I just got into the sport of mtb biking and i found a bike in fb marketplace and picked it up a couple days ago. It started making a weird noise and and the derailleur is doing this weird thing that’s i can’t describe and i can’t find anything on youtube or anywhere else. Can some please help me figure out what it is and how to fix it.
by Muggy493
5 Comments
It seems like your freewheel isn’t free. (Rear hub isn’t spinning when it’s supposed to be able to)
Hopefully someone else can chime in with more helpful fixit advice.
I’ve had this happen with rear sprocket cassettes that are excessively worn. It can grab the chain and retain it via burrs, effectively looping it around like line on a fishing reel. Except that you don’t have any line to give. Can you take a close up photo of the cassette?
you should have not gotten this bike. can you return it? they make the rear axle different than this design now which excessively squeezes the frame together. that and the cassette is not freewheeling like it should. I hope you didn’t pay more than $20 for this. (and I’m all for running beaters) maybe a bike shop can get it to run ok but you really need a better bike to hit actual trails.
Forget your derailleur, your rear wheel doesn’t free wheel (keep.spinning) when you stop pedaling. Something is broken or dragging. Might be related to derailleur issue, might not. But start there
Your derailleur should be just fine. The issue you are encountering is either in the hub bearing being too tight and binding or the free wheel is binding. If you take it to a bike shop they will correctly identify what is causing the issue. If it is the free wheel it would be around $20. If it is the hub it could range from $30-$70 odd depending if it is just needing adjustment or an overhaul. There is every possibility the hub may have damage from improper adjustment and may require the wheel to be replaced. One easy way to tell the two issues apart is to pedal the bike like you have in the video and let go of the pedals to let it spin, if the wheel stops quite quickly it is hub related, if the wheel still spins for a bit and the cranks keep turning it will be a free wheel issue.
TL-DR
Could be free wheel binding up
Could be hub binding up
0% chance of issue caused by derailleur