r/BikeRepair • • Aug 16 '25

PLEASE POST A PHOTO AND MAKE/MODEL/YEAR OF BIKE - THIS HELPS WITH ANSWERS

6 Upvotes

The more information you give us, the better we can accurately answer your questions. Thanks!


r/BikeRepair • • 7h ago

Kinda blown away by AliExpress seller customer service, NGL.

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1 Upvotes

I need a cassette body for my KHS 4000 Fatbike and honestly, the interweb is often shit for finding some of these parts. Bicycles in general can be very difficult to source parts (which you likely all know).

I found what I thought to be the part I needed from this dealer who sells on Ali Express and I placed an order. I'm very impressed with the effort that "Windy" took to make sure I'll get the right part.


r/BikeRepair • • 23h ago

Bike Repair That didn't go how I hoped... First brake bleed is an utter failure

2 Upvotes

I just did my first brake bleed. SRAM Level Stealth Silver w/ bleeding port and with DOT 5.1 on a 2019 Trek Farley 9.6. I toiled for weeks before doing it. Watched every video I could. Bought all the tools I needed. Made sure I had fresh DOT fluid. Went step by step meticulously, while watching the video. Zero bubbles.

  • I did only the rear to start as the line needed to be shortened.
  • I used a new stealth-a-ma-jig and barb.
  • Lever was set level and was the highest point in the system.
  • I used the SRAM piston retractor tool, rather than the generic bleed block that came in the BleedZone kit.
  • I thought I gassed out all the bubbles in the syringes prior to starting.
  • Did a vacuum at the end and pressurized the lever.

When I removed the syringe at the lever there was a slight overflow so I don't think I let any air in. No visible leaks.

Get on the bike and go for a ride and.. I now have mushiest, brakes I have ever used. Levers sink right down to the grips. I need to get it sorted for a ride this weekend so off to the LBS it is. Really wanted to be able to do this myself and have no idea where I went wrong but.. majorly pissed and disappointed.

I've referred to a few popular YouTube vids and read the SRAM bleed instructions, but here I am. What steps might I have missed?


r/BikeRepair • • 1d ago

vintage Sakae SA cranks loose

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0 Upvotes

The cranks on my bike somehow unscrewed themselves and i’m struggling to figure out how to tighten them. Any help would be great.


r/BikeRepair • • 1d ago

Eddy Merckx EMX-3 headset

1 Upvotes

Hi. Recently I bought a used EMX-3 bike. Could you please tell if this headset was standard for this bike? How could I removed it?


r/BikeRepair • • 2d ago

Bike Repair Rust prevention on Shimano parts

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2 Upvotes

I am currently repairing my Sparta Athos bike and I have a couple of painted shimano part assemblies (BR-IM41-F, BR-IM41-R and SG-7R45) where the paint has fallen off and rust has appeared. I have already removed the rust once on the brake part and it has come back from just sitting inside the house. Although it has not come back everywhere (see pictures). I also have various other shimano parts and a part for my front light that have exposed steel and could rust. My question is weather it is worth it to repaint these or not? And which paint I should use?


r/BikeRepair • • 2d ago

Bike rear wheel bearings

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4 Upvotes

Somehow my kid blew out the bearings on the back wheel.
Could uses some help on getting the axel out and how to get new bearings


r/BikeRepair • • 2d ago

Why is my seat always tilting back

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5 Upvotes

Ive tightened it but keeps on loosening and tilting back, not wobbly or anything. Is there a fix I can do or is something wrong?


r/BikeRepair • • 2d ago

Chain keeps falling off while pedaling

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2 Upvotes

My chain has been falling off the front chainring with increasing frequency. At first, it was just when I hit a jump or rolled over rocky terrain, now it will fall off simply when I pedal? Is my chain too loose from stretching? Or is it worn teeth on the front chainring?


r/BikeRepair • • 2d ago

Advice Is the crown race supposed to stick out that much at the bottom?

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2 Upvotes

I cannot get it to go in further it does the same thing at the top. they are cage ball bearings and this is a haro 200.2


r/BikeRepair • • 2d ago

Replace Un26 with a PP5 compatible setup?

1 Upvotes

I have a 25 yo road bike which works perfectly fine for me but I’d like to add on an inexpensive power meter. I was looking on Amazon at the PP5 unit (https://a.co/d/017b1ZnF) which is not compatible with my approx year 2000 Ultegra Cranks (has a square taper spindle, replaced it with a BB-UN26 model a few years ago). Any advice on how to replace that with a bottom bracket/spindle that the PP5 can bolt onto? Crank cannot have integrated spider.


r/BikeRepair • • 2d ago

Advice Strange sound.

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1 Upvotes

Only my second ride on the new bike I changed the pedals greased them up but there’s like a creaking sound coming from either pedals bottom bracket drive chain does anyone know what the noise could be or is it the bikes new and needs feeling in.?


r/BikeRepair • • 2d ago

My Bike (Cannondale Quick CX3) has only been ridden about 10 Miles and the intertube already punctured. Is this normal?

0 Upvotes

The last time i owned a bike was in my teens, and I rode that thing every day up and down mountains despite it being a road bike like the heedless kid I was. Tubes never punctured. Now I have this bike, which I'm told can take a little bit of roughness, and it's already popped despite me sticking mostly to roads and rough grass.

