odometer readings and 285's

moloss · December 11, 2005

ok switched from the 245/75/16 to 285/75/16.....first time towing my baby jeep I got 7.5 mpg ....didn't seem right so I thought that if going from 245's to 285's meant when the speedo reads 60mph that I'm really going 64.7mph....does that mean if I take 60 into 64.7 and get 1.08.....that I can mulitply the 1.08 by 7.5 to get my actual mpg? I hope my math is wrong and my mpg is better than that! one cheesy pic to go with question.....

redvett · December 11, 2005

ok switched from the 245/75/16 to 285/75/16.....first time towing my baby jeep I got 7.5 mpg ....didn't seem right so I thought that if going from 245's to 285's meant when the speedo reads 60mph that I'm really going 64.7mph....does that mean if I take 60 into 64.7 and get 1.08.....that I can mulitply the 1.08 by 7.5 to get my actual mpg? I hope my math is wrong and my mpg is better than that! one cheesy pic to go with question.....

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You need to get a tune or have someone recalibrate for the tire size. You need to recalibrate because your PCM,ABS,SDM are getting the wrong information. The result your fuel economy, performance,antilock & airbags are compromised. Along with your speedo being off. That in it self is a Federal offense.

moloss · December 11, 2005

I looked into a tune about a month ago but could not get any real information about what's the best to go with....everybody voted for the tune they bought but as far as non biased info I couldn't find any....there must be one out there that is the best overall value.....I don't mind paying for quality just want to know what I'm getting in return.

December 11, 2005

I looked into a tune about a month ago but could not get any real information about what's the best to go with....everybody voted for the tune they bought but as far as non biased info I couldn't find any....there must be one out there that is the best overall value.....I don't mind paying for quality just want to know what I'm getting in return.

<{POST_SNAPBACK}>

It seems that everyone who voted for their respective tune have no complaints. From everything I've read, they all seem like quality tunes. Personally, I went the most inexpensive route which was the wait4meperformance.com tune or more commonly known as the "Jesse" tune. For the price, you can't go wrong and he'll do anything you want.

redvett · December 11, 2005

Here is a site that figures out tire sizes.

http://www.dakota-truck.net/TIRECALC/tirecalc.html

Looks like your about 5 mph off.

Yes i have to agree with (chevydeerhunter) the Jesse/ wait4me tune is great espically the price.

beasleyiv · December 12, 2005

You're 7.8% off on average. Just take your miles driven on the tank and multiply it by 7.8% and add the value to your mileage. Then re-calculate.

05Quadrasteer · December 12, 2005

Here is the site I use to figure out the difference in speedometer due to tire differences; http://www.miata.net/garage/tirecalc.html

As stated earlier it is hard to get an unbiased opinion about tunes. I have the Westers in my truck. Until I find someone who has run numerous tunes with different programs how can you say which is best. Do what you feel is best, numerous forums have discussions about how people feel and what the service is like with each. Haven't heard anything really bad about any of the tuners out there.

Have a great day.

Bill

JAMIEZ71 · December 12, 2005

I agree with the way you calculated your mileage. I used to do the same thing on my old truck. I also agree with everyone else though saying get a tune. I also went with the Jesse tune. I haven't experienced any other tune but I do like the one I got from Jesse. Tune and have tire size adjusted.