Combined brake mod?

[godlesscommie]

Just throwing this idea out there before I start sourcing parts for a mock up:

How about a combined brake conversion on a scooter?
(Much simpler than the Honda version)

Two T connectors, two check valves, and a restrictor.

Both lines from both master cylinders will have a check valve, and then a T splitter. The T splitters will then be connected with a brake line that has a restrictor in it. Other end of the T splitters will be leading to the calipers, just like the original brake line.

That way, apply the front brake, and the rear will engage (at a lesser degree) and brake fluid will not rush into the other MC.

Same principle for the rear brake, too.


Any ideas?

[ericrockstar]

Be sure to where your seatbelt.

[godlesscommie]

Where?

[prodigit]

First of all, having 2 brakes brake through 1 master cylinder, will give less braking tolerance (or less braking power, as each brake will go less forward than with their own cylinders).

Personally I'd worry about the balancing of the brakes.
If they're not perfectly balanced, either one of them will brake harder, and easy get into lockup, while you may not even come close to the full braking potential of the bike!

Suppose you do get a brake lockup, and have to release the brake. And the lockup is only one (say, the rear) wheel.
You'd have to release the braking lever, and reduce braking on both wheels, to get out of the lockup; while on a normal separate brake system you could increase front braking while reducing rear braking.
All those that never have been able to recover from a rear wheel lockup and say it's impossible, have not much riding experience!
I've done this several times, learned it when I was a kid on a bicycle.
But from a front brake lockup there's no recovery, unless you have ABS.

By the time you want to correct the front brake from a lockup, the wheel can no longer recover in time before the front fork gives under the loss of grip.

The rear tire is much more forgiving in correction.

[godlesscommie]

You have valid points about brake lock up.
But, the two brakes (front and rear) would still be independently controlled.
What I am thinking about is adding a little bit of the other in the mix when one is applied.

I mean, Honda has the CBS where if you apply the front brake, you are actually applying 70% front and 30% rear brake.
Same holds true for the rear brake, but this time it's 70% rear, and 30% front.

Honda claims this adds stability to the bike, and shortens braking distances.
(Since the front brake is on the right, coming off the throttle and getting on the brake takes some measurable amount of time in the case of the unexpected, or panic braking situations. )

I was just thinking about coming up with a practical solution to throw some more braking oomph in the mix, in a practical way.

And, the restrictor in the line that connects the two systems would allow the main brake (rear on the left and front on the right handle) to have more authority.

[prodigit]

In MSF course they teach you to keep your hand flat on the handlebars, and roll it down as you roll the throttle. That way you can grasp the brake at any time.
Me personally, I develop a C-shape handgrip, between the thumb and the rest of the fingers.
I roll off the throttle, while at the same time grasp the brake. I never get stuck with acceleration while braking.

It's a technique I've developed over the years, they don't teach it at MSF course, but it's not that hard to learn, takes some practice. For me it comes naturally. Done it since day one I was on an hand throttle enabled vehicle.