Subject: Re: Braking tips from Darrell
Author: Darrell Dick
Date: Jun 4, 2002, 8:06 AM
Post ID: 1710371833
Hi David,
I did 3 things that really made a BIG difference. I did them sequentially
too, so maybe you can see waht the individual effects are.
First, I replaced the rubber brake hoses with ss braided lines. I had
always heard this was a big improvement. Well, not really. I would say
that the gains here are very subtle.
Secondly, I replaced the Brembo F08 caliper with a F09. This is pretty
much a bolt-on, except that the F09 is difficult to come by in the first
place and when I did find one (MG Cycle of course) it was a left hand and
the stocker is right hand. This requires the wheel bearings to be reset
in the wheel. There are 2 sets of snap ring grooves. No, I didn't figure
that out myself either. Along with parts, Gordon and Rick have some great
advice. Now the F09 was a significant improvement.
The whole issue is the ratio of caliper piston area to master cylinder
piston area. The stock setup is a F08 caliper with 2 - 38mm pistons and a
15mm master cylinder for a ratio of 12.8. The F09 has 2 - 48mm pistons
giving a ratio of 20.5 with the stock 15mm m/c. This made for a much more
powerful brake with better feel than the stock set-up, which, as anyone
knows who has tried one, is very wooden and requires a lot of effort.
This was a lot better, but I still wanted more power and less effort.
I found a 12mm Brembo master cylinder from a Convert. The Convert has a
split integrated system and the 12mm m/c actuates a single F08. This was
what I was looking for! With the 12mm m/c and the F09 caliper I now have
a ratio of 32. This gives a very powerful front brake with minimum of
effort, yet was still very controllable. Now I know my own personal
preference is for ratios around 30. I put the 15mm m/c on my Laverda that
has dual disks and 2 - F08s this gives a ratio of about 26. Pretty good,
but still not as good of feel as the Guzzi. The Lav originally had a 16mm
m/c.
A couple of more things. I have small hands and the reach to the brake
lever is an important issue. All Brembo m/c I have seen have adjustable
reach. Use it to get the most comfortable lever position. Pad composition
can also have a big effect. I'm using stock Brembo "green" pads with good
results, but there are a lot of choices. Pad area can also be a factor. I
haven't really done much investigation here. I know the F09 has a larger
pad than the F08. I suspect that the ratio of pad area to caliper piston
area is similar to the F08 though.
Some other resources: There are ratio charts available at
http://www.ducatimeccanica.comand http://www.vintagebrake.com . The
ducatimeccanica site is run by a stalwart fellow by the name of Rene
Waters who has helped me bunches in the past. It is a great site even if
you are not into Ducs. Vintage Brake are the guys with all the answers
when it comes to brakes. Check with Rick and Gordon at MG Cycle for your
Brembo stuff. Also look athttp://www.cosmotor.comfor Grimeca stuff. The
Grimeca brake components are genuine Italian and typically a little
cheaper than Brembo. They offer some more choices. I'm running Grimeca
stuff on my Ducati.
Sorry if this got a little long winded, but you asked for it.
Darrell Dick
Imlay City, MI
On Mon, 03 Jun 2002 14:43:40 -0700 David Washburn <dwash-@c4.com>
writes:
I have a disk brake Eldo which has substantially the same brake as the single disk setup as Darrell's "T". So Darrell, what did you do to optimize your brake? At this point I am planning to go to a smaller master cylinder to reduce effort at the lever. Ken Pitts put a square reservoir brembo from a Jackal on his race bike. Mark at MG classics suggested a 70's Honda M/C that was "heavily influenced" by the brembo of that period. How heavily? Mark says the caps are interchangeable. What a coincidence... Please do not inform Loopframe neophyte Chris Mitchell that I plan on putting a honda part on my Loop. It would break his heart. David |