What is the simplest way to lower the gearing on my touring bike?

I think everyone has provided some pretty sound advice, especially Daniel Hicks and his recommendation to go with the quickest and cost effective option by replacing your chainrings! With a 130/74 BCD, an ideal setup would be to swap in a 24/36/48 which would give you a great range at a cheap price.

The front derailleur is probably the least necessary component on your bike and, while shifting compatibility is a concern, I would recommend swapping in your new chainrings and setting everything up to test for compatibility before spending more money on a new derailleur. I have used mountain FDs on road triples and road FDs on mountain triples with a variety of indexed and non-indexed shifters and have had very little trouble over the years. Really, the only requirement is ensuring that the front derailleur is a triple and has the correct seat tube diameter/pull direction. (Your cascade of compatibility issues is something I've dealt with, but don't worry! There are lots of manufacturers who design compatibility issues into their gear, but they generally don't cater to the average touring enthusiast.)

Since you have an SGS derailleur (long-cage) you shouldn't have any issue with chain slack. For touring, the Deore SGS set up with an 11-32 is a great choice. At most, you may prefer to remove 1 or 2 links just to clean everything up. (I ride in New England on 24/38/48 x 13-32 and even with a full load I maybe walk it once a year).

When you start changing components such as your crankset you have to deal with special tools, frame clearance issues, bottom bracket fit, and Q-factor (the horizontal distance between your pedals). Mountain cranks have smaller BCDs but have much wider Q-factors which, for some people, can cause knee and hip irritation (which is exacerbated by long rides and clipless pedals). Long story short, if you are comfortable with your bikes ergonomics on long rides, leave it (or give yourself enough time to work out the bugs before attempting a 2k fully loaded).

Otherwise, take things one step at a time. If smaller chainrings don't give you enough oomph, throw on a new cassette which is quick and has few compatibility issues (12-36 is a common low touring range). More compact road cranks have a 110/74 BCD which won't help you on the low end (though, if your leg length permits a longer crank arm it might provide a very small advantage). Some mountain cranks have BCDs as low as 58mm x 20t, but I suspect that this option may be more trouble than it is worth. Some handy online gear resources include: rivbike.com, velo-orange.com, universalcycles.com, and sheldonbrown.com.

A cheaper way to ease the inherent suffering of long, steep climbs would be to trim some bike fat and touring load (a good technical and philosophical resource might be The Ultralight Backpacker by Ryel Kestenbaum or Just Ride by Grant Petersen). Some people might recommend trimming some actual fat, but we live in a world where everyone gets to ride a bike, not just 130 pound-25-year-olds. (No offense to the 25-year-old cyclists out there!)


Have some new parts on hand but need new frame - frame swap reasonable? or sell and purchase new bike?

Well, it depends…

Would you be happier cleaning a bunch of stuff out and getting a shiny new bike that reflects all you've learned? One that will "just work," or

Would it be a fun project to build up a bike from scratch? Would it feel good to know that you'd "built it yourself?" Do you have the time for the project? Is it ok with you to get stuck and make some mistakes – probably "wasting" some time and/or money?

If you decide to build, there are likely to be some unexpected "gotchas" along the way. So it is worth doing some reading and searching to see if others have run into similar problems. Sheldon Brown has a good piece on Upgrading Older Road Bicycles that may help you start thinking about the possible problems. Overtime the morass of bicycle standards has sorted itself out (a bit) so some of the problems that he mentions may not be issues. If you're looking at a frame you may find that the builder/seller publishes the key specs so that you can buy the correct parts. The specs will help you identify where the problems may lie. Some of the ones that come immediately to mind are:

Frame size and stem type, this decides if you can use your existing stem and the length of the stem you'll need.
Rear dropout spacing. This will decide how easy it is to use your old wheels.
Seat tube diameter (affects seatpost size and the front derailer clamp size).
Brake type and reach (distance from the mounting bolt to the rims, this is mostly an issue for caliper brakes).
Tire clearance.
The bottom bracket. It used to be that frame builders were tending towards 68 mm wide bottom brackets with British threads, but now there is a whole new generation of bottom bracket designs, so you may find that you'll either need to pick a frame to match your old one, or get a new one.

I tend to lean towards the build side, but that's partly because I can't afford the bike I really want…


Play in headset with no upper bearings on a tandem bicycle

A single bearing race really isn't very good at resisting torque perpendicular to its axis, so I'd be surprised if there wasn't meant to be a set of bearings in the top. Even closely spaced sets of bearings aren't great in that regard. Unless there's a special arrangement inserted from below, the lack of a top bearing would be likely to cause play, and possibly damage. The lower bearing should be checked in any case. The load on a tandem is quite high so I'd expect a robust design using the full available steerer tube length.


What's the purpose of the boot on a v-brake?

The idea is that it keeps the dirt and water that would otherwise get kicked on to the cable from getting worked into the noodle, contaminating the cable system and causing friction, corrosion, and poor brake feel.


Can I attach SRAM trigger shifters to a 31.8mm braze on adapter?

The Matchmaker interface has a little bit more going on than that. As you can see in this illustration from the SRAM Shifter and Brake Lever User Manual, the mating surfaces of the mount and the shifter are profiled for a secure fit.

It is true that you could probably make something that does the same job. A braze on FD adaptor with a flatted section filed on doesn't strike me as putting the shifter far enough away from the bar, but that's just a guess.
If a little metalworking doesn't bother you and running a mountain shifter is what you want to do, just filing a normal 22.2 shifter mount so it clamps reasonably on your presumably 23.8 main bar diameter is also probably an option. Depending on what bullhorn you have, this may put the shifter in a more useful section of the bar.
My vote for best present-day way to do what you're after here is run it di2 with a climbing shifter only. You can pair it with any current di2 RD you want, mountain or road. Super clean, super functional.


Are aluminum or steel chainrings more resistant to bending?

As far as My experience gets on mountain biking, cheap steel is more resistant than cheap aluminum, with expensive parts the story changes a lot because many different alloys are used by different manufacturers or even the same manufacturer changes the formula among models.

The advantage of steel anyway is that it can be safely unbent as long as the deformation is not too dramatic.

However, in my case, most of the bent chainrings come from hitting objects on rough trails, except one time that it was due to one of the chainring bolts comming off. I have been kind of a masher myself, but I have never bent a chainring due to pedaling force (I have broken a couple cheap freewheels due to this instead). So I think some other factor may be affecting your problem. A couple of them are:

Chainline: The pull on the chain should be pretty straight, so even under extreme forces it is unlikely to bend a chainring/cog. However a bad chainline makes the chain pull in a direction that is too unalligned with the chanring's plane. This can be due to a bad combination of components, specially a bottom bracket of the wrong spindle length, or, more commonly, a bad choice of gears. In a mountain bike the innermost chainring should be used with the 3-5 closest-to-hub cogs, the outermost chainring should be used with the 3-5 furtest-from-hub cogs and if there is a middle chainring it shoud be used (you guessed it) with the cogs in the middle of the cassete. Check the chailine of the gearing you are using most by looking at the chain so your line of sight is aligned with the point where thr chain leaves the cog and with the point where it enters the chainring. If the chainline is wrong you should esily note how the chain bends at the entering-the-chainring point.
Frame flex: If your frame flexes easily and you are mashing your pedals, both factors add up so when you are applying maximum force, components are most unaligned, causing forces to actuate on parts at wrong angles, thus making them prone to deformation, but the problem is not evident while evaluating the bike onthe workstand.
Bad shifting technique: Shifting gears while applying too much force causes all kind of transmission problems, from bent chainring teeth to bent chain links, broken chains, premature wear and even derailleur malfunction/damage. Proper technique, specially for downshifting while masshing pedals up a steep slope is to a) plan prior to shifting, specially shifting before you exhaust your momentum. b) Accelerate a little just before the shift. c) Ease the force on the pedals while at the same time applying the gearshift. During the whole shifting process you should practically just spin the cranks, you rely on innertia to continue in movement and that is what the previous acceleration was for. d) resume normal pedaling once the shift has completed and the transmission is working silently again. (noise is often a sign of bad shifting).
Bent parts: There may be something else bent on the bike. Particularily the crank spider or even the whole crankarm. If thats the case, it is making you loose the chainline at least two times per pedal revolution, once towards one side, once towards the other. This has happened to me with cheap, soft aluminum, square taper crankarms: with heavy use, the spindle interface deformed, causing the whole crankset to rotate off axis causing a set of not-so-funny symptoms, including chainsnap and front shifting difficulties. Careful inspection on the workbench wile manually rotating the cranks is advised. If this is the case, it is diagnosable by eye or a simple ruler/metric tape. A bent frame is less likely but not impossible, however, it may be harder to diagnose.


Air suspension unit for relatively low mass

I don't think (like the other answers) a suspension fork will do it.  There's another reason as well - suspension forks only isolate vibrations in one linear dimension, as you go over bumps, as well as up and down you will accelerate and decelerate, and pitch up and down.  So here are some other thoughts.  We might be able to offer more help if you give some idea of what the object is.

It's not unknown to use an underinflated inner tube as a shock absorber for light loads - but that's generally a flat object on a flat surface.  Providing suspension for a light object can be done by hanging it in a frame using bungee cords (shock cords).  The rubber provides some damping so it's better than just springs.  Might be hard to fit between you and the bars - but then if I was doing 30km/h over rough ground I wouldn't want a set of forks pointing at my chest as you've shown.  Either on a modified rack behind or in a modified front basket would be better.

Whatever means you use, for best performance you need to tune the system - with some means of sensing the vibration (smartphone app these days?) and adjusting either the thickness of the cords or the mass.


How long will I survive? 5 wheel spokes missing

Nope. Don't ride it. It's hosed. You risk catastrophic failure riding this wheel, Other spokes will snap soon due to more load put on them and uneven tension. That is if it's even true enough to not rub the brakes or chainstays.

You could replace the broken spokes and have a working wheel if your rim wasn't damaged severly like it appears to be. If you've rode on this for a while, there is a chance that the existing spokes are over stressed and should be replaced as well. I would rebuild the wheel with new spokes and rim if it was my bike.


