Alligator bites down with carbon brake pads, true floating rotors

Floating rotors have been here and gone in the cycling industry. Early Magura Gustav’s and Formula brakes used them. The issue was that without the “braaaaap” of a motor the sound of the floating rotor jangling around was quite annoying on a otherwise quiet bicycle. Did they solve that issue?

Ya I had some of the fancy Hayes Prime floating rotors. They are awesome for about 300 miles or so. The rattling sneaks up on you and ruins your rides! I switch back to standard rotors and suddenly my bike was silent

In general people have abandoned the floating rotor for 1 major reason, cost. However with major manufactures now making 2 piece rotors more common, I think it’s time to revisit the floating rotor.

The major benefit is so riders who are constant brakers. I don’t even know how many times I have had to true rotors which have gold, brown, blue and even purple heat discoloration an inch down the spokes, the floating design eliminates the warping that occurs from big time heat build up. Pair those rotors with some Cool Series pads, and you’re set.

Yes, in the past floating rotors have been a bit jingle-y, but modern brakes are offering more in the way of pad to rotor clearance than models in the past. I can say that I have not seen any issues in Magura or Shimano calipers with these rotors when paired with both factory and Alligator pads.

This rotor design, the pattern of the actual braking surface, doesn’t make any sense to me from an engineer’s point of view. So little braking surface and anything but a constant surface area that the pads cover while you brake surely creates higher than necessary rotor temperatures and some kind of noise and possibly vibrations. I have not yet understood why a big number of brake companies in the bicycle business go crazy about the design of their rotors while every other vehicle’s brake rotos look like the should do.

A link to good info on floating rotors and why you need float (scroll down to “Hat Attachment Mechanism”):

http://www.essexparts.com/shop/brake-discs/2-piece-competition-brake-discs/c7-stingray-z51-rear-racing-disc-pair.html

Floating side-to-side is not the issue, it’s radial expansion. No radial float will “cone” the rotor. I can’t imagine the lateral float offered by any bicycle-use floating rotor would be enough to deal with lateral deflection during cornering.

In cars, the lateral deflection of the hubs/wheels will cause pad knock-back, pushing the pads back into the caliper. More racing oriented calipers will include pad knock-back springs to keep the pads in contact with the rotor (only about 4lb springs).

@Myke- it may be a simple process, but each rotor has five or six rivets that join the aluminum spider to the steel disc; multiple the number of rotors by the number of rivets, and it *might* add up.

“Under hard cornering, the fork can bend, which can put the caliper’s pads in contact with the rotor unintentionally.” A total non-issue. BS reasoning like this is used when the product doesn’t have many real advantages.

Based on appearance alone, the center spider looks flimsy, and once bent, you’re likely to always have rubbing of the rotor. The early hope rotors had weak aluminum spiders. Shimano made their aluminum centers so stiff that there’s no weight advantage to them.

Oh, and I think the carbon pads should work pretty damn good with a carbon fiber rotor.

@ alligator – FYI, rotors that are blue got hotter than purple. It’ll be yellow, gold, brown, purple, then blue in order of increasing heat.

Blue would indicate about 600 deg F

@Bob can you enlarge upon your statement about Hope floating rotors being floating? Hope say they are http://www.hopetech.com/product/disc-rotors/#tech

No prob. Seems like a nice product for those that want to try it out.

I’m missing the point of these. Since the current Alligator Stealth are lighter and have the same braking surface what is the point of using these? Rotors last forever and there are no tangible benefits to two piece rotors on bikes IMO.

@Ol’ Shel’ I’m in agreement, there is no way in hell forks are bending under hard cornering in the tiny space from the axle to the brake carrier, sure the outter most wheel/rim/spokes are bending at the edge of the wheel, even then rarely, but this has nothing to do with the brake/disk interface. Even if it is bending, there is a lot of space already between the pads, several mm.

Sounds like marketing trying to sell a problem that doesn’t exist. If it does, prove it. Wouldn’t be hard I guess, how much lateral force is on a wheel in the corner? 10#, 100#, 1000#? Hang a weight from the outter rim in a sideways wheel, measure the rim deflection, now measure the fork and rotor deflection, I would be surprised if the fork and rotor deflection were anything above 0.

My guess is while going through a corner at such bending speeds your finger bouncing around on the lever, and the pads bouncing around in the caliper are going to move more than anything deflects making the whole point moot. And now your going to add the 2 piece rotor bouncing around too, seems to be just adding to the problem. Now when going on straights the rotor is bouncing into the pads and working against you. And they do bounce are noisy, as many have posted already.