Bicycle Mechanics - Why?!

After playing with my Hayes discs for a couple weeks i've come to realize something. The 1st guy who develops and markets an adjustable caliper mount will become a millionaire !

Seroiusly, i cannot understand why they don't make these. A mount which would have screwdriver accessable adjustment to line up the caliper with the disc. It would be adjustable for both slant (for lack of a better term) and distance towards and away from the wheel. On both my front and rear the discs and calipers are not lined up straight. On the rear i had to grind some metal off the caliper mounting area on just one side of the area that seats against the adapter. Otherwise the disc goes thru the caliper at a slanted angle that makes it impossible to accuratly adjust it and expect it to stay right w/o rubbing for more than a ride or 2. Not that i can't deal with it, but this would make it far easier to get the calipers adjusted correctly on the disc and would eliminate the learning curve for those new to discs completely. Absolutely perfect adjustment of the caliper would be possible.

I guess I don't really understand what you are talking about, but with my Deore hydralics it was very simple to align them. loosen the mounting bolts, squeeze the brake lever, tighten bolts, release lever

It's not the brakes that are at fault, it's the mounts. It's like this....say the 2 outer lines are the brake pads, and the inner line is the disc........

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Of course thats exaggerated, but you get the idea.

Ahh ok...yeah I have had the problem too. I ended up using shims to help the situation but could never 100% get rid of the rub.

Originally posted by dazco
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Of course thats exaggerated, but you get the idea.

I dont think I get the idea unless your saying that your rotor is bent. Slant adjustment? What does the caliper ever need to be slanted for? Maybe if your rotor was bent at the same angle all the way around (funny).

I thought i explained it about as good as possible. Focus on the part about the mounts ! The discs are perfectly straight. It's the caliper thats crooked due to mounts not being at a perfect 90 degree angle to the disc. I can't explain it any clearer than that, so i hope you can see what i mean.

Sounds like a frame design problem more than a caliper problem. Are the mounts welded inplace squared or perpendicular to the hub axle or are they slightly tilted?

A rotor that does not warp will help out the disc brake woes. Both my rotors are slightly warped and will rub the pads a bit.

Personally I think a design that allows the caliper to self adjust is the ticket.

I don't have a clue why your mounts aren't straight dazco mine are perfectly straight.

I don't either. However it's not uncommon from all the disc brake reviews i read. In any case, the adjustable mount i mentioned would be the perfect fix not to mention making it easily adjustable on the trail if they should start
rubbing.


are they slightly tilted?

Apparently. Whether it's the mounts or the paint i'm not sure. But in any case it only has to be very slight for the problem to exist. Yours may even be slightly off and you didn't notice because you have to sight it very carefully if it's only slightly off. And then it may not even be a problem. For me it was off enough to see easily, but about 10 seconds with a dremel on the caliper mounting surfaces was enough to make it perfect.

On automobiles, a floating caliper is often used. Most cars use just such a design. It allows the use of only 1 piston, negates the need for careful adjustment. and makes installation and removal easy. On the downside, they weigh more than fixed calipers, and they don't give nearly the stopping power.

Heck, if the caliper had ovalized mounting holes, you'd be set! You could probably get a small round file and open up the mounting holes enough to get the caliper some side to side play.

Here's what I do. I loosen my bolts on the caliper, and then squeeze the lever. I use a velcro strap around the lever to keep it tight. I then tighten down the bolts (SNUG, not tight).

Release, spin wheel, and check for rubbing. If there is rubbing, I stop the wheel where it rubs, lock down the lever again. Loosen the bolts, wiggle the caliper and retighten. Release lever and check again.

I end up doing this about 3 times until it's perfect. Once the rotor doesn't rub, I torque the bolts to spec. YES, I use a torque wrench!

L8R

Heck, if the caliper had ovalized mounting holes, you'd be set!

It does ! That has nothing to do with the problem tho That only helps with moving the caliper from side to side. Very necassary, but not what this thread was about.