Warped Rotor(s)?

[mindiraser]

I have a 13' Evo with about 4,200 miles on it. For a while now (as very low speeds) there is a pulsating that is consistent with the revolution of the front wheel/brake rotor rotation. At around 20mph and below (when you barely engage the front brake), the bike will "throb" to a stop.

I took it to Ducati a couple of weeks ago and they tried to pass it off as the ABS. Im pretty familiar with the rapid pulsating of ABS engaging on hard stops, but this isn't that. I have had a warped rotor on my 98' R1 and it was nearly identical to this.

Any experience in this and what would cause the rotor to get warped from basic city (non track) riding?

Thanks in advance!

[DarkMonster620]

I  can only think of sudden cooling...

[koko64]

Like an icy puddle splashing over the hot rotors?

What about gummed up rotor buttons?

[ducpainter]

It isn't the ABS.

Rotors on Ducs have exhibited that for a long time. It isn't warping as much as the rotor getting heat damaged from sitting in traffic and holding the front brake lever.

If the brake is applied while at a stop in stop and go traffic that section of the rotor gets 'heat treated' because it doesn't cool evenly and it grabs the pads differently than the adjacent areas.

Good luck getting a dealer to replace the rotors, but it's what is needed.

You can eliminate the issue from recurring by letting go of the brakes when stopped on a flat

[DarkMonster620]

It isn't the ABS.

Rotors on Ducs have exhibited that for a long time. It isn't warping as much as the rotor getting heat damaged from sitting in traffic and holding the front brake lever.

If the brake is applied while at a stop in stop and go traffic that section of the rotor gets 'heat treated' because it doesn't cool evenly and it grabs the pads differently than the adjacent areas.

Good luck getting a dealer to replace the rotors, but it's what is needed.

You can eliminate the issue from recurring by letting go of the brakes when stopped on a flat

YES, this too is a BIG possibility for the issue . . .

[koko64]

Good ol' heat saturation.
Car dealers are now putting warped rotors down as consumable parts not covered under warranty. Including them with pads, oil, filters, etc. Ducati doing that now?

[DarkMonster620]

Good ol' heat saturation.
Car dealers are now putting warped rotors down as consumable parts not covered under warranty. Including them with pads, oil, filters, etc. Ducati doing that now?

Have not dealt with that issue but "cristalization"  . . . And got the wty approved, while on sick leave.

[koko64]

Have not dealt with that issue but "cristalization"  . . . And got the wty approved, while on sick leave.

What is that? Metalurgy issue?

Have a good look at your rotors.

[Howie]

Another reason is uneven brake pad material transfer to the rotor.  Before condemning the rotors make sure the buttons are free, clean the rotor surface with a Scotchbrite pad and good brake cleaner, deglaze the pads with sandpaper and go bed them in.  This would be a DYI project since a shop would have to charge you a lot of money for something that might not work.  If the brakes still pulse, try another dealer.  Just curious, did someone at the dealer take the bike for a test ride?

[DarkMonster620]

What is that? Metalurgy issue?

Have a good look at your rotors.

Since new the bike was squealing, as per factory pads were replaced and rotor "cleaned" with 80 grit sandpaper . .   2nd time, pads replaced and again following factory instructions, took rotors to machine shop and they were "re-surfaced"  . . . 3rd time, "Please replace rotors" . . . were the factory instructions . . . have them in wty storage awaiting instructions on what to do . . . no other bikes have this issue . . .

The warping on my ritors was faulty manufacturing from china

[oldndumb]

Ditto wot ducpainter and howie said.

To go along with that take note of items 4 and 6 of http://brakeperformance.com/inspecting-brake-rotors.php

A warped rotor is easy to verity. Establish a fixed point to be within a millimeter or so of the rotor surface and rotate the rotor and look for variations. Can't get much easier.

Memory (a dangerous thing) tells me that some old drum brake era brake cleaners were proven to contribute to cementite accumulation if they were used on disc brakes rotors. Don't know if any of those formulations are still on the market.

[mindiraser]

Gentlemen, I appreciate ALL of your input and expertise/experience on this matter. Thanks a ton. Yes, I can see how the surface could be causing that sensation if it isn't consistent throughout the entire rotor surface. A buddy mentioned cleaning the rotor. I also need to raise the front wheel, spin the wheel and check for the rotor "wobble".

As of now, it is a minor issue and really is just a little annoying. Bike's brakes still grab great and have no issues with stopping. Ill keep you posted.

[Yogi]

Mine went at 2500 (replaced under warranty) and my friends at 1800 miles. I never hold the lever on when I have stopped. At 9500 (out of warranty) they have started again. Here is what I did to fix them.

Clean the rotor Buttons, use a small bolt and a couple of washers to clamp the button and spray brake cleaner around the button whilst you rotate it.

Make sure the button moves  in and out against its spring washer.

Get some scotch cloth and using brake cleaner scrub the rotors both sides, you should be able to feel the brake pad containments coming off the rotors.

Go ride and put some heat through your brakes. If your rotor buttons now move freely in and out and rotationally your rotor is now able to expand and contract in a uniform way. You may be able to reset your rotors. The first time you try your brakes you will still feel the pulsing you have to get them hot! It took me several consecutive runs from 60 -70mph very hard braking to get them to reset. They are much better now compared to before which felt like I had ABS, not on an 1100S.

As always be careful with brakes try them at low speed before trying to do a stoppie from 60mph approaching a cross road