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

New: Take part in the July Giveaway for VTUVIA SN100 Camouflage Fat Tire E-Bike $1679


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
Cannondale Criterium value
Today 02:04 AM
Ebike for riders 5ft tall
Yesterday 08:54 AM
First Metric Century
08-16-2022 03:26 PM
Help identifying date of manufacturing
08-15-2022 08:52 PM
Cycling photos while on holiday
08-15-2022 08:41 PM
Make a freewheel removal tool
08-14-2022 07:32 AM
Weak spring tension on the derailleur wi...
08-14-2022 07:18 AM
Woodsplitter in Pittsfield, Vermont
08-12-2022 06:19 AM
New Stator For My Ride1up Core 5
08-10-2022 08:49 PM
Jumps a Gear
08-09-2022 07:14 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. Jesper
17 posts
no avatar 2. ichitan
15 posts
no avatar 3. dinh thaihoang
11 posts
no avatar 4. ReapThaWhirlwind
9 posts
no avatar 5. Criminal
6 posts