Bigger tyres and your speedometer

RonH · Post by **RonH** » Tue Nov 06, 2007 8:49 am

Hi,

If you fit bigger tyres your speedometer will be out of sync. you can by a Speedometer Calibrator to fix that
My Jk is getting 33 inch tyres (1 inch more then stock)
Does anyone ever used these things and maybe we all buy our own we might share one?

any suggestions?

Cheers
Ron

khaiwi · Post by **khaiwi** » Tue Nov 06, 2007 9:09 am

It used to be a small gear fixed on the T-case for all TJ models, however changing the R&P ratio would also be another fix hehehehe, kiddin aside, upgrading stock wrangler to 4.56R&P and 33"tires will bring you back to almost factory odo meter reading.

Jeep after market parts include a list of gears to correct odo reading after tire size change.

I am not sure if the new model is still manual or electronic where it can be calibrated.....

mike0967 · Post by **mike0967** » Tue Nov 06, 2007 9:11 am

Hi RonH, think that speedometers are never that accurate, at least they always show a descrepancy of 2-3 km/h compared to my GPS reading. Actually I do not know which one is the correct reading, but I noticed a difference when I put the bigger tyres on which was about 3 km/h. Maybe you just crosscheck with your GPS first if you feel a big difference ?

khaiwi · Post by **khaiwi** » Tue Nov 06, 2007 9:21 am

Mike, always trust the GPS.... the odometers are meant to show a bit to the higher side for several reasons.

abdalla · Post by **abdalla** » Tue Nov 06, 2007 2:08 pm

I dont really think 1 inch will make any difference, plus the JK is not mechanical like the TJ, it has some electronic device ... & not cheap costs like Dhs 1000 ... but if your interested check ME4WD.com they sell them.

mike0967 · Post by **mike0967** » Tue Nov 06, 2007 2:13 pm

Khaiwi wrote:Mike, always trust the GPS.... the odometers are meant to show a bit to the higher side for several reasons.

Yes Chief, I rather trust the GPS, clear, the difference between GPS and Odometer is now about 3 km/h and before the bigger tyre it was about 5 km/h, so when the ODO is on 120, the GPS says 117 only.

Bradley · Post by **Bradley** » Tue Nov 06, 2007 8:16 pm

mike0967 wrote:
Khaiwi wrote:Mike, always trust the GPS.... the odometers are meant to show a bit to the higher side for several reasons.
Yes Chief, I rather trust the GPS, clear, the difference between GPS and Odometer is now about 3 km/h and before the bigger tyre it was about 5 km/h, so when the ODO is on 120, the GPS says 117 only.

:iagree:

Miro · Post by **Miro** » Tue Nov 06, 2007 10:48 pm

Hey RonH
They have the speed calibarator through the agency, Expensive I guess, After fittin my 32s i have a diff of around 8 to 10 km.h.. GPS is amazing though rather than the headache

RonH · Post by **RonH** » Wed Nov 07, 2007 1:51 pm

Hi,

The speedo computer thingy costs 1250 Dhm at me4x4.

http://www.me4wd.com/store/index.php?ac ... a4129688b7

If there are more JK owners in this group we could share?

Let ne know