Theoretical Blaster Top Speed

darederek

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May 31, 2010
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keep in mind that this is without wind resistance, friction, weight etc. just how much the wheels spin and how far you would get. here we go

okay so we say 8500 rpm. the primary reduction of the blaster is 3.227. so with the crank spinning 8500 rpm, the clutch output will be spinning 2634.03 rpm

next we will do what 6th gear affects. the 6th gear ratio is 0.905. so with the clutch output spinning 2634.03 rpm the output to the front sprocket will be spinning 2910.53 rpm.

now the secondary reduction ratio with 14/40 gearing will be 2.86 so with the front sprocket spinning 2910.53 rpm the rear will be spinning 1017.67 rpm

now with 20 inch tires each revolution will move you 62.83 inches so at 1017.67 rpm you will be moving 63940.21 inches per minute. or 60.55 mph

thanks to Paulie B for finding my error the first time i did this I:I
 
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Nice job man, here's a link that I found that makes calculating this all out really easy.

Converter

Just gotta know a few things.
Engine RPM's:
Primary reduction: The blaster is 3.227
Transmission gear ratio:
Front and rear sprocket sizes:
Tire height:

Here are the transmission ratio's you can find the top (Theoretical) speed in any gear.
6th gear 0.905
5th gear 1.056
4th gear 1.25
3rd gear 1.667
2nd gear 2.214
1st gear 3.091
 
nice work im not the greatest when it comes to math (there goes my future in porting even though i never had one) so how did/would you go about taking the over rev from the fmf into acount ???
 
you would have to know what rpm to plug in at the beginning. looking at a comparison dyno sheet this is right around the peak of any left bend pipes
 
you would have to know what rpm to plug in at the beginning. looking at a comparison dyno sheet this is right around the peak of any left bend pipes

thats about what i was thinking to take it into acount fmf doesnt produce much over rev might be a 1-3 mph differnce but hey that could be win or loose when bringing down some ol 4 poker :D
 
I know that one of my kids blasters ran 51.2mph on the dyno in 5th gear with a 14t & 40t sprockets in (i believe) 5th gear, now add in wind resistance weight of rider and all the other factors and i am sure it will be a little less than 50mph.
 
i topped out @ 56 with 14/40 recently. last month i THOUGHT it put it out 64 on my GPS but satellites wasnt reading correctly after realizing this a week later. i was souped thinking i toped 64 lol