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Discussion Starter #1
My (newish to me) 04 ST4s (abs) has a brake shudder during medium to hard braking.

Tried brake cleener rotor scrub....
Tried freeing/cleaning the retainer buttons.....
Tried some realy aggressive braking to heat things up......

I think the rotors are warped....thoughts on replacements? Duc parts guy says OEM rotors could do the same thing.....

EBC?

Or just new pads?

Or the banjo bolt possible fix?

I feel like I could put new rotors on ($$$$) and have the same issue.....

Any input would be appreciated.....
 

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I had this same problem and ended up replacing the rotors with OEM. I could not find any company out there making the rotors for this bike with the ABS rings...so we are kind of limited.
 

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It could also be the steering head bearings.
 

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I had this same problem and ended up replacing the rotors with OEM. I could not find any company out there making the rotors for this bike with the ABS rings...so we are kind of limited.
what, you cant just transfer the rings onto the new rotors? :confused:
I beginning to dislike the ABS more and more for what you'd nomrally expect to be able to do for upgrades to any Ducati.
 

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Had this issue real bad on my st way back, 'specially when two-up. Had the forks rebuilt, new bushing, etc, surprise, surprise, no more shudder! I think many people change rotors for the wrong reason. I have tracked this bike hard and still can't produce the shudder. Now qoing on 40K.

I have a friend with a s4rs and the ducati dealer put rotors on his bike regularly! So, I would think that the Ohlins front end would be secure enough stock, and he is just streeting his bike. There seems to be no ryme or reason for these issues sometimes.

mark
 

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Discussion Starter #7
re

Braketech doesn't show anything for the abs bike....I emailed them.

It was just serviced....previous owner.....the reciepts show head bearings torqued.......

I had a Sport1000 with this same shudder (and on an 04 ST3), on the sport I changed the forks and it was still there......

That's my fear, new rotors ($$$$) and the same thing still happening.....

Are the new oem rotors changed? any better?

Thanks for the input....
 

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It was just serviced....previous owner.....the reciepts show head bearings torqued.......

Adrian:
Torquing the head bearings won't solve the problem if the bearings are shot. To check the bearings, put the bike on the centerstand, have someone press down on the back of the bike so the front wheel clears the pavement. Then grab the forks and vigorously move them front to back - if there is any movement, either the bearings were not torqued correctly, or the bearings are shot. You can also check the wheel bearings at the same time by moving to the side of the bkie, grab the top and the bottom of the wheel, and again try shaking the wheel. If it moves, the chances are the wheel bearings need replacing. If you change you head bearings, make sure you know the exact position of the fork tubes before you slip them out of the thriple tree.

Good luck...
 

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Discussion Starter #9
No play..

No play in the front end anywhere......

With the front up, spinning the wheel and holding the brake lightly, if the rotors were bad I'd expect the wheel to catch or grab at some points but it doesn't......

Could it be the tire? Or air in the lines somewhere? (I did just swap the risers-resivor might have tipped sidways during install-but it shuddered some before that)

It's the same with the ABS off........

It's driving me nuts......:eek:
 

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I too need to replace rotors..Only one is warped and its not the ABS side. However if i decided to go for aftermarket I would drill the 6 holes for the ABS ring in the left side one myself. I do not think its rocket science. Just use the old one as a template.

Starting to get pissed with the pulsation so have to do something soon!! And i do know its the rotor for me as it is 0.009 out on a dial gauge.
 

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A cheap solution for warped disks is drilling out the round thingies connect the centre to the disk itself and replacing them with different ones with more room so they become full floating. They wont be perfect after this, but it should help.
Think a company named Spiegler makes them, some others aswell prolly.
 

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99% chance it's the rotors. There have been many threads on this over the years and I experienced the same thing on my ST4s. Don't even think about putting new OEM rotors on. I went with Braketech ductile iron and never again had a problem, plus braking performance was greatly improved.
 

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Yes agree with filantroop. There is a company here that converts to full floating and looking at the tolerance on disc warpage for my full floating triumph, the duc would be ok.

Problem was the cost of conversion was similar to new discs!!
 

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99% chance it's the rotors. There have been many threads on this over the years and I experienced the same thing on my ST4s. Don't even think about putting new OEM rotors on. I went with Braketech ductile iron and never again had a problem, plus braking performance was greatly improved.
Not saying they don’t warp, surely they can, but I'd say many, if not most, warped rotor claims are really caused uneven build up of pad material, or frozen (or otherwise hard to move) rotor buttons. Maybe the better performance after switching to Braketech iron rotors had more to do with the rotor material and the fact that they are full floating (OEMs are not) than the OEMs apparent willingness to warp as soon as the rider even thinks about stopping??? Just because people have had better performance after spending huge money on aftermarket rotors, doesn’t prove the old rotors were warped. It does point to possible bad choice of OEM pad or even rotor material, but not necessarily being warped. I’d like to have a hook-up at a dealership that aloud me to collect all those “warped’ OEM rotors!

Yes agree with filantroop. There is a company here that converts to full floating and looking at the tolerance on disc warpage for my full floating triumph, the duc would be ok. Problem was the cost of conversion was similar to new discs!!
I had the STM full floating conversion on my old SS900. I picked up a pair of snowflake rotors from a guy local to me at he time. When I installed them along with a new set of EBC HH pads, the shudder was so bad you would have thought they were shaped like a pretzel. They were straight, however. Installed the full floating STM buttons, and they were forever smooth! Mad a lot of noise though. Very loose fitting. I keep thinking I want to do that to the ST as well, but haven’t really had that big of a problem with it. I do get shudder from time to time, sometimes pretty bad, but a few hard stops generally makes it go away.
 

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I got a couple of those spacers at a local guy, think it cost me like 50 euros for 2 disks or something.

I like the noise the floating disks make :)
 

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I lived with the same issue for a year. Tried to clean the rotors and keep the buttons free, but in the end I replaced the rotors with EBCs this past winter. Now the braking is perfect. Duc parts guy said that I could replace with OE rotors, but they would just warp again. Sound advise. Now I'm going to turn the old rotors into shop clocks!
 

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Has anybody tried surface grinding rotors lately. Its been a long time ago, but I had a guy at a gas station grind the iron rotor on my 860. He hooked it up in a brake rotor grinder for cars, and it came out in good shape. I'm wondering if a surface grinder would fix the warp on the stainless disks we have now - a grinder like they use for car cylinder heads, etc.
 
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