Tire size again!
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Joined: Aug 2002
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From: Vancouver USA
Tire size again!
I have a 97 F-150 that currently has 285x75x16 tires on it. The stock size was 235x70x16. I feel as if the power is greatly reduced, and that it shifts late when climbing hills. What kind of difference can I expect if I go purchase the stock size tires?
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Joined: May 2002
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From: Chicago Area
Tire size again!
You can expect a major difference, especially if you have a high (numerically low) final drive ratio.
To tell exactly, you need each tire's "Revolutions Per Mile". You can get that at the dealer or at tirerack.com. Multiply the ratio of the oversize RPM to the stock RPM times your final drive ratio to get the effective drive ratio.
For example, if the os RPM / stock RPM is .9, then a 3.55 axle will seem like a 3.195.
MrBSS
To tell exactly, you need each tire's "Revolutions Per Mile". You can get that at the dealer or at tirerack.com. Multiply the ratio of the oversize RPM to the stock RPM times your final drive ratio to get the effective drive ratio.
For example, if the os RPM / stock RPM is .9, then a 3.55 axle will seem like a 3.195.
MrBSS
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Joined: May 2002
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From: laguna niguel usa
Tire size again!
[updated:LAST EDITED ON 19-Aug-02 AT 11:03 PM (EST)]A good compromise is either a 245/75-16, 255/70-16 or a 265/75-16. I put the 265/75-16's on my 97 F-150 4.6 2WD and noticed almost no power loss.
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jettfuel
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Apr 11, 2003 02:08 PM
