Wisper Brake Squeal Driving Me Crazy

[guerney]

When I received these today, for a split second I worried they'd make my bike look posh. But then I looked at my bike, and laughed at the notion.

 

[FastFreddy2]

Isn't (brake block) squeal due to resonance? Bit like wiping a wet finger around the rim of a glass?

The Clarkes brake blocks are (apparently) designed for MTB/Hybrid bikes, probably targeting 29" MTB's and 700c Hybrids, both with 28" wheels. The Wisper 705 comes in 24" and 26" flavour as far as I can tell. Doesn't that suggest the Clarkes super-duper triple density brake blocks may be producing some unexpected resonance because they are fitted to wheels with a smaller circumference than the wheels they might be designed for? The asymmetry of the design with a longer trailing edge looks like a good way to induce resonance too.

These symmetric brake blocks ar so cheap they could be cut to a suitable size - if necessary.




"Suitable" meaning both sides are short enough to be squeal free?

This 'resonance issue' is a suggestion, not statement of fact BTW.

 

[Wisper Bikes]

Isn't (brake block) squeal due to resonance? Bit like wiping a wet finger around the rim of a glass?

The Clarkes brake blocks are (apparently) designed for MTB/Hybrid bikes, probably targeting 29" MTB's and 700c Hybrids, both with 28" wheels. The Wisper 705 comes in 24" and 26" flavour as far as I can tell. Doesn't that suggest the Clarkes super-duper triple density brake blocks may be producing some unexpected resonance because they are fitted to wheels with a smaller circumference than the wheels they might be designed for? The asymmetry of the design with a longer trailing edge looks like a good way to induce resonance too.

These symmetric brake blocks ar so cheap they could be cut to a suitable size - if necessary.

View attachment 54001


"Suitable" meaning both sides are short enough to be squeal free?

This 'resonance issue' is a suggestion, not statement of fact BTW.

Hi FF, this is a very interesting point. Let me get back to you, my immediate thoughts are; as this issue happens rarely there may be another cause, but certainly it’s worth me checking.

All the best, David

 

[Wisper Bikes]

Hi FF, this is a very interesting point. Let me get back to you, my immediate thoughts are; as this issue happens rarely there may be another cause, but certainly it’s worth me checking.

All the best, David

All good, the brakes and pads weare correct for the wheel sizes.

And of course we only supply hydraulic disc brakes now on all our bikes.

All the best, David

 

[PC2017]

"Suitable" meaning both sides are short enough to be squeal free?

Same style I use on 26" but branded jagwire, swear by em.

 

[FastFreddy2]

All good, the brakes and pads weare correct for the wheel sizes.

And of course we only supply hydraulic disc brakes now on all our bikes.

All the best, David

I prefer cable operated disc brakes because they are easier to maintain, but in the 2020's I would not understand relying on rim brakes? I vaguely remember putting a disc brake on my 1996/1997 (I think) Gary Fisher mountain bike. It came with a disc mount on the front fork, so I bought a new wheel and an RST disc brake system. I've not used rim brakes since. Fortunately, modern bikes costing £200+ come with disc brakes as standard.

 

[guerney]

The Clarkes brake blocks are (apparently) designed for MTB/Hybrid bikes, probably targeting 29" MTB's and 700c Hybrids, both with 28" wheels. The Wisper 705 comes in 24" and 26" flavour as far as I can tell. Doesn't that suggest the Clarkes super-duper triple density brake blocks may be producing some unexpected resonance because they are fitted to wheels with a smaller circumference than the wheels they might be designed for?

I use those Clarks brake blocks, and there's no squealing emanating from my bike's 20" aluminium rims.

Isn't (brake block) squeal due to resonance? Bit like wiping a wet finger around the rim of a glass?

Perhaps the OP should try cutting a couple of small "V" shapes out from the flat parts of the pads? If he's lucky there will be no resonance, if unlucky there will be a discordant chord comprising of two or more notes, and if not lucky enough those notes will sound in tune.

 

[FastFreddy2]

I use those Clarks brake blocks, and there's no squealing emanating from my bike's 20" aluminium rims.

...................

Perhaps the OP should try cutting a couple of small "V" shapes out from the flat parts of the pads?

I would imagine there are so many ingredients needed to create resonance, it would be pretty difficult to produce the effect - if someone wanted to. Back in the day, (so 50 years ago) I might have experienced a similar effect with the (back then) smaller brake blocks. It was the high speed 'gripping' and 'slipping' sequence that created vibration, and the noise of the brake blocks shuddering as the wheel passed through the brakes.

I'm sure where the caliper is anchored is important, the longer the actuating system, the greater the opportunity for movement/vibration. While there is the suggestion of toe in being required, the amount of that could also affect the opportunity for vibration. Too much toe in leaving parts of the brake block without contact with the wheel rim. That being the case, another opportunity for resonance?

 

[guerney]

 

[guerney]

BTW, in case anyone is considering buying these (post #21):

https://www.ebay.co.uk/itm/353765075624


...contrary to the official Clark's store on ebay, the pads linked below definitely fit. Just tried them. Pin removal for pad replacement is a bit fiddly: If the catch doesn't disengage after pushing the part of the pin protuding from the opposite side to the loop, the catch has to be disengaged using a slim bradawl or something similar, and gently pulled out with pliers, using as little force as possible to avoid damaging the pins.

https://www.ebay.co.uk/itm/185986937268