Roll 'em up next to the Corolla's, and the stock 235's on an F-150 don't look so bad. But under that big truck body, and with a topper, they appear a bit on the small side! I'm interested in going to 31x10.5" meats, and I'm looking for input from others who have done the swap. I see about 1/4 of all '92-'96 F-150s with the upgrade, so I assume it doesn't raise too many problems.
The 31" tire I want weighs only 6 lbs. more than the stock size, adding a mere 30 lbs. to GVW. This would not affect inertial- or momentum-influenced handling characteristics on a 4500 lb. truck. Tread contact patch is 1" wider, having minimal/unnoticeable impact on fuel use and rolling resistance. Tire is 2" greater in diameter, allowing lower RPM in cruising, although reducing acceleration. Given my 3.55 axle, I doubt I'd feel that reduction. Heck, even F-250s with those 32" tubes on them come with 3.55 axles! Section width widens 1.7", possibly causing radius arm rub although I have not measured full-turn clearance yet.
And those be my theories. Opinions are welcome and input on the swap is desired I'm curious as to how much water my estimates hold! But above all...was the swap worth it? Thanks!

 

My dad had a 1987 custom F-150 that came with 32x11.5 tires. I put em on my 1996 F-150 when he sold his truck cause they were bran spankin new (the tires) Everything is fine on the back, but in the front the clearance is minimal. When I hit a large dip, the tires rub the fender (not good) and I dont want to raise my truck so when it comes time to get new tires im gonna track down a set of stock wheels and go back to the stock tire size.

I found it made my truck ride a little rougher and it handled funny at first, but I got used to it. Truck looks a little beastlier with the bigger tires, but mine doesnt have the power to roll on em. Someone suggested a new rear end would help but I have no idea where to get a new one or how much it would cost.

Thats my experience. Of course the tires you are looking at are an inch smaller all around, so it could be diff.

 

I put 31 x 10.50's on my '93 2WD and although I do get some rub at full lock, I love the looks and noticed no changes in handling characteristics other than a slightly softer ride. I noticed no "seat of the pants" decrease in performance either. I say go for it!

'93 F150 XLT Supercab
5.0, AOD, K&N, Gibson

 

[updated:LAST EDITED ON 08-Jan-02 AT 09:56 PM (EST)]My used 96 4x4 came with new Firestone 31 x 10.5 Wilderness TA's. A very slight rub on the radius arm is noticed in a lock-tite turn which I never due, so no problem. I have the stock aluminum rallye wheels. Local Ford dealer rebated the Firestones and I went shopping. Replaced them with 32 x 11.5 BFG All-Terrain KO's. Rub is NO worse than 31's. Some people report a rub on the front plastic damn under the bumper, but I have no problem. The truck is a EXT cab with tall fiberglass cap and stock suspension. I think the 32's look like a perfect match. They are actually a little more narrow than the numerically narrower Firestones. I prefer a taller thiner tire than a shorter fatter tire like you see on a lot of jeeps.

I have the 300/6 with 3.55 gears so I never had too much power. What I did notice is once you get rolling the truck seems faster in each gear which it is. I zip around (much faster) in 4th gear when I used to be in 5th. When I grab 5th now I'm breaking the speed limit. Not sure about gas mileage but it is up. I usually am risking burning up a fuel pump trying to squeeze 200 miles out of a tank. I was working on my truck tonight and noticed 208 miles with almost a quarter tank left. The speedo is easy to recalibrate also. Check out the 96 photo gallery. Mine is the blue one on the left side when it had the 31's on. A guy has a (red or orange) F150 with 32's on. See what you think...

Chris

 

I have a 93 F-150, 4X4, regular cab, long bed. I'm currently running 31X10.5 Bridgestones. It has the chrome-spoke Ford Factory 8" rims...have no idea what the off-set is. When I bought these tires I was looking for a good compromise between mild/moderate off-roading and everyday driving (and looking good ). So I opted for the 31X10.5s. Performed well, no rubbing that I'm aware of, tasted great and was less filling. But, not too long ago I put 2" leveling coils on the front. Changed the over all appearance, big time. Now I'm wishing I'd gone just a little bigger...33X11.5 maybe. Certainly not much bigger than that,though. From my limited research, it should be able to handle the 33X11.5 now that I put the new springs up front. With out the springs...I don't know. I've got the 302 w/3.55 gears, so I know I'd probably suffer some. Like Shotgun above, I'm drooling over the BFG All Terrain KOs in 33X11.5 Unfortunately my Bridgestones only have 18K miles on them and it's tough to rationalize (to the wife anyway) swapping them out yet. I suppose it all comes down to a matter of personnal preferance. Good luck!

 

Gentlemen, your input has proven invaluable. I have all the information I need to make my choice. It shall be 31x10.5" Dunlop Radial Rover R/Ts on the stock wheels. I will then reprogram the speedometer according to procedures in an earlier post. The time and effort you have all contributed to my inquiry is very much appreciated. Thanks a bunch and happy trails!

 

 

about your switch to 31s i did that exact switch and i love the look and feel .The dunlops are really quiet "for a big tire"
i did not bother with the speedo the difference is very small
1987 f150 4X4 4.9L farmer four tranny

 

You got the Dunlop R/Ts? I agree.. they are a surprisingly quiet tire given how aggressive the tread design is. They are actually quieter than the old style BFG All-Terrains which were replaced. The tire shop was trying to sell me the new BFG AT KO in that size. I told them that everyone and their brother has the KO, and I wanted something unique. So far I have nothing but positive words for the Dunlops.

 

if you want a tire that not many ppl have go with the yokohoma geolander at+ very quiet tire if you get them rotated on time.. nice tread too

 

Can any of you comment on how your gas mileage changed when going from 235/75 to 31x10.5? I'm planning on making the change but want to know what it's going to cost in gas first. Thanks in advance.

 

Kudos for searching, but this post is over 12 years old.

At any rate, your fuel mileage is going to depend on your gear ratio, transmission, engine size, and a bunch of other variables.

 

Oh, I saw the date. I thought it'd be a good place to start, anyway.

Not sure what gears I'm wearing, but it's a 300 with the T18 or T19 4-speed. I'm keeping everything the same but the tires. I know there will be some mpg reduction due to adding tire width and rolling resistance. Just wondering if anyone could tell from experience how much of a hit that will be.

 

Hard to say without knowing what gears you have. With 3.55s you'd hardly notice a difference. My guess is you have 3.08s, like a lot of trucks with that powertrain. Shouldn't make enough of a difference to notice. Maybe 1-2 MPG.

 

It may not kill the mpg but if I know anything about that gear ratio its that little things like putting on a toolbox or adding some weight somewhere will be noticed for sure in the power department. 31's could be done with that ratio for sure but it will be a slight but still noticeable difference in how the truck accelerates.