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I work in automotive brake design.
I read all of the brake 'noise' topics on here with some interest.
Porsche have another take on brake noise....
The same logic applies to brakes on mountain bikes - discuss đŸ˜‰
I see it as a feature, not a bug. Pedestrians can hear you coming for miles instead of being surprised. I just wish I knew how to make it more consistent (I am still using Hayes HFXs, though, they were always a bit unpredictable.)
Mine currently squeal and don't work lol
The Spyres on my CdA howl like mad!
It's probably my fault fitting a fresh set of pads and setting off in the pouring rain to bed them in...
One thing I like about this video:
they talk about the resonance frequencies and that the complete surrounding system affects those...
Bikes: this explains a bit why certain brakes don't make trouble on bike "A" and a lot of trouble - maybe - on bike "B".
Rims, tyres, spokes, hubs, forks, brake mount, even the frame itself - all mechanical sub systems influence the brake squeal...
Quite some time ago: had such a mountain bike with terrible problems with the front brakes. Started to swap parts and stuff until the problem was gone.
(Same brake on a different frame, fork, wheel: never made any problems.)
Theoretically the brake manufacturer, the fork and bike manufacture would have to work together for every type of new bike to avoid these resonance frequencies. But that's not possible. The rapid model change and the "number of bike models, forks, wheels" is way too high.
Logical then: the end customer is the "tester" and the one who has to start "tuning" stuff if there is a problem...
"Theoretically the brake manufacturer, the fork and bike manufacture would have to work together for every type of new bike to avoid these resonance frequencies. But that’s not possible"
This is EXACTLY what every car manufacturer does. We test every brake/wheel/disc/hub/suspension design/body to minimise occurence and volume for every brake noise event.
We do have an advantage - we are responsible for each and every part in the system/sub-system.
@JAG: neat Job you have. Yes - the car companies have the big bucks and put a lot of effort into testing and sub system development.
But the bike manufacturers do only basic frame testing like fatigue and ultimate loads - but very little to none is done on the "unwanted dynamics/resonance" side of sub systems. And very little testing in "mud and crap".
Testing of dynamics of the fork, one (main-) axis: yes they do.
Complex 6dof testing of the whole assembly fork + brake + hub + wheel + tyre: normally nothing is done there. Only for bikes which they send into competition they give to the professional bike racers and they test "on the trail". But this is only for one bike model out of one hundred?
A mountain bike model has sometimes up to 5 "sub versions" - all with different forks, brakes, wheels, tyres... - and this might change again after model change 1 or 2 years...
A too difficult task to really to learn all the dynamics for every bike sold...- this ends up - sometimes - frustrating for the customer and also for the sub systems supplier. Like the brake supplier. Suddenly he hears that his brakes are crap... - but they are only crap in a certain mix of other sub systems. And this the brake supplier can't know when he sells 20 000 brakes or so to one bike manufacturer.
Car industry, airplane industry - they all have different test strategies and do much more than the bike companies. But a 100 employee bike manucaturer simply can't do this...
Interesting field!
My Banshee spitfire resonates /howls with 4pot calipers on the rear. I've tried a few and swapped from other bikes & ruled out alignment or contamination and think it's the bolt on dropouts that don't like it.