Author Topic: Brake Noise/Fork Vibration  (Read 6004 times)

Chester

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Brake Noise/Fork Vibration
« on: October 08, 2009, 07:27:03 PM »
Since taking delivery of my RST equipped with XTR brakes & Grizzly rims the front brake has made an ear piercing screech worthy of an ASBO, also during high speed braking +30MPH the forks start to vibrate; I've tried the mud/slurry fix suggested by Andy B to no avail, I've ridden miles of downhill (including Birdlip three times) with brakes lightly applied trying to bed-em-in, to no avail; I've had the bike back to SJS who checked it out, rode it and confirmed it does make a noise, but everything is OK, just ‘ride it in the rain more!’
With over 40 years of cycling and many different bikes (4 Thorn) some of my bikes have been nicer to ride than others; but the brake problem is so irritating, this is the first bike I have owned that is not a pleasure to ride, my 5 months old RST is now gathering dust in my garage awaiting its fate.
Can anyone offer a solution to this brake screeching/vibration problem; or should I get rid of the RST and buy something else; I just want to enjoy cycling again.





brummie

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Re: Brake Noise/Fork Vibration
« Reply #1 on: October 08, 2009, 07:48:29 PM »
Try some different ( brand ) pads?
I seem to remember in the CTC magazine a suggestion of filing/cutting a vertical slot ito the brake pad about 10mm from the front of the pad. ( Don't file/cut too far into the pad though.. that'd be dangerous !)
 

stutho

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Re: Brake Noise/Fork Vibration
« Reply #2 on: October 08, 2009, 09:15:38 PM »
There are lots of different fixes out there to find on the net - because none of the fixes are 100%.  I too had a lot of problems trying to silence the banshee that lives inside my RST.  What eventually worked for me was to add a 'brake booster' plate.  That was 4 years ago, at the start of the summer I was doing an overhaul on the bike and I thought 'I don't need this BB Plate any more'....  2 days later I had it back on!  Oddly my wife's RT has never made as much as a squeak.

Anyway like I said no fix is 100% guaranteed to work but try enough of them and you should get there in the end.  What we are tiring to do with these fixes is to change the frequency of vibration. (It is imposable to get rid of it)   


A few fixes to try - AT YOUR OWN RISK

Toe in
Toe out
file a grove on the pad (on the end nearest  the back of the bike)
put a little talcum pounder on the rims ( I think the idea here is that the talcum cleans and polishes the rim a bit - didn't work for me)
Clean down the rims with denatured alcohol or meths  (DON'T use petrol or diesel)
Check the rim is centred on the hub (need a dishing tool for this)
Change pads for a different brand possibly a multi compound block?
fit a Brake Booster Plate
Change Brake arms!

Many more out there on the web - JUST DON'T oil or grease the rims!!

 

Fred A-M

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Re: Brake Noise/Fork Vibration
« Reply #3 on: October 08, 2009, 11:15:35 PM »
What are your brake pads?

If they are Shimano, I'd swap them for another brand.......there's been a number of reported instances of them effectively scouring rims to shreds and I had to swap some shimanos out due to a similar problem, although in my instance, this was limited to wet conditions.
 

geocycle

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Re: Brake Noise/Fork Vibration
« Reply #4 on: October 09, 2009, 09:23:59 AM »
As others have said there are a lot of possible solutions.  I have grizzly rims with the swiss blue pads.  The rear is absolutely silent and was from day 1, the front was a little noisy to start with but is now also silent, probably due to my toeing in the pad.  IIRC here was not much space between the rim and the block which limited how much I could adjust it at first.  The vibration could indicate the headset is very slightly loose, loosen the bolt through the cap, then the stem bolts, tighten the cap, tighten the stem.
 

PH

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Re: Brake Noise/Fork Vibration
« Reply #5 on: December 07, 2009, 12:06:17 AM »
I’ve tried just about all the suggestions above, some have temporarily reduced the squeal non have ever cured it.  This is on a front wheel which has done around 5.000 miles.  I’ve also tried three different models of brakes, some are slightly better than others, but there’s not been a lot in it.  The quietest result came from a really excessive amount of toe in, but this both reduced the effective braking and caused the tip of the block to wear quite quickly.
I’ve now given up on the proper pads,  I’m now using £1.99 ones from Wlkos and they’re silent (well almost)!!  The braking is at least as good, I’ve got them set with normal toe in.  The only issue is longevity, the first pair lasted just over 900 miles, but they didn’t get much wet use.  I changed them last week and will see how they cope with winter use.  It does mean frequently checking for wear, which isn’t that big a deal.
This is on the front, on the recently built rear there’s no problem.
I also have the Grizzly rims on a 700c tourer with canti brakes, it has never squealed but the braking isn’t quite as good as with Vs.