From what I can see here:

http://www.conti-online.com/generator/www/de/en/continental/bicycle/general/innovation/Protection_en.html

...you are going to have an excellent tire. These tight-fabric protection (kevlar or aramid, I guess) work great (at least are working great in my Marathon XR).

For XC and off-road, I think the tight fabric might be preferred over the thick-inner-rubber protection (a la Schwalbe Marathon Plus) due to performance issues (weight and rigidity, mostly).

Another option would be to use anti-puncture tape (Mr.Tuff, Sttones) between the tire and the tube. On the road, these have served me very well (after I finally gave up being skeptical - suffered so long in vain...). In the other hand, on off-road, where pressures are lower and tire deformation is higher, perhaps the built-in protection is a better choice.

Hope this helps


As you are starting from nothing, it doesn't matter whether you use a freewheel or a cassette. The 7 speed chains are the same regardless. I would look around for a secondhand wheel, as it will be much cheaper, and you'll want one that comes with cogs, tyre etc.
If you are lucky the chain isn't too worn, and it will just work. You may, perhaps, need to adjust the gears as the offset might be different


Can a 9x3 front derailleur fit on a 7x3 configuration?

Yes. A front derailleur marketed as for a 9 speed system will work normally with your 7 speed set up. Really the front derailleur doesn't care how many cogs are in the back.  Generally, using a front drive system designed and marketed for "X"-speed systems will work in an "X+/-1" system.  For example, I use 10 speed crankset in combination with a 9 speed rear drive.  In addition mixing brands of shifter and front derailleur is possible (a SRAM front shifter can be paired with a Shimano front der and vice-versa) resulting in normal performance.  This does not hold true for the rear drive, where brand of shifter and derailleur must match to have normal performance.
Considerations should be given to the cable routing of your bike: does the front derailleur cable approach the der from the top? Or from the bottom?  Front derailleur's are designed to be actuated either by cable pulling from above (top-pull) or from below it (bottom-pull). Which type you require is based on your bike's designed cable routing.  Many front ders these days are termed "dual-pull" and are actuated from either a top pull or bottom pull cabling.  The bike determines this requirement.
Related to this is how the front derailleur mounts to the bike. Most commonly a clamp band is used around the seat tube and this serves as a mount point and by virtue of the design is manipulated to get the derailleur in proper alignment with the chainrings. A bicycle will be built utilizing one of three different sizes of seat tube diameter, the front derailleur must have the correct size clamp band (or come with shims allowing proper fitting).  There are other mounting designs of front ders too.
When a front derailleur is chosen for a particular front drive of a bike, a few important specs must be adhered to achieve nominal performance.  The number of teeth of the largest chainring and the difference in the number of teeth between the largest and middle chainring.  Both of these should match the specs of the front derailleur.
One further thought related to your question and desire to upgrade some componentry. Seven, eight, and nine speed hardware can be considered the same in regards to "speed."  Their derailleur's actuation ratio are the same, meaning the derailleur will move the correct amount to move the chain the correct amount to achieve the correct shift distance whether the shifter is 7, 8 or 9 speed. The right numbered shifter should be used with the same number of cogs.


Yes, all 9-speed Shimano rear derailers share the same actuation ratio as all Shimano 7-speed ones,  except for pre-7700 Dura Ace.

I've never seen a 7-speed chain rub inside a 9-speed RD cage. If somehow that were an issue, an 8-speed chain would work fine.


Damaged paint on fork dropouts (magnesium) – is it dangerous?

It probably won't peel further (you can apply whatever paint you want around the edges if you want), but the issue is just cosmetic.

My suggestion is just to ignore it and move on with life.


Sounds to me like your derailleur is not properly shifting (to the smaller cog) in those gears you mentioned.

First thing to check (imo):
Put the bike in a bike stand or position it upside down, shift onto smallest rear cog.
Watch the cassette/chain whilst pedaling with one hand and shifting with the other hand. Check if the chain properly shifts each time you press the shift button with your hand. Do some shifts require more than 1 'click' of the shifter before the chain moves? Are any cogs being skipped? Are the outer most cogs (biggest/smallest) on your cassette ever reached by the chain (if you cannot shift into these (biggest/smallest cog) your derailleur limits will be improperly adjusted or (for biggest cog) cable tension may be too low.

Probably a cable issue (a cable in bad condition (even though it might look like nothing is wrong with it) can cause issues similar to the one you are describing). Especially when downshifting (to a smaller cog) this can cause issues since when up-shifting you 'pull' the derailleur to the next cog using the cable (you can determine the force on the cable with your thumb so even with a little more cable friction you'll likely be able to up-shift just fine) and when downshifting you are relying on the derailleur spring to move the derailleur into the desired position.

The issue could be with your shifter also but it's less likely in my experience.

A few things to check:

Remove cable from rear derailleur by undoing the cable clamp bolt, then pull the cable taught with one hand whilst shifting with the other hand. See if the cable moves smoothly through all the gears (both in up-shifting and in down-shifting). If the cable is not moving smoothly in either direction, remove the cable housing from the shift cable and check again, if the problem (cable not moving smoothly) is gone without the cable housing you know the issue lies with said cable housing.
Check the cable housing for any exterior damage (cuts, sharp bends etc.). If you have a lot of spare length (cable housing) and if the damage is near the ends of the housing you could consider shortening the housing to remove the damaged length. If that is not the case replace the entire piece of housing which shows the exterior damage. If the cuts are not deep enough to cut through the plastic/rubber of the cable housing then the cuts might not be a problem. As soon as the cuts result in exposed metal they will rust (if they are not stainless steel) which could very likely cause (undesired) extra cable friction.
Remove the shift cable from the housing and check it for any fraying/rust/loose wires sticking out etc. If the cable is rusty you could clean it with for example steel wool and lubricate it but your best option is to replace it (preferably with a stainless steel variant). If the cable is frayed or damaged in another way definitely replace it.
Check the condition of the cable housing end caps, are they bent/deformed in any way? If so definitely replace them.
Check (without shifter cable attached) the rear derailleur, check how smooth it moves (by pushing it from side to side with your hand), lubricate the linkage pins.
Whilst the shift cable is removed from the rear derailleur, move the derailleur from one side to the other side of the cassette by hand (whilst turning the pedals with your other hand), check if the chain can reach all the cogs (if the limits are set incorrectly the chain might A: not move far enough to reach the biggest/smallest cog or might not move onto said cogs far enough causing it to 'fall off' (jump to the cog next to it) when putting any pedaling force on the chain or B:move too far causing the chain to fall off the cassette (in between frame/cassette or in between hub/spokes and cassette). You should be able to move the derailleur by hand (when the chain is on the biggest/smallest gear) such that the center of the upper jockey wheel of the derailleur is approximately 1-2mm further than the biggest/smallest cog itself. (please check the Park tool video -linked below- on derailleur adjustment for more info on this)

Cable end caps:

I would personally suggest replacing the following:

inner shifter cable
shifter cable housing
shifter cable housing end caps

The cable housing and end caps shouldn't cost much, especially when bought in bulk (10+ meter). You can also buy sets which are meant to replace the cables on just one bike, but they are much more expensive and I have not personally noticed a difference in quality.

There are special pliers for cutting cable housing which are great but you can work with normal side cutters also, just have to make sure the cable is cut straight and when cutting brake housing cables make sure the 'spiral' (metal spiral that runs through the core of the cable housing) doesn't have any sharp pieces sticking out after cutting (you might have to cut a few times to get it perfect).

You can definitely do it yourself. Derailleur will have to be readjusted (cable tension) after you've replaced the cable, there are a lot of tutorials online on how to do that.

Some tutorials you might find useful:
Replace shift cables:

Adjust derailleur:

Note: when replacing the cable you'll only have to re-adjust the cable tension after having installed the new cable (assuming all (other) prior adjustments were correct), it can't hurt to check the other adjustments whilst your at it (how to do that is shown in the video :) )

https://www.parktool.com/blog/repair-help/rear-derailleur-adjustment

Adjusting derailleurs is very doable as long as your cables are in good condition, if they are not then you might be adjusting for an hour and you won't be able to get it to shift correctly (similar to your situation now).

Alternatively:
Your derailleur or derailleur hanger could be bent. You can check this with a derailleur alignment gauge (or in very severe cases it can be seen with the naked eye). On steel frames you can usually bend the derailleur hanger back if it's bent. On aluminum frames you'll have to replace the derailleur hanger (separate piece) if it's bent. This seems quite unlikely based on your description of the cause (backpedaling) but I thought I'd mention it just in case..

Here is some info on derailleur alignment:

Derailleur hanger alignment: https://bit.ly/2TVoYUJ

DIY derailleur hanger alignment tool: https://bit.ly/2RRvbyz

Align derailleur hanger without special tools: https://bit.ly/2TTF6Gj

How to straighten a bent derailleur: https://bit.ly/3aL3VdQ

Some more useful info:

https://www.parktool.com/blog/repair-help/front-derailleur-adjustment
(thank you for the suggestion @Argenti Apparatus )

Hope this helps, let me know if you have any questions.


Does having bigger wheels mean less effort pedaling?

Assuming a completely smooth road and neglecting the weight of the wheels, it makes no difference: you still need to do the same amount of work. Essentially, larger wheels give you a higher gear ratio, so doubling the diameter of the wheels would mean you'd only need to turn them half as many times, so you'd only need to turn the pedals half as many times, but you need to press twice as hard on them.

But, in reality, there are limits to what you can do. If you need to lift 100kg of wood, it's easier to lift 10kg at a time, even though the total work done is the same as when you lift the whole lot at once. Similarly, you'll be more physiologically efficent (and comfortable!) pedalling with certain ranges of cadence and force.

Bigger wheels roll over bumps better. As an easy thought experiment, consider a pit whose width is equal to the diameter of your wheel. Obviously, the wheel will fall right into the pit. But if you consider a wheel with twice that diameter, it will only drop a little way into the pit as it bridges over it.

In practice, though, there aren't a whole lot of wheel sizes to choose from.  Either you get a folding bike with small wheels, or you get a non-folding bike with wheels about 62cm/29in in diameter (or about 56cm/26in for mountain bikes).


