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Old 08-29-2011, 01:02 PM
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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?
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Old 08-29-2011, 04:51 PM
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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.
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Old 09-01-2011, 02:31 PM
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Re: Speedo Recal

Quote:
Originally Posted by rangersplash85 View Post
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.
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Old 09-01-2011, 03:26 PM
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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.
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Old 09-01-2011, 04:26 PM
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Re: Speedo Recal

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Originally Posted by H2rescue View Post
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)
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Old 09-01-2011, 05:17 PM
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Quote:
Originally Posted by JayB View Post
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.
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Old 09-09-2011, 04:55 PM
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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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