View Full Version : Speedometer

02-28-2006, 10:08 PM
I just bought a F-350 Crew Cab.
It needs bigger tires.
How much bigger can you go without screwing up the speedometer?

Explorer guy418
02-28-2006, 10:25 PM
i think pre much every biigger tire u put on will screw it up somewut.

03-01-2006, 02:30 PM
u can get bigger just get it recalibrated after.. but ya.. id say bout 2'' is bout the tallest without noticing much of a diffrnce..
i got 38s on mine and i havent fixd it yet.. and when my speedo says 100km im doin 130km..[cheers]

03-01-2006, 11:57 PM

03-02-2006, 03:11 AM
who cares

03-02-2006, 04:27 AM
I went from stock 31's to33's on my bronco and my speedo was out by %10

03-02-2006, 08:01 AM
usually you can up size two times before it gets to far out but most of the guys that do this are loggers that the last thing on our minds....lol[cheers]

Toe Jam
03-02-2006, 12:22 PM
ya i went from stock to 33's on an f150 and i'm approxamilty 15 % off

03-02-2006, 01:41 PM
I got 35's and mines out by about 20k

03-02-2006, 03:20 PM
I got 35's and mines out by about 20k

so when you're stopped and your speedo says zero, you're actually going 20? [wako]

03-02-2006, 03:20 PM
divide the new tire size by your old tires size to figure out what percent you're out.

Old tires - 31s
New tires - 35s

35/31 = 1.13

so that means you're out by 13%, so when your speedo reads 100 you're actually going 113. or at 50 you'rd doing about 57

03-02-2006, 03:25 PM
theres a guy in vancouver

he makes the km counters for taxi's, well he used to before they went digital

he makes reduction boxed for on your tcase. If your trcase has the mechaincal speedo then yu need one of those...

if its like my truck and has a digital vss (vehicle speed sensor) then there is a spedo box somewhere in your vehicle. It has settings on it for tire sizes, gears exc...

so...call the drealshp and ask them where it is, they will make u bring it it to change it, prob cost 100 bucks...

or ask a local shop if they know...

03-02-2006, 07:13 PM
Just get big tires if u speed u got a excuse for the cops