31" vs P235/LT235 Tires...

[Sparks]

Hi All,

I'm about to take the plunge on new skins, 66K on the original Wilderness AT's & I can't wait to get 'em off. The question is: What can I expect for changes in ride, handling, fuel economy, etc. *IF* I change from the Wilderness AT's to: (1) Michellin All Season's 31x10.5x15, or (2) Michellin All Season's LT or P 235-75R-15. Some people say fuel economy will go up w/ larger tires - others say it will go down. Thots?

I drive 100 miles roundtrip to work each day on Interstates - doing about 70 - 80 MPH. I expect this to make up about 99.9% of my mileage. The rest will be distributed over wooded trails and beach sand on Cape Cod.

I'd especially like to hear from those who have a similiar driving routine.

Thanks!

Steve

[This message has been edited by Sparks (edited 01-17-2000).]

 

[S.Matsushige]

Steve-I went from 235s stock and ran 30s for quite some time on my '91XLT. I currently have 31s on them and have had them for about four months now. I have never changed the gearing on my speedometer so I know my mileage readings are off. The mpg did drop but I contribute it to the speedometer gearing. The ride seems to be a little smoother and depending on what kind of gearing you are running it might affect your acceleration a bit. I'm running 3.73 limited slip so it isn't too bad. All n all I think it shouldn't do too much to your mileage with the 31s, but it'll surely make your Explorer look pretty cool. Hope this helps.

 

[Sparks]

Hi - thanks for the info! Based on your feedback, I bought the 31x10.50x15's today. Michellin LT X Radials. They look great on the truck, and the ride is nice, too. They were on sale at Costco - $40 off a set of 4. I bought 5 of 'em (the spare has to be the same size) for about $550. That was mounted, balanced & installed. It also hets me lifetime balancing & rotation.

Thanks again,

Steve

 

[DannyB]

Hi Sparks, I'm debating the same dilema. What happened to your MPG and power? Any significant difference?

 

[Sparks]

Danny,

I'm very happy with the results.. smoother ride, appearance, etc.

The difference in fuel economy is negligiable - as it is with power as well. Keep in mind that 99% of my miles are on Interstates in the 70 - 80 MPH range. If you have more city driving, I suspect it would be more noticeable - on both points. I have heard (and have yet to try) that changing the stock air filter to the K&N variety (or equal) improves performance - and in some cases brings it to better than before.

In short, I wouldn't hesitate to do it again!

Steve

 

[ex91]

hey i when from 235 to 31x10.5 15 mud kings with no power diff or lift om my 91 xl 4rd with 170,000km on it and it got 3.55 well mabye the truck says that but the com print out from the dealer says 4.10 and 4.10 was an opp for my truck with the super coolent pack and i only get 300-to 400km to tank full so what gears do you think I have??

 

[S.Matsushige]

Steve-I'm glad to hear that you went ahead with the 31s and got a good deal along with it. I got my BFGs from Sam's Club with the same type of service warranty. I personally think the Explorers should have come with 31s to begin with. It just makes the truck look much better. And Danny, the mileage and acceleration would depend on your gearing. But the ride to me is much smoother with the extra rubber. I get about 18-19mpg but is a little more because the speedo and odometer is uncorrected for the 31s. I have 3.73LS rear and a 5 speed on my '91XLT.

 

[DannyB]

Thanks for the info Matsushige, how can I find out my present gearing (I assume we are talking tranny gears!)?

 

[S.Matsushige]

Danny-its actually the rear end gearing. You should be able to find it on the drivers side door tag under axle. It'll either be two numbers or as in my case mine is D4 for 3.73 limited slip. After finding the numbers, refer to the topic of "Axle Codes" under General Exploration. I think if you have codes 45(3.55), D4(3.73LS) or D2(4.10LS) you'll be okay. I believe D4 or D2 are the prefered gears to have. Hope his helps.

 

[DannyB]

Matsushige, thanx for the info. It does reads D4 as you suspected. Thanx again!