25
votes
Accepted
Infeasibility of a mechanical wind-up spring KERS (Kinetic Energy Recovery System) for bicycles
Ain't gonna happen.
If you want to store energy of a 100kg cyclist+bike going at 40 km/h (plausible if you want to brake at the end of a downhill), you want to store:
0.5 * 100 * (40/3.6)^2 = 6170 J
...
- 15.9k
12
votes
Infeasibility of a mechanical wind-up spring KERS (Kinetic Energy Recovery System) for bicycles
The idea looks nice at first glance, but the deeper you get into the details, the less attractive it becomes:
You need to be able to modulate your brakes. As such, you need some transmission between ...
12
votes
Is it okay for my rear derailleur to be as "compressed" as this when in the lowest gear on the bike?
There's no issue with it looking like that while in small-small. It's very normal.
The derailleur's total capacity number defines what large/large combination is supported while still allowing the ...
- 76.9k
9
votes
Is it okay for my rear derailleur to be as "compressed" as this when in the lowest gear on the bike?
Maybe your chain is too long. It’s always hard to tell from photos.
If there is still tension on the chain in the smallest sprocket + smallest chainring combination it’s probably fine. You’d need a ...
- 25.1k
7
votes
Accepted
How do I get off my totally stuck freehub body?
Just to be clear, the part shown on your pictures is called a freehub body (black cylinder with splines). It incorporates the ratchet system enabling the hub to engage one way and to disengage the ...
- 3,321
6
votes
Accepted
Stem top bolt wouldn't screw in after transport
It sounds like your steerer plug dropped down slightly during transport. This would indicate it wasn't torqued sufficiently. This could be an issue of maintenance or it could have come from the ...
- 866
5
votes
Infeasibility of a mechanical wind-up spring KERS (Kinetic Energy Recovery System) for bicycles
Part of what makes bicycles attractive is their simplicity. The simple frame-sprockets-chain-wheel with a few ball bearings in between, plus two simplistic brakes, is making the entire system light ...
- 1,531
5
votes
Stem top bolt wouldn't screw in after transport
When you say "top stem bolt" what I am assuming you mean is the bolt used to preload the headtube bearings while aligning and tightening the stem to the steerer tube. That top stem bolt is ...
- 5,475
5
votes
Stem top bolt wouldn't screw in after transport
The top bolt is there for preloading the headset before you tighten the stem, it doesn’t provide the clamping force on the steerer.
Provided the two side clamp bolts on the stem are up to spec (...
- 4,101
4
votes
Accepted
Should a track cog's asymmetrical lock ring be installed so the flat end faces the cog?
Install it text visible.
One way to know this is the intention is that the "<- 40Nm" would be lying if you flipped it.
I'm not totally sure why the design is like this. The only thing I ...
- 76.9k
3
votes
Accepted
Unmounting a stuck rear derailleur
It appears that the pivot bolt is corroded solid with the body of the derailleur.
WD40 doesn't do much for aluminum oxide corrosion. You could try a torch on the affected area. Direct it near the ...
- 76.9k
3
votes
Mechanic disk brake hose length for trials
Compressionless brake housing is good at allowing only minimum friction buildup with the housing wrapped even multiple times around the steerer, presuming it was set up long enough to do so. The bike ...
- 76.9k
3
votes
Accepted
Mechanic disk brake hose length for trials
Yes it probably affects brake performance but not by much.
Right now you have about 180° of direction change because you go “out” and down (+90°) and then back “in” (+90° = 180°) even though you could ...
- 25.1k
3
votes
What are the counter-intuitive surprises an amateur bike mechanic encounters, after pedals and cables?
Not all Schrader valves are the same diameter.
Valves that feature the rubber protection at the bottom (as pictured) usually have this protection layer in addition to the standard diameter. Such a ...
3
votes
What are the counter-intuitive surprises an amateur bike mechanic encounters, after pedals and cables?
