Let's do the Rottor Buttons Again!

[Don]

Hi Guys

I thought I'd pass on the method I used to get more float on the semi floating front discs - to 'cure' the dreaded pulsing brakes! :rolleyes: Advantage is you don't have to take off the front wheel. I used a 'G' clamp and a block of wood to dish out the washer on the back of each botton to increase the side float of the buttons.

First photo, get a small block of wood and drill a 20mm flat bottom hole 3mm deep. (Forstner or Spade bit).

The hole goes over the button on the outside of the disk and the 'G' clamp applied as shown in the second photo. Screw up quite firmly. The depth of the hole prevents over doing it!!

Third photo shows back of a finished button. Side float is a little over 1mm. Brakes are beautiful and smooth now. :lover: :)


:aussie:

[Nooj]

to 'cure' the dreaded pulsing brakes!

Then I haven't warped my disks afterall! :banana:

[go_modem_go]

to 'cure' the dreaded pulsing brakes!When does this occur? Never had that feeling. And I ride really hard in my local mountain slopes...

But thanks for the tip! Great engineering - will the washers stand up to a little twisting & bending?

[falco03]

i've felt that sensation. it feels just like a warped disc, but not with the intensity. kind of mushy almost.
i've kept mine clean with a little brake cleaner and manually turning them.
but, this is a great tip, don.

[Don]

A few guys have had the problem and it's mostly caused by the rotor buttons sticking up with dirt etc. I cleaned the buttons quite regularly, but decided to try this - other guys have used other various methods to free up the buttons.

I think if you do a lot of heavy braking, it's not so much of a problem. I've noticed after track days, mine was a lot better - for about a week!! :rolleyes:



:aussie:

[arcangel]

OK, one more time for the slow kid... What are "floating" disks, and what advantage do they provide? Please type slowly... (slunks to the last seat of the short bus...)

[Prilliant03]

Floating discs mount the rotor on bobbins that allow a little lateral movement. This keeps the braking surface square between the pads. It also means the caliper can be rigidly mounted. When the bobbins seize the lateral motion is lost leading to a pulsing feeling at the lever as the braking force rises and falls.

[go_modem_go]

I've had this tool drilled by a carpenter friend - Great Tip!

I felt a very light pulsating feel after 3000kms on partly dusty roads in France & Spain - the job described above has completely freed up the buttons again!

I now have several copies of the wooden block made and distribute it to friends with semi-floating discs (many of them) as a gift :)

Little sidenote: What pissed me off was that a friend complained about rattling noises when standing still and playing with his front brakes on his recently acquired '98 BMW R1100R (he hasn't got a clue about bikes). I looked closer and discovered that his 85k km Beamer came with a brand new set of fully-floating Brembo brakes, with revised ABS, and a brand new (incredibly expensive) Wilbers shock conversion front and back - the bastard! I'm nearly jealous (not of his 1100R, it's still a rubber cow, but with the supension and new brakes it worked amazingly well for a tourer/cruiser!)

Thanks Don for posting this cheap and easy fix!

[falco03]

OK, one more time for the slow kid... What are "floating" disks, and what advantage do they provide? Please type slowly... (slunks to the last seat of the short bus...)

what prilliant said. the rotor itself isn't fixed solidly to the wheel or the rotor carrier (the gold snowflake thingy that holds the rotor.) it "floats" on those little round things (rotor buttons) so it can move with the braking forces.
if you examine the rotors carefully, you'll see that the rotor is separated from the rotor carrier by a fraction of an inch. it's the rotor buttons that keep it suspended from the surrounding structure.
now, look at your rear brake. it's a fixed rotor. it's mounted solidly to the wheel.

[desmodromic]

What's the deal with bending the tabs until the spring washer is flat? I've seen other threads where the recommendation is to bend the tabs back ~30 degrees.

[Firebolter]

It allows for more movement or "float"........That's why guys are bending them

[desmodromic]

The question isn't why to bend them, but how far to bend them. Some people recommend bending until the spring washer is flat, others recommend that you bend each tab 30 degrees past flat so that the spring washer is concave.




