Brake pad thump at the rim seam
#1
Tortoise Wins by a Hare!
Thread Starter
Join Date: Feb 2006
Location: Looney Tunes, IL
Posts: 7,398
Bikes: Wabi Special FG, Raleigh Roper, Nashbar AL-1, Miyata One Hundred, '70 Schwinn Lemonator and More!!
Mentioned: 22 Post(s)
Tagged: 0 Thread(s)
Quoted: 1549 Post(s)
Liked 941 Times
in
504 Posts
Brake pad thump at the rim seam
While braking the brake pads thump on every rotation when it meets the rim seam. I’ve noticed this on many rims, even when the seam joint looks pretty clean. Are there any tricks for reducing this tendency? Thanks.
#2
Senior Member
I got a small nick in my front rim, first I used am emery board between the rim and the brake pad, gentle pressure on the brake and rotated that spot on the rim back and forth to sand it down, then used some 150 grit sand paper on a sanding block to further smooth it out. Be gentle, don’t do more than you need to make the sound acceptable.
#3
Senior Member
Join Date: Dec 2010
Location: northern Deep South
Posts: 8,895
Bikes: Fuji Touring, Novara Randonee
Mentioned: 36 Post(s)
Tagged: 0 Thread(s)
Quoted: 2599 Post(s)
Liked 1,924 Times
in
1,208 Posts
In increasing order of effectiveness:
Brake a lot and wear the rim out. Replace the rim.
If you build your own wheels, turn the rim around in the wheel. Or reverse the skewer (front wheel only).
Emery board, file down the joint. Problem is, there's often a broken pin in the rim, and the joint only "opens" when the brake is applied.
Brake a lot and wear the rim out. Replace the rim.
If you build your own wheels, turn the rim around in the wheel. Or reverse the skewer (front wheel only).
Emery board, file down the joint. Problem is, there's often a broken pin in the rim, and the joint only "opens" when the brake is applied.
#4
Half way there
Join Date: Sep 2015
Location: North Carolina
Posts: 2,955
Bikes: Many, and the list changes frequently
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 985 Post(s)
Liked 879 Times
in
526 Posts
A few swipes with a flat file have resolved those issues for me. A file is easier to control than hand-held sandpaper so you will better target the high spots.
Last edited by Moe Zhoost; 03-08-20 at 07:25 AM.
Likes For Moe Zhoost:
#5
mechanically sound
IME:
Try all manner of sanding and filing and straightening, with little effect.
Tolerate until annoyance level reaches peak.
Get new rim/wheel.
Try all manner of sanding and filing and straightening, with little effect.
Tolerate until annoyance level reaches peak.
Get new rim/wheel.
__________________
#6
Senior Member
Join Date: May 2017
Location: Northampton, MA
Posts: 1,909
Bikes: 36" Unicycle, winter knock-around hybrid bike
Mentioned: 15 Post(s)
Tagged: 0 Thread(s)
Quoted: 930 Post(s)
Liked 393 Times
in
282 Posts
Personally I'd try to understand which of three things is happening:
- mismatch in the position or shape of the joined ends - seems like you ruled this out.
- rim not true at the joint to a degree that spoke tension can't fix - I have a wheel that has this, fortunately there's enough float in the caliper that it hasn't proven an issue (but then my brake is only for drag on moderate hills, not stopping)
- rim profile distorted on both sides of the joint such that the ends much each other but not the rest of the wheel - you might try using a pair of calipers or better yet a micrometer (for the flat faces more than precision) to measure the width there vs. elsewhere
Any attempt at improvement beyond removing material is probably only something that can happen with the wheel fully de-tensioned, while built up that joint is under immense compression.
- mismatch in the position or shape of the joined ends - seems like you ruled this out.
- rim not true at the joint to a degree that spoke tension can't fix - I have a wheel that has this, fortunately there's enough float in the caliper that it hasn't proven an issue (but then my brake is only for drag on moderate hills, not stopping)
- rim profile distorted on both sides of the joint such that the ends much each other but not the rest of the wheel - you might try using a pair of calipers or better yet a micrometer (for the flat faces more than precision) to measure the width there vs. elsewhere
Any attempt at improvement beyond removing material is probably only something that can happen with the wheel fully de-tensioned, while built up that joint is under immense compression.
Last edited by UniChris; 03-07-20 at 01:59 PM.
#7
Old fart
Join Date: Nov 2004
Location: Appleton WI
Posts: 24,777
Bikes: Several, mostly not name brands.
Mentioned: 153 Post(s)
Tagged: 0 Thread(s)
Quoted: 3582 Post(s)
Liked 3,395 Times
in
1,929 Posts
If it's a front wheel, turn the wheel around so the lip passes on the trailing edge of the seam. Sometimes that's enough. Otherwise, or if it's a rear wheel, emery board, flat file, etc. as mentioned above.