I’ve got a KH29 (08) with a Magura brake. Boy is it noisy (I remember this from biketrials but thought that the grind was to blame mostly, turns out that’s not the case).
It’s so loud it’s almost embarrasing to brake when there are people closer than 100m as I’m afraid I’ll pop their eardrums or give them a heart attack.
So any thoughts on remedies:
True rim - did this yesterday (didn’t seem to help in my apartment at least)
Adjust toe in - havn’t played with this yet
Get a booster - thinking of it, will help with frame flex also.
Wear in the gear, ie ride lots in mud etc - “just riding along” atm
Change pads - I like the original blacks for this application
Pour molten led into the frame making it more solid.
Mine on my 29er squeals a bit but not too bad, normaly only at low speeds, at higher speeds its normaly pretty quiet. Normaly with bike trials it is the tar that makes them so load. Dont put tar on a rim if you are only using it as a drag brake, dam its load (but very powerful).
It may get quieter with time. I would just put up wit it.
magura’s official line is that pads should always be parallel to the rim.
I tried toeing in, but it didn’t reduce squeal for me.
I’ve also run grey, black, and funny yellow trials pads at various times. All had a bit of a squeal.
It seems to squeal more or less depending on weather / muddyness.
I think it is slightly quieter once it has worn in a little.
It’s quite useful if you’re in a busy area - normally unicycles are so quiet that you can come up behind people without them noticing, using the brake is good to let people know you’re there.
FWIW, I’ve run Maguras on my tandem for ages and not had a problem with squeaking. They’re HS66, but the caliper end is identical to the HS33 (the 66 was the version with drop bar levers, now sadly discontinued). Normal black pads. I probably toed them in a bit when I set them up just out of habit (just a couple of bits of paper under the back of the block) - I don’t remember doing anything special.
But that doesn’t really help you… Are you sure everything’s tight? A lot of brake vibration problems are down to things being slightly loose or worn pivots (not really applicable to Maguras). Are the rims clean? Try harder compound blocks (but I think the black ones are about the hardest anyway)?
Otherwise, try just riding along with the brake on for a bit to get the pads to bed into the rim nicely - that sometimes helps.
The brake on my coker can sqeal a bit under light braking, especially if it’s a bit wet - but I’m sure that’s down to it being a cheap bendy BMX caliper.
Everything is tight, it actually got even worse when i tightened the screws more… go figure.
Lightweigh stuff tends to resonate, but the KH29 is hardly lightweight (well the frame is though which may explain the magnitute of resonance a little bit). I guess wearing in is needed. Btw I spat some water on the pads, that kept is quiet like a mouse for 5-10 meters of downhill…
The front of the pad should make contact with the rim just before the back of the pad does - this translates to setting the front of the pad about 1mm closer to rim than the back.
personally i toe out, if the front of the pad touches the rim first then the front edge will vibrate. Think about pushing a foam block across a table, if you drag it with only the tail end touching it will be fine. But pushing it so the front edge is touching will cause it to grip, deform and then slip, causing vibration.
My Maggies squealed when I first put them on my 36er with a powdercoated airfoil rim. I spent an hour sanding them pollishing the breaking surface of the rim to make it nice shiney bare aluminum and presto, no more squeaks.
Does the KH29" rim have machine sidewalls? If it doesen`t I would get rid of all the paint on the breaking surface. It made a world of difrence for me.
I had major squeeks with my maggies on my 36. It happened with any rim. I semi-solved it by hot glue gunning sandpaper to the pads; it still let the uni stop, and ground away the powder coating.
Q - You guys keep bragging that Magura brakes don’t squeal. I just fitted new ones and they squeal a bit. Why are you guys lying?
A. Noooooo, we’re not lying. Well, maybe a little. My HS-33’s squealed somewhat when brand new until the pads wore in a bit. I’d suggest taking sandpaper to them - put the sand paper on a flat surface and rub the pad on it until the factory finish has gone. Also scuff the rim walls with 3M Scotchbrite pads too. Mine have never squealed since. What Maguras don’t need is toe-in like V-brakes. Set the pads dead flush to the rims. Remove your tires to really see clearly what you’re doing.
Big Dave’s additional comment - Another thing that may cause squeal is lack of boosters, air in the lines (not getting full power) and loose bolts.
Hope you find a solution; it’s likely my KH29 will have the same problem.
I decided to grab the pig by the b****, so no half measures this time.
I’ve:
Sanded the rim (it had a very rough surface with tracks in it and a nasty weld join which caused thumps every revolution). If i where to guess the 08 rim is to blame (the 07 version is nice and smooth)
Sanded the pads (most likely not the culprit, but got rid of rims imprinted “tracks”)
Rebuit the whole wheel (stock build was off center and out of true)
I’ll:
Get a brake booster
Adjust the pads more precisely
And if that doesn’t solve it I’ll just live with it - hopefully I’ll get my booster this week so I can give it a try. (I won’t check what did what but report on the final result.)
My brakes usually squeal when aluminum oxide from the brake surface has gotten into the pads. For me, cleaning pads and the rim with a degreaser like Simple Green, and perhaps lightly sanding the pads, does the trick.
After saying how quiet mine were, they have now started to squeal realy badly. I think it was after they got damp in the rain yesterday. They have goten wet many times before and stayed quit though, weird.
I think I may try that, although everyone stares anyway, why not tell them you have brakes by making a little noise?
