Brake squeal after cleaning rims

[E-wan]

I am running magura hs33 breaks with koolstop pads for css rims and rigida andra CSS rims on a nomad MkII

I wanted to realign the pads closer to the rims and thought I would clean some of the mud off the rims to help align the blocks.

Prior to this I never had any squeal form the from rim and a mild squeal from the back rim

I cleaned the front rim with kitchen paper and water
Cleaned the rear with dry kitchen paper as it was less dirty.

After cleaning the front squeals a lot and the rear squeals less than before!

Any idea how to try and sort this and reduce squeal?

I suspect that the small groves on the css coating may squeal less if they have more mud etc in them, the squeal on the front rim reduces when riding in the mud.

Thanks

Ewan

[E-wan]

oh and I have boosters fited and pads are paralel to rim
tried new pads too and makes no difrance

[jags]

same thing  happened to me very annoying but great craic when your in a group ,craicks everyone up.
you just need to toe in your brake blocks takes a bit of fiddling around but the front of the brake block should hit the rim first , then let some rubber build up on the rims.
 Dan might have a better trick up his sleve.

[Danneaux]

Hi Ewan!

Yes, jags had the same thing happen to him last February. I offered some suggestions here:
http://www.thorncycles.co.uk/forums/index.php?topic=3976.msg17735#msg17735

I think they might also help in your case. Squeal (the high-frequency noise) nearly always results from judder. Jag's problem also started after a cleaning -- as did mine, in years past. The cure in all cases was to add a bit more toe-in, at least till fresh rubber can be deposited on the rim.

Several years ago, jags had a squeal he cured with a little sandpaper:
http://www.thorncycles.co.uk/forums/index.php?topic=2236.msg11140#msg11140

Jawine recently offered a helpful suggestion that worked for her:
http://www.thorncycles.co.uk/forums/index.php?topic=4689.0

I hope this helps. Please let us know how this works for you. If you still have noise, we can try something else.

Best,

Dan. (We have answers! Maybe not the right ones, but they're answers!)

[Andybg]

The comment about the answer is like the morcome and wise. I am playing all the right notes just not neceseraliy in the right order!

[Danneaux]

Haha; you're right, Andy! Didn't realize I'd alluded to a funny. Here is the long version of M&W's famous 1971 Christmas performance:
http://www.youtube.com/watch?v=R7GeKLE0x3s&feature=related

Tune in at 10:56 on the timeline for the relevant exchanges.

All the best,

Dan. (making a note of the answers and answering the notes...)

[E-wan]

thanks for the suggestions but toe in isnt realy posible with maguras as the pads click in and out when the pad hits the rim at ana ngle it just rotates it self slightly, though the angle that the psiton is pushing the pad at changes, this then just resultes in unevenley worn pads after a while.

Wil try the talc idea though

Ewan

[Danneaux]

toe in isnt realy posible with maguras...

Ah, got it, Ewan. A though scouring of the Archives reveals the best bet  for most running Maguras with or without CSS rims is likely to dirty-up the rims a bit; the dirt seems to be more critical with the CSS rims.

On the other hand, Andre had good luck with *cleaning* his rims as a means to cure squeaky Maguras (I think I've summarized his old post fairly). He used blue spirits for cleaning stubborn diesel deposits off his rims.

"Dirt" in the form of talc does sound like the next-best step to try, Ewan.

Best,

Dan.

[E-wan]

Talk on the rin completely reduced the squeel for the first day, since then it has squeeked slightly but a lot less than before.  Also breaking performance was slightly reduced after aplying the talk as might be expected but it now feels as though I have more progressive modulation.  A downside of css rims and koolspop pads with maguras that I had noticed is that they are a bit more immediate than red pads and aloy rims.

will report back after I've riden a bit more and riden in the wet.

Ewan

[Danneaux]

Thanks for the followup, Ewan!  This sort of real-world data and reportage will really help others down the road...I can't imagine you're the only rider who will experience noise with this kind of setup and it is nice to hear you're on-track toward a solution that helps. Well done!

All the best,

Dan.

[E-wan]

squeel returned after a few days of riding in the wet. may try talc again or I have a few pairs of standard black magura pads that I could install and ware through to encourage more rubber to build up on the rim and see if that has any effect

Ewan