/r/bikewrench
A community of cyclists - some with questions, some answers
A forum for folks with questions about bicycle repair.
Post your problems, and we will try to get your bike rolling again. It really helps if you can provide pictures and/or video.
A community of cyclists - some with questions, some answers
Post questions to get help.
Post your problems, and we will try to get your bike rolling again. It really, really helps if you can provide pictures and/or video.
You can also consult our FAQ or the list of people willing to help locally.
Post Rules and Guidelines
Questions about bike repair only. If you just want to post a picture, this isn't the place for it. Full rules.
"Is this cracked / safe to ride?" - If you have to ask, don't ride it. We probably can't tell from a picture just what condition your bike is in. Take it to your Local Bike Shop and ask them. If it's carbon, a specialist repair shop may be required. They should have the equipment and expertise to inspect it properly.
Please use the weekly thread for post follow ups and acknowledgments. Tag helpful commenters if you want them to receive a notification.
Comment Rules
Play nice
Stay on topic / No jokes, especially not false answers as jokes.
Other Websites:
Sheldon Brown's Bicycle Technical Info. A comprehensive resource with answers to common and obscure questions, data tables, etc., including a glossary which also serves as an index.
Park Tools' Repair Help including illustrated text and video guides to service procedures.
Cold Setting Steel Frames: adjusting the dropout spacing on a old frame to fit a more modern drivetrain. A comment with an overview and links to more information.
Other helpful subs:
r/bicycleengineering: bicycle technology from an engineering perspective.
r/wheelbuild and r/Framebuilding for construction of those components.
r/Bikebuilding for discussing and showing off bikes built up from a frame. See also r/xbiking.
r/Vintage_bicycles/ for pre-1986 bicycles.
Outlets for posts that don't belong here:
r/BikeMechanics Discussions among bike mechanics, professionals and advanced amateurs. Looser rules than /r/bikewrench.
r/JustRidingAlong "Pictures and stories of some of the most egregious user-error and bad luck damage on bicycles."
or just plain r/bicycling, which also has links to more subs.
/r/bikewrench
254,176 Subscribers
Rear Wheel i little lose, but rotation is center.
I just upgraded to Tru axle Frame boost but my hub is not boost type so i purchase the adapter, i found that the rear wheel is kinda loose a little but not noticeable even i shake the bike left and right. the axle lock is already tighten. i still try to run it the wheel spin is straight. i found it kinda little loose when i move the wheel left and right and compare to my front which is not loose.
Are this normal due to adapter? or theres already a problem?
09:15 UTC
TRP hy/rd: Piston movement with blocked calipers
My brakes started to feel really spongy lately so I decided to bleed them. I've followed the protocol by TRP but even after bleeding them the piston moves quite a lot. Does that mean there's still air trapped in there or is a bit of movement on the piston with blocked calipers normal?
09:14 UTC
1x10, duraace 7900 cassette& Rderailleur, 4600SL trigger shifter, narrow wide 34t. No matter how much i adjust it, it slams into gear when downshifting. Enough for my foot to slip off. Btension makes it smoother downshifting but higher gears slam into gear. Its only when putting down powet. Advise!
07:55 UTC
Schrader valve keeps getting sliced. Should I switch to a Presta valve?
I bought a Snapcycle R1 step thru fat tire bike back in Oct. I kept getting flats on the rear wheel and changed the inner tube four times that month. I contacted Snapcycle.
Eventually, they agree to send me a new rear wheel. Stating they haven't had a problem like this before. I realized the hole where the Schrader valve goes kept slicing the valve. I'm thinking maybe there is an insert that wasn't included for the hole of the Schrader valve on my rear wheel.
Is there something that goes inside of the hole to avoid this? If not, should I try a different type of valve that isn't close to the edges of the hole? Snapcycle finally agreed to pay to have it looked at but I don't have a car right now. Is this a quick fix? If I can do it at home that would be ideal. I don't want to drill it and risk making it worse.
07:50 UTC
Fork service
Hello guys, i wanted to ask y'all if you know if there is any specific kit for the fox 38 grip damper rebuild kit? Because i can not find any kit for the 38, only for 32 34 36 and 40. Even on fox site its the same.
My fork is a Fox 38 Rythm 2023 with a GRIP damper.
