Just to be clear though, 11-speed MTB cassettes do not require a new longer freehub, because the large cog overhangs.


Is it safe to ride a dual suspension bike in sub freezing temps?

If you're riding in temperatures that are only a few degrees below zero, I wouldn't worry too much. As suggested elsewhere, make sure you keep a closer eye on maintenance (brushing off snow/ice, lubrication, etc).

The colder it gets though, the greater the risk that drivetrain components will fail. I've had at least free hubs, where the pawls would stop engaging (i.e. no forward propulsion). I'd say that all your parts will be more brittle in such conditions, so take it easier on your bike than you would normally.

Also, I've heard anecdotally that it's better to store your bike at sub-freezing temperatures if you ride regularly in the cold. The reasoning is that the snow and ice on your bike won't melt and find it's way into moving parts. This will be more important with the pivots on a dual suspension.


Can e-bikes speed up my commute? Which class?

Of course an ebike will be less effort and leave you less sweaty. And of course the faster the bike, the shorter the commute.

Class I: The key thing about this is that it's pedal assist only. The motor will only turn on while you're pedalling -- and it'll cut off at 20 mph -- so going faster than that will require you to pedal. Going downhill with a backwind and pedaling like a demon, you could feasibly go 40mph or faster.

Class II: These bikes have a throttle (combined usually with a pedal sensor) so the motor can turn on without pedaling. So you can go from 0 to 19.9mph without pedaling. At 20mph, regardless of whether you're using the throttle or pedal-assist, the motor will cut out and you'll have to pedal to go any faster or to maintain speed -- note that these bikes are usually heavy so even pedaling you're more than likely to quickly lose speed back down to 19.9mph unless you are pretty buff or you're going downhill. Technically, Class II  are limited to 20mph for electric assist but it's often possible to bypass that control with a firmware upgrade or setting in the control panel.

  Speed Limiters: On most Class I and II bikes, the speed limiter is a hard cutoff. The motor can give you 100% power up until 19.9 mph and then when you hit 20.0 mph, the motor gives you 0% power and you have to pedal to maintain speed. The bike usually quickly loses speed (as pedaling a heavy bike at 20.0 mph is non-trivial) and the motor kicks back in at 19.9 mph. This can cause some jerkiness around the speed-limiter zone especially if you were using pedal-assist because the bike suddenly gets very heavy at 20 mph (it's not as noticeable with a throttle, where it just feels like the motor is cutting in and out).  More expensive bikes will more smoothly ramp the power down: 100% power at 19.0 mph; 80% power at 19.2 mph; 60% at 19.4; etc. etc. and then smoothly ramp the power back up while  you're accelerating.

Class III: These bikes have a throttle (combined usually with a pedal sensor) so the motor can turn on without pedaling. These are limited to 28mph for electric assist but it's often possible to bypass that control with a firmware upgrade or setting in the control panel.  For example, some are sold with an "off-road only" switch.

All of these are limited to 750 watts of electric assist power as well. For more info: https://electricbikereview.com/guides/electric-bike-classes/


Mounting a 12v motorcycle light on bike seat rails?

Similar lights are often fitted to pannier racks, especially on e-bikes. I've had a plastic part with the right holes that would be easy to modify, but it came with a topeak rack.

It wouldn't be hard to fabricate something. The easiest way is probably to start with a saddle mount for a water bottle cage and make an aluminum plate. Some sellers of offcut sheet metal on ebay will cut to size, then you'd only need to drill the holes, but you can cut it with a hacksaw. I'd probably use 3mm plate.

I assume you've been sensible about light levels and colours and won't dazzle or confuse anyone.


Friction shifting 9 speeds using an 11 speed rear derailleur

It won't necessarily just work, and there is a way of predicting whether it will with good accuracy, barring a borderline case.

If it's a Shimano 7, 8, 9, or 10 shifter in friction mode, it probably won't work.

Friction shifters have some variance in their total cable pull between models. It's easy to measure by marking the cable and using a ruler or caliper to note the total movement of the mark.

Take that total cable pull number and multiply it by the actuation ratio of the rear derailleur. For Shimano road 11, it's basically 1.4. That number has to be equal to or greater than the total cog-to-cog distance of the cassette, which for Shimano 9 is about 34.8mm. If it's less, the rear derailleur won't have enough total movement.

The reason there can be borderline cases is because rear derailleur movement for a given input is actually a curve, not a perfect ratio, and the exact start to finish value is going to depend on the high limit setting. But it's pretty close to just being a ratio.

