Help with ratio

I am not running the exact same set-up as you are describing, but it is very similar. I am using 26" wheels, a whizzer sheave (15" diameter) and a torque converter like this, with a 5 hp briggs and stratton engine.

I don't completely understand your description, but on my set up I am running a 4" pulley on my belt that is attached to the rear wheel. This pulley is on a jackshaft mounted to my seat post. On this same jackshaft mounted outboard of the 4" pulley is my comet-style driven clutch. My driver clutch is mounted to the engine crankshaft.

This set up seems to work well for me. I can climb some pretty steep hills without pedaling to assist and I get a top speed of around 32 mph on a straight flat. My speed numbers may be misleading, because my engine does not seem to be running at its true capacity. It seems like with this set-up and a 5hp engine that is actually putting out 5hp, the bike should be able to go up to 40. My bike is fairly heavy though, I have a battery, vintage (heavy) back rack, 2 gallon tank and a lot of metal added on for gussets and bracket braces.

Also, here is a ratio calculator that I found helpful.

Hope that helps,

Gilbert

My bike is in pieces right now, so I can't get a close-up of the area from the angle that would be most helpful, but here are a couple.

Looking at the side of the bike that the belts don't run on, you can see one of the pillow bearings that I use on the jackshaft.

I am not sure if you are still looking for pictures of a jackshaft set up, but I am getting my bike back together and I took this one. On the right is the driven comet-style clutch. Inboard of that is the pulley that has the rear drive belt on it. Next to that is one pillow block bearing, and on the other side of my bracket is another pillow block bearing. I am using a 3/4" keyed shaft to mount all these components on.

That seems like a lot of weight hanging off the end of that shaft. Have you noticed any bend starting in the shaft? Love the look of your bike!

That picture is such a close-up, its a little misleading. The distance from the outside of the bearing to the end of the shaft is 4 inches. I have not noticed any flex or bend in the shaft yet. It is a 3/4" shaft as opposed to the usual 5/8" so its pretty thick, but I will keep an eye on it.

Thanks for the compliment. You are the guy with the really nice Simplex bike right? I think you also gave us that wonderful information about simplex tires fitting a 26" bike rim. I want to buy some of those tires someday, but they are a little too expensive for now.

I have a build thread in the DIY section entitled "Roadmaster Project" that has a bunch more pictures.

Gilbert

Yeah, that's me with the simplex. Your right, those tires keep going up. Last year they were $99, now up to $135! I'm working on a simplex 3 wheel now, it's going to cost $450 just for tires and tubes.

I'll check out your build thread. Keep up the good work!

Rick