Forscan adjustment for larger tires?

[BobsterD]

Can anyone tell me if a adjustment needs made in Forscan when running larger tires? Going from 225's to 235's. Want to make sure the speedo remains accurate.

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[bgn]

It can easily be made to 235/65R17 since it is a factory option. I believe it's in the body control module tab.

 

[Glen Baker LLC]

Bob,
Check out this thread. You are probably going to need FORScan.
https://www.mavericktruckclub.com/forum/threads/recalibrate-speedometer-for-larger-tires.80294/

OR
Any of the below threads that are listed at the bottom of your thread.

 

[Itsdavebr0]

225 to 235 is not a larger diameter tire. That is the tire width. Unless the tire aspect ratio is the same, but it wouldn’t change enough to necessitate changing anything with FORScan.

 

[ScottyC]

225 to 235 is not a larger diameter tire. That is the tire width. Unless the tire aspect ratio is the same, but it wouldn’t change enough to necessitate changing anything with FORScan.

According to Tire Rack looking at a Continental CrossContact LX25 tire (available in both 225-65R17 and 235-65R17 and used only to compare diameter as both are the same tire) the 225 clocks in at 28.5 inches overall diameter vs the 235 which checks in at 29 inches overall diameter.

 

[Itsdavebr0]

According to Tire Rack looking at a Continental CrossContact LX25 tire (available in both 225-65R17 and 235-65R17 and used only to compare diameter as both are the same tire) the 225 clocks in at 28.5 inches overall diameter vs the 235 which checks in at 29 inches overall diameter.

Right, wider tire but the same aspect ratio means larger diameter. OP didn’t mention an aspect ratio. Could have been 235/60-17 which is a smaller overall diameter tire.

70mph on the speedo means 71.2mph actual speed.

I noticed my speedometer is off by more than that much with the same size tire as stock, just a different brand.

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