We wanted to enter our turbo CBR929 bike in a 200mph shootout. Basically
take the bike out to a deserted airplane landing strip, twist the throttle
and hold on in top gear and see if you can break 200mph. Why not, right?
Well, stock the CBR wusses out at 175mph our so, we checked. Well, not
good enough. A while ago Performance Bikes did an article on thrust,
and we like what they did, so here is our spin on thrust.
Basically,
as you go faster, wind resistance is a really, really big deal, especially
on bikes. We need something called thrust to overcome this annoying
problem. Thrust is drive wheel torque divided by rolling radius - basically
it's how much torque you put to the road. We can get drive wheel torque
from our dyno torque chart. We can get rolling radius in feet by measuring
the diameter of our drive tire and multiplying it by Pi (3.14 "ish"),
or just mark the tire, roll it 1 revolution and measure the distance
it rolled.
We used
this info, along with our dyno results of a stock CBR, it's gear ratio,
drive ratio, and wheel diameter to make the following chart.
The thrust required is the thrust we need to overcome
wind resistance, and you can calc it using your top mph and all the
gear ratio stuff. We can see the stock bike with stock gearing tops
out where the thrust required is larger than the thrust available in
6th gear, about 175mph. Now do the obvious thing, turbo the bike to
get more power!
What happened?
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1039
riverside street suite10 
