Hayes Disc Rub

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bassmonkey

Likes Dirt
I'm running Hayes HFX9 HD's with 8" rotors atm and I can't get them running perfectly without some slight rubbing on the pads each rotation. I've tried adjusting the caliper mounting until they're as spot on as seems possible, and the geeza that sold me the bike suggested I try putting thin cards between the rotors and pads for a while and giving the occasional squeeze on the lever -- which I've tried -- but I still can't get 'em perfect.

Am I being a bit too anal? Is a slight bit of rub to be expected on 8" rotors?
The bike and brakes are brand new btw, but I've been giving the rig a good thrashing over the past couple of weeks so I figure everything should be broken in fine by now.
 
R

Rik

logged out
I don't know what's best, but I always tolerate a little bit of disc rub if I get good power and feel, as long as it isn't noticeable drag whislt riding.

You could always try and shim the rotor bolts ever so slightly if the rotor isn't straight?
 
B

bassmonkey

Likes Dirt
Soz... I don't know what 'shim' means, Rik :?

Also, does anyone know if the 'cards between the rotor/pad' thing actually does anything at all? Sure, it widens the pads initially, but it seems like once you squeeze the levers a few times without them in there the brakes self-adjust back to exactly how they were before you did it.

edit: okay; I found out what 'shimming' is, but what's the go with doing that on rotors? Washers seem a bit extreme, but I guess they'd work if the rotor is pretty out of whack. My rotors seem pretty true, but I haven't taken them off the hubs to check. I s'pose it'd have to be the rotors being very slightly out of true that's causing the rub. You'd think the shit would be perfectly true when it's brand new. grrr! >_<
 
Silver Wahoo

Silver Wahoo

Likes Dirt
It's unavoidable with 8 inch rotors, You could spend half a day shimming and spacing your caliper, get it spot on and as soon as your finished your first run down a hill, BAMMMO brake rub!!!! :? Just ride dude, I doubt it's slowling you down...
 
j5ive

j5ive

Jonny Sprockets Bike Shop
I get it too, pisses me off. I've found even that the rotor has a memory, if you bend it totally over one side (instead of shimming it) it will return back to center after a few rides. The best way to get it resonable is to adjust it after a long DH run. Also if it is out of true just bend it back with your thumbs carefully, just like truing a wheel.
 
S

Simo

Likes Bikes and Dirt
my rotors rub. you get used to the constant, annoying, dry grinding sound after a while :D
 
M

matt462

Likes Dirt
There are tools around to clean up the mount on the fork. Sometimes there not straight, can't remember the name of the tool but it was in AMB a few months ago.
 
Grip

Grip

Yeah, yeah... blah, blah.
Bassmonkey... shims are not washers. Shims get down to being measured in thousandths of an inch... we're talking thin as cigarette papers here. Also... NO shit is perfectly true when it comes out of the factory... don't care, no way, no how, end of story. I've seen BRAND new frames with woofs you wouldn't believe. You also said you've been giving the bike a thrashing and that your BRAKES are new... what about the rest of the front end? Wheel bearings/front hub etc? Any wear ANYWHERE in that area is going to mean things aren't going to BE ABLE to line up "perfectly" the way you'd like.

And finally, I might have misunderstood what j5ive was talking about, but if you can "bend" your rotor ANYWHERE with your thumbs then something is seriously farked and you need to get that looked at.
 
Grip

Grip

Yeah, yeah... blah, blah.
CHEWY said:
woof grip?
Click to expand...
and a bow-wow right back at you chewy...LOL

Seriously though... this really makes me realise how old I am... maybe I should start a competition to see who knows what it means???? Check your PM chewy, but don't tell anyone and we'll see how many know????

Cheers
 
wombat

wombat

Lives in a hole
Grip said:
And finally, I might have misunderstood what j5ive was talking about, but if you can "bend" your rotor ANYWHERE with your thumbs then something is seriously farked and you need to get that looked at.
Click to expand...
Actually I'm yet to come across a rotor I couldn't bend with my thumbs. Just leave it attached to the wheel (that might be where the confusion is) and flex it with your thumbs. You'll find you can do some real damage.

Liability warning: don't do on a good rotor, watch for sharp edges, enure the rotor isn't connected to a car battery, do not perform this act under live powerlines or in a cyclone...actually no, if you were planning on doing it in a cyclone go for your life....
 
Grip

Grip

Yeah, yeah... blah, blah.
wombat said:
Grip said:
And finally, I might have misunderstood what j5ive was talking about, but if you can "bend" your rotor ANYWHERE with your thumbs then something is seriously farked and you need to get that looked at.
Click to expand...
Actually I'm yet to come across a rotor I couldn't bend with my thumbs. Just leave it attached to the wheel (that might be where the confusion is) and flex it with your thumbs. You'll find you can do some real damage.
Click to expand...

AND I'M A BLOODY DICK HEAD!!!!!! The word is "ROTOR" and yet for some reason (and I'm going to blame exhaustion here) I was seeing j5ive trying to bend his CALIPER into position with his thumbs.

Jesus-tap-dancing-Christ! But at least you've got to admit there REALLY would be something wrong if he could bend his caliper with his thumbs.
 
B

bassmonkey

Likes Dirt
Grip: The whole bike is new (03 Stinky)

Gutty: It's pretty much a constant, slight rub on each rotation on the front, but the rear is more intermitant. It has the same constant rub once per rotation, but sometimes it gets worse for a little while and makes a metallic buzzing/vibrating.

Thanks for all the input, I was kinda expecting I'd have to live with it, but I'm still a bit concerned about the rear one as it's much more annoying than the front.
 
M

matt462

Likes Dirt
when the pads are brand new there is very little space between the pad and disc as they wear you start to have less problems. Then when you replace the pad the problem comes back for a while.
 
Weasel

Weasel

Likes Dirt
Dude i've been racing road bikes for years and even the most expensive bikes have disk rub as the pad are squeezed togeather by pistons acting under hydrolic pressure.
When you release the brake lever there isnt anything pulling the pistons away from the disk physically.

They move slightly but only because the pressure behind them has dropped.
If you had mechanical disks it would be a diffrent story
 
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