The man in the bike shop said there was no obvious sign of what did it and that the puncture was tiny, but that these things are expected and that I should carry three intertubes with me at all times? Is that normal? Sorry for this question probably seeming noobish, but I'd like an answer directly from people who might know better. Thank you much!


r/BikeRepair • • 2d ago

Front wheel not centered

1 Upvotes

Got my Fuji mountain bike a couple of years ago, and just recently started riding a bunch. It sounded funny going around turns at higher speeds, and I had trouble balancing on the bike with no hands. Finally I looked down at the front wheel and saw this:

Just weird. Tire is not centered. What you can't see is the disk brake. At first I thought I would just have to move one end of the axle. Then it got complicated in my simple brain. First, everything is true (vertical). It isn't like the wheel is slanted off vertical. Then I noticed the disk brake is tied to the frame. So if I try to move the tire on the axle from left to right, I have to adjust the disk pad clamp too. Is there a simple way to fix this? Responder in another thread said "dishing", meaning that the spokes needed to be adjusted. Two things came to mind: 1) I don't think I can change the spokes that much, ande 2) the funny thing is the disc brake is on the short side. Any suggestions on how to get the tire centered?


r/BikeRepair • • 3d ago

Chain slap tips?

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3 Upvotes

Clutch is on but I still get bad chain slap


r/BikeRepair • • 3d ago

Replacement screw for Shimano ST-M739 cable access cover

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2 Upvotes

I bought this ST-M739 shifter/brake lever combo from someone last year and finally have time to work on my bike (last photo attached shows a 1994 GT Zaskar that im working on).

All screws for the cable access cover are stripped, I was able to get two of them out, one isn’t yet moving and the fourth one is missing altogether.

What screws do I need to order to replace those please? The internet tells me M3x6mm screws but those don’t even remotely fit.

Would appreciate any advice! (Also how to get that little screw out that’s so stripped that nothing takes to it).

Thanks in advance!


r/BikeRepair • • 3d ago

Replacement screw for Shimano ST-M739 cable access cover

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1 Upvotes

I bought this ST-M739 shifter/brake lever combo from someone last year and finally have time to work on my bike (last photo attached shows a 1994 GT Zaskar that im working on).

All screws for the cable access cover are stripped, I was able to get two of them out, one isn’t yet moving and the fourth one is missing altogether.

What screws do I need to order to replace those please? The internet tells me M3x6mm screws but those don’t even remotely fit.

Would appreciate any advice! (Also how to get that little screw out that’s so stripped that nothing takes to it).

Thanks in advance!


r/BikeRepair • • 3d ago

Truing stand storage problem

2 Upvotes

Hello, I recently have gotten a truing stand, dishing tool, and my other tools are starting to get unorganized. The space is limited due to dorm living in college. However I have most of the basics and need a light box tool set up. I am wondering if there are any that have an attached peg board. I have tried looking and even looked at what some co-ops have however they are always to large for a dorm.


r/BikeRepair • • 3d ago

Every rotation of the tire has a noise

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0 Upvotes

Every rotation of the rear wheel (on Aventon Adventure M) has a noise and I maybe feel a small vibration on the rack. It happens when the tire pressure valve crosses the top of the rotation. I can't see any place where there is any rubbing or bumping of the wheel to the fender or frame. Any ideas?


r/BikeRepair • • 3d ago

Replenishing sealant at home, using a homemade sealant.

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0 Upvotes

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It was time to top up the sealant; the front tire’s pressure had been dropping—not sure if that’s related, though.

Since I set up the tubeless system myself at home, I used a homemade sealant recipe I found online. It worked perfectly—the tires, rims, and rim tape were all brand new and had never been exposed to sealant before.

While I was at it, I also replaced the valves. It wasn’t strictly necessary, but since I was already deep into the work, I figured I might as well get it done.

For the next tubeless maintenance session, I plan to take everything apart to clean it and true the rear rim, which has a slight wobble—it’s just one of those things that bothers me, haha!

I just wanted to share my experience with a cost-effective tubeless setup.

As the saying goes, "Tubeless is life"—and it’s true. Zero headaches.


r/BikeRepair • • 3d ago

Togliere bullone con frenafiletti

1 Upvotes

Sto smontando i bulloni delle forcelle del mio monopattino elettrico, nella ruota posteriore sono riuscito a svitare etitto tramite chiave a brugola e bussola, sulla ruota anteriore i bulloni della ruota non vogliono svitarsi in nessun modo ho provato di tutto, sono letteralmente "saldati" per la grande quantità di frenafiletti rossa che contengono quasi tutte le viti del mio e scooter, come posso ovviare? Non ho avvitatore e stavo pensando di scaldare il tutto e evitare subito può essere una buona idea?


r/BikeRepair • • 4d ago

Magura TT breaks

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1 Upvotes

OK guys so I have an old p5 that has Magura TT8 breaks. My only issue is I legit cannot find them anywhere on the Internet. That’s why I’m coming here. What’s really annoying is it? It’s legit just a bolt on the brake lever. That’s not working. My brakes. Work completely fine. It’s just I can’t tighten it because the Bol and the brake level broken.

if anyone has brakes for sale, I will gladly buy them. Can someone please just let me know if the bike gods are real than someone must have these brakes.🙏🏽🙏🏽🙏🏽


r/BikeRepair • • 5d ago

does it sound weird?

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1 Upvotes

r/BikeRepair • • 5d ago

Brake and gear problems pls help

1 Upvotes

My brakes have been off if I turn my bike upside down and spin the wheel it will spin then it will suddenly stop at a certain point and the brakes will close when it happens also my gears on my bike will shift up randomly without me touching it and it’s not exposed to do that pls help

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r/BikeRepair • • 5d ago

Advice Polygon Tambora g4 shift issues

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0 Upvotes

My Polygon Tambora g4 shifters only shift once then becomes dead. It shifts up once and down once and then both shifters die