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Discussion Starter #1
I know this horse is long dead and buried but for anyone still interested:
I have a 2006 ST3S abs and it had brake shuddering, grabbing, pulsing, or whatever you want to call it.
I checked the head bearings and adjustment and it seemed ok. Tried cleaning the rotors. Scuffing them with abrasive, changed the pads to EBC HH sintered which I've had good luck with.
The new brake pads seemed to help the most. Then I cleaned and loosened each individual brake button and the unwanted motion while braking completely disapeared.
So that led me to start to think it was the brake buttons. I had a similar problem on a BMW GS and it only went away when I cleaned the mounting hardware and replaced some of the wave washers and the bolts. Those brakes have been very good for over 100k miles.

I finally bought some new brake buttons and removed the original ones and replaced them with the new buttons.
I've only ridden a couple miles but it seems to be gone with doing nothing else.

I removed the rotors from the wheel. And I chose to grind off the mushroomed backside of the original buttons. One could drill them also.
The new buttons are a perfect fit and very easy to install.

Pictures for reference. The rotors look scored but they are still pretty straight and smooth for 29k miles.

The buttons I bought:
981817


Ground off washer/button
981818
981819


Before:
981821


After:
981824


Mounted:
981822
981823
 

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I've done this to a few sets of rotors over the years. Button kits were available from a few vendors, STM and TPO are the ones I've used. This absolutely cures (masks to be honest) the brake judder problem if caused by a very slightly out of true rotor. It works, but it is the final nail in the coffin for your rotors. They wear at the aluminum carrier and become very very sloppy. Depending how often you ride, you'll get a few seasons out if them, so definitely not a bad thing to do. As a bonus, you also eliminate brake drag. I have a set of those same rotors, non-ABS version, and a set of 998 style "star" rotors that are both suffering from brake judder and are in need of this mod. After living with this a few times, I instead decided to replaced them with rotors that are true. The bad rotors are hanging on the wall as "garage art"...
 

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They wear at the aluminum carrier and become very very sloppy.
How absolutely true you are SS904.
Mine did that after a few thousand Km, but I fixed it with a 0.5 mm wavy shims behind the E clip ( please correct the terms if wrong).
In addition when I dismantled them , I took them to a shop where they put them on a horizontal lathe and run them down a few 1/100s of mms. It seemed to do the trick. I have done appx 35,000Km since then and all is fine.
 

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can you get button kits that would make rotors full floaters? Have the full floater rotors on the Griso as stock, the rest of Griso front brake system appears identical to what is on my '07 ST3s .... thanks for any knowledgeable replies !
 

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That is exactly what this thread is about. OP shows the Brembo button kits he bought to do exactly that, make the rotors full floating.
 

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On one set I had converted, I tried something similar with thin shims / washers that I bought somewhere. It helped with the side to side slop, but my bigger concern was the aluminum carrier "holes" were elongated. The wavy spring washers are a good idea, but depending on the spring force that have, it kind of eliminates the full floating thing. The OEM riveted buttons have stiff spring / washers too. They have some give, but they are not full floating because of those springs.

A few years ago this same discussion came up. The wear on the rotors with floating buttons was described as "the cost of using race parts on the street"... Pretty spot on, IMHO.
 

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I’m pretty sure original set up on my ‘07 ST3s is called semi-floating rotors , the Griso rotors (full floating) certainly provide much more wiggle than what I can get on my ST3s even after a very diligent cleaning ... sorry for way I worded first question , the original post led me to believe he was going for improvement on worn out original semi-floaters on his ST ... did not realize at some previous point he had made the switch to full floaters and that he was looking for replacement ....
Craig
 

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Not to belabor this, but he wasn't. He took his OEM semi-foaters, busted out the OEM buttons and installed full floating buttons. The difference is the spring / washer deal and the OEMs are riveted on. The Brembo buttons he pictured have no spring and are attached with flat washers and cir clips, likely just as your Griso rotors are.

Maybe I confused the issue with the discussion about those "wavy shims" stelbo mentioned. My thought was if the wavy shims added enough spring force, he may have reverted back to semi-floating. More likely he has found a better middle ground and is a viable option.
 

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Discussion Starter #9
Sorry for not responding sooner but I mostly wanted to get rid of the pulsing, shuddering, or grabbing that I had with the "stock" semi-floating brembo starflake ST3S abs rotors.
That was my main goal. If they worked better fine. The friction, or steel, portion of my rotors were almost 5mm and had no run out. I realize that using the free floating buttons will probably cause more wear in the aluminum mounting portion of the brake rotors.

My ST3S rides so nice but it was completely spoiled by the shuddering or whatever of the front brakes. I had it down to just a bit at a certain road speed but it would become worse the harder you braked.

This is cured it, so far, and I'll bet it will be good to go. I also could not find a new set of rotors that I thought would fix the problem. There are some available but I didn't want to spend $400 on an experiment. If these wear out prematurely I will go down that path at that time. I actually bought some new rotors to try to solve this issue but they don't have a way to mount the abs ring. The online seller assured me they would work and of course they didn't so I'm trying to sell them now.

Once I'm able to get in a decent amount of miles on these I'll report back. I ride almost everyday but at this time I'm not going to work and mostly just staying home.
 

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thanks for posting up your results ! Makes me feel so much better that I had understood your issue completely and was not being a "dumbass" with my question .... while I am always trying to learn more 'bout our great bikes , it can sometimes be difficult when there are folks waiting to ridicule .... anyway glad you have good result , the Griso brakes are all still original (25000km) with no excessive wear on carrier , the only difference in brake components from the ST3s is the buttons other than ABS .... so keep an eye on things and I'll bet you get great service life out of your setup .... I do clean the buttons on both my Italian bikes on a regular basis ...good luck,and enjoy the ride
 

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100% on using those full floating buttons then having them flog out your alloy carriers. Happened to me and I was shocked at how quickly the carrier elongated and the amount of elongation. I maybe managed another 6000 miles at best.
I also think that full floating rotors are manufactured with a harder grade of Aluminum. They must do if they are getting a substantially longer life.
 

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Corse1 ,Not sure if you promoting the full float buttons or telling us they ruin the carrier quickly ... thanks for any clarification
 

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Discussion Starter #13
Imo there is an issue with some of the Brembo snowflake front rotors. It might be minor but for some reason that and other things make the shudder/pulsing/grabbiness very apparent and there is no other cure. I purchased new rotors but they don't allow use of the abs ring so I'm not using them. The brake buttons were the only other thing I could think of other than buying another set of rotors. I wasn't going to clean the stock buttons every time I wanted to go for a ride. Or just live with the ridiculous brake issue. If the rotors become super loose and wear out because of the floating buttons that doesn't concern me because they were unusable before. I'll monitor their looseness and report. I'd expect more wear because there is more clearance and movement now.
 

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I did that modification about 10 years ago. Indeed after a few years, through an MOT inspection, it was pointed to me that there was not a lateral movement but a back and forth ( sorry, do not know the proper word for it). It was then that I shimmed the rotors with wavy shims and it stopped. If in the future (to be expected) it does it again I will add some 0.1 mm and carry on, until they are out of specs. The trick has worked for all these years.
 

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Discussion Starter #15
Stelbo, thanks for that info! I'd like to find the proper sized wavy washers just to add a bit of tension.
Thanks again and good riding!
 

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Corse1 ,Not sure if you promoting the full float buttons or telling us they ruin the carrier quickly ... thanks for any clarification
Definitely not promoting them as they were not cheap. I should have put the funds into new discs. I have a photo of the wear somewhere that I will post when i find it.
 
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