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MountainBikeReview.com's Forum Archives - Brake Time
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squealing sound in my formula b4 sl, is this normal? (3 posts)
|  squealing sound in my formula b4 sl, is this normal? | rhys
Mar 22, 2003 5:37 AM | | I need help with these, I recently got a pair of formula b4 sl( nice brakes, and pretty damn light!). I noticed that everytime i hit on the front brakes, i hear a squeal, is this normal? Can anyone suggest for a remedy for this, i would really appreciate it. |
| Here............ | Mike T.
Mar 22, 2003 6:51 AM | | ......is something that I recently wrote on disc brake squeal. Maybe it will give you some insight. It is not normal for your B4SL to squeal but it is not necessary that the squeal is because the brakes are B4SL. Read on -
First and foremost there is NO disc brake which NEVER squeals and NO disc brake type which ALWAYS squeals. Also there is no specific area where brakes have more problems. From super dry Scottsdale Arizona to wet Seattle there will be a few screaming brakes in every area of the country. Some brakes seem to have more problems than others but in general it's one of the following :
* Dirty ( oily ) rotors - clean thoroughly with Isopropyl Alcohol
* Dirty ( oily ) pads - clean with Isopropyl alcohol, then use emery paper and scuff the pads. Remember they need to be newly bedded in, so the first stops are not what you expect. If braking power is drastically reduced, replace pads with new ones.
* Loose rotors and loose calipers - tighten them up.
* Loose cones in the hub - again tighten them.
* Loose spokes - sometimes you can detect this if you rub a little grease exactly where the spokes are crossing/touching each other. If the noise changes, then you need to retighten the spokes.
* Loose quick-release - especially on alloy dropouts the q/r sometimes works itself into the alloy, the tension gets less and the axle starts vibrating.
* Loose suspension bolts - seems to be a problem on the older I-drive bikes, but not only them. Check the owners manual for proper torques.
* Loose Headset - adjust to specifications.
* Loose .... loose... loose ANYTHING. Yes even a loose saddle can make a noise if vibrated by the brakes.
* Incorrect alignment - use a Gnann-o-mat or Hope Spot tool to machine the tabs or use the CPS on Avid brakes.
But no matter what, some brakes just squeal. It seems like a lot of the problem comes from other parts of the bike where a harmonic vibration set up by the brakes manifests itself in an audible squeal. You have to work case by case, find the vibrating part and somehow cure it. I once had a squealing brake that was instantly cured by switching to a rotor from another manufacturer.
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So there you go Rhys. Don't blame the brakes themselves but the bike as a whole. You could probably bolt those brakes to another bike and there would be no squeal. Also you could possibly bolt another set of brakes to your bike and all would be quiet.
As the companies strive to produce lighter and lighter brakes their lack of mass contributes to the problem. They have to address things like flexibility and vibration at the same time as weight. They do quite a good job considering.
The B4SL I have used have been dead quiet.
Mike T. (mcm # 717) |
| re: squealing sound in my formula b4 sl, is this normal? | itsdoable
Mar 24, 2003 5:09 AM | | I have B4's (non-sl) and they squealed (not loud, but enough) when new. Cleaning rotors, pads, etc... made no difference, but after a month+ of riding, the pads have settled in and they are quiet. |
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