Actual speed with 35s

[Jarrod B]

So I have 35/12.50 17s on the truck now. Stock size was 265/75/16.


Ive been told I would be going faster and online calcs show me going slower like 6mph.

Then again its saying stock is 60 and 35s are 54mph netting 9% too slow.

Stock Tire - 265/75R16 >Search Tires Tire 1 - 35x12.50R17 >Search Tires
Section Width: 10.43 in 265 mm
Section Width: 12.51 in 318 mm

Rim Diameter: 16 in 406.4 mm
Rim Diameter: 17 in 431.8 mm

Rim Width Range: 7 - 8 in
Rim Width Range: 8.5 - 11 in

Overall Diameter: 31.64 in 803.65 mm
Overall Diameter: 34.77 in 883.15 mm

Sidewall Height: 7.82 in 198.62 mm
Sidewall Height: 8.88 in 225.55 mm

Radius: 15.82 in 401.82 mm
Radius: 17.38 in 441.45 mm

Circumference: 99.39 in 2524.5 mm
Circumference: 109.2 in 2773.6 mm

Revs per Mile: 657.3
Revs per Mile: 598.2

Actual Speed: 60 mph 100 km/h
Speedometer1: 54.6 mph 91.0 km/h

Speedometer Difference: - Speedometer Difference: 9.879% too slow
Diameter Difference: - Diameter Difference: 9.01%

[Buffalo444]

I think you're misunderstanding the information its giving you. 60 mph is how fast you are going when the speedo says just under 55. at 60 on your speedo you are going bout 65-66 mph with 35 inch tires. I hope this helps.

[Jarrod B]

sooooo then i should be expecting to be going 5mph ish faster than what the speedo says? i just wanted to know so i dont get pulled over for speeding lol

[Stroking]

I have 35's on my truck. I call it the ten percent rule. If it says im doing 30 im actually doing 33. If it says im doing 70 then im doing 77. Get it??

[Buffalo444]

Well id just expect to be going about 10% fast then what your speedo says, so 33 at 30, 44 at 40, 55 at 50, etc. If you have a tuner or programmer you aught to be able to have it adjust the speedo for your tire size my power programmer III wil adjust my tire size up to 35 inches.

lol well dang Stroking, you beat me to it.

[bauer]

Ive got 35's and that 10% rule is accurate

[Jarrod B]

that 10% makes sense. i was watching it and others around me on their speed.

thanks yall!

[Goose350]

You can fix the speedo with AE, Jarrod.

[tturbonegro]

315 75 16

Speedo says 25 I'm doing about 28...
Speedo says 65 I'm doing about 70...

[Jarrod B]

I know on the obs trucks i am allowed like 8 reprograms.


whats the limit on the sd? and if i do it, is everything on the programing, and internal sensors would be adjusted?