GS 80 Basic: brake tuning

[davidulo]

Hello
this is David from Italy
I hope I can post and ask things in english on this forum... ;-)

I have a GS80 Basic and would like to tune the front brake

I have read some of the posts but can't really read German... hopefully some good willed member can help me... I see many links and interesting info here, with some alternative that are new to me

I think there are 3 alternatives:

1. mount a 320mm disc brake
2. mount a 4 piston caliper
3. mount a double disc kit

on number 1.
I see a couple alternatives. HE has a interesting and cheap solution (same as available here http://www.bmwbayer.de/index.php?page=product&info=1065), but I think the disc of the Basic has to be broken to mount the HE one, as you still need the base on the wheel to mount it.
Probably the solution from Wunderlich (http://wunderlich.de/frame.php?Make...1&lay1=2&lay2=12&lay3=9&lay4=4&prodid=8155000) allows not to break the original disc (the disc mount looks exactly like the original one...) does anyone know if this is correct? I would prefer not to break the original disc if I have to mount a new one...

on number 2.
there are many different calipers that can be fitted to the original (or to the modified) disc, including Billet, Nissin, and also BMW/Brembo like this one (http://cgi.ebay.de/Brembo-4-Kolben-...aftradteile?hash=item255a14369a#ht_500wt_1151) which I think I understand can be mounted on my Basic without the adapter...
my question is: do I need a new brake pump to make the calipers work? Do I have to watch the disc thickness also? Is one caliper preferrable to another?

number 3
I haven't really considered this, it is too costly I think! Or is there a good priced solution for this?

I would love to hear any general suggestions from you as to what solution is better? 1 or 2? I know that 1+2 is the best, but I think it is costly for me...

maybe you also ahve some hints and information on alternative solutions and German internet shops where I can buy cheaper

thank you!!!
David

 

[Stephenb]

No. 2 is the simplest and best value for money in my opinion. I used a left caliper from a 2000 R1200S, its a 4-piston Brembo and they are all the same on later BMWs, just needs about 4mm material taken off the mounting bosses (to center it correctly over the rotor), plug 'n play with your exisiting master cylinder and rotor (disc for you Europeans), no worries about pad thicknesses either, it all fits just fine:

Big (!) improvement over stock. Not sure whether your authorities allow that modification. Better ask before you do it.

Option #1: I have heard stories of people that had the 320mm HE kit and went BACK to a 4-piston caliper, not worth the money they said. Your mileage may vary.

Option #3: it can be done.

No 1 and especially No. 3 are big $$$ items.

 

[Joerg_H]

Hi David,

Original von davidulo
I think there are 3 alternatives:

1. mount a 320mm disc brake
2. mount a 4 piston caliper
3. mount a double disc kit

There are 3 other, less expensive possibilities ... brake performance is, among others, determined by the friction between (a) brake disc and brade pads, (b) tire and street.

The first thing would be to replace the standard brake pads against sinter-metal pads - on my GS (which AFAIK uses the same brake as your Basic) this brought a sensible performance increase.

What tires are you using? If this is some real enduro profile, then change to some more street-oriented profile (such as Mitas E08).

Third suggestion: Stainless steel brake lines. While they do not improve the brake performance as such, they provide a much better feedback - and this, in turn, allows for better, finer dosing.

 

[davidulo]

Original von Joerg_H
Hi David,

There are 3 other, less expensive possibilities ...

The first thing would be to replace the standard brake pads against sinter-metal pads

What tires are you using?

Third suggestion: Stainless steel brake lines.

thanks Joerg

steel brake line: I already have the Stahlflex mounted. Less spongy response, but probably no real increase in braking power though. Necessary, however.

Tyres: have had a few (anakee, tourance etc.) Now I resolved on Heidenau K76, a better on/off compromise than other tyres... I do a good 40% off road with this bike... and most of the times I do this with my wife on board...

as for the sinter-metal pads, can you recommend some specific product? Which ones do you use? I have no idea what pads I am mounting right now...!!!!

ps
also, I have Wilbers progressive damp on the fork, this has helped control and overall sensation that brakes work better... however in terms of effectiveness, I doubt this has really brought a better braking power...

 

[davidulo]

Original von Stephenb
No. 2 is the simplest and best value for money in my opinion.

Stephen
this is good advice, thank you

I also thought this would be the first step. Cheap and easy. I was waiting to hear if it really did improve the situation, and I think your opinion is enough.

also, No.2 does not prevent from doing No.1 one day...

thanks!
D

 

[Stephenb]

I wasn't stating the obvious but Joerg is absolutely right: stainless steel braided brakelines and different pads will improve the braking to a degree. The tires have an effect as well although it will be difficult to "measure" as it highly depends on the surface.

You have done a couple of things already. Personally, I wouldn't waste my money on a pair of super-duper organic green Gulfer (or whatever) brake pads if I can get a 4-piston caliper for the same money (mine was 50 Euros shipped to Canada), most likely with pads that have some live left in them. The 4-piston caliper increases the active piston area by about 70% by design. I haven't done the math on the brake pad area increase but it should be about the same. Braking is indeed greatly improved.

Just my experience.

 

[davidulo]

thanks Stephen
I will definitely change the caliper and will consider any other tuning after that

Do you have an exact spec (BMW telienummer) for the caliper that fits?

I seem to find a few on the eBay, but am not sure they are exaclty the same...

ex.:
1) http://cgi.ebay.it/PINZA-FRENO-ANT-...essori_Moto?hash=item53d9ae4b84#ht_1725wt_909

2) http://cgi.ebay.it/ws/eBayISAPI.dll...064090&ssPageName=STRK:MEWAX:IT#ht_500wt_1151

3) http://cgi.ebay.it/ws/eBayISAPI.dll...24085&ssPageName=STRK:MEWAX:IT#ht_2342wt_1136

look pretty much alike, but not sure

D

 

[Stephenb]

They will all fit, they're all the same. Remember, some machining (shave off approx 4mm) on the mounting bosses is required to center the caliper over the rotor.