Have questions or want to discuss cycling? Join Now or Sign In to participate in the BikeRide community.


Chain tightens....
#1
My son has a BMX bike with freewheel. When you pedal the chain will get tight then loosen up. i checked the crank and it appears that it is not bent. i do not see anything on the back sprocket that is out of whack. Any suggestions on what to look for?

Thank you.
  Reply
#2
usual cause is the wheel out of line with the frame, check that the gap either side of the tyre is the same both sides at the chain stays and that it doesn't alter as you tighten it, can be caused by damaged drop outs.
If it persists, you may want to use a chain tensioner like these;
also check for damaged teeth and the chain ring out of round.
  Reply
#3
(03-22-2011, 12:36 PM)trevgbb Wrote:  usual cause is the wheel out of line with the frame, check that the gap either side of the tyre is the same both sides at the chain stays and that it doesn't alter as you tighten it, can be caused by damaged drop outs.
If it persists, you may want to use a chain tensioner like these;
also check for damaged teeth and the chain ring out of round.

Thanks Trevgbb.

the wheel is aligned with the frame okay. What are drop outs? i never thought to check to make sure the chain ring is flattened on one side i will do that.
  Reply
#4
I've found that this usually comes from the front chainring being out of round or not centered on the crank as trevgbb mentions. Depending on how the chainring mounts to the crank, you may be able to adjust this.
  Reply


Forum Jump:

[-]
10 Latest Posts
Continued learnings from bikepacking
Today 02:01 AM
What are the pros and cons of using a 26...
Today 01:55 AM
I got new Tioga FASTR X Tires (Ask Me An...
Yesterday 03:18 PM
Are You Riding the TDF
Yesterday 12:20 PM
Tour de FRANCE 2025
Yesterday 09:52 AM
The great thing about trikes
Yesterday 09:27 AM
Japanese Bike Brands
Yesterday 08:27 AM
Gandolfi "Super" model 1985-86 racing bi...
07-04-2025 01:33 PM
How I used to clean my bike
07-03-2025 04:43 PM
Cassette shifting Problem
07-03-2025 02:51 PM

[-]
Join BikeRide on Strava
Feel free to join if you are on Strava: www.strava.com/clubs/bikeridecom

[-]
Top 5 Posters This Month
no avatar 1. GirishH
23 posts
no avatar 2. Flowrider
19 posts
no avatar 3. meamoantonio
17 posts
no avatar 4. Jesper
14 posts
no avatar 5. enkei
13 posts