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[Dan_Lockwood]

I have a question about braking force, kind of mathematical too.

I've seen customs with right hand drives that have mounted a brake rotor on the trans output shaft and run sans brake on the rear wheel.

In my case I may be using a 90 degree gearbox with a 2.75:1 ratio to drive a rear single wheel similar to a touring bike, but my rear belt/chain ratio will be 1.2:1.  Not your normal 3:1+ we use today.

So I'm looking at using a Honda GL1800 final drive (2.75:1) and mounting my rear drive sprocket on the wheel studs of the final drive.  From there back to a touring 5.5"x16" wheel with an auto tire, 185/55-16R.

I can mount a rear brake from the touring bike, but I thought it would be kind of cool to use the Honda rotor and caliper as its already setup.  I can also add a mechanical Wilwood park brake caliper just in front of the caliper already there.

My question is this, what affect does the 1.2:1 final belt ratio do to the braking force is I brake on the drive sprocket instead of the rear wheel.

My thought is that it would be 20% less effective doing it this way than rear wheel mounted.  This is okay as I need to have a lot less rear wheel braking than the front, so this may end up being a self imposed proportioning (bias) valve.

Here's a GL1800 final drive.  I would use the front four bolts to do the mounting and then just cantilever the gearbox off the rear of the 1" thick mounting plate.  It's plenty strong enough as the four bolts hold the entire rear weight of the GL1800.  You can see the lug bolts sticking out.  I would machine my drive sprocket to center on the hub and then be retained by the bolts.



Here's a complete rear swingarm from a ne GL1800 with rotor and caliper installed.  You can see from the rotor cross hatch that this has just the setup miles before they stripped it down to do a trike conversion.  So really, brand new.



This what Morgan Motor Co. does for their reverse trike powered by an S&S 2L Wedge motor.  They run through a Miata trans, which is what I would do as well.





I just thought if I used the GL1800 final drive complete with the brake setup, it would be kind of cool as well as it does reduce the weight of the rear wheel.  If you haven't ever picked up a touring rear wheel and tire, you should try it sometime.  These things are very heavy, so keeping it a bit lighter would not be a bad thing.

I know there are lots of guys here that do ground up builds for things other than bikes, so this may be of interest too.

Teaser...





Thanks and have a great week.

[Dan_Lockwood]

So with all the gearheads here, nobody has an opinion on whether the front mounted brake on the drive sprocket versus the brake mounted to the rear wheel, will provide less or more braking force?

The other down side would be that I would be applying all of my braking force through the belt/chain rather than on the actual drive wheel touching the ground.  But we down shift all the time and can skid the rear tire with the engine braking force, so it may not be a problem at all.

Any thoughts out there guys?