Don't believe we've had a MC sizing discussion for about 24 hours, so thought it was my turn...

Building a Midi with pretty much the same calliper / disc / pad combo front to back. Only difference is that the front twin-pot caliper pistons are 44.5mm and the rears are 41.3mm.

I already have an unused 0.7 MC that I could put to use on the rear circuit. If I source a 0.625 MC for the fronts, then that will offer 60/40 distribution... am I in the right ballpark for a Midi?

That said, I actually have two 0.7 MC's... if I fitted both, then I'd have 54/46 distribution... is this straying into too dangerous ground? Aaand... I have a proportioning valve gathering dust on a shelf... I could stick it on the rear line and drop some of the pressure going to the back?

I know there's an element of 'suck it and see', but I'm aiming for the set-up that's most likely to succeed first time round as I hate fannying about with brake lines!

Cheers all.

[Edited on 8/8/17 by scootz]

I have identical calipers (41mm twin pots) front/rear, with a 0.7 feeding the rear, a 0.625 feeding the front. It's been a good, useable set up and remains so.
Brake balance bar is still heavily balanced towards the front, so add that to the equation...

Thanks.

My pedals are billet-aluminium and there's not enough material to accept the industry standard 30mm-ish brake-bias sleeve. Also, the sleeves are steel, so I couldn't weld it in place (although I've seen AP fitting instructions which suggest that bonding is acceptable).

Therefore I'd planned to fit a solidly-mounted non-adjustable bar (sorry - should have mentioned this at the start!).

I guess I could try the 0.625 / 0.7 combo on a flat bar and tweak the rear circuit with the proportioning valve?

This shows the calcs for 2 x 0.7 MC's.

I see the 'Line Pressure' has come up with red text (indicating a warning). Is 1413 psi really too much???