# Top Speed of Belt Drive Chinese 4 Strokes

Something like this???...lol...DAMIEN

I'm think that's why the newer Huashengs are limited to 6800 rpm.... they SAY it's for engine longevity, but I think it's to keep the Delorean Effect from surprising hapless motor-bicyclists.

I'm think that's why the newer Huashengs are limited to 6800 rpm.... they SAY it's for engine longevity, but I think it's to keep the Delorean Effect from surprising hapless motor-bicyclists.
It'll go beyond 6800 rpm. The 6800 rpm is where max horse power is at.

It'll go beyond 6800 rpm. The 6800 rpm is where max horse power is at.
An the time dilation starts to kick in at 6900 Rpm. Once you hit 7500, it really starts showing. At 10k you're traveling in time.

DT did you know that GPS speed can be off on the high side by 4-5mph?
Don't believe you're getting 32mph with this setup. With 9t drive sprocket
and 36T rear sprocket, and 5:1 gear box, your max speed at 6800 rpm is: 26.2 mph.
6800 divided by 5x4 x 6.78 x 60 all divided by 5280= 26.2
With a 10T drive sprocket, it would go to about 29mph.

DT did you know that GPS speed can be off on the high side by 4-5mph?
Don't believe you're getting 32mph with this setup. With 9t drive sprocket
and 36T rear sprocket, and 5:1 gear box, your max speed at 6800 rpm is: 26.2 mph.
6800 divided by 5x4 x 6.78 x 60 all divided by 5280= 26.2
With a 10T drive sprocket, it would go to about 29mph.
Yeah I figure it might be off some, I used my phone GPS & typically its can be off 1-3mph in either direction. With my friends side by side riding next to me, top speed on my bike by his speedo was 31mph. Its definitely low geared, & can climb trees. I personally need to get the 80tooth & 90tooth pulleys & do some testing, I think the 90tooth might be perfect.

Yeah I figure it might be off some, I used my phone GPS & typically its can be off 1-3mph in either direction. With my friends side by side riding next to me, top speed on my bike by his speedo was 31mph. Its definitely low geared, & can climb trees. I personally need to get the 80tooth & 90tooth pulleys & do some testing, I think the 90tooth might be perfect.
Also depends on your gps system. Some of them are quite accurate, if you are willing to spend more than a few bucks.

Also depends on your gps system. Some of them are quite accurate, if you are willing to spend more than a few bucks.
I think I'm going to order another grubee engine & tranny, & a shift from them as well. I decided to shift kit my micargi rover, since it is so low geared. Might not be as reliable, with shift kit but idk, cause I've never had 1 or been around them.

Fabulous. Buy the 4:1 belt drive, and if you use 10T drive sprocket and
a 41T wheel sprocket you hit a sweet spot at 32mph. And the belt
drive will have bearings!!!

DT did you know that GPS speed can be off on the high side by 4-5mph?
Don't believe you're getting 32mph with this setup. With 9t drive sprocket
and 36T rear sprocket, and 5:1 gear box, your max speed at 6800 rpm is: 26.2 mph.
6800 divided by 5x4 x 6.78 x 60 all divided by 5280= 26.2
With a 10T drive sprocket, it would go to about 29mph.
Assuming 26" tires are being used.

Sidewinder Jerry's mph speed formula

(RPM x Wheel Diameter x π)÷(1056 × Total Reduction)=MPH

(6,800×26×π)÷(1,056×(5×(36÷9)))=26.2989385016

(6,800×26×π)÷(1,056×(5×(36÷10)))=29.2210427796

To be a bit more accurate use the tires circumference. Its easy to do with the roll method of making a mark on the tire and floor rolling one revolution making a second mark and measuring the distance. Tires of the same size will vary.

Replies
33
Views
2K
Replies
6
Views
1K
D
Replies
19
Views
4K
Mike St
M
D
Replies
13
Views
2K
Replies
7
Views
1K