07:11 UTC
What am I missing to attach the bike poke with the saddle?
https://reddit.com/link/1if0ohv/video/luk181720hge1/player
My bike seat got stolen with the post a while back and I finally wanted to get it fixed so I ordered new parts on amazon to replace them. I first ordered a seat and realised it didn't come with a post, so I then ordered a post but then realised when I stick the post in there's nothing stopping it from just sliding out. Am I missing some other clamp to attach this on? I've searched online for a clamp but they only seem to turn up with post clamps that tighten the pole to the bike frame. Maybe I missed something in my materials or I need to buy something new. Thanks
06:53 UTC
Took off my cassette and pulley wheels to clean, drivetrain skipping all over the place after reinstallation
06:02 UTC
Stupid question - what is this object? (Shimano 105 R7000 Groupset)
Has a squishy sticker at the back of it
Anyone know what this thing is used for? I ordered a 105 R7000 groupset and this thing came with it. I don't know what this is.
Edit: Solved! It's a back up plate that attaches to the seat tube (according to Shimano's official instructions).
05:01 UTC
chip on carbon wheel in
just wanting some opinions on whether this looks alright to keep riding on. winspace hyper wheelset
04:58 UTC
My rear hydraulic brake is almost non functional.
When I first get on the bike the brake is non functional, if I pump it it gets a TINY bit better but not by much.
I saw online that I unscrew part of the brake, hold the handle and screw it back down. This seemed to work for a second as the brake lever seemed to get 'tight' again but it didn't work and I was back to where I was before.
I've been riding very slow on side walks in case I have to emergency stop, but I commute daily and I'm a bit scared.
Any ideas?
04:24 UTC
My rear hydraulic brake is almost non functional.
When I first get on the bike the brake is non functional, if I pump it it gets a TINY bit better but not by much.
I saw online that I unscrew part of the brake, hold the handle and screw it back down. This seemed to work for a second as the brake lever seemed to get 'tight' again but it didn't work and I was back to where I was before.
I've been riding very slow on side walks in case I have to emergency stop, but I commute daily and I'm a bit scared.
Any ideas?
04:24 UTC
Advice needed - Threaded freewheel hub.
I have a set of Stans ZTR 29er wheels with DT Swiss 370SL hubs and the freehub is threaded. What replacement hub do I need? New to all this and a bit stumped as there seems to be a lot of different types so any advice/held/recommendations will be greatly appreciated.
04:13 UTC
Single Speed Build. Play in hub
02:59 UTC
Rotor hits the brake
I had a bad flat a few days ago (hit a deep sharp-edged pothole with debris) and immediately deflated my rear inner tube. Rolled on it for about 20m before I stopped and checked. Had no spare tube so I taxi'd home and parked my bike until I got an tube to replace it.
When I replaced the tube and placed it back the rotor doesn't sit proper anymore and the rear wheel can't spin. Is this a deformed rotor or something else?
02:52 UTC
52T Chainring with a Deore Derailleur - Could it work?
I currently run a 46T chainring 1x with a Deore long cage derailleur m5100 with a 11 - 51 rear cassette with no issues. I am wanting to swap it to a 52T wondering if anyone has tried this before? Assuming I get a new chain could it work? I’ve checked and I have room on the frame so it won’t be an issue from my measurements
02:28 UTC
Cogs fit very loosely on the freehub
Hello,
is it normal for the cassette to be as loose as on the movie? I haven't paid much attention to this issue with my previous cassettes, but I bet I would notice such a poor fit... It is a CS-M9000 (XTR) 11x 11-40 cassette on Novatec SB-792 hub. Checked with 2 hubs: On the first movie it is a brand new freehub (as I wanted to upgrade to a 6-pawl one). Seams totally hopeless. On the second movie there is the old freehub - a bit better, but still, unacceptable... Any solution to that?
02:17 UTC
BB bushings/shims?
Replacing BB on 10 speed, to a Shimano BBR60. Son disassembled crankset and told me that he misplaced two "washers" one from each side of the BB. He described them as very thin washers that go over the BB output, residing between the BB and crankarm.
What are these used for? Are they required and if so, what would they be called? I tried the Shimano site but had no luck identifying the part.
02:14 UTC
Shimano Ultegra Di2 not shifting
2014 Bianchi Intenso with SM-EW90-A junction box and BT-DN110A battery (newly replaced).
Battery was charged overnight and charger indicates that battery is full, though using the shifters does not trigger the battery indicator light on the junction box. The bike will cycle the gears for crash protection mode just fine, but does not shift when using the levers. Cables plugged and unplugged, everything seems solidly connected.
Any suggestions on next troubleshooting steps?
02:09 UTC