In your case, I would purchase based on reviews (for durability) and feel.  Merino have the advantage of tending to stink less.  However, if you are riding only once a week (not sounding like a commute) it's less of an issue for you.  Some people will likely argue that one or the other lasts longer, but the reality is that manufacturing techniques vary so widely that you can find good examples of either extreme in both makes.  Wool generally requires a bit more attention with care (not drying on high).

My sock collection is about 95% wool.  I used to lean towards coolmax (or other synthetics), but wool socks now feel so nice to me that I can't see a reason to go back.  The only synthetic socks I regularly use now are my vapor barriers, which almost always get a wool over the top.


Can I put a 2.3 mountain bike tire on what now has a 2.10 tire. 26 inch

In terms on the rims/wheels, you certainly can.
In terms on the frame and forks, you have to make sure that you have enough clearance for the tyre, plus extra room for the wheel to wobble a bit (wheels/tyres distort during normal use, how much depends on wheels, brakes, frame etc) and room for mud/dirt/ other things.
You also have to consider whether the front derailleur (if you have on) will hit the tyre during use.
I would personally not use a tyre if the clearance on each side is 5mm.
EXTRA:
Wheel wobble link 1 They have issues with tyre rub, possibly due to weak wheel
Wheel wobble link 2 They have issues with tyre rub after increasing tyre width


What bike computer (speedometer) to get for mounting on the rear wheel?

I've decided to go the cheap route - I got a Cateye Enduro 8 (which is wired, but not long enough) and I'll modify it to extend the wire.

If I start using my bike more (or I break the Cateye) I'll look at getting something like the Garmins @zenbike mentioned.


Depends what you mean by city bike and road bike.

If you mean converting a bike with flat bars to one with drop bars there are issues. Flat bar bike frames are typically longer than drop bar frames, because flat bars place the rider's hands closer to the head-tube than drop bar hoods or drops hand positions do. Also, compatibility of brakes, levers/shifters and derailleurs can be problematic.

It is very likely you would end up replacing a significant fraction of the components on the bike, and it would be more cost effective to sell it and buy the bike you want.


Can a worn drive-train be upgraded incrementally or should it be all at once?

It really depends on how worn out the drivetrain is. The best way to check this is by checking your chain with a chain gauge. If the gauge reads under 1.0 you might be alright with just changing the chain out. If it reads 1.0 or higher (ie the guage at its max reading easily fits onto your chain or even has some play) you probably have a toasted drivetrain.  That is not always the case - sometimes I'm surprised by how worn out a drivetrain can appear yet still be improved with a new chain. On the flipside, which is the more common side, if you have a chain that reads completely worn out chances are the rest of your drivetrain has worn with it and replacing the chain will only make things worse. You'll know pretty quickly if this is the case and if it is you'll to start replacing other components:

Replace your chainrings if you chain jumps or chainsucks in the front. Sometimes you can get away with just replacing middle and/or small chainrings as the largest chainring tends nto to wear out as quickly.
Replace your cassette if your chain jumps in the rear or shifts very poorly or both. With newer cassettes there is no option of chainging individual cogs. It's all or nothing.

If you don't own a chain gauge or you're unsure as to what components need to be replaced, find a good mechanic to inspect it for you. They should be able to diagnose your issues and suggest replacement parts as needed.


Explanation on the lineup of Shimano Derailleurs

refer here:
https://productinfo.shimano.com/download/pdf/spec/3.1/en
Mostly this is MARKETING.
Shimano tend to use the same designs for a lot of their products, but typically these are introduced earlier on higher groupsets and are 'trickled down' to lower ones.
Also your picture is quite old and SRAM have since complicated it considerably with its 'Eagle' groupsets.
If you refer here https://si.shimano.com/
then you can look at the actual diagrams for each derailleur
Referring to my first link, the current 'XTR' consists of three derailleurs:

M9100-GS
M9100-SGS
M9120-SGS

then Deore XT is:

M8100-SGS
M8120-SGS

SLX is:

M7100-SGS
M7100-SGS

Deore is:

M6100-SGS
M5100-SGS
M5120-SGS
M4120-SGS

This is the exploded diagram for M9100-GS/SGS
https://si.shimano.com/api/publish/storage/pdf/en/ev/RD-M9100/EV-RD-M9100-4387D.pdf
GS means long cage, and SGS means super long cage
The parts differ in the jockey wheel cage, which is two pieces of metal or carbon fibre enclosing the two jockey wheels
The outer cage is here
https://www.sjscycles.co.uk/gear-spares/shimano-xtr-rdm9100-outer-plate-assembly-sgs-type-y3fa98080/ for SGS
https://www.sjscycles.co.uk/gear-spares/shimano-xtr-rdm9100-outer-plate-assembly-sgs-type-y3fa98070/ for GS
both parts are VERY expensive because if you refer to my first link they are both made from carbon fibre. The SGS is 90mm cage (wheel axle to wheel axle) while GS is 74mm
The spec shows that this is 237g vs 240g, which you might think is nothing and indeed it is, but the spec also notes that the GS is designed for Shimano's 10-45t cassette, and SGS for the 10-51 cassette. Because of the extreme size of modern MTB cassettes, and Shimano's Shadow design (where there is only one sprung pivot, not two), a derailleur that works well with a certain large cog size might not work so well for a smaller cog.
So we can see if we look elsewhere CS-M9100-12 is 357g for the 10-45t and 367g for the 10-51t. Again, this is not a big difference, but if you are a strong athlete and do not need the low cog, then it makes no sense to have it, because with the smaller cassette range you get 28-32-36-40-45 cogs, which are BETTER than 28-33-39-45-51, in that smaller steps mean you can more likely pedal at your best cadence. If you are not a strong athlete that doesn't matter so much, and you'd be grateful for the extra 51t gear on hard climbs.
So the XTR (XT Race) has a philosophy of offering a small adjustment to suit the specific preferences of elite athletes.
The other XTR RD is
https://si.shimano.com/api/publish/storage/pdf/en/ev/RD-M9120/EV-RD-M9120-4388D.pdf
If one looks down to Deore XT, then  M8120 is THE SAME DESIGN as M9120, and M8100-SGS the same design as M9100-SGS
But, the lower knuckle on the XT ('plate body') is GFRP and the one on the XTR is CFRP. The latter is a very high quality material, the former not so much.
The outer cage plate on the XT is aluminium, rather than CFRP:
https://www.sjscycles.co.uk/gear-spares/shimano-deore-xt-rdm8100-outer-plate-assembly-sgs-type-y3fw98080/
and it's 7g heavier as a result (the inner plate is the same)
The XTR uses higher quality lighter fittings, such as this one:

at 10g
whereas the XT is 18g

The jockey wheels on the XTR are 20g vs 26g
https://www.sjscycles.co.uk/gear-spares/shimano-xtr-rdm9100-tension-guide-pulley-set-y3fa98090/
https://www.sjscycles.co.uk/gear-spares/shimano-deore-xt-rdm8100-tension-guide-pulley-set-y3fw98010/
And so on.
This results in the XTR being 44g lighter. So it's slightly lighter, slightly higher quality, and far more expensive.
If you look at SLX, then comparing the table it's almost identical to XT. But the outer cage plate is 66g rather than 35g, as it's made of steel
https://www.sjscycles.co.uk/gear-spares/shimano-slx-rdm7100-outer-plate-assembly-sgs-type-y3fy98050
In addition, SLX (and its road equivalent 105) uses relatively cheap jockey wheels without sealed bearings. An athlete could expect to give up 1W (out of 300W) because of this.
So the SLX and XT derailleurs are all but identical, except for the jockey wheels and a cage plate, and if you had purchased a bike with SLX derailleur then you could very sensibly replace the jockey wheels (which are also more durable). Possibly the cage plate too, although it might be a different colour!
Looking at the M6100 then it appears to be almost identical to the SLX
https://si.shimano.com/api/publish/storage/pdf/en/ev/RD-M6100/EV-RD-M6100-4677.pdf
except there is a slightly different bracket axle, and the inner cage plate is steel rather than aluminium. This adds up to 10g.
Again, you could effectively upgrade your M6100 derailleur to XT level by replacing the jockey wheels, and maybe the cage plates (though this latter is not so crucial, though lighter weight hanging off your wheel can't be a bad thing).
For 2020-1 Shimano have split 'Deore' into three levels:

