How does tire size affect your RPM's?

Might as well throw these two in there.

 

One more for good luck

 

It'll be fine. Get your speedometer recalibrated so you won't claim you lost a ton of fuel mileage. Around me a lot of people still use 11R22.5 so you get better money for used tires or casings. That's a regional thing so l would check around or ask your tire shop. I know no one wants my worn out 11R24.5 casing lol

 

hey bro that doesnt sound right cuz we have 2 peterbilts from factory 1 with 11r22.5 and other lp24s both on 355 and do 70mph at 1500rpm, u truck sounds like it should have 11r22s and some one switched to lp22s with out calibrating the gauge or ecm

 

also have a t660 with 336 on lp22s from factory and does right around 70mph at 1500

 

WOW. Thats high. I turn 1500 at 77 with super singles.

 

Is it an ex Werner classic by any chance?

 

1500 at 65/70 is pretty common for tons of trucks.

 

The difference in speed is dictated by REV/MILES factor.
Tire 1 has 500 REV/MILES.
Tire 2 has only 475 REV/MILES.
Tire 2 will move the vehicle 5% faster for the same RPM.
Check on the manufacturer website and you'll see.

 

Use a GPS Navi system to read the real speed.
The bad fuel mileage could be because of the higher rev than usual.