Bicycle Mechanics - grabby, screechy, V brakes

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mharter
05-12-09, 05:21 PM
Hi folks!

The Avid Single Digit V brakes on my Surley LHT are grabby and screechy. I have set the pads carefully to be just barely towed in, as suggested in several other posts, but that has not solved the issue. I noticed that the brakes wiggle a bit on the posts, so I put plenty of grease in there to dampen any vibration, but that made no difference either. I've started with the pads that came with these brakes, and when they wore out I replaced them with Kool-Stop pads. Both sets of pads had this issue.

What tricks are there to making V brakes work best? Are V brakes supposed to act this way?

Thank much!
Matt

Mr IGH
05-12-09, 06:54 PM
My v brakes don't do this. Is the bolt that holds the brake arm to the studs too long? There should be almost no wiggle.
Panthers007
05-12-09, 09:41 PM
Which set of Avid Single Digit v-brakes do you have? My Trek 7.5 FX came the SD 3's. They were horrible. Stop you good, but went out of adjustment if you looked at them. I replaced them with SD 7's. Excellent brakes! I've never heard a complaint about the SD 7's.

What variety? And what type of rims are they being used on?

johnknappcc
05-12-09, 11:29 PM
I thought you didn't have to toe-in v brakes??? My wife's aren't toed in and they are quiet as all get out, and they would still flip you.
Mondoman
05-12-09, 11:54 PM
As the others have mentioned, wiggling on the posts sounds worrisome. Make sure the bolt securing each brake to the mounting post is secure. Are these brakes new or do they have a fair number of miles on them? Can you replicate the noise with the bike up on a stand?
remsav
05-13-09, 12:02 AM
This youtube video helped alot tryng to figure out how to put it together when I replaced my v brakes and pad. Only time I had screechy brakes were with a canti and that was the rim and not the pad I found after 3 pairs of different brake pads.

http://www.youtube.com/watch?v=RPOS9b1yIYE
operator
05-13-09, 07:26 PM
I thought you didn't have to toe-in v brakes??? My wife's aren't toed in and they are quiet as all get out, and they would still flip you.

Wrong.

Any brake pads that squeal without toe-in obviously need to be toed in. This includes 99% of the v-brakes out there.
mharter
05-13-09, 08:01 PM
Thanks for all the input!

The rims are a Sun CR 18 on the back, and a Mavic Open Pro on the front.
The brakes are SD 7s.

I've made sure that the pivot bolts are as tight as is safe, I don't want to strip or break them. Are there different lengths of bolt?

I had toed in the last set of pads too far and the noses wore too quickly, so I don't want to repeat that process, just a little toe is all I want to do. They only squeal when it is wet out, and the front is the loudest.

Matt