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Re: Gearing, again

To: autox-cm@autox.team.net
Subject: Re: Gearing, again
From: "John A. Carriere" <jacircts@mich.com>
Date: Sun, 20 Jul 2003 23:04:50 -0400
I agree with Kirk.  Lower toothed pinions reduced the loads in the layshaft
and gears, but at the expense of the higher loads at the driveshafts.  The
drive shafts are stronger than the integral layshaft, so that is a good
trade off.  Gordy McIndoe runs an 8:31 in his Formula Atlantic also for
that reason.

With the S2000, we ran an 8:31 R&P and ran a 14:36 integral layshaft first
gear.  We did not want to go lower than 14:36 because the effective
diameter (at the inside of the teeth) of the shaft of the 12:38 first gear
was smaller that the rest of the shaft.

As our redline was 7600, the gear ratios are not as important as the speeds
at the redline.  We ran 49,62,73,86 and never hit the limiter in 4th for
the 2 years we ran that car.

Hope that Craig Henry gets the car running soon.  It would be fun to see it
again.

John

At 07:50 PM 7/16/03 -0400, you wrote:
>Hi Mark
>You know me, I dump the clutch and accelerate hard coming off the line, 
>usually not using the clutch going up or down. Hell, I even have been 
>known to miss a shift or two. When I built my car in 1991 I chose a 
>7:31 ring and pinion not only for the low end grunt but also because it 
>would allow me to use beefier gears. Graig Taylor did blueprint my 
>Hewland though. In 12 years I have never broken or chipped a gear.
>Get some one to buy my car and I will buy Tommy's. Best of both 
>worlds... I get a new car and you guys get a slow driver for Tommy's 
>car.
>I will be co-driving Norm Beaver's Lotus Super 7 in D/M this year at 
>Nationals but will be there to watch C/M run for sure.
>
>Kurt Eikenberg
>C/M88


JACircuits Autocross Timing Systems 
    http://www.mich.com/~jacircts
- Timing the SCCA Solo II Nationals since 1985
                                ***********

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