12-speed
11-speed
10-speed

The latter of these would previously have been known as Alivio, but due to people sharing inaccurate diagrams like  yours they decided to call it 'Deore', as it allows them to sell a lower quality groupset a higher price and most people won't notice.
We can see this if we refer to the M4120 derailleur in the specification table, where we see no 'GFRP', and lots of 'resin', which means 'cheap plastic'. Shimano may use different kinds of 'resin', but it's a sign you have a relatively cheaper derailleur.
If we look at M5100 and the diagram https://si.shimano.com/api/publish/storage/pdf/en/ev/RD-M5100/EV-RD-M5100-4675.pdf
then it turns out it's based on the M8100/M7100/M6100 derailleur
https://si.shimano.com/api/publish/storage/pdf/en/ev/RD-M6100/EV-RD-M6100-4677.pdf
however the spec notes it's '11' rather than '12' speed. The 11-speed jockey wheels have a different part number, so are likely subtly different.
The M5120 and M4120 derailleurs appear to use similar construction, but M5120 has 'Shadow+', which means it has a clutch, whereas M4120 does not. The clutch mechanism is in fact identical across XTR, XT, SLX, Deore.
Looking beyond Deore, scrolling down we find M3100 Alivio, which is in fact (looking at older spec sheets) based on M3000 Acera, so Shimano have reduced the quality of Alivio to Acera level.
Of course there wasn't much difference before. Comparing M3100 Alivio (which would previously have been called Acera) with the M2000 Altus, then the specs show only very minor differences, and it would be hard to call the Alivio a meaningful upgrade on the Altus.
The other difference with Alivio/Acera/Altus/Tourney is they are a different design intended for older drivetrains which used a triple or double front chainset, and a smallish cassette sized 11-36 or 11-34. This is very different from the current Deore-XTR, which use large 10-45 or 10-51 cassettes, which require a different derailleur design.
The distinction specifically with Tourney is that it doesn't follow the 'Shadow' design, which means it uses Shimano's older design, from more than 20 years ago.
The TX800 appears based on RD-M280 from 2012 https://si.shimano.com/api/publish/storage/pdf/en/ev/RD-TX800/EV-RD-TX800-3745.pdf which in turn will be based on much earlier derailleurs.
So there is not necessarily a big quality difference with Tourney, but Shimano don't really guarantee that - for example, a Tourney shifter might use lots of plastic internally whereas Altus might be more metal. It's more that Tourney is outside the groupset hierarchy and is not promoted or marketed - it's their intention to push people toward more profitable parts.
Note also that Tourney parts are typically made in Shimano's Indonesia factory, whereas higher grade parts are made in Malaysia, and the newest parts in Japan. A lot of people prefer 'Japan'.
As far as Di2 goes, Shimano haven't bothered with it for the latest series of parts. Maybe they will in the future. It's an electronic gear shifter for XTR and XT, which adds a motor to the derailleur.  SRAM do have a slightly more advanced version of this called 'AXS', which is wireless.
Actual racers might not use even 'XT', if they aren't sponsored - for example, for brakes SLX and XT turn out to be almost identical, so you might find a bike with XT derailleur and SLX brakes.
As far as Saint goes, it's arguably Shimano's highest quality kit, but it came out in 2012, and uses 10 speeds, not 11 or 12. It's for downhill racing, which means it's strong as a priority, and won't work with a large gear range. It doesn't use any plastic except for the clutch mechanism, and the design is related to circa 2012 XT, and has little to do with modern stuff. Zee is the cheaper version of Saint, so some steel parts in place of aluminium, and SLX/Deore quality jockey wheels rather than the XT-grade sealed bearings on the Saint.
So you can't make too many generalisations, but generally XT is always high quality, XTR is for people who are sponsored or have lots of money, Deore and SLX for drivetrain purposes tend to be very similar, Alivio, Acera and Altus tend to be similar to each other and lower quality than Deore/SLX (but you can't just go by name, as the model number differs), while Tourney might be lower grade, but will lack anything vaguely recent in terms of design. Note also that Tourney has a bunch of different model numbers.
As far as SRAM goes, I don't care too much about them, but they have 'AXS' electronic wireless shifting, and then they have their 'Eagle' brand which refers to 12-speeds, which they got before Shimano. Initially this was very expensive, but now they have released several grades:

XX1 Eagle (Axs)
X01 Eagle (Axs)
GX Eagle
NX Eagle
SX Eagle

and are promoting these. This is quite confusing, as as your diagram shows they used to have the top 3 but not the bottom 2.
I have seen more than a dozen reports of broken SX Eagle derailleurs snapping at the top knuckle, due to use of poor quality plastic, so it's not clear where the quality level comes at all, as because on the one hand they want to promote 'Eagle' = good, but on the other hand the SX Eagle probably comes around Shimano's Alivio level (which is 9 speed vs SRAM's 12) in terms of quality of construction.
So don't believe for a moment that SRAM is less confusing, or that you can rely on brand names. In fact an older 'Deore' derailleur' might be higher quality than a newer SLX one. So....


How is the riding experience of a Rohloff hub different than derailleur gears?

I can only compare the basic Shimano Acera and Deore (3x8) deraileurs to the Rohloff 14-speed hub, but these are my observations.

On the Rohloff hub

Rohloff, like most hub gears is slightly less efficient than a well-maintained derailleur, as this PDF study explains. In my experience the difference is not noticeable, perhaps because I've mostly used cheap derailleurs.
Changing gears is always impossible if significant force is on the drivechain.
A short pedalling pause is required to shift gears.
It is possible to change to/from any gear when stationary or coasting.
Gear inches change between gears is simple and predictable (roughly the same percentage per click).
The gap between the gears is fairly large.
Some gears are noisy (eg 7th)
There are a couple of gears which need a bit of care shifting or you end up temporarily in top gear.

On a derailer

Most gears run quickly and efficiently. Several gears are noisy/inefficient due to chain angle.
Changing gears is sometimes tricky if there a large force on the drive chain. It depends on which change is being made, some are really easy and smooth, others need some care.
No pause to fast, gentle pedalling is required to shift gears.
Only possible to change gears when pedalling.
Two shifters means that shifting quickly to a predictable-length gear a skill that requires a bit of thought.

YMMV, but I find the Rohloff to be efficient and simple to use. We use it on a tandem, so it may be that the pause needed when shifting is less distruptive on a solo bike.

However, I also expect that an experienced racer would be able to shift their high-spec gears much more quickly and efficiently than any hub gears and that this might mean that derailleurs are the only option for racing. That and the fact that you can't seem to connect them to brifters.

(reworked from this answer)

There are a number of (mostly positive) opinions from Rohloff owners here.


All you need is a 7-speed chain. You’ll have to shorten it by a few links after purchase (they’re sold excessively long for funkier gear arrangements), which should be done with a specific chain tool. This tool will also be needed in order to remove the current chain.


Is reverse pedaling good for smooth gear change?

Most setups are supposed to have at least some sound when switching gears. Depending on your derailleur/setup the sound may vary from a short click to longer sound of chain grabbing around the gears.

The switching is supposed to happen without pedaling backwards, so you should not do it. Normally it is not okay to switch gears with highly tensioned chain, such as during the climbing, so you should find a moment to switch speeds when pedaling forwards will not have any effect on speed, which means the speed must be higher than the speed you could achieve by pedalling. It sounds very complicated, but in real life should happen almost instinctively, without thinking at all, just get the "feeling" on what gears lead to what speeds with your cadence.

If the switching is not smooth anyway, there's good chance you have to adjust the derailleur. Some random manual on how to do it can be found here: http://www.artscyclery.com/learningcenter/shimanorearderailleurs.html


Gears jumping/slipping from the rear cogset on a new bike

Parts need a break in time to stretch, flex, and do what they do before they kind of settle in. When I worked at a bikeshop, we told our customers to come in after a month or 2 so that we could go through and get everything tuned up to where it should be after the break in period.

Not only is your situation normal, most bike shops WANT you to bring it back to them, so they can get it running the way it should so you are happy with your purchase. Take it back to the shop and have them tune it up, it should be included in the purchase price.


The RL and OG might be date codes. Assuming these are 2 different chains, RL would denote 1993-December and and OG would denote 1990-July. If you think they are newer than that, the chart isn't up to date, but if you follow the pattern, RL could be 2019-December and OG could be 2016-July. The second set of dates makes a lot more sense based on what I can see visually from picture.


Recommendation for panniers to carry a laptop for daily commute That's available in the UK

You could always get a laptop sleeve and slide that into a big enough pannier.

Timbuk2 has a couple pannier options that both have an included laptop sleeve and are designed to be easily carried off the bike. One converts to a messenger bag, the other more of a "shoulder bag". Looks like Timbuk2 has some of their stuff sold retail in the UK, and they also do direct orders with international shipping. I don't have either bag, but I do have a laptop messenger and a couple regular messenger bags from them that I've been happy with.

Their site is a bit of a pain to provide links to, but looks like Basil has a similar kind of laptop messenger pannier. Their site shows plenty of distribution in the UK.

Ortlieb's rear/larger panniers have an "Office" and "Downtown" line that both seem to be designed to accomodate a 15 inch laptop (via a sleeve/insert you purchase separately). Two different mounting options.

What I actually do when carrying the laptop on my bike is either bungee a laptop messenger to the top of the rack or stick a (well-padded) sleeve into a pannier


When your bike was overhauled they likely replaced the shifter cables. The cables will stretch over time. The result is the derailleurs don't shift as accurately as they should. It is a fairly simple process to readjust them. There are many on line tutorials that will show you how to do this yourself. If you don't feel comfortable doing it yourself your local shop can help you.


How long between spoke adjustments on a mountain bike?

A well built wheel should go years without needed truing. If you are truing the wheel every 2 months something is wrong with the build.

There's no way to know via the internet, but my guess is that it's one of two things.

The rim is bent slightly and requires significantly uneven tension in the spokes to get
the rim true.
There isn't enough tension in the wheel overall to keep the wheel true.

The way to diagnose this is to get a spoke tensiometer and measure the tension in the spokes, since the wheel is slightly offset to compensate for the braking disk, one side will have slightly higher tension than the other, but the spokes on any given side should be roughly equal. The rim should have a maximum spoke tension rating and the closer you
can get the wheel to that the stronger and more stable the build will be. Most rims are rated to at least 100kg of tension.

A good wheelbuilder will have the spoke tension meter in his toolkit. They are relatively expensive and require some practice to get accurate readings.


What kind of panniers is this tubus rack flange for?

This would work with my pannier set. I have Axiom Monsoon panniers with a hook at the bottom that would fit right about there.


What is the handlebar size for an old road bike?

If you don't have good measuring tools (and know how to use them, but that's not too hard) it will be very hard to tell the difference between 25.4 mm and 26 mm – until you try to fit the bars in, then it will be obvious…

For a bike of that vintage odds are good (according to my recollection and Sheldon Brown's Crib Sheet) that the size is 25.4 mm.

So what you should do is by a set of 25.4 mm bars (ideally from a nice LBS that you want to support anyway) and see if they fit. If they don't and you can't return them get a 0.3 mm shim – Nitto and I think some other make them. If you're feeling flush get it with the bars just in case.


I am looking at buying a tacx turbo trainer however I am only putting out about 200w on a bike

I got a Tacx Flow two or three years ago, so my answer is based on this. Also I don't use it all that much...

As regards power output, I have never measured mine when riding on the open road. I have only ever got power readings when using the turbo. I generally get readings from the headunit in the 200W range (probably anything between 150 and 400 depending on effort) but the flow itself is plenty easy enough to ride. Now how closely my turbo-calculated 200W will tally with your 200W is anybody's guess, but my gut feel is that there won't be a problem with them being too hard to ride.

If you're stuck between the Blue or Sartori I can't help much there. But what I would say is that if you can afford to go up to the Flow, then although out-of-the-box it is "just" a trainer, you have the possibility to upgrade to use the Tacx VR software at a later date. I do not believe that anything beneath the Flow gives you this option, and this was my reason for settling on the Flow.