jags

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Re: Brake Noise/Fork Vibration
« Reply #6 on: December 07, 2009, 01:41:02 PM »
i had the same problem,last resort i took of the pads gave them a rub of sandpaper hey presto squeel gone ;) hope that works for you .when im on my own i hate the noise ,but when im with a groop of lads i love it ,cracks them up ;D ;D

PH

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Re: Brake Noise/Fork Vibration
« Reply #7 on: December 07, 2009, 09:23:29 PM »
i had the same problem,last resort i took of the pads gave them a rub of sandpaper hey presto squeel gone ;) hope that works for you .when im on my own i hate the noise ,but when im with a groop of lads i love it ,cracks them up ;D ;D
I doubt that would work with the carbide rims, they'd just wear the pads smooth again in a couple of miles.

PH

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Re: Brake Noise/Fork Vibration
« Reply #8 on: January 02, 2010, 10:16:15 PM »
I’m now using £1.99 ones from Wlkos and they’re silent (well almost)!!  The braking is at least as good, I’ve got them set with normal toe in.  The only issue is longevity...  I changed them last week and will see how they cope with winter use. 

To awnser my own question -  The Wilko pads lasted 260 miles of winter use :o  Would maybe have lasted another 100, but I'd need to be checking them every 10 miles.
I bough some of the new Koolstop carbide specific pads, they squeal the same as the Swisstop.
I'm running out of ideas, I might have to revert to an aluminium rim, which would be a shame... and more expense... I might see if I can borrow another fork to at least define the problem. though I don't really want to start changing the bike.

sbseven

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Re: Brake Noise/Fork Vibration
« Reply #9 on: January 03, 2010, 12:18:35 AM »
This brake noise problem is a weird one, with some people suffering badly and others (myself included) having no problems.

Maybe a long-shot and I'm not sure where you're based PH, but it might be worth saying, just in case somebody else lives near by and you can try swapping some parts?

Also, if you state exactly your combination of frame, rim, calipers etc., maybe somebody with the same frame and rims AND no squealing may be able to lead you towards a possible solution combination?   

My setup is a Raven Nomad S&S, Rigida Andra CSS, XTR, Blue swissstops. Both rims have been silent from new after an initial set up with a tiny amount of toe-in. Now at 1300 km with no issues. Not much help to PH though, I know... ::)

Shaun

PH

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Re: Brake Noise/Fork Vibration
« Reply #10 on: January 03, 2010, 04:26:11 PM »
I'm certainly open to suggestions.
The bike is a Raven Tour.
Rim Grizzly CSS
Brakes tried - original Shimano Deore, Avid Arch Rivals, Old style parallel push XT.
Headset recently replaced, adjusted correctly.

Remedies tried;
Excessive toe in - works to an extent, but the braking is affected and I wore away half the pad with the other half hardly being touched.
Toe out - made no difference
Pad square to rim - deafening!!
Brake booster - made no difference, the one I have has a slot one side and I'm not sure the bolt isn't moving within it.
Using non specific blocks - A lot better, but wear far to fast.
Reverse the rim - Makes no difference which way round I put the wheel in.

The rim has been on for at least 4,000 miles, the recently fitted rear one is silent!
The front was prone to squeal even with a standard rim, but careful adjustment would cure it.

Any ideas?
« Last Edit: January 03, 2010, 04:27:55 PM by PH »

geocycle

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Re: Brake Noise/Fork Vibration
« Reply #11 on: January 04, 2010, 11:07:47 AM »
I've got exactly the same as PH: raven tour, Grizzly rims, swisstop blue pads, but as posted above no noise at all on rear and the front became silent very quickly (less than 100 miles).  I have avid ultimate calipers but I doubt they make a difference.  I put the intial noise from the front down to the fact that I couldn't get much adjustment on the pad but it went without further tweaking. 

The only difference I can imagine between front and back would be the possibility of some movement in the forks/headset under braking and the fact that the back is heavier?????????? I wear pads more quickly on the back.  That said, I've done >3000 miles on the same set.