Exact MM for Squatch speedo 2mph fix?

[Laminar]

For some reason this whole speedo recal thing doesn't feel like an exact science, which is weird because it should be.

The trick is that tires aren't actually round, and the diameter of a tire changes with air pressure, temperature, and speed.

Sponsored

 

[WuNgUn]

Edit: my bad... I was looking for the relearn option in "service procedures".... I had to go back to the modules page and run the relearn there

 

[zuke]

For some reason this whole speedo recal thing doesn't feel like an exact science, which is weird because it should be.

On factory 285s my speedo read 60 and I'd be going 58. Now on 315s I'm going 61 when it says 60. I chose to leave the factory number alone, which was 2525. That sounds waaay too low based on all these calcs that show 26xx or even 27xx.

It's FM (Freak'n Magic) Cause tire manufacturers lie.... the only way to get the Real number is to measure the tire yourself.... measure from the center of the rim to the ground to get the real rolling radius of the tire, Then radius times 2 for diameter, then diameter times Pi for circumference... That number can be changed by ambient temperature and tire pressure, as well as tire wear on aggressive mud terrains.

Measurement is the only way to be sure...

 

[WuNgUn]

There is no reason to measure anything.
If you swap out your 31's for 37's, take your truck for a drive and note the difference in speed compared to GPS...
If the difference is 12% for example, simple change whatever number is in the BCM by 12%
Rock and roll!

 

[zuke]

There is no reason to measure anything.
If you swap out your 31's for 37's, take your truck for a drive and note the difference in speed compared to GPS...
If the difference is 12% for example, simple change whatever number is in the BCM by 12%
Rock and roll!

^^^^^^^^^
Truth!

I was just explaining the science for @Tricky Dick so he doesn't have to go on believing it's magic

Sponsored