Questions tagged [mechanical]

Repairs, maintenance, mechanical issues, or drivetrain parts.

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9 votes
4 answers
2k views

Infeasibility of a mechanical wind-up spring KERS (Kinetic Energy Recovery System) for bicycles

I'm curious about an explanation for why a wind-up spring KERS (Kinetic Energy Recovery System) isn't worth it for a bicycle. The system I have in mind is instead of braking the rear wheel you engage ...
  • 411
1 vote
2 answers
67 views

How do I make my ATLAS BEACH X TYPE BIKE Electric and built for winter driving?

Front Wheel: 26" x 1.75 x 36H x 12G Alloy-Cruiser, Bolt-On Rear Wheel: 26" x 1.75 x 36H x 12G Alloy-Cruiser, W/Shimano Coaster Brake Front Hub: Alloy Bolt-On, Sealed, 36H x 12G x 3/8" ...
3 votes
1 answer
107 views

Need help reassembling bike shifter

I recently needed to change my shifter cable, and I ended up taking apart the entire shifter instead of doing it the easy way. I was able to change the cable, but couldn't put it back together again. ...
2 votes
2 answers
106 views

Mechanic disk brake hose length for trials

I have an Avid BB5 front disk brake on my 20" trials bike, and when I bought it from a shop that claims to specialize on trials bicycles, it had a pretty long front brake hose (80 cm/30"). ...
1 vote
3 answers
121 views

Bianchi Bike - Help Identifying Model

I'm looking at buying a Bianchi bike, I was wondering if anyone can tell from this image the type of bike, model and year. The owner bought it 2nd hand so doesn't have much info. Any assistance would ...
1 vote
1 answer
107 views

Upgrade shimano tiagra mechanical disc to tiagra hydraulic disc brakes

I currently have a Scott Speedster 20 with Tiarga 10 speed mechanical disc brakes. Is it possible to upgrade my brakes with the hydraulic version of the tiagra groupsset (by just buying these parts e....
  • 13
5 votes
3 answers
391 views

How to lock a saddle clamp to stop it from loosening during riding?

I borrowed my son's bike (a simple mountain bike) and I have problems with the saddle: I pushed it as far as possible to the back (so that it tilts down as much as possible otherwise I have the ...
  • 1,007
3 votes
1 answer
94 views

Steering torque

What defines the steering torque? What is an average value for e.g. city bikes and downhill MTB? Is the static torque largest for returning the steering to zero position, depending on (radial) load ...
  • 281
10 votes
2 answers
623 views

What mechanical effect causes the requirement to replace 11 speed chains at 0.5% wear rather than 0.75%?

As far as I understand, the difference between 10 and 11 speed chains is in the thickness of the plates. The length and the inner width of each link remain the same. This in turn means the size/...
  • 17.4k
3 votes
1 answer
143 views

Direct mount derailleur movement when tightening thru axle

I've a direct mount rear derailleur and when I tighten the thru-axle the rear derailleur moves inwards towards the spokes, around 5mm. I'm getting recurring problems with gearing (I frequently take ...
3 votes
2 answers
506 views

Do split frames for belt drive bikes need special screws?

I have a belt drive Cube bike, and the frame is Aluminium. The rear triangle has a split to accommodate the belt, there's a screw right above the rear sprocket, on the right side of the bike - see ...
  • 377
17 votes
8 answers
5k views

What are the counter-intuitive surprises an amateur bike mechanic encounters, after pedals and cables?

Pedals It's pretty obvious that one of the two pedals needs be tightened counterclockwise, but which one? A brief reflection on the right pedal's sense of rotation (while pedaling forward) with ...
3 votes
1 answer
299 views

Cantilever brake is missing its mounting screws and washers, how do I replace them?

Context I am fixing up a BSO where the rear cantilever brake is missing. I want to keep this project green and cheap, and there is a good supply of used cantilever brakes online. But they often come ...
  • 2,120
4 votes
2 answers
267 views

Removing Nexus 8-speed IGH from hub shell

see update at the bottom I'm trying to remove my Nexus SG-C6001-8D from its hub shell to grease it. Sadly Shimano's documentation doesn't cover the process of extracting the internals from the hub ...
  • 377
0 votes
3 answers
99 views

Mechanical disc brake caliper round pads 23 mm diameter

I’m trying to find round brake pads of ca. 23mm diameter. They are for a Valk bike brand sold online in Australia. There is no brand or model evident on the brake caliper or levers. Almost certainly ...
  • 259
9 votes
2 answers
732 views

