Question about speed reading with new tires

[prplprowlr]

I am wanting to get a set of 37x12.50x17 bf all terains so to keep the stock look but give me a little more tire. Does anyone know how bad this will affect the speedometer? and if so how much will i be off? Any help will be appreciated.

[timgco]

I am wanting to get a set of 37x12.50x17 bf all terains so to keep the stock look but give me a little more tire. Does anyone know how bad this will affect the speedometer? and if so how much will i be off? Any help will be appreciated.

The faster you go, the more it's off.

I thought it was around 7 mph at 75mph. just buy a Superchips programmer or Hypertech. you'll want to redo your shift points anyhow wwith the larger tires.

[f5fstop]

Also, take it for a spin with a good GPS unit, and compare. Sometimes, they are slightly off from the factory and larger tires will bring it in line.

[Captain of the Titanic]

37/35 = 1.057 = 5.7% off

Ie. At 10 miles an hour, you will be traveling 10.57
At 100 mph, you will be traveling at 105.7 mph....