So if that's something you might want to do in the future.... well buying the VR upgrade for the Flow will be cheaper than buying a new VR turbo.


Is graphite grease suitable for bicycle bearings?

Daniel R Hicks's answer-as-a-comment:

  As it says, it's intended for lubricating sliding parts. Not ideal for ball bearings. –  Daniel R Hicks 2015-06-23 11:48:24Z

  "Dry lubricants" are not a good choice for ball bearings, as they do not exclude water. The #1 role of bicycle bearing grease is to keep water out. –  Daniel R Hicks 2015-06-25 12:05:18Z


Proper use of shimano chain measuring tool

According to this PDF I found it seems that your chain still has life left in it.  It's when the ping drops between the pins that your chain has stretched too much.

This is pretty good: 2700mi is about 4400km which is approaching the expected lifespan of a chain (5000km).  I've had decent chains which haven't lasted nearly that long.
 (Admittedly I do occasionally ride in wet weather.)

(Apologies for getting this messed up earlier.)


Is there any good software to track and compare rides using my own computer

I use IPbike for Android. It has strava upload in case you want it but also gives you files in sensible formats by sensible means. It's got sensor integration but I use it with only GPS. You can give it a good try before you buy.

The author is no stranger to this site; despite being almost a neighbour of mine according to play store, I've no connection (except for having eventually bought the software)


Can a road bike stand constant 40km/h for long distances?

Stopping distance is definitely something to be aware of. As speed increases, the distance needed to stop increases non-linearly. For illustration, in cars, with 1 sec reaction time:

20 km/h = 8m
30 km/h = 13m (50% increase in speed, 63% increase in distance)

(Source: http://www.nzci.co.nz/tools-calculators/stopping-distances.html)

In other words, it may feel safer than it really is.

Also make sure your conversion has a brake sensor cutoff, you wouldn't want your braking distance increasing because the motor is pushing while you're frantically trying to stop.


A wheelie is riding along on your rear wheel, using the torque from pedaling to keep the front wheel up.

A manual is rising along on your rear wheel, coasting and shifting your mass backwards behind the rear wheel to keep the front wheel up.

You do not need suspension to do wheelies or manuals. You can find an enumerable amount of videos of people on YouTube doing wheelies and manuals on full suspension mountain bikes, hardtail mountain bikes, and even fully rigid mountain bikes, trials bikes, and BMX bikes.

Generally speaking, you don't add suspension to a bike that didn't start out with it. Rear suspension has to be designed into the frame. Suspension forks can technically be added to almost any bike. However, frames that were not designed for front suspension will have their geometry altered and likely aren't capable of handling the forces that come along with riding that requires suspension.


Tips for adjusting Shimano M355 hydraulic brakes

First, I think you made a good decision. Hydraulic disc brakes are the way to go, and the M355 are really nice for the price. Also, I assume brake pads/discs are not contaminated and caliper is straight in relation to the disc.

These are indeed the cheapest brakes, and therefore there is not much place for adjustments. If without touching the lever the pads don't touch the disk, and when you apply they do, than I would say they are ok. Maybe you would like them to do have a tighter feel, but with this model there isn't much you can do apart from lever distance to handlebar (play with this a little to feel confortable).

I don't think overbleeding helps. It shouldn't cause any harm, but the brakes were designed to work in a specific way, so it might affect behavior under heat, or might be causing the "instant brake" feel you are talking about, or might cause rubbing with new pads.

Another thing to notice is that it is normal, even in good brakes, that the rear and front feels slightly different, because of expansion on the tube under braking (there is so much tube going to the rear, right?). And also, as the rider you are more sensible to brake forces in the front, and they affect more the dynamics of the bike.

One thing I would recommend you to do is to bleed according to manufacturer's instructions and try to adapt. The change from pads or mechanical disc is huge in terms of the relation between lever force - braking force, and it is normal that as a rider you need some time to feel comfortable as you change muscle memory.

For example, on my road bike I always pull the lever/pads with as much strength as I can to do an emergency brake, whereas in my mountain bike with hydraulics I have to re-teach myself that I must always modulate brake lever even in an emergency brake. The dynamics are very different.

Of course there might be something wrong with them, but from your description I doubt it. If you can't take it out of your mind though, go to a shop, pretend you want to buy a bike with the same brakes as you have and ask for a small test-drive :)


The 29ers without front suspension exist, but they are a bit pricey since they come from niche manufacturers. Many people want SS drivetrains since they want pure simplicity.

Surly ships some of their complete bikes such as the Ogre as rigid 29'ers (the Karate Monkey can also take gears).

There are some other options though. One common option is the Kona Unit which has a derailleur hanger which you can order from Kona as seen here:

Or an internal gear hub as seen here:

Note that both these options require at a minimum a new rear wheel for the Unit.

Also, note that Surly sells their rigid forks as well as do companies like On-one and what not, so you can get one installed after market.

Finally, yet another option: Get 2 bikes (something cheap and not likely to be stolen for city use, one for trail use).


They may be called R-clips in the US. The hole of the R encloses the fender stay (the metal rod). The stay is one of the fender's points of contact with the frame/fork and it prevents the fender from flopping around. A hex bolt goes through the legs of the R into an eyelet (i.e. a bolt hole) on each side of the frame or fork. The link goes to a US online only store (Velo Orange). However, your local bike store could probably order similar items from their distributors, and you could also find them on other sites. I do not recommend any specific retailer; I only selected Velo Orange because they have decent pictures and descriptions.

Not all fenders may attach to your frame/fork's fender mounts with R-clips. The pic below, courtesy of Sheldon Brown's site, shows SKS's breakaway stay fitting. The fitting is designed to quickly break away if something (e.g. a stray branch) gets jammed between the fender and the wheel. This should hopefully save your fender.

Or if you look carefully at the image below from road.cc, some stays may be designed to bolt directly to an eyelet without an additional piece of hardware. The stays are bent in a little loop, and it seems like you'd put a hex bolt right through that loop. Look where the fender stays connect to the frame near the bottom of the seatstays.

I am not certain if R-clip is standardized terminology in all parts of the world. In English, some differences exist between US and UK terminology (e.g. US: crankset and Campy, UK: chainset and Campag), and I'm not sure if this term is identical on both sides of the Atlantic.


Changing from Ultegra 6800 crank to r8000 dual power meter

This FC-6800 and the FC-R8000 are parts based on the same design standard, Shimano Hollowtech II. Here you can find all the compatible pieces : https://bike.shimano.com/en-EU/technologies/component/details/hollowtech-2.html - So it will be compatible.

The only issue you can have if is your new powermeter have an external part on the arm crank, like the battery of the Stages powermeter. This part can interfere with you bike frame. So be sure you have enough space between the crank arm and your frame. This dimension is not part of the Hollowtech II design standard.


The maximum tire pressure should be written on the sidewalls. Often the embossed lettering is hard to read, shining a flashlight at an angle can give you the contrast to make it easier to read.


Chain is reluctant to shift into hardest gear on rear cassette


Shimano brakeset hood model compatibility

The hoods are different for different models of levers, but the ST-2200 uses the same ones as the ST-3300.

The part you need is Shimano Y-6CU 98040. Ask your LBS to find it for you. Alternatively, you can look for 3rd party manufacturers as well but I doubt they will have something for an entry level part like this. Shimano's documentation indicates that the ST-3400 levers do not use compatible hoods (and the style of the ST-3500 onwards is different).


No, road brake levers are not compatible with v-brakes. If you're dead set on switching to drop bars on a bike with v-brakes, you'll need to either switch the brakes to cantilevers or use a travel agent to correct the pull ratio. Personally, I'd just switch to cantilevers. I've never used a travel agent, but I've heard they can be finicky.

There's also a question of shifting compatibility. The first thing to check is that the brands match. Sram and Shimano are not cross compatible, so if you have one on one bike and the other on the other, you'll have problems.

The second thing to check is the number of gears. Ideally, you want the same number in the front and the rear. If they're different you'll have problems.

You also need to know if the mountain components that are most likely on your hybrid are compatible with road shifters. If it's all 9-speed Shimano, you should be good. If it's 10-speed Shimano, you're going to run into compatibility problems. One more thing to mention with Shimano is that they have sometimes used hybrid specific front derailleurs that work with just fine with mountain shifters, but sub-optimally when mixed with road shifters. Sram 10-speed is all cross compatible between mountain and road. And I don't think Sram even makes 9-speed stuff anymore. If they do, I'm not sure whether or not it's cross compatible between mountain and road. Someone else, feel free to edit it in.

I know, you practically need a flow chart to keep it all straight. If in doubt, check with your LBS.

It's also worth pointing out that your position on the bike will change. Road levers will put you leaning farther forward on the hybrid. It'll be enough to be noticeable and possibly uncomfortable. You might be able to correct with a different stem, seatpost, and/or seat position. But be aware if you start messing with the stem you're going to change the way the bike steers.


Do any bike sharing schemes provide a way to rent or share helmets along with the bikes?

In Melbourne, we have a bike share scheme. You can buy helmets for $5 from various outlets and then return them for a refund of $3 (they are then cleaned and reused).

Despite this, many people are saying that Australia's compulsory helmet laws are responsible for the lack of success of the bike sharing scheme.


Can a Mamachari be fitted with an 11 speed 52-36T crankset and FD?

If you want to fit a modern crank you'll need to be able to fit a compatible bottom bracket. Right now you have a threaded bottom bracket shell with a non-cartridge bottom bracket. If the threads are ISO/English standard and the width is standard threaded BB road width (68mm) then you can fit an external bearing road BB and road crank. The BB shell looks a bit wide though.

The other major issue is clearance between the chainstay and large chainrings that the frame was not designed for


Crank is slipping freely occassionally when pedaling; occasional "clonk" sound

More information would be helpful. What kind of bicycle? How old is it?

Assuming the bike has a freewheel or a freehub, there are a couple of things you can check.

For example, if the bicycle has a freewheel (in other words, if it is older), it may need lubrication inside the freewheel. Automatic Transmission Fluid (ATF) is a great lube for that application, or you can buy various oils. I would advise against using WD-40 for lubricating a freewheel.