Gates CDN - frequent belt failures

update at the bottom I ride a belt drive bike fitted with a Gates CDN front sprocket (on the crank), a CDN belt and a CDX rear sprocket. Around the 2200km/1400mi mark, the CDN belt failed and teeth ...
  • 377
2 votes
4 answers
463 views

How to increase brake responsiveness on Microshift style STI brifters paired with mechanical disc brake

I have a set of microshift style STI brifters. They are paired to a generic brand mechanical brake set on a Kent Nazz gravel bike. I can't seem to get the brakes to be as responsive as I would like. ...
  • 155
0 votes
2 answers
221 views

What is this on the cassette? (don't quite know how to describe)

So I've attached the images of this weird piece of metal "on" the smallest cog of the cassette. Can anyone advise me on what is happening here? It does not interfere with the riding as far ...
  • 173
0 votes
2 answers
129 views

Disc rotor rubbing against pad when bike is tilted

There is a fair amount of lateral movement of the rotor between the pads in the rear wheel break calipers. I have played about trying to centre the rotor as best as I can to stop the ching noise ...
4 votes
3 answers
1k views

Stripped brake mount on fork lower

I noticed that one of the bolts used to attach the brake to the fork is stripped and found many solutions but wanted to know if continued use will make it worse with and without repairing it. Also ...
  • 91
1 vote
1 answer
108 views

Why do steerer expander plugs have nesting threads?

I'm looking at expander plugs as I work on a modification for my new build. I note that the M6 bolt that holds most of them - like the Enve on my desk - threads into a larger, internally threaded, ...
  • 123
4 votes
3 answers
577 views

Is buying a used bike bad if you are not expert?

Is it a bad idea to buy a used bike that is somewhat expensive ($1000 range) if you don't know much about bike mechanics? Of course you can find a checklist online of what wear/damage to look for, ...
  • 1,237
0 votes
1 answer
137 views

What is the Mechanical advantage provided by mechanical disc brake caliper

I'm designing a tricycle and I wish to put mechanical disc brake calipers but I only got leverage of brake lever, I'm also searching mechanical advantage/leverage provided by mechanical brake caliper ...
5 votes
1 answer
337 views

Rear Mech Too Far Forward

I recently crashed my road bike in the city on some tram tracks, a terrible experience and don't recommend. I came off the bike and the bike itself landed on its right hand side and sustained damage ...
  • 303
0 votes
1 answer
684 views

Use Shimano 105 R7000 shifters for Disc brakes

I have 2 spare R7000 shifters which I used on my rim brake equipped road bike. I've upgraded to Ultegra some time ago. I also have a Tiagra gravel bike with mechanical disc brakes that uses Tiagra ...
  • 497
0 votes
2 answers
96 views

Rear derailleur won't go to smallest cog (road bike, MICROshift R8)

I checked, When the shifters are such that the chain should be on the smallest cog, the cable still has a slack, which I understand then it means is not a cable adjustment thing, If a very gently ...
  • 472
10 votes
2 answers
2k views

Chain popped out of derailleur and wrapped around itself - how? why?

During my ride yesterday, I've hit a really weird mechanical and would love to understand. So here's the situation - I'm riding along, start on a hill, stand up and push some power, suddenly hear ...
1 vote
1 answer
839 views

Difference Between SRAM SX eagle chain and SRAM NX eagle chain(12 speed)?

I have a Trek X-Caliber 8 with a SRAM SX Eagle 12 speed drive train, but I only have a SRAM NX Eagle chain. What is the exact difference between the two chains, and how can I modify my chain to make ...
  • 113
0 votes
1 answer
117 views

Looking to change from Octalink Claris to Shimano 105, will the frame be compatible with a 105 hub?

Since road bikes are sold out almost everywhere. I was thinking about upgrading my current road bike with a new group set. My current bike a Scott Speedster 50 (2015) currently has a Shimano Claris ...
  • 203
3 votes
5 answers
485 views

Roadside / Temporary fix for skipping chain

Recently I was out riding when my chain began to skip in the big ring due to heavily worn components. The situation worsened surprisingly quickly such that within a few miles I couldn't practically ...
  • 131
1 vote
1 answer
79 views

Grip shifters on wrong side

My new grip shifters were installed on the opposite sides than I'm used to. Can I easily just switch them back to what I am used to?
4 votes
2 answers
291 views

Dangerous feature on a new 20" wheel kids bike? EZBuild pedals

TLDR: Rather than threading a pedal directly into the crank arm this bike maker has an EZBuild feature. The pedal is threaded into a cast aluminum part at the factory that rotates around the crank ...
  • 18k
6 votes
1 answer
290 views

Ultegra 6600 right shifter lever alignment

Have a set of Ultegra 6600 SL shifters that I'd love to put to use, but encountered an oddity with the right hand (rear) outer shift lever. It appears the lever return goes too far and so as a result, ...
  • 61
4 votes
1 answer
331 views

Skipping bolts on seatpost , please help?

