For everyone that has changed tire sizes on their FiST: did you just learn to live with the speedometer being off? I've switched to a 205/50R16, changed the rolling diameter with FORScan to the largest option, and my speedometer is still slow by about 2.6%. I know that doesn't sound like much, but it's driving me insane. I tried changing the actual "tire size" option in FORScan as well to no avail. To be honest, the speedometer I can live with, but the odometer bothers me more. I tried to make a HEX edit to the rolling diameter line in the IPC ASBUILT data, and ended up bricking my IPC and had to jump power to it to flash it again.
I feel like making the change in FORScan didn't do anything because my speedometer is off by basically the exact same amount as my tires are larger than the factory 205/40R17.
The Fusion and F-150 forums have TONS of FORScan related info, but the Fiesta seems to be programmed differently than them. They are able to edit a line in the BCM to any arbitrary number to edit their rolling diameter.
Thanks for any insight anyone may have.
I feel like making the change in FORScan didn't do anything because my speedometer is off by basically the exact same amount as my tires are larger than the factory 205/40R17.
The Fusion and F-150 forums have TONS of FORScan related info, but the Fiesta seems to be programmed differently than them. They are able to edit a line in the BCM to any arbitrary number to edit their rolling diameter.
Thanks for any insight anyone may have.