A similar kind of skip/slip can happen occasionally (say, once in a few hundred miles of riding) with a freehub, and it doesn't necessarily mean anything is wrong. However if it is more frequent, you may want to service the hub, or have your local bicycle shop service it.

If the freewheel/freehub is not the source of the problem, the drivetrain may be worn. The chain can skip, or jolt forward, if the cogs in the rear are worn excessively.


How effective is checking spoke tension by ear?

That depends on how good your ear is. If you can tune a stringed instrument effectively, then tensioning a wheel by ear is very effective. Identical spokes that have the same pitch when plucked should have the same tension within the margin of error for any tensiometer reading. The catch is you need a tensiometer to get the relative tone for the proper kg/f tension on the spokes, unless you have perfect pitch and can remember up to four different tones for a single wheelset.
Keep in mind that for a wheel with any amount of dish, the tension, spoke length, and therefore the pitch, will almost certainly be different from one side of the wheel to the other. Therefore, once you have your tone for a given kg/f reading it will only be accurate for one side of one wheel (there are exceptions, such as a front road wheel, or a flip flop rear wheel). Flange heights and spacing vary from front to rear hub and side to side as well, also with some exceptions. Also worth noting that different gauges and shapes of spokes of the same length and tension will have a different ring to them. In short, don't assume that the pitch of properly tensioned spokes on one side of one wheel apply to the rest of the spokes on the wheelset, and certainly don't use the pitch of a spoke on a wheel as a reference for a completely different type of wheel.
Anecdotally, I was discussing this very issue with a friend of mine the other day. He said that he believed tensioning by pitch gave a valid reading, but that he couldn't do it because he was mostly tone-deaf. So to reiterate, if you don't have a pretty good ear musically, then this isn't a viable method of checking tension.
To summarize, with a good ear you can use pitch to check tension on spokes, but it's more of a timesaver than a replacement for a tensiometer as you need a baseline tone at proper tension to check the rest of the spokes against.


I cleaned my cassette and changed my chain, now my freehub is slipping. What are the possible causes?

It is likely that your cassette is worn.

A new chain on a worn cassette will skip, because of the mismatch of the shape of the teeth on the cassette with the chain's spacing (which is shorter than what the cassette expects due to wear).

You can visually inspect your cassette for wear by either looking for gaps in how the chain meshes with the cassette, or looking at the teeth to see that they aren't well shaped.


What is the quantifiable benefit of compressionless brake housing?

It's about distance, not force. Coil housing is not at all impaired in its ability to transmit force once any distance between its coils has been taken up (so no to your second question.) On any rim brake that doesn't have egregious bends, the practical difference between compressionless and coil housing is marginal. It's a little stiffer and more responsive feeling, but the advantages of it are small and possibly outweighed by the increased fragility, installation hassle, and/or expense of compressionless. On a mechanical disc, or a rim brake system that forces egregious bends in the housing, it's a different story.
Total pad gap on a V-brake or dual pivot caliper is around 5mm. On a mechanical disc it's 0.8-1mm. Yet the lever throw powering both is the same; the needs of a brake lever designed for a human hand doesn't change between the two. This demonstrates that in terms of lever movement to pad movement, mechanical disc brakes run at about a 5 times greater leverage ratio, or mechanical advantage. You have a great big lever throw producing a very small amount of movement. That's how disc brakes are powerful despite a rotor being such a smaller circle than a rim. Mechanical discs can have problems with being difficult to set up in a way where the rider doesn't run out of lever travel, and since compressionless helps conserve lever movement by eliminating housing compression, it is good to use in this role and is often one of the main ways of helping out a bike that is having issues with the levers bottoming. This is often most pronounced on long continuous rear brake housing runs, which most disc bikes have.
The effect of coil housing creating wasted lever movement becomes much more pronounced whenever there are tight bends in the housing path, which will cause the gaps between the coils to open up and need to be closed again by the braking force. The helical nature of the individual strand path in braided compressionless brake housing mitigates this effect almost entirely in most cases on bikes. The same effect can sometimes be used to create good brake feel on bikes with brake routing that forces awkward bends.
It is worth pointing out that compressionless brake housing does have a dark side compared to coil. Coil housing, being made of thick steel, is a very robust design that is much more able to shake off or only be incrementally affected by damage, abrasion, kinks, and material degradation. Compressionless brake housing is something of a glass cannon in comparison; it's a bunch of steel wires that fundamentally don't want to stay together and resist the forces they're being put under, but are able to do so because of the standout properties of the layer of kevlar fabric that constrains them. The system is also wholly reliant on the right special ferrules being used to keep wires from pulling through. Compressionless brake housing is safe, more than reliable enough for bikes that are reasonably maintained, and not prone to failing suddenly when it does fail, but it is less age- and abuse-resistant than coil.
EDIT: As ojs pointed out in the comments, I had the part about the effect of compression being amplified 5x wrong, which I initially wrote. I've edited this answer to be something I can stand by, but see that it was likely accepted on the basis of incorrect reasoning, so I'm open to it being taken down or un-accepted as the answer, neither of which I can do.


Adapter for moving bottle cage up/down while using frame's bottle cage braze-ons

There are a number of commercial products available to move bottle cages up or down from the existing braze-ons. They're marketed as a Bottle Cage Relocator or Bottle Cage Adapter, but essentially they're all a flat piece of metal with holes drilled into it that may have some finishing work to make it look nicer. Given they're in the $10 range it's probably a better use of your time to buy one than DIY.


Is the same effort required to maintain a set speed using different sized chainring / cog combinations with same ratio

Here are some points taken from the literature:

Mechanical efficiency is usually 88-98% for majority of deraileur systems (when clean,lubricated and new)
Drivetrain efficiency decreases with smaller rear cogs,
Highest efficiency can be reached at high torques and low cadence,
Chainline effects are negligible, imposible to note with measurement apparatus,
Higher efficiency can be obtained with a single-speed as opposed to derailleur use, and there may be a few reasons for this.
Efficiency of an internal gear hub is generally lower than this of a derailleur system*

So in your case it's likely that the 48/16 setup will give a slightly higher mechanical efficiency. Also once you've gained the desired speed higher rotational inertia of larger sprockets will help keep the speed at slightly lower effort. On the other hand lighter and smaller sprockets will make it easier to accelerate. However all these changes will be barely noticeable on the road, and especially when the drivetrain is already worn.

Some research has been done in the past on this topic, and there are also pages like this one, where the data on resistive forces within the drivetrain can be bought..

*Reference: Wilson, David G. Bicycling Science 3rd ed. 2003. p. 342-344


Fitting a 9-speed 11-50T cassette on MTB: which derailleur?

https://bike.shimano.com/en-EU/product/component/alivio-m4000/RD-M4000.html   says that derailleur will handle

Low sprocket_Max.    36T
Low sprocket_Min.    32T

ANSWER: You cannot run a 50 tooth cog with that derailleur.

You might be able to use a hanger extension, but that will make the small gears even worse.  Wolf Tooth's Roadlink allows up to 40 tooth, and Wolf Tooth's Tanpan says 44 or 45 tooth is the maximum cassette size supported.  Note these are for 10 and 11 speed.

If you're absolutely stuck on a 50 tooth rear cog, then you're looking at a SRAM 12 speed Eagle setup, which will not be cheap.  Cassette and shifter must change, and its very likely your freehub won't fit the cassette, and then the OLD will be too large to fit in your frame.  Not a good plan.


Do you want this as an able-bodied person to play with, or as a disabled person because your legs don't work? If the latter, (two wheeled) bicycles are out of the question unless you're young, fit, and slightly insane (I say this because it's certain you will fall off a two-wheeler, probably more than once, and if the guy I watched/helped is any guide, you are likely to also fall off at speed at least once).

The problems differ based on the type of bike or trike. The most suitable IMO for conversion are SWB ASS bikes (short wheelbase, above seat steering) and trikes. The "hand-pedal" part is the same in all cases. Look at any handcycle, but essentially you mount standard handgrips on bicycle pedal axles, then add brake and gear levers. The cables from those need to be long as they flex as you pedal. The pedals mount to standard bicycle chainring(s) and a standard "bottom bracket" (even though it's not at the bottom any more). That bottom bracket mounts to the top of the steerer tube and the chain runs to a standard bicycle rear wheel.

The trike will be easier to ride and harder to fall off, especially up hills. Handcycles go up hills very slowly. Most handcycles for wheelchair users are trikes, normally delta trikes (often with with negative trail). Negative trail makes them easy to build, hard to ride, and unstable at speed. But since you're already looking at a few thousand dollars, easy to build helps to keep the cost down. The more expensive ones are usually better designed for speed (however I have been very unimpressed with the ones I've seen from a rideability point of view). The conversion can be very easy - you "just" build an arm with a wheel at one end, pedals at the other, and a steering pivot in the middle. You can even buy those premade as wheelchair accessories (http://www.riomobility.com/en/manualhandcycle/index.htm). If you can do that, scratch building the seat/rear wheels shouldn't be too hard. "Conversion" now means "chopping up random bikes to get bits" rather than "add hand-pedals".

But very few foot-pedal trikes are delta trikes, and the ones that are are slow. That's because deltas are inherently unstable, especially when braking and turning (very common in racing or in an emergency). A second hand recumbent tadpole is also likely to be easier to find. Search for "recumbent trike" and you will find a lot of tadpoles, few deltas. Converting a tadpole you'll need to insert a bicycle headset into the frame in front of the seat/behind the cross-member, extend that up, then build your pedal/steering unit on top. The chain will twist when you steer, but that's ok (world record setting speedbikes commonly do this). The chain goes to the rear wheel, and you'll need two idler cogs to bend it up to your cranks. http://www.TriSled.com.au in Australia have built at least one of these but it was very expensive (take a $4000 trike, add a couple of weeks work to convert it to a handcycle). It did, however, work very well :)

Converting a SWB bike is likewise fairly easy. Remove the existing stem and handlebars, build your hand-pedal setup to plug into/onto the existing steerer tube, weld on a couple of idler cogs, and you're done. Don't paint it yet! First try riding it. You will fall off, and may decide to revise how the chain idlers work. The first mount you build may well not be strong enough, especially.

