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Discussion Starter · #1 ·
Any advice would be appreciated...
1012440


Reference: 2006 ST3S ABS
One of the front rotors is .0005 out of flatness and as a result I feel pulsation and have slight pad residual on the one disc.
I doubt if the rotor can be made flat and true... maybe, don't know.
So, I'm thinking of replacing the rotors. Other than OEM; any other suggestions??
Thanks.
 

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Do a search in this section. The topic of pulsating breaks comes up quite frequently.

There are some things to try before you buy new rotors. First, free up/clean the buttons. Use some brakeclean and something to jam in the center to spin the button. A dowel with a taper will work nicely.. Wipe away any residue from the rotor before using to avoid contaminating the pads. Some people find that this helps/resolves the pulsating issue. Another thing to do is take a Scotch-Brite pad to the rotors to get off any pad material that may have baked on. If pad material is stuck on the rotor, it can make the brakes "pulsate." Once resolved, some say (and I do, but don't have any proof that it works) to keep the brakes released after you come to a stop so as not to transfer pad material to the extremely hot rotors.

Our rotors are pretty thin to begin with...I don't think they can be machined.
 

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If that doesn't work could try replacing with full floating buttons maybe, need 5mm thickness to work. Corse Dynamics offers them.
 
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...some say (and I do, but don't have any proof that it works) to keep the brakes released after you come to a stop so as not to transfer pad material to the extremely hot rotors.
This is pretty old advice (and good advice, in my opinion) for bedding in new pads/rotors. Like you said, I don't know if there's any proof that it works, but it makes sense to me.

Try the button trick above first and see if that fixes the issue. If not, look around for new rotors. I would not try machining them. You ight be able to get them true, but by the time you're done, they'd be too thin to use.
 

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i get them machined regularly, but the success depends entirely on the skill of the machinist.
 

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Back to the beginning: You feel that .0005” runout is causing a noticeable issue ? One half of one thousandth of an inch ? How are you able to measure that accurately ? Notice any difference in the surface finish or color ? I think more like you might have hard spots from overheating which you feel in the lever.
 
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I also suffer from the front brake shudder (or "judder" as the Brits say) -- it was comforting to discover that this is a near-universal issue across the ST range, but also dismaying to read there is no agreed-upon solution, much less diagnosis.

I do think it's worth revisiting this topic, as most other threads on this subject are 5-10 years old. I've read every single brake shudder thread on the forum here, and compiled a summary below.

As I understand it, there are three primary solutions -- none of which should be considered a guaranteed fix.
  • Clean the rotor bobbins thoroughly, as road grime inhibits their ability to [semi] float. This is a common method and solution to shuddering on fully-floating rotors on other bikes. In my research here, the best case scenario on STs is that this alleviates some symptoms for a brief period of time. It had no impact on my shudder.
  • Replace the stock semi-floating rotor bobbins with fully-floating bobbins. This requires some [relatively] significant effort and may ultimately damage the inner rotor carrier, which wasn't designed to handle the force of the floating rotor and so the bobbins wear out the aluminum. Unclear how long this will take -- some riders report not seeing any significant damage for years or at all.
  • Replace the brake rotors with a different (or thinner) aftermarket product, i.e. Braketech or Galfer, or find thinner OEM rotors from other models. This is expensive, and most frustratingly, may not solve the problem depending on which rotor you choose (i.e. if you elect to stay with OEM rotors). This appears to be the most consist solution, however.
Other riders have reported switching brake pads and cleaning their OEM rotors thoroughly solved the issue, but again, not consistently.

Anyone else want to chime in with a new or revisited fix to this problem? I have it REALLY bad, and will likely try swapping out the bobbins and pads next before I fork over hundreds for new rotors.
 

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I've been through this a few times. There is really one way to get rid of this problem.

Not my picture, got it from a Ducati Facebook group, but it sums up the permanent fix nicely.
1012797


I have a small collection of bad rotors. I'm going to be making a clock or two...

For the record. I've replaced my snowflake rotors with other Brembo parts. One with a "star" rotor from a 998. The other was a 996R rotor. Both have been fine. It seems the snowflake rotors are more of a problem than any other Brembo rotors.
 

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The clock is awesome!! I have a multistrada with same issue. I replaced the buttons with full floaters, it is not 100% fixed. Much better but still present.
 

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I thoroughly cleaned the buttons by making a small arbor so I could spin each button with a cordless drill while applying brake cleaner to Make sure there was the intended semi floating movement between buttons , center and rotor. They were relatively frozen in place before I freed them up.
 
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Discussion Starter · #11 ·
Back to the beginning: You feel that .0005” runout is causing a noticeable issue ? One half of one thousandth of an inch ? How are you able to measure that accurately ? Notice any difference in the surface finish or color ? I think more like you might have hard spots from overheating which you feel in the lever.
Thanks for the responses and information. I think I'll approach this with a good cleaning, per suggestions and perhaps a new set of pads. Perhaps a EBC set...? Any recommendations?

The front rotor in question was on the side of the wheel which was 'tacoed' after hitting a rock (didn't see it). Dr. John's, frame and wheel straitening, in Anaheim was able to straighten the wheel, it turned out fine. However, he said the one rotor was out... I'm going off what he said. There is obvious evidence of deposits on the rotor so hopefully a good cleaning n pads will make the difference.
 
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