I calculated my gearing to speed

biknut

biknut

Well-Known Member
I think this is what it works out to but I really have no idea if this is possible. 7000 rpm??? I saw 33 mph today.

20....crank gear
82....clutch gear

10....counter shaft sprocket
40T.... rear wheel sprocket

The Atomic BB
26x2.125 tire 81.8" circumference


RPM MPH

1000 4.7
1200 5.7
1400 6.6
1600 7.6
1800 8.5
2000 9.4
2200 10.4
2400 11.3
2600 12.3
2800 13.2
3000 14.2
3200 15.1
3400 16.1
3600 17.0
3800 17.9
4000 18.9
4200 19.8
4400 20.8
4600 21.7
4800 22.7
5000 23.6
5200 24.6
5400 25.5
5600 26.5
5800 27.4
6000 28.3
6200 29.3
6400 30.2
6600 31.2
6800 32.1
7000 33.1



Cadillac AV Sport
36T sprocket
26x1.95 tire 80.25" circumference


RPM MPH
1000 5.2
1200 6.2
1400 7.2
1600 8.3
1800 9.3
2000 10.3
2200 11.4
2400 12.4
2600 13.4
2800 14.5
3000 15.5
3200 16.5
3400 17.6
3600 18.6
3800 19.6
4000 20.7
4200 21.7
4400 22.7
4600 23.8
4800 24.8
5000 25.8
5200 26.9
5400 27.9
5600 28.9
5800 30.0
6000 31.0
6200 32.0
6400 33.1
6600 34.1
6800 35.1
7000 36.2


Stunner
36T sprocket
24x3 tire 76.625 circumference
The overall ratio is 14.76


RPM MPH
1000 4.9
1200 5.9
1400 6.9
1600 7.8
1800 8.8
2000 9.8
2200 10.8
2400 11.8
2600 12.7
2800 13.7
3000 14.7
3200 15.7
3400 16.7
3600 17.6
3800 18.6
4000 19.6
4200 20.6
4400 21.6
4600 22.6
4800 23.5
5000 24.5
5200 25.5
5400 26.5
5600 27.5
5800 28.4
6000 29.4
6200 30.4
6400 31.4
6600 32.4
6800 33.3
7000 34.3
 
Last edited:
biknut said:
I think this is what it works out to but I really have no idea if this is possible. 7000 rpm??? I saw 33 mph today.

20....crank gear
82....clutch gear

10....counter shaft sprocket
40....rear drive sprocket

rear wheel circumference
81.8"

RPM
1000 4.7
1200 5.7
1400 6.6
1600 7.6
1800 8.5
2000 9.4
2200 10.4
2400 11.3
2600 12.3
2800 13.2
3000 14.2
3200 15.1
3400 16.1
3600 17.0
3800 17.9
4000 18.9
4200 19.8
4400 20.8
4600 21.7
4800 22.7
5000 23.6
5200 24.6
5400 25.5
5600 26.5
5800 27.4
6000 28.3
6200 29.3
6400 30.2
6600 31.2
6800 32.1
7000 33.1
Click to expand...

4.1........Primary drive ratio
4..........Final drive ratio
16.4.....Overall drive ratio
 
Iv heard 6000 is typicaly the max for bearing based wristpin engines and 8000 for bushing based. Though I have no idea why bearings are slower then bushings.
 
Black_Moons said:
Iv heard 6000 is typicaly the max for bearing based wristpin engines and 8000 for bushing based. Though I have no idea why bearings are slower then bushings.
Click to expand...

I can live with 6000 rpm. That's 28 mph and that's really fast enough for my little puppy.
 
biknut said:
I think they're low rpm.
Click to expand...


That has no meaning...... And makes no since. I have over revved there lawn mowers think modified goverer. They lasted years and years. There just good motors.. If you rev the day lights out of any motor its not all that good for them.

The old bushed China two smokes were practically invincible. Now they have a badly designed roller bearing that can and will give if over revved.
 
Norman and I have some B&S that turn 5 to 7 grand. I've seen guys turn them 10. It's pretty intense when the rod turns loose...........:D
 
Ilikeabikea said:
Norman and I have some B&S that turn 5 to 7 grand. I've seen guys turn them 10. It's pretty intense when the rod turns loose...........:D
Click to expand...


That sums it up right:D I have made the rod come loose!rotfl Tucumpseh engines always blew up before a Briggs with me. Throwing a rod that is..

Now I believe both motors are made in the same factory now..
 
Black_Moons said:
Iv heard 6000 is typicaly the max for bearing based wristpin engines and 8000 for bushing based. Though I have no idea why bearings are slower then bushings.
Click to expand...

It's not the bearing...It's the hammer!

A correctly honed bronze bushing offers more surface area during the "hammer" of compression/ignition.

Jim
 
biknut said:
I think this is what it works out to but I really have no idea if this is possible. 7000 rpm??? I saw 33 mph today.

20....crank gear
82....clutch gear

10....counter shaft sprocket
40....rear drive sprocket

The Atomic BB
26x2.125 tire

rear wheel circumference
81.8"

RPM
1000 4.7
1200 5.7
1400 6.6
1600 7.6
1800 8.5
2000 9.4
2200 10.4
2400 11.3
2600 12.3
2800 13.2
3000 14.2
3200 15.1
3400 16.1
3600 17.0
3800 17.9
4000 18.9
4200 19.8
4400 20.8
4600 21.7
4800 22.7
5000 23.6
5200 24.6
5400 25.5
5600 26.5
5800 27.4
6000 28.3
6200 29.3
6400 30.2
6600 31.2
6800 32.1
7000 33.1
Click to expand...

Cadillac AV Sport
36T sprocket
26x1.95 tire

rear wheel circumference
80.25"

RPM 1
1000 5.2
1200 6.2
1400 7.2
1600 8.3
1800 9.3
2000 10.3
2200 11.4
2400 12.4
2600 13.4
2800 14.5
3000 15.5
3200 16.5
3400 17.6
3600 18.6
3800 19.6
4000 20.7
4200 21.7
4400 22.7
4600 23.8
4800 24.8
5000 25.8
5200 26.9
5400 27.9
5600 28.9
5800 30.0
6000 31.0
6200 32.0
6400 33.1
6600 34.1
6800 35.1
7000 36.2
 
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