In both cases you will probably find that having the pedal unit pivot forward makes getting on and off much easier.

One other option is a rowing bike - Thys make them commercially, and apparently they're not bad to ride (but they definitely work your legs as well as your arms)


The shelf life is going to be different depending on the quality and composition of the specific tire, and the storage conditions.  In general though, you should be able to see if a tire has gone over or not: if the rubber is still soft and pliable, it should be fine to use.

I'd guess that your tires are still okay, but without seeing the tire i can't give you better than a guess.


Some disc-brake specific wheels use rims that are not designed for rim brakes. To accomplish what you want you need a wheel with a a disc-brake hub and a rim-brake rim.

With that setup, assuming the fork widths are the same, you should be able to switch wheels between bikes without problems. The only drawback is the slight increase in rotating mass from having extra material in both the hub and the rim.

An example would be this wheel from Mavic available at Nasbar, but your LBS should be able to easily build up wheels for you if they don't have something specific in stock.

To use your dynamo I think you are forced to have custom built wheels, but it should still work fine.


If the chain isn't worn (which it probably is not, kids bikes don't get high mileage) it might be worth trying to save, but you may end up spending more compared to getting a new one.

Penetrating oil, a wire brush and a lot of effort may free it up enough and get it reasonably clean.

Removing the rust chemically is problematic. Something strong enough to work with the chain in place may damage paint or plastics. There are safe products such as Vapo-Rust but the chain would need to be removed and soaked for an extended period of time. Also, new chains for 10 or 15 speed bikes are inexpensive. Instead of buying chemicals, just buy a chain.


Chain Splitter vs. Chain Tool vs. Chain Breaker

Most likely the same.

I think there are only really two "chain" tools (i.e. tools with "chain" in their name). One is used to break a chain, and goes by names such as chain splitter or chain breaker. So you'd use this for removing a chain completely off the bike, for example to replace it. You might also want to look at Power Links in this context, as using a Power Link means you can sometimes avoid using a chain splitter altogether (which requires a degree of precision).

The other is used to hold a freewheel/cassette in place, and is called a chain whip. You'd typically use this in conjunction with a lockring, when you want to remove the freewheel/cassette.

Unfortunately I've heard both called a "chain tool".


Flat bar conversion - shifter is skipping a gear

Correcto, unfortunately for you, the latest (4700) Tiagra system uses a different cable pull to previous 10-speed groupsets, therefore the shifters are pulling the wrong amount of cable for your derailleur. It won't get better, however much you change the tension.

You could get a new 4700 derailleur, which would match the shifter and work with the existing cassette, keeping the flat bar.


Can a child seat attached post-manufacture be as good an attachment as a manufacture installation?

TL;DR  I feel trailers are a safer option for small children, but the circumstances of your commute may mean that a trailer is not an option or is a huge inconvenience.  In that case, I believe that a mechanic installed child seat is/can be just as safe as a "factory" installed child seat and likely far less expensive than a new bike.

I (personally) don't ever recommend that type of child seat.  Even expert cyclists can crash and since children are often not good at crashing (they don't have instincts to roll, etc) those seats worry me.  Accidents happen and those style of seats have never felt safe enough for a small child (let alone an infant).  Both of my children (now three and four) have been towed hundreds of miles in a trailer, which essentially encloses them in a roll cage.  I've had times I've slid off trails into snow banks, and a rear seat would forced a child's head under snow.  With a trailer, it simply tipped into the bank and had no ill effects.

All that being said, I don't think their is really a difference between the factory installed model and a well built child seat installed by a good mechanic on a bike properly setup for a rear rack.  In your case, if you were looking at the money to purchase and entire new bike, I may consider simply purchasing a trailer which would work with many different bikes and possibly be of other use to you as well (some are convertible and can be used for non-cycling activities as well).  If money was an issue, I personally wouldn't differentiate between a factory installed model and a mechanic installed model.


Bleed port diameter on Magura HS 11 rim brakes?

The threaded ports on Magura brakes I have worked on are bigger in diameter than Shimano, so the bucket tool in your picture would not fit, don't waste money on one uneccesarily, though you can get kits like that to suit a whole range of different brakes.
However, Magura have a feature called "Easy Bleed Technology" where you only need to put a syringe (minus plunger) into the lever bleed port. There are manuals and other guidance on the website https://www.magura.com/en/components/techcenter/?p=2633  (also https://www.magura.com/media/1742/hs11_hs33_2014_en_06.pdf though you note this is an old version).
This would allow you to do a simple burp of the lever with just a syringe, though I would use original Magura brake fluid to maintain the warranty ("Application.of.not-original.MAGURA.parts.and.lubrication.products" would void the warranty, as will "Incorrect Maintenance").
Note that in my experience, Magura brakes, especially entry level, have an amount of flex and therefore modulation. This can be good for many users, however it can feel spongy if you are used to a stiffer feel. So if once you have burped the brakes, the brakes stop the wheels well but have plenty of modulation, it may not be due to air in the lines. Just bear that in mind.
It sounds like something you're comfortable doing it but if you have any doubts, no harm in waiting for the bike shop.


We can generalize the main areas where one can load weight as such:

Front rack vs. Rear Rack
High (on top of rack) vs. Low (in panniers)

The most commonly accepted points for load distribution are as follows:

Keep dense, heavy items low to the ground. The lower you & your bike's center of gravity is, the more easily you can keep yourself upright. This means loading heavy things into panniers (bottom up, like a grocery bag) and leaving less dense items for the tops of the racks (sleeping bags/pads, etc)
Be careful about putting too much weight on the front wheel. One advantage to having weight on the front wheel is that as you turn, it will turn with you--unlike weight over the back wheel. However, too much weight on the front, especially if the center of gravity is too high, will cause you to over steer, or have to steer very rigidly.
Make sure your load is balanced. You didn't mention anything about this, and although it seems like common sense, I want to make sure it's included. An unbalanced load will cause you to have to compensate by continually steering in the opposite direction. You should be able to roughly balance your pairs of panniers by holding one in each hand.

I haven't used a handlebar bag myself, but the same logic applies. Weight in such a bag will have a very high center of gravity, as well as the ability to turn with you. Therefore, it might be a good place for maps, snacks, phone/keys/wallet, patch kit, etc.


If the grips are rubbery, the streamers should push in, though some force will be needed. That tight fit is necessary as there's only friction to stop them falling out again.
I certainly wouldn't cut the grips, but if you're really struggling, shaving the end of the plastic plug so it's more tapered will be all you need to do as once it's started you can push quite hard. That assumes the grips have a hole at all, as pictured. Most do on kids' bikes but some don't (e.g. the ones I put on my daughter's bike that came off my mtb)
It's a few years since I fitted streamers, but I didn't have my full tools with me at the time, and didn't have too much trouble.


Can the extreme heat from powder coating influence frame integrity of older bikes?

No, 400F will not affect frame integrity.


While pro riders often change gearing or whole bikes depending on the nature of the race or the stage, you do sometimes see compact cranksets, particularly among domestiques in mountain stages or races.

A big-name example is Tyler Hamilton in the 2003 Tour De France. After crashing and breaking  his collarbone before the huge mountain stages he was unable to climb out of the saddle. FSA who makes compact cranksets and was a team sponsor set up his bike with a 52/36 crank; allowing him to climb seated.  FSA did a couple of releases and maybe ads about it - and I started to see a lot more compact doubles in local rides.

Just note - a lot of times you can accomplish the same goal (bigger and smaller gearing) by switching the typical 12-23 racing cassette for one that is 11-25 or 11-27 at a lower cost.

You can play around with Mike Sherman's Bicycle Gear Calculator to help you make a decision.


You didn't say where you live (what country?), so you may not have this particular option for a store, but you could use a 3/8" drive extension:

http://www.lowes.com/pd_337346-22328-85817_1z0wcg7__?productId=3380286&pl=1

With a 3/8" drive hex driver:

http://www.lowes.com/pd_338623-22328-85226_0__?productId=3387790

(You might also be able to find a T-handle hex driver that is long enough, although a quick google search didn't turn one up for me.)

This is of course assuming the base of the hex driver will fit into your fork tube, which it may not, you will have to check.
Also, before trying to loosen anything you should spray the bolt / any seized parts with penetrating oil (like WD-40 or PB Blaster) & let it sit for a while. That alone might end up being enough to free the stuck parts.

If you do get it apart, you should really consider doing a proper overhaul on it & determine if it is even fixable / worth fixing.


Replacing Quick Release skewer with through bolt axle

Hubs that can retrofit to take through bolts are fairly uncommon, and some Googling confirms that your wheels are QR only. Through bolts are an idea that never really took off, and now probably never will with through axles becoming much more common.

Through bolts create a stiffer structure and may mitigate the problem you're having in some situations, but if what's actually happening has more to do with the axle squirming in the slot, I'm dubious about their ability to really fix that. In other words, they help a lot with rub that occurs due to flexing, but I don't believe they add clamping force above and beyond what a good QR can do.

Another important piece of this may be that the stock Aksium skewers are very basic external cam ones that, for the benefit of being light and cheap, are somewhat clamping force impaired compared to good internal cam skewers such as Shimano. Internal cam skewers apply much more clamping force, and it can make all the difference with problems like you're having.

Making sure the tab/post facing on the frame and fork is good is also important, although I'd really hope a Pinarello to come pretty much perfect in that regard.


How can I lower the gear ratio on my son's bike?

The specific model of rear derailleur you have is an Acera RD-M360 SGS, produced about 2009-2011, for 7 or 8 speed drivetrains. Shimano very helpfully provides archive specifications on the product info page.
Looking in the 2009 spec PDF we can see that the max size of the largest sprocket the derailleur will handle is 34. I believe 12-34 freewheels do exist, but you might have to hunt around to find one. That would be the cheapest way to lower gear ratios. (I'm guessing the crank on this bike does not have replaceable chainrings.)
Removing and installing freewheels is very straightforward, but requires a special freewheel removal tool to  get the old freewheel off, and there are many different types of tools for different freewheels. See this Park Tool Repair Help video for how to select the correct tool. Other than that you only a large adjustable wrench in addition to basic tools.
A larger range freewheel may require the chain to be a few links longer, which unfortunately means sizing and installing a new one. I installed an 8 speed rear derailleur on my son's single chainring bike recently and used the chain sizing directions for 1x drivetrains in this Shimano manual. This is working fine so far.