It allows for more movement or "float"........That's why guys are bending them

[20Hz]

If you get tired of cleaning your buttons (or if your fucking rotors warp out at 3K despite cleaning the buttons :()you can also save up a couple of hundred dollars and do Spiegler's DIY kit that has ff buttons and ductile iron (or SS if you prefer) swept area, and you re-use your stock carriers. Worked like a champ for me, much cheaper than new FF rotors.

[bikpaintr]

[QUOTE=go_modem_go] I looked closer and discovered that his 85k km Beamer came with a brand new set of fully-floating Brembo brakes, with revised ABS, and a brand new (incredibly expensive) Wilbers shock conversion front and back - the bastard! I'm nearly jealous (not of his 1100R, it's still a rubber cow, but with the supension and new brakes it worked amazingly well for a tourer/cruiser!)
QUOTE]

What makes you think the Wilbers are "incredibily expensive"? I've supplied these for BMWs & Aprilias to customers in Europe, Aus & the U.S. and the prices are very reasonable for a premium custom built shock. Lots of guys on the Futura forum are running a rear Wilbers.

[venturaII]

So tell us.....what's "reasonable"? :)

[MRKI]

How much movement of the rotor do you guys have after this mod: not lateraly but...i donn't know how to say this... up and down, left and right from the center. I have about 2mm of this movement. Is this normal?

Thanx

[bomfunk]

I just bought a pair of rotors from somebody here. the rotor itself is loose on the carrier and button washers (the flower looking ones) are bent back. is it normal and i'm just paranoid or are they beat up? my other pair is solid as one piece. if you shake this one in your hand it rattles a bit. here's a pic, please advice guys.

[Exdukenut]

The rotor button fix on this one looks, IMHO, a little too overdone. My understanding of the procedure was to bend them up probably 1/3rd of what those have been done by.

After doing the procedure, yes, they will rattle. They become what are called full floaters, as opposed to the OEM ones which came as semi floating, or somewhat rigid, but due to them having the buttons in the first place, they are in fact semi not solid. If that makes sense.

:cool:

[kiwifalco]

Clear as mud, anotherspliff? J/K. Totally agree with Ex, they have been heavy handed, just the scratch marks alone show that but they are not a wasted purchase, just bend them back to where they need to be, not up solid, not down flat, it is a good thing.cheers,kev.

[bomfunk]

So the fact that they are overdone a bit, does it affect performance or reliability? if i bend them back as they should be is it gonna be all ok, or i should do/check smth else as well? how much of a wiggle/rattle is ok and not?

thanks for all advice guys. :worship:

[kiwifalco]

As long as the tab themselves haven't been weakened to the point of susceptible failure you will be good to go & the disc has slight movement & an Irish jig too.:):):)

[Nooj]

Looks a bit of a scrappy job with the gouge marks, but they should work just fine.

[vtguy]

so,if i feel that pusling on hard braking, my buttons are seized? disc brake cleaner to clean them?

[hank]

A good read:
http://www.apriliaforum.com/forums/showthread.php?t=31289&highlight=rotor+buttons

[richardsperry]

Stupid question for you... What should us Yanks use for a bit? 20mm is .7874 inches, and the closest we can get is 13/16" or .8125" Would that be too big?

[anzacinexile]

Stupid question for you... What should us Yanks use for a bit? 20mm is .7874 inches, and the closest we can get is 13/16" or .8125" Would that be too big?

But yourself a set of metric bits cheapskate :kidding:

Seriously, they can be a sod to shift and without a good quality, good fitting bits, YOU WILL bugger up the heads

[go_modem_go]

I didn't know they still make non-metric bits (except for a few British oldtimer cars such as Rolls-Royce and Blériot-Whippets from the 1920's, at a massive surcharge)

Isn't metric SI sizes in tools Global Standard everywhere from Antarctica to the North Pole, and anywhere inbetween?

As for the wooden blocks to loosen the floaters:

No problem to have them oversized a little. I had several drilled from 18mm - 35mm, and they all worked. Fifteen eights of a distance gill, or one hundredweight and seventytooth of a yard would do (or whatever weird units are out there in the colonies :D)

http://img241.imageshack.us/img241/1633/buttomblockde6.jpg
http://img241.imageshack.us/img241/96/buttonadjustyv3.jpg