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12-02-2009
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#1 |
 
Join Date: Jul 2007
Location: Bartlett, IL
Posts: 7,169
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Speedo Gear info
formulas for calculating the correct gearing
We will do 2 scenarios.. one going from a 3.45 to 4.10 one going from a 315/35R17 to a 335/30R19 wheel Assuming the car is a 3.45 ZR-1 the Drive gear is 15t and Driven is 42t http://www.*************.net/c4/vett...Gearshtm.shtml **CF** nice speedo gear chart First the wheels: 25.7"dia (17) and 27"dia (19) figure out the difference.. 27/25.7 = 105% now (Drive New/Drive Old) * (Driven Old/Driven New) or (15/15) * (42/X) = 105% (1) * (42/1.05) = X (1) * (42/1.05) = 40 check (1) *(42/40) = 105% so for the tires change to a 42t Driven gear for the 3.45 to 4.10 3.45/4.10 = 84.14% (13/15) * (42/43) = .8666 * .976 = 84.6% to get the right gearing it will take a little work but it is not too bad
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1990 Corvette ZR-1 #1051 Watson Headers (2" Primary) - Flowmaster Cats - Borla Catback Late Model IH - Plenum Coilovers - 4.10s Custom Interior NCM Lifetime Member #978 |
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12-02-2009
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#2 |
Join Date: Aug 2008
Location: Houston 90 Red ZR-1
Posts: 2,320
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Re: Speedo Gear info
The best way would be to put that in an Excel spread sheet with all of the formulas in the background so when you change gear ratio or tire size it recalculates the outcome. Maybe when I have some more time I'll create it. Then it could be made a sticky or put in the tech section for everybody to use.
Last edited by rhipsher; 12-02-2009 at 12:47 AM. |
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12-02-2009
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#3 |
  Join Date: Mar 2006
Location: Innsbrook, Missouri
Posts: 1,727
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Re: Speedo Gear info
OH thank goodness, i was afraid to click on this post,
I was terribly afraid it was a picture of Jeff in a speedo....  I want to take this time to thank the powers that be it was not...
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12-02-2009
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#4 | |
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Join Date: Jul 2007
Location: Bartlett, IL
Posts: 7,169
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Re: Speedo Gear info
Quote:
 You would just be jealous anyway 
__________________
1990 Corvette ZR-1 #1051 Watson Headers (2" Primary) - Flowmaster Cats - Borla Catback Late Model IH - Plenum Coilovers - 4.10s Custom Interior NCM Lifetime Member #978 |
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12-02-2009
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#5 | |
 
Join Date: May 2007
Location: Peoria, AZ
Posts: 9,155
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Re: Speedo Gear info
Quote:
My eyes.... My Eyes 
__________________
GOLDCYLON - 91 ZR-1 #2014 GOLDCYLON - 90 ZR-1 #2794, 4L60e (Formerly Schrade's) GOLDCYLON - 11 CTS-V Arizona State Director  91 WHITE/BLACK #2014. 380 P&P&PCed,Ported Heads, Jeal Long tubes, Corsa Exhaust/FIKSE FM-5s /LED TLs, LED Headlights, Front Wilwood 6 piston narrowlite calipers and rear Wilwood caliper street shop mod,CNCed Coolant Pipes,TPI Cvr,Filter cover,Stainless Bolts, DRM/DOM PROM /ZFDOC mod build #102,DRLs,BMAD with stainless Debris Screen,Coplan Air Blaster, Pioneer APP Radio 4,Brey-Krause HB,Sub Bar,Fire extinguisher seat mount,DRM Coilovers,LEDs everywhere,Compass mirror (orange),V1 DIC hidden display, Homelink sun visor, Carbon Fiber top x3 and APSIS Carbon Fiber interior, APSIS CF Steering Wheel/NAPA Leather, Banski trailing arms, Guldstrand front suspension,urethane bushings from Prothane (total suspension) ZFDoc drive shaft safety loop, raptor shift light (orange),AO engineering louver front plate, Console seat cushion, 96CE seats with black custom Sheepskins, ss billet catch can,Viper remote entry/alarm,Cragar Rear Louvers,LED side louver lights, Dewitts Radiator with SPAL fans and a Woods 160 T-Stat 90 RED/BLACK #2794. 4L60e Automatic Stage V by RPM Transmission, TCI Dedicated TCM, OBX Stainless Headers, Corsa Exhaust, SAN Secondaries and Haibeck PROM, Exotic Muscle Coil overs, LED Interior Lights, LED Tail Lights, LED Headlights, 94 Sport seats with black custom Sheepskins , Cragar rear louvers, GS Front calipers, Banski Trailing arms, APSIS Carbon Fiber steering wheel, Front and Rear Baer Eradispeeds, DRLs, Guldstrand front suspension,urethane bushings from Prothane (total suspension), Dewitt's Raditor with Dual SPAL fans and a Haibeck 170 T-Stat 11 RED/GREY CTS-V |
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12-02-2009
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#6 | |
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Join Date: May 2007
Location: Chicagoland, IL
Posts: 9,709
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Re: Speedo Gear info
Quote:
Keith, It would mean the end of civilization as we know it. |
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