How thin can a single front disc be allowed to become ?

Sibbo · Post by **Sibbo** » Thu Oct 15, 2015 3:15 am

and no, I'm not going to tell you how thin/ thick mine is ... but she stops just fine.

ME 109 · Post by **ME 109** » Thu Oct 15, 2015 4:35 am

Sibbo wrote:and no, I'm not going to tell you how thin/ thick mine is ... but she stops just fine.

Manual says 4.5mm
4mm would pull it up for me.

Sibbo · Post by **Sibbo** » Thu Oct 15, 2015 7:17 am

Well, mine is 4mm and it pulls me up pretty well but the price of a new one from Motobins is 250 quids ... $527 + postage !
Shudder !

Kurt in S.A. · Post by **Kurt in S.A.** » Thu Oct 15, 2015 7:20 am

Yeah, that whole stopping safely thing is over rated!

Kurt in S.A.

Major Softie · Post by **Major Softie** » Thu Oct 15, 2015 2:00 pm

The minimum thickness on a disc is for two reasons: stability of the disc material, and the dimensions of the caliper/pads.

On these old bikes, the disc starts out so thick that is is possible for the disc to become thin enough that, with severely worn pads, the caliper pistons may travel out too far, which could lead to them jamming (sudden violent stop), or catastrophic brake failure (sudden violent stop when you hit that thing in front of you because you have no brakes).

So, I personally would never run a disc past it's minimum spec with really worn pads, as I consider that to be suicidal. With nice new to 50% pads? Well, probably a terrible idea, but one which some crazy Aussie bastard could probably get away with.

Bamboo812 · Post by **Bamboo812** » Thu Oct 15, 2015 2:15 pm

S.Meyer has them for 199 Euro: http://www.meyer-bikes.de/index.php?pag ... 111236566b

Sibbo · Post by **Sibbo** » Thu Oct 15, 2015 5:19 pm

Bamboo812 wrote:S.Meyer has them for 199 Euro: http://www.meyer-bikes.de/index.php?pag ... 111236566b

Thanks, that's much cheaper but it doesn't mention R80 ST which is my model. I'll email them and ask.

Bremsscheibe /6/7,RS,RT 1974-1985

Bamboo812 · Post by **Bamboo812** » Thu Oct 15, 2015 5:24 pm

Yep, different part number; MaxBMW lists them for $377.36, but S.Meyer lists the correct one for 199 Euro: http://www.meyer-bikes.de/index.php?pag ... 4111236005

Sibbo · Post by **Sibbo** » Thu Oct 15, 2015 5:46 pm

Thanks, very much appreciated !

Now I just have to steel myself to another A$400 on top of the last $800. But this has to be done.

Airbear · Post by **Airbear** » Fri Oct 16, 2015 12:55 am

Mine measures 5.0mm, but I keep it well greased.

er, that's a joke, a very silly joke.

I've just ridden home from town with two new tyres (Lasertec and Pilot Activ) on beautifully balanced wheels, and a very wide grin. I love it when front and rear tyre replacements coincide. I had to keep telling the old dear to take it easy in corners for a while, but would she listen?

Sibbo, if you had a new bike you would be paying dollars like that for each service.

Boxerworks.com

How thin can a single front disc be allowed to become ?

How thin can a single front disc be allowed to become ?

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Re: How thin can a single front disc be allowed to become ?

Re: How thin can a single front disc be allowed to become ?

Re: How thin can a single front disc be allowed to become ?

Re: How thin can a single front disc be allowed to become ?

Re: How thin can a single front disc be allowed to become ?

Re: How thin can a single front disc be allowed to become ?

Re: How thin can a single front disc be allowed to become ?

Re: How thin can a single front disc be allowed to become ?