View Full Version : Speedometer/Odometer

February 16th, 2012, 09:43
Upgrading my tires to 32 BGF KM2 with 355 gear ratio.

I understand my speedometer will be off, so would be my odometer.
Not wanting to spend $50 on speedo gear.

As far as speedometer, i can always rely on my GPS so it wasn't much of a concern.

My concern is, would it affect my Jeep performance (PCM, transmission shift point and sensors, etc) since it will be thinking im driving at a slower speed?
And with the odometer clocking in a lower mileage, would this (as far a DMV is concern) be a mandatory to have the speedo gear replaced?


February 16th, 2012, 10:03
Should have no effect whatsover in the sense you are thinking of. The only thing that should cause performance loss is the size and weight of the tires themselves. Dunno about the DMV thing... I'd say no, i know its not required in my state or any state around me

February 16th, 2012, 11:39
Are you positive it has no effect on performance?

February 16th, 2012, 16:05
It wont mess with the motor in anyway all the motor uses engine speed for is to raise the idle a pinch while it notices the vehicle in motion (at least on my ax15) But just as you'd expect the motor will be more sluggish with the bigger tires. The only bummer is you wont be able to accurately keep track of the vehicles actual mileage for maintenance and your mpg. Quaratec doesn't sell them for all that expensive http://www.quadratec.com/jeep_knowledgebase/article-46.htm

February 16th, 2012, 20:29
Thx for the link.
Looks like the cheapest i've seen.

February 16th, 2012, 21:00

Think this is where I got mine. I paid less than $50 for a new (Crown replacement) gear and O ring, shipped. Get the part number for the gear you need, and Google it.