How much will this change RPM?
11-01-2010, 05:23 PM
#1
Senior Member
RACING JUNKIE
Thread Starter
Join Date: Feb 2007
Location: Michigan
Posts: 1,900
How much will this change RPM?
If I change my slicks from 33x16.5-15 to 32x16-15 how much will this change my RPM at the stripe? Right now it's 7100. Both of these tires are M/T with stiff sidewalls.
11-01-2010, 05:48 PM
#2
Senior Member
RACING JUNKIE
Join Date: Aug 2007
Posts: 1,523
I figure you'll slow about 4 mph if you stay at 7100 rpm or you'll have to raise your rpms another 222 rpm. That is using my spreadsheet. Here is a site you can try also.
http://www.golenengineservice.com/ht...rs.html#DRcalc
http://www.golenengineservice.com/ht...rs.html#DRcalc
11-02-2010, 06:09 AM
#4
Senior Member
DYNO OPERATOR
Join Date: Apr 2008
Posts: 504
75 RPM per inch of roll out change, brother
Mike, if the two tires at pressure are 3" different in circumference as the diameter implies, then there will be an additional 230 RPM at the stripe with the shorter tires. Measure the actual circumference of your old tire and the new one to verify the roll out is 3" shorter as guessed.
Bruce
Bruce
11-02-2010, 03:17 PM
#5
Senior Member
RACING JUNKIE
Thread Starter
Join Date: Feb 2007
Location: Michigan
Posts: 1,900
Re: 75 RPM per inch of roll out change, brother
Originally Posted by TopspeedLowet
Mike, if the two tires at pressure are 3" different in circumference as the diameter implies, then there will be an additional 230 RPM at the stripe with the shorter tires. Measure the actual circumference of your old tire and the new one to verify the roll out is 3" shorter as guessed.
Bruce
Bruce
I should've put in my thread that at the same mph how many more RPM's will it turn. Thanks guys.
