[DeTomaso] Speed Calculation

[zumzum at cox.net]

Myron,
1000 RPM / 2.98 GR X 80.0' CIR / 1096 = 24.49 mph @ 1000.
Jeff

---- Myron Zadony <MZadony at fleetresponse.com> wrote:
> Hi Jeff,  It all sounds good.  Which gear ratio are you using?  The final Drive is 4.22:1 & the 5th gear is 0.705:1 (US L).  My tire is 80" in circumference.  I don't come out wih anything that looks like MPH.  Myron.       From: zumzum at cox.net [zumzum at cox.net]
Sent: Saturday, July 10, 2010 5:12 PM
To: PANTERA GROUP (detomaso at realbig.com); Myron Zadony
Subject: Re: [DeTomaso] Speed Calculation


Myron,
Back in 1971 at high school, I came up with a formula that works the best for speed calculations based on rpm.
RPM divided by OVERALL GEAR RATIO times Tire Circumference divided by 1096 will equal miles per hour at 1000. rpm. ALWAYS!!!! VERY ACCURATE.
Now of course gear ratio is the combination of the trans gear and rear end.
This I believe is the best formula ever. Never found one better.
If you do not know your tire cir then use the Tire Rack charts. I hope this helps you.
Or either haul ass and have fun regardless of your speed.
Jeff Cobb
Mangusta 1196
___________________________________________________________________

---- Myron Zadony <MZadony at fleetresponse.com> wrote:
> I have my speedometer removed & sent out to Palo Alto Speedometer for repair. I am going on a short trip of about 130mi all Interstate highways I need to know what RPM will equal to the MPH. I have a 1974 L pretty much stock. Rear tires are: Pirelli P7 285/50 VR 15. I need to know what 60MPH is, 65MPH is in RPM's ?? Any help would be appriciated. Thanks, Myron (the other guy in Cleveland) #6928 74 L.


--
Jeff Cobb