How many RPM's at 70 mph is normal

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04-10-14 | 04:54 PM

#16

cobalt91

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From: MI

Nice chart Yamae!

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04-11-14 | 04:06 AM

#17

Yamae

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From: Japan

Quote:

Originally Posted by PureDrifter

tire size?

Why do you ask that?

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04-11-14 | 04:13 AM

#18

BluesImage

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From: GA

Thanks for the chart!

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04-11-14 | 09:45 AM

#19

Legender

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Joined: May 2010

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From: TX

Now I'm really confused... yesterday I left work and pegged the cruise on 70 going home and it hit 2150 RPMs...
Today I went to Ft. Worth at 6 AM and traveled down to the toll road and hit 75 and pegged the cruise control... RPMs were at 1950... huh? How did that happen? Then about 30 minutes into the trip RPMs hit 2300 and stayed there the rest of the time and all the way back. I never touched the cruise or changed the speed and the RPMs changed on me. I don't know how/why that happened....anyone?

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04-11-14 | 09:46 AM

#20

PureDrifter

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From: California

Quote:

Originally Posted by Yamae

Why do you ask that?

Because tire size, gearing, and trans gear/overdrive are what determine RPM at speed.

If he's running very undersized tires his cruising RPM will be considerably higher. Same issue when running shorter (numerically higher) rear end gearing.