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

New: Take part in the January Giveaway for a Trifox Carbon MTB Riser Handlebar


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
My Bicycle memories
Today 03:46 AM
Bicycle renovation suggestions.
Today 03:16 AM
Trifox carbon frames
Today 01:33 AM
2021 Pro Road Cycling
Yesterday 04:18 PM
Can someone identify this Bottom Bracket...
Yesterday 01:21 AM
11-42 cogs on Road bike?
01-24-2021 12:24 PM
Big Basso, Tiny Colnago
01-23-2021 08:11 PM
NewBikeShopper (intro & opinion request)
01-20-2021 01:57 AM
1983 Trek 720
01-20-2021 12:23 AM
brakes
01-19-2021 11:25 PM

[-]
Top 5 Posters This Month
no avatar 1. Criminal
20 posts
no avatar 2. RollOn
6 posts
no avatar 3. Yevhen
5 posts
no avatar 4. NewBikeShopper
4 posts
no avatar 5. Bliip
3 posts