larger tires ? speedo?

[EXPO]

Hi everyone , thinking of lifting my 05 expo and going from a 265/70/17 to a 285/75/17 ( 31.5x10.5 and 33.8x11.6 ) how much will this effect my speedo ? or tranny or anything? thanks for any help!!!

 

[walnuts4x4]

it should only affect the speedo minimally.... but any good quality programmer can adjust for everything... I'm gonna order an Edge programmer for mine... currently 56mph means I am doing 65mph... but thats with the 37s... i use my GPS if i need an accurate speed now lol

 

[tonydiv]

http://www.dakota-truck.net/TIRECALC/tirecalc.html

Here's a handy calculator

 

[Lane24]

This is a good one too. let's you actually see the size diffference.

http://www.miata.net/garage/tirecalc.html

 

[WHOISMOOTOO]

Its funny you mention the gps i would have never thought about it till i got one for christmas, from stock 17" to 24" at 60mph on the speedo and im doing 62mph so not too bad and no more speeding up at those radar signs to see how fast your really going now i am gps verified.

 

[nvycrmn]

yeah i use my gps as well when im on road trips cuz my speedo is off too. dont really care locally but hate gettin those speeding ticket out of state!

 

[Remo]

I just do the math...easy enough for me. You just need to know the % change in diameter.
Going from a 30" tire to a 33" tire is a 10% increase in diameter...
So, I add 10% to whatever speed I'm going.
Example: Speedometer says 60 mph, so I'm really going 66 mph.
Using the GPS works, but remember its not instantaneous if you are accelerating or decelerating and its probably not as accurate as the speedometer in the truck.

 

[tonydiv]

Also remember to add that percentage to your mileage when you figure that out too. You'll still be upset by the number, but it may keep you from complete depression.

 

[Remo]

Also remember to add that percentage to your mileage when you figure that out too. You'll still be upset by the number, but it may keep you from complete depression.

Exactly!!!