"Bump" every time I actuate the front brake
03-17-11, 03:07 PM
#1
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"Bump" every time I actuate the front brake
I just put my CR-18's on my bike and went for a ride. Every time I actuated the front brake, there was this "bump" once per rotation. What could this be caused by?
03-17-11, 03:09 PM
#2
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Find the bump, describe the wheel in that spot... Could be out of true, could be a rock in the brake caliper, could be something in the tire, could be a loose spoke or could be, you ran over a unicorn
03-17-11, 03:12 PM
#3
Constant tinkerer
My guess is that the seam isn't flush where the rim is joined together. But just find the spot where it's grabbing. That will tell you more than we can online.
03-17-11, 03:12 PM
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wheel out of true (side to side).
Wheel has a lump in it (for example from a hard impact that blew out a tire and bent the rim).
wheel has a spot of grease on it
tire is not seated on bead, or has a bubble, or is somehow rubbing the brake pads
brake pads are not centered, aligned, or wheel is somehow losing contact with the pads for some other reason.
you should be able to find the cause visually. Spin the wheel, and gradually apply the brake.
Wheel has a lump in it (for example from a hard impact that blew out a tire and bent the rim).
wheel has a spot of grease on it
tire is not seated on bead, or has a bubble, or is somehow rubbing the brake pads
brake pads are not centered, aligned, or wheel is somehow losing contact with the pads for some other reason.
you should be able to find the cause visually. Spin the wheel, and gradually apply the brake.
03-17-11, 03:56 PM
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It's definitely the seam. I noticed, when I got them, that the seems were very visible, which was a bit confusing for me.
What course of action can I take to correct this problem? I ordered them from Velo-Mine over Christmas, and this is the first time they've been on the road.
What course of action can I take to correct this problem? I ordered them from Velo-Mine over Christmas, and this is the first time they've been on the road.
03-17-11, 04:10 PM
#7
Constant tinkerer
If it really bothers you, you could contact them and try returning them. IMO it's really not a big deal. Run the wheel "backwards" if you can, so the brake pad isn't jamming the seam everytime. Or carefully file it down flush. It may never be perfect, but you can make a big improvement with a file and something to smooth out the filing.
EDIT: I guess what I meant to say is that it's not a big deal once you fix it the best you can.
EDIT: I guess what I meant to say is that it's not a big deal once you fix it the best you can.
Last edited by FastJake; 03-17-11 at 04:21 PM.
03-17-11, 04:13 PM
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It is a noticeable jolt that rattles my handlebars a bit, so I consider it to be a big deal. I had thought about flipping the wheel around to see if that helped any. I contacted them to see what they thought about the situation. I'll be going out for a ride later tonight. I'll try flipping it around to see if it helps any.
03-17-11, 04:34 PM
#9
Your cog is slipping.
Sand it flush with really fine sandpaper. The sidewalls of CR-18s are machined anyway so if you're careful, you won't even be able to tell when looking at it.
03-17-11, 05:58 PM
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03-17-11, 06:10 PM
#12
Your cog is slipping.
Legit. I've seen countless rim seams that do this.
03-17-11, 07:25 PM
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I missed the once per rotation thing lol, when my headset was loose it would clunk when I used the front brake.
