speedometer reading

[TheJimmy]

I was adjusting my tune for the new tires i bought 305/40/18 and the tire size calculator told me it was 730.9 revs per mile but I had to put that in the tuner in incriments of 5 so how far off will the reading be and in which direction if i put 730?

 

[Wicked GT]

You won't notice a difference using 730 versus 731. I would imagine it would only be a tenth of a mile an hour at most.

 

[TheJimmy]

OK just making sure i didnt want to get pulled over thinking i am being good and be speeding

 

[michael.konor]

As an FYI for future adjustments, I found the best way to set your RPM's is to use a GPS. It'll give you your exact speed, so it's just a matter of roughing in the first setting, and then adjusting the setup in your tuner until both the speedo and GPS match.

 

[TheJimmy]

i have found a tire size calculator online that i use i do not have a GPS so i cant do that but thanks for the idea

 

[stkjock]

Simple math?


1 rev/mile off?
1/730=.001

.001 =.1%

At 65 that's .065 mph

 

[Digital_Synapse]

^this