Couple weeks back I bought this aluminium single-bolt seatpost . Now, just 20 days later, the nut that tightens the the mechanism to fasten the saddle rails to the seatpost is skipping around and not ...
  • 312
1 vote
2 answers
127 views

Keeping rim brakes centered

Nice to talk to you all again. I've been refurbishing a classic women's city bike for my girlfriend (vintage French - the bike not the girl ;) it's shaping up groovy. The primary problem I'm ...
  • 89
6 votes
2 answers
586 views

Tool/proceedure to remove Shimano direct mount rim brake bearings (Ultegra in this case)

Looking for some advice on what tool I need/the process to remove the pivot bearings from the Shimano Ultegra direct mount rim brakes. It looks like I'll need a hook wrench(?) to get at the rear ...
7 votes
1 answer
449 views

Pad spacer and mechanical disc brakes

My bike, a Trek, has Tektro mechanical disc brakes. Do I need to insert a pad spacer when the wheel is removed to prevent the brake from locking if the lever is accidentally moved?
  • 71
4 votes
2 answers
885 views

Shimano Deore hydraulic brake problem

I have a bike (Cannondale Quick MX) I used frequently until last fall, when I got a driving license (not my first, well out of my teens) and a car to use. The bike is 3 1/2 years old now. Since the ...
3 votes
1 answer
86 views

What bike crank do I have and how can I re-attach?

So during quarantine i've picked up a hobby of bike riding. Recently while going for an afternoon bike ride I noticed one my pedals were shaking but I just ignored it. When I was finished riding I ...
  • 31
5 votes
1 answer
611 views

How to make sure that the brake cable anchor bolt properly holds the cable?

I am referring to the bolt, in the V-brake, that holds the cable on the opposite side of the noodle (as in this question). Yesterday I loosened that bolt to take the wheel off (I learned later that ...
  • 523
2 votes
2 answers
335 views

Tiagra levers moving loose

Lately I have noticed that, whenever I use the bar-end lever to shift the gears up (both front and rear) for the first couple of actions the lever feels loose: it moves to the end of its range without ...
  • 6,629
3 votes
0 answers
62 views

Can't find a "friction screw" for a friction shifting system

I recently broke one of the two speed levers ajuster (friction screw) that adjust the pressure between the levers and the cable. It's made in plastic as shown in the picture below. I would like to ...
  • 31
1 vote
1 answer
140 views

Front chainring issues + can I install Falcon Friction thumb shifters to an Shimano STX derailleur set?

I'm interested in trying friction shifters, also to save space on my cockpit. I bought a Mongoose Hilltopper 1994 recently and I want to play with it a little. A bike mechanic told me in order to ...
  • 11
2 votes
1 answer
323 views

Dent on aluminium frame?

I have a Cube Stereo 120 2018. When I was driving today a car hit me. I'm fine but the bike has a dent in it made by the car door. Can it be fixed? Can I still ride it, and go MTB? Can I make a sort ...
4 votes
2 answers
441 views

Help identify fender mounting clamp?

My bike has metal fenders that attach to the frame through ~3mm steel arms that are clamped and held in place with a piece of plastic that is screwed to the frame (M5 bolts) - as shown on the photo. ...
2 votes
1 answer
152 views

Stiff Shifting Levers

I was helping a friend build a bike from used ultegra 6700 components, and for some reason the shifting levers feel really stiff or difficult to shift, particularly when increasing in cable tension (...
9 votes
1 answer
734 views

Is it necessary to reinforce a carbon fiber steer tube?

There seems to a belief circulating online that carbon fiber steer tubes need to be reinforced with the compression plug specifically underneath the clamp points of the stem. If this is true, why isn'...
  • 9,888
3 votes
3 answers
5k views

How to remove a stuck SRAM AXS (Dub) crankset

I wanted to remove my relatively new SRAM RED eTap AXS crankset from my bike and I'm having problems trying to loosen (meaning: being unable to) the main 8mm hex bolt on the drive side, the step shown ...
3 votes
2 answers
4k views

Where are the bearings in thru axle hubs?

So I’ve looked all over the internet to find an anatomy picture of a thru axle hub, because I don’t understand where the bearings go, and I can’t find anything helpful. Can anyone help me understand ...
14 votes
8 answers
6k views

Loose spokes after only a few rides

I have recently joined the cycling world after committing to losing weight. I am a heavy rider at about 28st (390 lbs) and have after some advice gone for a GT Avalanche. I have had the bike less than ...
  • 151