debating gear ratios

fifty-two_f1 · 2011-02-07 05:07:55

Engine RPM Calculator (http://www.csgnetwork.com/multirpmcalc.html)

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Feb 10, 2011 | 07:35 AM

#16

fifty-two_f1

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Fleet Mechanic

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From: Jamestown, IN

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Feb 10, 2011 | 08:10 AM

#17

ALBUQ F-1

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From: NM

Quote:

Originally Posted by hellfirejim

For those with a rpm calculator, what rpm would I be at 70 mph if I have 28 inch tall tires and a 3:23 rear gear?

Hmmm maybe that should be 65 as that is the speed limit......

thanks
jim

It's the speed limit up there, but the interstates here have speed limit of 75 and no one goes less than 80. No way I want to ply with semis at those speeds in a 60-yr-old truck! 55 is plenty for me.

Feb 10, 2011 | 08:47 AM

#18

hellfirejim

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From: 50 miles west of Chicago

The advantage of being a darksider is my modern suspension can keep with traffic on the highway....

Anybody get an rpm number from above??

jim

Feb 11, 2011 | 08:51 PM

#19

fifty-two_f1

Thread Starter

Fleet Mechanic

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From: Jamestown, IN

Have not bought the axle yet, but it is sounding better. I called the guy for some rough measurements and he said from perch to perch 38.5inches. It is around 54 inches from backing plate to backing plate and he said it was around 59 inches with the drums and all.

Feb 13, 2011 | 08:30 AM

#20

48 Steel

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From: Colorado Springs /Mesa AZ

I need the final gear ratio in the tranny that you are using. Then I can give you the RPM's you are looking for.

________________________________
46 Ford Tudor - Street Rod
48 Ford F1 - Custom (darkside)

Feb 13, 2011 | 08:44 AM

#21

hellfirejim

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From: 50 miles west of Chicago

Sorry it is a turbo 350 so the final gear is 1 : 1. If it is not an issue can you also tell me about a 29 tire? I don't suspect it will be more than a couple hundred rpm.

thanks

jim

Feb 13, 2011 | 08:52 AM

#22

48 Steel

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Joined: Oct 2006

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From: Colorado Springs /Mesa AZ

Here is some Info.

Tires = 28 "
MPH = 65
Diff gears= 3.23
Tranny gear = 1/1
RPM = 2,519

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Feb 13, 2011 | 08:58 AM

#23

hellfirejim

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From: 50 miles west of Chicago

Thank you as that is about perfect for cruising. If I get the 29 tall tire I should be about 2,200 rpm my guess. Still in the range, right where the motor makes its torque.

Thank you.