So last week I did a big ride (340 miles over 5 days) from London to Llanberis.
At one point we were dropping down a pretty big hill, at speeds touching 40mph.
I pulled my brakes a few times, just to control the speed and keep it to a level that I felt happy.
After a while the brakes started to squeal really loudly, and didn’t feel as responsive as they should.

After we’d had a brief stop, and got on our way again, the brakes were back to silent operation, and felt as they should.

Bike is a Giant Defy with 105 levels/calipers and (almost new) genuine brake blocks.
Oh, and I’m approx. 100KG, which probably didn’t help ;o)

What was going on?

hot rim/brake pad material the pads were ‘grabbing’ slightly on the rim as they softened and causing vibration.

they can get very hot – I managed to get some burning rubber flung out of a set of front canti brakes on my cross bike on a long south downs descent.

As wwaswas says, over heating.

Some pad compounds are better at dealing with heat than others but few descriptions/reviews mention it. I was recommended SwissStop Green by the local wiry old goats that have been riding longer than I’ve been alive. They do seem to work better than any others I’ve tried in all conditions and they’ve not faded on me yet.

Thanks Guys – I suspected it was something along those lines…

Could be lube dripped from cassette / chain onto rear rim?

Try braking with different ends next time to see if it’s rear only.

Chakaping – It was from both ends – I tried pulling the brakes alternatively to check this out.

swap out the standards to swisstop … much, much better performance
and less noise.

replacing the standard brake blocks with swissstop greens* is just about the best upgrade you can make to a road bike. The improvement is huge.

after that, a nice pair of tyres, the improvement is noticeable.

after that, any ‘upgrade’ you make is going to feel just a little pointless.

(*other brake blocks are available, but really, you need look no further)

On tyres, currently I’m using a pair of Veloflex open Corsas I got from Ribble for £52.50 and I will never go back to any other tyre; they are suuuuuuperb.

Swisstops don’t eliminate the noise, just not quite so loud. I’ve got the new ones on my M40C’s and they still squeel..

If swisstops are a bit spendy, next best are Clarks CPS240

my swisstops cost £250! They are excellent, and given that they came on a bespoke set of new aero brakes specific for the bike, I am delighted. But it is the combination of pads and brakes that have improved the bike immensely.

The comment about replacing tyres is so true. A huge upgrade for about £50-70.

+1 for swisstop, and check the toe in of the brakes.

SwissStop Green are £22 for 2 pairs on CRC a tad cheaper than TiRed’s 😉

I’ve the Yellow jobbies and now a new set of the new Grey ones that have replaced the Yellows.

Toe in a problem, not a fat lot of adjustment on Red calipers..

Just to inform, I’m on my third set of Swisstops since April when I bought the R5ca, M40C’s on it, don’t last very long do they. But then I’m a shite decender and hang on the brakes so that has a lot do do with it..