A 7/8/9/10 Shimano shifter in friction mode has a little bit of movement beyond where its last detent position would have been, but not very much. Since these generations are designed to pair with a 1.7 actuation ratio rear derailleur, that small bit of movement is not likely to be enough to compensate for the fairly large difference in actuation ratio.

I don't have any experience putting 9-speed chains in 11-speed derailleurs. Sometimes that direction of mismatch can cause rub between the derailleur inner cage and the chain. 9 speed chains don't tend to experience this in 10 speed derailleurs and 11 speed chains are only something like 0.2mm narrower than 10, so 0.1mm per side. It will probably be fine to run 9 but you could do 10 or 11 to be safe. The shifting may be laggier but it's unlikely to matter with friction.


Trek 26" mtb disc, how to change up crank set /gear size?

There are several things to consider. As @Batman has suggested you may have a clearance issue between the 48 tooth gear and the chain stay. The chainstay is the part of the frame that extends from the bottom bracket to the rear drop out. Because it tends to widen as it gets closer to the rear axle it may hit the largest ring gear. You may also have an issue with the bottom bracket axle length. Different offsets may move the new crank in or out. Offset is the distance from the inner face of the smallest ring gear to the point the axle enter the crank arm. This may be mitigated by staying with the same brand but not guaranteed. You may also be beyond the tooth capacity of the rear derailleur. This is calculated by adding the tooth difference of the cassette and the tooth difference of the crank. A 12-32 cassette would have a difference of 20, a 22-32-42 crank has a difference of 20. The derailleur must have a 40 tooth capacity. The front derailleur must be compatable with a 48 tooth gear. If all this seems like a lot your chain may be to short when you are done.


What chainrings are compatible with the Dura Ace 7900 crankset (apart from 7900 chainrings)?

You need to check on three things to ensure that your new chainrings will work:

The number of arms on your spider. Road bikes typically have five.
The bolt spacing. This is most commonly expressed in BCD, or Bolt Center Diameter. The idea of BCD is a simple one, it's the distance from the center of a crankbolt to the crankbolt immediately opposite it on the crank. However, this is not necessarily an easy thing to measure. For one, the crank is not flat and it's difficult to measure across the bulge in the middle. Further, on a five arm spider the measurement has to be taken from an imaginary bolt since no bolt has a direct opposite. However, Sheldon Brown comes to the rescue as usual. His site has an explanation of how to find the BCD measurement with a ruler and a bit of math.
It is also a good idea to consider is the original chain compatibility (compatible with 9-speed or 10-speed). 10-speed chainrings should be used on a 10-speed drivetrain, but you can probably still get away with using 9-speed stuff in most cases. The chainrings may vary in width slightly due to slightly narrower chains on 10-speed drivetrains. It's rarely a problem using a ring that is too narrow on a larger chain, however you probably couldn't use an chainring intended for an 8-speed drivetrain on 10-speed drivetrain.


What are the advantages of angling your saddle down?

In general, I don't know why one would do this. Especially men.

Here's what Sheldon Brown has to say, and I tend to agree:
"If the saddle is tilted down in front, the rider will tend to slide forward onto the narrower part of the saddle. Women who are riding on saddles that were designed for men frequently tilt their saddles down. This will relieve some of the discomfort from the saddle itself, but creates new problems: The downward slope of the saddle causes the rider to tend to slide forward, and this can only be counteracted by pressure on the hands. Thus, poorly-angled saddles often are the cause of wrist, shoulder and neck problems, due to carrying too much of the rider's weight on the hands."

Lennard Zinn mentions that a "very slight" tilt in either direction may be optimal for some riders; but no more than ~2 degrees. Basically the same reasons that Sheldon Brown mentions. The downward forward tilt adds pressure on the arms, back, and shoulders due to sliding forward.

You want your "sit bones" to be on the widest part of the saddle. If you slide forward, the pressure will shift from the sit bones to the perineum; and that's probably a bad thing. There are special cases for tilting the saddle nose downward; but for the general rider it's not necessary.


How do I evaluate the value of a used bike?

Well, the simple answer is a bike is worth as much as someone is willing to pay for it.

As guidelines, a few websites may be useful:

Craigslist (See what similar bikes are going for in your area)
EBay (Online retailer)
Bicycle Blue Book (Gives values for certain bikes; can be useful as a rough guideline)
Bikepedia (Gives values for certain bikes when new, along with their original components)
Velobase (Database of vintage cycling and marketplace)