[pixelninja]

Do disc rotors come in different thicknesses???

I ask because I currently have a set of Hayes 9's on my bike. I recently built up a second set of wheels so I don't have to keep switching tires when I want to commute, and I bought some Hayes replacement rotors (http://www.universalcycles.com/shopping/product_details.php?id=5018&category=25).

Today was the first time I've had a chance to use these new wheels. I put them on this morning and the amount of brake drag is horrible, and its not because the brakes are not in line with the rotors. Its because the rotors are so snug between the pads. Thinking that maybe something else was going on, I put back on my primary set of wheels and they spin fine. Its as if the replacement rotors are thicker than the original rotors. Even when my original rotors were brand new, I never had this problem.

Anyone have any thoughts on this?

 

[stoney]

yes.5

 

[Jim Mac]

Here's a couple of thoughts:

1. I have been told that rotors may have a slight difference in size, but it's slight. I have run Shimano rotors on Hayes calipers and Hayes rotors on Shimano, for example.

2. You didn't accidentally squeeze your brake lever while your wheel was out? That would push this pistons in and thus potentially create more drag then what you're used to. If so, you have to pull out the pads and reset the pistons.

 

[binary visions]

Re-set your pistons.. Pull out the pads, push the pistons in all the way with the open end of a 10mm wrench, re-install your pads and pump your brakes. Should fix it.

Just don't push on that little post in the middle of your pistons.

 

[pixelninja]

2. You didn't accidentally squeeze your brake lever while your wheel was out? That would push this pistons in and thus potentially create more drag then what you're used to. If so, you have to pull out the pads and reset the pistons.

No, I'm pretty sure that didn't happen. After I put on the new wheels, I took them off and put back on my old wheels and they spun fine. I'll go out at lunch and reset the calipers, just to be sure.

 

[binary visions]

How many miles are on your old rotors? They could be simply worn down a bit, so your pistons would be set inward a small amount to compensate... thus, it wouldn't have happened when they were new, but it causes a problem when you have brand new rotors.

 

[johnbryanpeters]

When you change wheelsets, loosen the two bolts that hold the caliper to the adapter. Put the new wheel in, grab a handfull of brake, and tighten the screws. This properly centers the caliper.

The reason this is necessary is a slight difference between wheelsets in the distance between the rotor mounting face and the locking nut for your cone (for ordinary wheelsets, I can't comment on 20 mm).

Pain in the ass, but it works.

 

[davep]

How many miles are on your old rotors? They could be simply worn down a bit, so your pistons would be set inward a small amount to compensate... thus, it wouldn't have happened when they were new, but it causes a problem when you have brand new rotors.

Rotor wear combined with slight tollerance variation is the most likely cause.

There is a much easier way to re-set these, especially if you change wheels often. Your Hayes came from the factory with a small plastic plate to stick in your caliper, between the pads, for traveling. Just take the plate and shove it in there, and it will push the pads back a little 're-setting' them for a new set of wheels. Just remember, no matter the method, You will need to 'pump' the brakes back before they work.

If you do not have the shipping/travel piece, any LBS that sells lots of hayes should have some floating around.

 

[Wumpus]

yes.5

I borrowed a set of wheels from Loco that had Hayes rotors, and they were much thinner than my magura rotors.

 

[pixelninja]

Thanks guys. I borrowed a couple tools from a co-worker and everything is working. The ride home should be much more enjoyable now.

 

[DRB]

The quick (and probably damaging way) is to loosen your quick release and move the wheel side to side. That typically moves the pads back enough so that they'll reset to the wider rotor.....

 

[erikkellison]

I thought the quick way was to take the wheel out and insert a large, flat bladed screwdriver in there, and rotate it, pushing the pads back (hopefully there's not too much fluid in the system, though I'm not quite sure if this matters with Hayes, I'm only used to open bath systems). Put the wheel back in, loosen the vertical mounting bolts so the caliper can be slid back and forth. Then center the caliper over the rotor, irregardless of the presence of the pads/pistons, and clamp it down. Then pump the brake to compensate. This method will make sure your pistons aren't over-compensating for alignment deficiencies, and make sure everything is straight. You have to push the pistons all the way in first though, so they progress to the rotor at the same rate, so the thing remains centered.

 

[mastercycleman]

Just don't push on that little post in the middle of your pistons.

What happens if I push on the thing in the middle, I reset the pistons a long time ago, and ever since, when I make a even remotely hard stop, it feels like it vibrates al over the place.

 

[JapaneseZero]

Can i run Magura rotors with my saint brakes?