Shimano hubs, or any other cup and cone hubs are notoriously hard to service. They are very easy to take apart and clean, but getting correct retainer nut tension right is almost black magic. Too ...
2
votes
Dangerous feature on a new 20" wheel kids bike? EZBuild pedals
This is garbage. My nine year old is an inexperienced bike rider. No tricks, no hard use. After a year the pins that lock the pedal in place have bent and now the pedal will no longer hold its ...
- 21
2
votes
Bianchi Bike - Help Identifying Model
After spending a good bit of time searching with google images i've come to the conclusion this bike is probably either fake or badly restored.
There are many images of white 1980's Bianchi's.
None of ...
- 17.8k
2
votes
Bianchi Bike - Help Identifying Model
Some observations:
Its an `80s bike at best - the downtube shifters and severe rake on the forks show its no newer. The cranks appear to not be cottered, so it is newer than the 70s.
The current ...
- 114k
2
votes
How do I make my ATLAS BEACH X TYPE BIKE Electric and built for winter driving?
Thinking about the "built for winter driving" part of the question and the variableness of a Chicago winter.
You can expect
wet
snow
ice
Your bike comes with fenders so it's ready for messy ...
- 19.4k
2
votes
How do I make my ATLAS BEACH X TYPE BIKE Electric and built for winter driving?
If you want an electric bike with all the parts integrated, then you kinda have to buy it as an ebike already. There is no easy way to add a mid-drive or rear drive without a lot of work, and there ...
- 114k
2
votes
Need help reassembling bike shifter
Shimano has great documentation.
https://si.shimano.com/en/manual/search?q=SL-RS36
Between the exploded view mentioned by @superman.lopez and these you might be able to figure it out.
- 21
2
votes
Infeasibility of a mechanical wind-up spring KERS (Kinetic Energy Recovery System) for bicycles
To summarise the discussion, having this non-electrical KERS doesn't make sense because of its reduced capability.
It only helps with coming to a sudden stop, whereas an internally-geared-hub (IGH) ...
- 441
2
votes
Unmounting a stuck rear derailleur
Well that's a puzzle ! I am not familiar with this derailleur, so here's my guess:
You appear to have a bike frame with an integrated hanger, as in not easily replaceable. So any damage could write ...
- 114k
2
votes
Accepted
Should this bolt be tightened?
That is the B-axle. It should be tightened to 8-10 Nm using a 5 mm hex key. Here is an excerpt from the dealer's manual to illustrate this:
- 3,321
1
vote
Is it okay for my rear derailleur to be as "compressed" as this when in the lowest gear on the bike?
Bike is shifting smoothly?
Derailleur almost touches the cassette, but no actual rubbing?
You're fine.
- 11
1
vote
Can a crankset have its chainrings' alignment notch not aligned by design?
This may be the most primitive solution, but you can try both the "erroneous" orientation in the exploded view and the orientation where the notches align towards the pedal or crank arm.
...
- 1,153
1
vote
Should a track cog's asymmetrical lock ring be installed so the flat end faces the cog?
For the very smallest cogs, which I belive is 12-tooth, the chain can hit the lock-ring. The choice then is to make a thinner-diameter lock-ring to clear the chain, but that means the notches for the ...
- 3,277
1
vote
1
vote
Accepted
Upgrade shimano tiagra mechanical disc to tiagra hydraulic disc brakes
The new shifters and brake calipers you link to should come with new gear cables in the box. If they don’t, it will make your life easier to thread new gear inners through the new shifters rather than ...
- 12.4k
1
vote
What are the counter-intuitive surprises an amateur bike mechanic encounters, after pedals and cables?
Chain skipping
A worn chainring looks fine to the untrained eye.
A worn cassette looks okay too, mostly because we see the unworn sillhouetted biggest cog easier than any other cog.
Conversely a worn ...
Only top scored, non community-wiki answers of a minimum length are eligible