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-   -   2001 Wrangler couple of tire questions (http://www.wranglerforum.com/f27/2001-wrangler-couple-of-tire-questions-47636.html)

wolfen 03-28-2010 03:48 PM

2001 Wrangler couple of tire questions
 
When we bought the Wrangler it had stock steel rims, and it still does, there are no mods to the body,or frame, 2.5 eng with an auto trans. When we first got the Jeep it had 215/75-15's on it. I wanted bigger tires so I put 235/75-15's on it. Well I finally got around to reading eth entire owners manual today and I found out after looking on the Jeep itself that it originally came with 205/75-15's
I currently get about 200 miles on a tank of gas, and she'll get up to 55 but I don't win any races.
My question is since the jeep originally had 205's on it did I change anything when I put the 235's on it?
With eth 215's I got 260 miles to a tank, but I really want to keep a decedent looking tread on the tires, not some street tread since summer is coming and I'd really like to go back in eth woods again.
Should I go back to 215's? Or are the 235's ok?

InfernoGirl 03-28-2010 03:59 PM

Your speedo/odo will be off going up in tire size, so your mpg calculations have been off unless you've been accounting for the difference. When your speedo reads 56.3mph, you have been going 60mph. Your wheels are only turning 720.4 revs per mile, instead of 767.5. So you have been going farther than your odo reads.

A 235 is roughly a 29" tire, which is fairly short for a TJ, my '01 came with 30's from the factory... You can go up to a 31 on a stock TJ just fine.

wolfen 03-28-2010 05:19 PM

Ok thanks I get that :)

Now how about the gas mileage, does that big of a change make a dramatic mpg change from 260 to 200 miles a tank or should I start replacing injectors LOL

Oh btw I'll delete that other thread if I can

chucky cheese 03-28-2010 05:57 PM

Quote:

Originally Posted by wolfen (Post 584205)
Ok thanks I get that :)

Now how about the gas mileage, does that big of a change make a dramatic mpg change from 260 to 200 miles a tank or should I start replacing injectors LOL

Oh btw I'll delete that other thread if I can

Without alot of calculations Take a gps with you. It will give you correct mph and actual distance traveled so you can get a true mpg reading.

wolfen 03-28-2010 06:42 PM

Thanks guys and girl, that explains a lot I thought I did something really wrong, I've been working on cars and trucks since I was 10 but the only time I ever changer tire size was on a strip car we built for the short track, so speed and mpg really weren't on out to do list.
but basically if the odo is that far off I'm probably getting more mpg that before I changed tires in the first place :) the only thing that bothers me is when inferno girl said when I'm showing 56.3 I'm really going 60, the only reason it bothers me is that means everybody around here is really going 70 in a 45 like I suspected

InfernoGirl 03-28-2010 07:25 PM

Yep, keep in mind that your speedo is off... Like Chucky said, if you can run with a gps, you can verify how far off, and adjust accordingly. It's likely off by about 3mph, not bad, but depending on how far over you tend to drive anyway, it could get you a ticket... ;)

wolfen 03-29-2010 03:43 PM

Oh yea around here I'd get a ticket, I'm not rich or thumping rap music so the local cops aren't afraid of me, but then everybody else including the cops with a handful of donut pass me the way it is even if I show 5 over.
As fas as a gps I'd assume I still get the same mpg as when I had the 215's on it, cause in a even 10 day period I still use the exact same amount of fuel to go back and forth to work taking the exact same route, and I do appreciate all the help and info you guys have provided me :) Thats why i stay here.

kenjo 04-01-2010 11:49 AM

Tire size calculator
 
This is a helpful tire size calculator that shows the effects on speedometer readings with tires larger than stock:

Tire size calculator

:D

wolfen 04-01-2010 06:50 PM

thank you very much I just got home and looked at this, you just saved me an hours worth of Google searching.


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