I'm going to take my bike with me on a plane. Do I really need a special bike travel bag to have it transported safely?

I recently flew to Europe with my wife, and we brought along our bicycles. Our solution was to disassemble them the night before and place them into cheap Nashbar bicycle bags. We wrapped pipe insulation foam around just about everything to avoid damage from handling. For extra protection, we then stuffed these into the standard bike boxes provided (at a minimal cost) by the airline. I would highly recommend the internal bags, as the TSA opened both our boxes during each flight, and did not bother to close the boxes back up. Wheels or other components could have easily fallen out in flight had we not used canvas bags inside the larger boxes.

Also, be very careful about which airline you choose to fly on. Most airlines have a surcharge for checking bicycles, and this can vary wildly between carriers. Our tickets were initially on Delta, who wanted to charge us $200 per bicycle per leg. With a 2-leg trip to Amsterdam and back, this would have cost $1,600 to ferry our bikes, which was ridiculous. Thankfully, we discovered this within the 24-hour cancellation window and switched to Continental, who only charged $100 per bicycle per itinerary, costing us only $400.

At the end of the day, though, transporting your bike via airlines is expensive and annoying. Our next touring bikes will absolutely have S&S couplers to allow us to fit the bikes in regulation-size checked luggage, which should help us avoid airline surcharges and additional TSA inspections.

Good luck!


Mountain bike tires vs. road tires - from crushed limestone to pavement

Gravel tires are normally a little knobby:
 versus completely smooth for a road tire.

One strategy is to run a gravel or combination tire in the front and a road tire in the back. A combination tire is one which is nearly slick in the middle with knobs on the sides, so you might want to try one road tire on the back and one gravel tire on the front. Combination tires aren't great at road or off road, but they're passable on each. Certainly will be an improvement if you're running big knobby tires on the road, but not as much of an improvement as if you went to complete slicks. Two combo tires might be more durable than a combo/off road tire and a road tire though.

The main issue is that gravel is sharper than asphalt, so you'll want a bit tougher of a tire. On the other hand, if you're mostly on the road, knobs are bad. So you'd have to play around with it to some extent.

For what its worth, I currently have an old mountain bike with Geax Evolution tires on the front and back (they're combination tires). If the gravel is packed enough and you're not overly zealous, they seem to work fine. The rolling resistance on the road isn't bad either (though they are a bit noisy, and you'll want to play with tire pressures for gravel and road). Another good option might be something like Kenda Kwick or WTB All Terrain or Specialized Burrough (all slightly more expensive and not exactly equivalent, but the idea is there).


I'm changing from 8-speed to 10-speed will I need to replace my rear Hub?

Answer: No you don't need a new hub.

However, you will probably need to put a small (~1mm) spacer at the back of the cassette, otherwise you won't be able to tighten the whole cassette down. Also be aware that prolonged use of a 10-speed cassette on an 8/9-speed freehub body will cause dents to form in the freehub body (because the 10-speed cogs are so narrow). The 10-speed freehub bodies have taller splines, so they avoid this problem (but don't work with 8- or 9-speed cassettes).


That really depends on your definition of "hassle free" and how much of a newbie you are. Personally, I always find square taper bottom brackets to be a pain the &*$#!

The square taper bottom bracket requires a special tool to remove it. The ever helpful Sheldon Brown has a list of the different types. the first or second one on the list is the one you want. It's a bit awkward to use, especially if your bottom bracket has had time to "seize" into the shell. You'll need a different tool for the integrated bottom bracket on the new tool, the Hollowtech II tool on that same list. It's much easier to use.

You'll also need a tool to remove your old crankset. The cotterless crank puller near the bottom of that same list should be the one you need. It's pretty easy to use, but be careful. There are two different sized heads and if you use the bigger one when you need the smaller one, you can strip the threads on your crank and then it's very difficult to remove.

Changing cranks and bottom brackets almost always effects your chainline. I can't find any measurements for either your current crank or your new crank. There are ways to measure and adjust for this though. Sheldon once again explains it all very well here: http://sheldonbrown.com/chainline.html.

It's also important to remember that one side of the bottom bracket has left-hand threads. I can never remember which one, but luckily it's usually labeled on the external (integrated) bottom brackets. If someone else knows off the top of their heads which one it is, feel free to edit it in.

Good luck!


7 speed cassette on a direct drive trainer from freewheel bike

Yes the Direct Drive Trainer (DDT) should work fine with your bike and yes you're on the right path...

You will need a 7 speed cassette and 4.5mm of spacers for a 7 speed cassette to fit on a freehub designed for 8/9/10 speed cassettes. If the DDT has an 11 speed freehub you would need an additional 1.85mm spacer and maybe a 1mm spacer.  Yeah, lots of spacers...
Before buying your DDT make sure it supports your bike's rear wheel spacing: 130mm and 135mm are the most common.  BUT some of the older 7 speed bikes also used 126mm. An inexpensive Walmart bike likely has flexible tubing in the rear triangle so even if yours measures 126mm it could be forced to fit 130mm.  But just to be safe, remove the rear wheel and measure the inside distance between the dropout faces.  If the bike isn't 130mm then you should also see if it is easy to pull apart the dropouts 5mm. If the frame is made of aluminum frames tend to be much less flexible than steel frames.

Also note that since you're going to want to reinstall the rear wheel at some point you're not trying to permanently bend (aka "cold set") the frame but rather just coercing the frame to fit the 130mm trainer.  Steel in particular is very forgiving so flexing it a bit won't do any damage.

Yes the number of teeth in the largest cog does matter. If the new cassette has a lot more teeth then the chain may be too short and need replacing. Alternatively you can use the too short chain and just make certain to not shift onto a rear cog which is too big.  Doing so typically causes the rear derailleur to bend and get forced into the rear wheel. Never a happy ending...

7-speed cassettes and freewheels have the same pitch:
  pitch = width_of_cog + width_of_spacer

So whatever shifters you have on your bike should work fine with the 7-speed cassette instead of freewheel.

The adjustment for shifting may be off a bit so don't be surprised if you have to do some derailleur adjustment.

There are bicycle co-op's and other similar bicycle advocacy organizations which recycle and rebuild donated bikes.  If you have one nearby they should be able to provide a very inexpensive used cassette and maybe even some spacers.


What brand of frame has a star cutout behind the seat?

I think these were the old school Malvern Star bikes.

We used to ride rusty versions of these bikes at my Nana's caravan park on holidays.


As far as I've heard the reason for not having the cap on is because without it changing the tube is somewhat faster.


Practical way to park many bicycles in one garage for everyday use?

You don't say what other uses you have for the garage, but lets presume the floor space is a premium, otherwise a row of bikes racks is the obvious, cheap and best solution. 7 bikes will fit into 5 meters, and stick out about 2 leaving plenty of space .

But you have 3.5 meters high, use it.... Rope pulley from the roof for as many bikes as you need to free up floor space.  These bikes would probably be less used ones. One or two bike stacker might be worth looking at e.g.

A wall hanging system such as
Or

I would look at floor mounting for daily used bikes and hang/suspend from ceiling ones used less often. One thing I would say is get it sorted - theres nothing worse than trying to get out for a ride and having to move a million bikes before you get to the one you want.  With kids, having a place for their bikes gives you a valid reason to 'tell them off' when you trip over a bike left lying around randomly at the door way. While you at it, have a place to store helmets, gloves, pumps, car racks etc that is easy to access and setup so each item has its place. Once you have a place for everything, everything will be in its its place.

The other thing I would say (from experience), is don't procrastinate, over think it and try to get it perfect first time, do something, if it does not work well, change it.


How do I identify what cassette type I have?

How to chose a new cassette:

the make of the drive-train, which you may find on the body of the rear derailleur. (let's assume Shimano)
the number of cogs on the cassette (let's assume 10)
the number of teeth on both the largest and the smallest cogs on the cassette (let's assume 42 and 11)

The number of cogs determines the type of chain (10 cogs = 10-speed chain) and of course the type of cassette you'll want to order. (in our case a ten-speed)
The two teeth counts tell you which cassette you'll need. In our case it would be an 11-42 cassette.

Don't forget to check the front chainrings for wear. Excessive wear makes them look like shark-teeth.

Also you'll need tools to remove the cassette, a chain-whip and a brand specific lockring tool, as well as a chaintool.

Don't throw away the worn chain too quickly, you'll need it to determine the number of links on your new chain since chains sold longer than required and have to be shortened to the correct number of links.

On YouTube you'll find a number of videos explaining the procedure.


This is a strange problem you're describing. Having them chronically come loose to the point of falling off is not a common problem, and even so the obvious solution is more/proper tension, but if the wheel was essentially rebuilt already (all new nipples?) then one would hope it's in the reasonable ballpark, 100-120kgf drive side depending on the parts used. If you only mean to say you've had the lost ones replaced with brass, then getting the whole wheel tensioned up would hopefully fix it.

The other thing to do is apply a no-disassembly-required spoke prep such as DT Spoke Freeze or a wicking oil-resistant low/medium-strength threadlocker such as those made by Loctite or ND Industries. A small drop is applied at the spoke/nipple interface on each nipple, and it wicks in. It only takes a minute to do the whole wheel so it's a cheap solution if it works. Many but not all bike shops have this in the shop.


Disc brake producing noise after a crash

An unaligned caliper (the unit that sits over the disc) is far more likely than a bent rotor. It's more exposed and susceptible to being knocked.

You should first try to realign your disc brake caliper as this will quickly show if it is a rotor straightness or caliper alignment issue. This is a simple job and will only require the correct sized hex wrench.

Loosen the bolts that secure the caliper to the frame or fork. If an adapter is used (generally on rear) loosen the bolts that hold the caliper to the adapter.
Lift the wheel off the ground.
Spin the wheel and while it's spinning apply the brake.
Let go of the brake and spin the wheel again. Apply the brake and keep it applied.
With the brake lever still in re tighten the caliper.
Spin the wheel again if it still rubs you may have a slightly bent rotor.