tire swap what rpm

Old 08-25-2008, 10:41 AM
  #1  
john910
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Default tire swap what rpm

we are running a s-10 350 sbc , turbo 350, with ford 9 inch with 4.86 gear.and hoosier 32.0 x14.5 x15. want to go to smaller and shorter hoosier 29.5 x 11.5 x15 right now at finish line we are at 6000 rpm's .any ball park idea what rmp might be now. thanks.
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Old 08-25-2008, 12:11 PM
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johnracer
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I'd say around 6400-6500rpm.....
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Old 08-29-2008, 12:44 PM
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dak697
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4.86 32"tall tire @6000 RPM
should be @ 118 mph

if the only thing that chages is RPM then these would be your #'s

4.86 29.5" tall tire at 118 mph
should be just over 6550 RPM
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Old 11-05-2008, 04:59 PM
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russ67chevelle
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my math @ 118 mph would be a tick below 6500.so id split diffrence and say right on at 6500,good luck
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Old 11-05-2008, 05:49 PM
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fla1976
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According to my spreadsheet, the RPM will be 6505 @ 117.83 mph.
But, the only sure way to know is ,DO IT.
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Old 11-05-2008, 07:21 PM
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russ67chevelle
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MPH X 336(WHICH IS THE CONSTANT) X REAR GEAR RATIO / TIRE DIA.


THIS FORMULA WILL WORK NO MATTER WHAT MPH YOU PUT IN.BUT THIS FORMULA IS WITH A TIGHT CONVERTER.A REAL LOOSE CONVERTER WILL OBVIOUSLY BE MORE RPM.
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Old 11-05-2008, 07:25 PM
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us7race
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Everytime I change tire size every inch is about 2-300rpm in the 1/8th.
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