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Smaller pulley on the SC or bigger pully Driving (archive)

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Posted by MORE on February 09, 2000 at 16:25:16:

In Reply to: Re: Change SC pulley to smaller size. Max is 9psi posted by Paul E on February 09, 2000 at 16:16:57:

In the 10 speed anology the SC is the wheel of the bike and the pedals is the car's engine. Put a BIGGER pully on the engine side (the part that TURNS the SC) and you get more boost by spinning the SC faster. IF there is a smaller pully on the SC then less belt travel is needed for the same amount of revolutions. Hence, putting a smaller pully on the part of the SC that is being driving by the Engine and it will spin faster.

Of course I AM assuming that the faster the SC spins the more boost it creates. I've never actually installed one.

: : : : :
: : : : : Not thinking about playing around with the boost anytime soon, etc., but how exactly could that be done?

: : : I could be wrong, but , intuitively, it would seem that you want to ENLARGE the pulley for higher boost. You know, larger pulley can drive belt faster creating more boost, etc, etc...Also, why do you say 9 psi is the max?? With my Vortech from Dinan, it'll accept boost levels into the low 20s...Of course, if you have a Powerdyne, then true, 9 psi is as high as you can go. Even then, you still run the risk of that damn internal Powerdyne belt disintigrating!

: : Imagine you're riding your bicycle. If you want to go faster, you shift to a SMALLER gear in the back. Same story - want torun the SC faster for more boost? Smaller pulley.

: I think that's the wrong analogy....Its the gear in FRONT in a 10 spd which is the DRIVE gear...Just like in a SC, its the DRIVE pulley we're talking about changing..In a 10 spd, with 2 gears in front which are the drive gears, and 5 in the back, to reach gears 6 - 10, you shift to the LARGER drive gear up front....From this analysis, you need to go with a LARGER drive pulley to increase the boost...

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