Questions regarding mph & mpg with 15" wheels

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#11

06-22-2009 | 11:39 AM

RamSport97

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From: Crystal River, FL

Quote:

Originally Posted by olyelr

Its actually pretty simple. Once you get the percentage that new tires are bigger, then you just multiply that into the overall mileage of the tank of gas.

If the odometer shows you traveled 245 miles and the new tires are 12% larger, than it would really be 274.4 miles.

Well that is pretty simple!

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#12

06-22-2009 | 11:15 PM

olyelr

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From: Elk Rapids, MI

Quote:

Originally Posted by Magnumpwr16

haha i know man i completely agree, but the inside door jam of the truck says "225" for stock tires, and believe me, they were the wimpiest things i had ever seen! My last ram had 265's, much better looking. Thanks for the info!

And as far as a recalibration that someone else had mentioned in the thread, how much would that be and what's involved? I didn't know that could be done, sounds like that would fix everything, the mph, mpg, etc.

I think all the door jams say that, mine does and it came with 265's when I bought it new.

As far as re-calibrating your speedo, it can surely be done, but its not as simple as plugging in a tuner and pushing buttons. Since your truck is a 97, I believe you have to change the small sprocket(s) for the speedo, which I am not even sure where they are located, nor where to get the proper size replacement. Someone smart will chime in.

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#13

06-23-2009 | 03:33 PM

Magnumpwr16

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From: Rockland County, NY

yeah for right now i can just calculate the mpg's with the percent correction, which i have looked up and found the adjustment to be 8.6%. As far as mph and true odometer readings though id really like to correct that sometime in the future. I went to my local dodge dealership this morning and asked if the speedo can be recalibrated for bigger tires and they said it "Can't be done." so anybody have any other ideas? I really dont wanna do a superchips or anything like that.

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#14

06-23-2009 | 11:30 PM

dodgeram07

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From: ohio

http://www.jcwhitney.com/JET-PERFORM...0221_10614.jcw

i wonder if that works ,,,, but hell 160:0 for that get a used tuner

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#15

06-23-2009 | 11:59 PM

olyelr

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From: Elk Rapids, MI

If I'm not mistaken, a tuner will do nothing for changing your speedo with a 97 or older Ram. You need to change the size of the sprocket.

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#16

06-24-2009 | 12:14 AM

Miami_Son

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From: Los Angeles, CA

The door sticker refers to the tire size on a base model 2X4 truck. Get your build sheet and you'll know what size tires actually came with your truck new and what it was calibrated for.

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