View Single Post
Old 07-12-2015, 12:48 AM
Tony01's Avatar
Tony01 Tony01 is offline
Motorized Bicycle Elite Member
Join Date: Nov 2012
Location: San Jose, CA
Posts: 612
Default speed vs acceleration... not satisfied

So in my quest to get the highest speed with the simplest transmission, I've found the maximum speeds and capabilities of different types of transmissions for my 3.5hp Briggs powered Schwinn. But none of them gives me both 50mph and good acceleration.

CVT gives under 40 with awesome acceleration, MT at 8.02 gives a reliable 40+ cruise with embarrassing but bearable acceleration.

Setup: Final reduction: 44t sprocket with 12t or 15t drive.

MaxTorque 3.2" to 7" pulley half inch A-section v-belt

(12t) 8.02:1. 47mph @ 4900rpm. slow acceleration under 100% hookup at 20mph.
(15t) 6.42:1. 51mph @ 4200rpm, after half a mile. Acceleration almost non-existent, ran many red lights.

CVT comet knockoff .Listed ratios are w/o CVT. CVT goes 2.7:1 to .9:1. Then 10t to 23t, then to final reduction (triple overall reduction)

CVT will not let my engine rev past ~900rpm above spring rating, no matter what I do:

(12t, 8.43:1, 2200rpm springs) 32mph @ 3150rpm, .9:1
(12t, 8.43:1, 3300rpm springs) 37mph @ 4100rpm, 1:1
(15t, 6.75:1, 3300rpm springs) 39mph @ 4100rpm, 1.2:1 (testing incomplete, will continue in the morning)


The MT when hooked up 100% above 22mph, gives the best top speed and all-around performance. CVT pulls hard to 30+ then levels off. The Briggs power band is 3000 to 5100 from my testing. Is there any way to double the CVT rpm range? Make the MT hookup better?

I'm strongly considering selling the CVT and using the funds to construct a 2nd jackshaft and two-speed autoshift transmission. I'm happy with the MT from 25 to 45mph and could use a lower, freewheeling gear to get that 'kick'

Any easy suggestions on what to do next?
I don't always listen to Alice in Chains..... but when I do, SO DO THE NEIGHBORS
212cc 2-speed
Reply With Quote