C5tor
Chief Comedic Instigator
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- SF Bay Area, CA
Well, I guess I will find out. I ordered both 9mm and 10mm. I guess I'll test them and see how they feel for my purposes.
My main problem with the stock foot brake is it is either on or off, and it has zero feel. It just locks up no matter how softly I press it. That was why I was going to try the hand brake (plus my son isn't experienced with foot brakes.)
So, I installed two LHRB setups over the weekend. (This is using the LHRB hose I got from Liquid Performance.) One was 9mm and one was a 10mm master cylinder. After using them both, I am definitely torn. Both have their pros and cons.
The 10mm feels super solid and firm. Very little lever movement before it bites. It feels firmer than my front brake. But it also doesn't have as much leverage. At full squeeze, it can lock up the rear (especially) at higher speeds, but it take a lot of effort. One or two fingers would probably not get it done, three fingers minimum.
The 9mm doesn't have the solid, firm feel of the 10mm. Lever travel is much longer for the 9mm. I can actually pull it almost all the way to the bar if I wanted to (and yes, I bled the system several times). But it has a lot more leverage, and pulling it in about half-way can lockup the rear. And effort is much less. One or two fingers is all you need. So, of the two, it is much easier to modulate on the 9mm.
At this point, I think I'm going to swap out the 10mm for a 9mm. I wish Brembo had a 9.5mm or a 9.3mm master cylinder. That would be pretty ideal. I think I saw Magura had a 9.5 clutch master cylinder, but not sure if it is compatible with Dot4 fluid or not. (I've heard bad things about using dot4 in a setup that is designed for mineral oil. But not sure if that applies in this case.)
My final conclusion is that both options seem to offer a lot more feel and modulation than the stock foot brake did. At least, that is my experience. I couldn't modulate the rear foot brake at all, it was either on or off as far as locking up the rear wheel. Your experience and expertise might be different than mine, though.