Plus sized Speedometer Adjustment

[Greek6486]

Hi all,

Anyone had to adjust your speedometer to after getting larger diameter tires? I'm about to be running 285/35/20 fronts and 315/35/20 rears. My tuner said that they aren't able to adjust the 2016 speedometer threw the tune and said I have to use some program called Forscan. Anyone dealt with this?

Thanks!

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[Greek6486]

Nobody knows anything about this? lol.... Does everyone just not care about the speedo?

 

[msweet]

Look at the "asbuilt" thread in DIY.

I'm running 315/35r20 and did adjust it through Forscan, but it messed something else up. It was almost like a limiter at certain revs in different gears. I went through everything that I had adjusted and found that one line change to be the issue, YMMV.

Suffice to say I changed it back and now just drive a few ks under the speed limit past speed cameras etc

 

[stang1971]

I am on a 315/35/20 in rear and changed mine with Forscan an d its almost perfect. I have no side effects and the car pulls hard in every gear.

 

[ahl395]

You can also use a Whipple Flare Tool to correct the speedometer

 

[webelevy]

You can also use the ScT X4 to adjust revolutions per mile for your rim/tire choice based on actual rollout.

http://www.ntwonline.com/Revolutions-Per-Mile-Chart.aspx

 

[SR56]

You can also use the ScT X4 to adjust revolutions per mile for your rim/tire choice based on actual rollout.

http://www.ntwonline.com/Revolutions-Per-Mile-Chart.aspx

I tried the SCTX4 and it didn't seem to do anything. Still off 2-3 MPH speedo being faster.

 

[dgc333]

The Ford ProCal software allows you to make adjustments for gears/tire size.

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