A while back,because RT handle bars were fitted, a longer front brake line was required. A braided line was fitted which made a world of difference to braking efficiency. Rear braking on the 75 is pretty ordinary and was wondering if anyone out there has fitted a braided rear brake line to improve rear braking.

Just another inane question from an amateur in these matters. Cheers Tom:shock:

I put them on about 12 months ago and they made a world of difference, there was actually some feel to it and it didn't just feel like putting your foot into a jelly (jello).

Hmm. I've often fitted braided hoses when the original needed replacement and any improvement in feel has been marginal at best.

The limiting factor is the diameter of the piston in the master cylinder. Unless you increase the size of the piston there'll be very limited improvement in the effort required.

The piston diameter of the front master cylinder of 8-Valve bikes is 13mm, 16-Valve bikes have a 20mm diameter.

BMW actually reduced the diameter of the rear master cylinder from 13mm to 12mm from 1988.

Given that the rear brake doesn't do much in terms of stopping the bike and nor is it intended to do so, as long as it's capable of holding the bike when stationary and capable of adding a bit of stability when braking hard, it's safer to have a relatively weak rear brake.

good onya tom ...

glad to hear the old girl is still travelling well ....all of us enjoy the wind in the face mate and even better if you fell more confident about the front end braking

many of us are still travelling on original old and i suspect expanding rubber lines

where did you get the stuff ?

will we see you at neranderra ?...or perhaps bathurst ?

Hi Tom,
I did this mod on my outfit to improve the rear brake action, suggesting that it wasn't necessary on a solo, but if you want a less spongy action you could try it.

https://www.k100-forum.com/t3739-mod-to-rear-brake

Paul.

Thank you all for your words of wisdom.Will probably replace the line shortly. Charlie, have just had the old girtl painted ( to remove all the evidence of various drop incidents) and am turning it into a naked. Will post some pictures in due course. Unable to make Narrandera but will be getting to Bathurst. Thanks again... Cheers Tom

Hi Tom,
Just one thought if you are replacing it with a non original BMW line check that the new line is OK for the regular compulsory inspection if you have them there. In NZ we can have a vehicle rejected if you can't show that the replacement line is approved and the manufacturers who produce them over here give you a sheet of paper with the specific approval number on it. It generally only gets noticed if you upgrade to braided lines like I did for SWMBO's Volvo 245. I originally got a set of US DOT approved braided lines from the US and NZ WOF (Warrant of Fitness) said no go must have NZ DOT approval number GRRRR! So I still have a spare set of US approved lines.
Regards,
K-BIKE

G'day K-Bike,thanks for that info. Apparently new brake lines are supposed to be approved by the motoring authority. When the bike (or any other motor vehicle) needs to be inspected to renew registration, the mechanic who does the inspection does not seem to be interested in inspecting replacement parts ( e.g. brake lines). They only check tyres, lights and horn. So not as fussy as in other parts of the world. Cheers Tom