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-   -   Speedo Recal (http://www.jeepgarage.org/f109/speedo-recal-27793.html)

JF_Inferno 08-29-2011 01:02 PM

Speedo Recal
 
I have been running Nitto Terra Grapplers for the last 4 months. I went up to 275/65 18. Look great! I get compliments all the time...way more masculine/meaty tire. I noticed right away a more heavy feeling when accelerating and tremendous change in MPG's. Im averageing 17.5 (Evic) primarily hwy and some city and hand calculations (app) 16.6 a tank. To which I continue kicking myself for not getting the hemi.

However I have read and used an online MPG convertor that enlightened me that due to larger tires my speedometer is now off by 2.5 mph (60mph now = 62.5). So this can greatly affect my mileage and mpgs. I have called the local dealer and they can recalculate for a quoted price of $65.

I'm curious if any of you guys running larger than stock tires have had the recalcuations done and/or noticed the diffrences in MPG's?

rangersplash85 08-29-2011 04:51 PM

Re: Speedo Recal
 
I'm running JK Sahara take-offs right now. Haven't bothered with a recal. It works out to about a 3% difference so I just factor that into my speed and milage. At 20 mpg should only make about a .6 mpg difference.

JayB 09-01-2011 02:31 PM

Re: Speedo Recal
 
Quote:

Originally Posted by rangersplash85 (Post 475135)
I'm running JK Sahara take-offs right now. Haven't bothered with a recal. It works out to about a 3% difference so I just factor that into my speed and milage. At 20 mpg should only make about a .6 mpg difference.

Same here. Haven't changed any calibrations.
I still average 20mpg mixed over the last 4500 mi. :thumbsup:

H2rescue 09-01-2011 03:26 PM

I believe the dealer can only recalibrate to the smallest and largest size that came factory on it. Don't think they can do it for larger than factory tires iirc.

JayB 09-01-2011 04:26 PM

Re: Speedo Recal
 
Quote:

Originally Posted by H2rescue (Post 477117)
I believe the dealer can only recalibrate to the smallest and largest size that came factory on it. Don't think they can do it for larger than factory tires iirc.

All the wheel/tire combos on the WK2 are the same OD (or at least within a few mm)

H2rescue 09-01-2011 05:17 PM

Quote:

Originally Posted by JayB (Post 477146)
All the wheel/tire combos on the WK2 are the same OD (or at least within a few mm)

That's what I'm saying. I think dealer can only recal. those very small increments.
There was another thread somewhere where a guy had it done at the dealer. I'll try an find it, but iirc he went one size taller and one size wider than the factory and they couldn't do much for him as far as recalibrating.

Ernest 09-09-2011 04:55 PM

Re: Speedo Recal
 
Most of the larger tires people are using (up to 32" or so) have a speedo error of only 2-3 mph at 60 mph. In a 60 mph zone, running at that indicated speed, you're not likely to get a speeding ticket for those extra 2-3 mph. But if you're 10 mph over, the cops are not going to buy your story about forgetting about your new taller tires. I speak from experience. (Several experiences, actually!) So don't worry about recalibrating the speedo. Just stay at designated speeds, and figure the percentage difference in tire circumference from stock to calculate your correct average mpg.


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