coffin --> radial master cylinder sizing?

[BK_856er]

My '07 695 has been happily running the stock 12mm clutch master (APTC wet clutch) and a 16mm brake master (larger 900ss part) paired with 4-pad SBK calipers.

I've been thinking about changing to the Brembo RCS radial setup for more precision and better feel.

Is it correct to use the same bore size when making this change?  I have a forged Brembo 19x18mm brake MC on my 749s, which has the same calipers as my monster, and the setup is quite nice.  But the fulcrum distance is different on the coffins, right?

Not exactly sure how best to size the Brembo RCS for the monster and avoid surprises, especially with the clutch.

Anyone have experience with this?

BK

[Speeddog]

Leverage ratios are different amongst the 3.

If you like the setup your 749 has, use that sizing.

I wouldn't spend the money on a radial master, bang:buck is low.

[BK_856er]

I've never let low bang:buck stop me before!   

BK

[Speeddog]

I've never let low bang:buck stop me before!   

BK

Then rock out with a radial clutch master!

APTC is definitely less spring pressure to fight against, so you could use a unit with bigger piston/less leverage than your 749.

[He Man]

just a question, but the radials are meant to increase leverage, so technically, shouldnt they be easier at the lever?

[Speeddog]

Radials are just different packaging.
Piston sizes and leverage ratios are chosen to work in that packaging.
The fundamentals of the hydraulics are the same, the 'load' (clutch, caliper) is the same.

[ducpainter]

I've ridden an SS with a 749/999 brake master, and the lever feels like squeezing a brick...no feel at all.

I much prefer coffin, or pee cup, masters.

[koko64]

DP, single or dual disc on the SS?

[ducpainter]

DP, single or dual disc on the ☼?

Dual.

Not a mod I'd be interested in.

[koko64]

The original coffin master on my M900 is very powerful. With sintered pads the front chirped under harder braking even on hot days. Wet braking was very nervous. I changed to platinum pads on Nicks suggestion for more feel. I had a 999 master on my previous M900 with twin discs, gold lines, sintered pads and the feel was great.

Maybe go for a Dyno tune and just try different pads.

[ducpainter]

What's wrong with powerful? 

I like coffin, and pee cup, masters.

I also like 4 pad calipers, but I'm not likely to buy a set.

I'll figure it out.

[koko64]

Power is good, even better with feel.

[BK_856er]

Brembo RCS brake MC @ 19mm seems like the right choice, since I have effectively the same setup on the SBK and like it.

The APTC clutch MC is harder for me to figure out.  Stock is 12mm with unknown (to me) leverage distance.  Brembo RCS clutch MC is available in 14, 16, 17, 19mm piston diameter options + the RCS 16 or 18mm leverage distance.  I suppose 14mm is the safe bet here.  My SBK uses a 16x18 Brembo billet clutch MC, but of course that's a standard dry clutch and probably not well suited to the easy-pull APTC and its narrow engagement range.

BK

[Speeddog]

I really like the OEM Goldline 16 with regular 32/34 calipers or 4-pads.

In comparison, a 16 coffin or even pee-cup big pivot 16 have more leverage built in by the geometry.
So they will have a bit more power, at the expense of more lever travel.

They feel a bit squishy to me, but it's well within the normal range of preference amongst folks.
I don't like the feel of radials on a clutch, the pivot is in an odd spot so the lever swings awkwardly.
As a reference, I really like 15/39 gearing on my M750, so my preference may not be anything like yours....

I suspect you'll get a bit more powerful feel as the 695 is lighter and position is more upright (I'm assuming stockish SBK).
I'm running a set of 4-pads that I bought from Supafly, he had them on his 620.

I will try to dig out the leverage numbers, I have some here somewhere.

[BK_856er]

OE leverage numbers would be great to have.  I found measuring on the bike to be iffy at best with 1mm precision.  Strange that not everyone prefers radial masters, but as stated I suppose it's a preference thing.  So many factors when you consider MC, pads, calipers, discs, chassis, suspension, speeds....

BK