315 75 R16 thoughts or experience

[lotzagoodstuff]

I currently have 285s on my truck but I am considering upgrading to a set of 315 75 R16s that I have, I know I'll have to use a 2" body lift to get the clearance, but I have some questions I am hoping some of you who have upgraded have been through already:

- Will 315 75s fit on factory Ford 1993-1997 aluminum wheels?
- I have a stock but good running IDI 7.3, 5 speed and 4.11s. I think I will appreciate a taller tire for lower RPMs and hopefully increase mileage, but I know it's not that simple as there are some potential drawbacks from spinning a larger tire.
- Will my fuel mileage go down significantly?
- Will my truck drive like a broken roller skate?
- If I hate the taller/wider tires and I go back to 285s, will my truck look goofy with a 2" body lift?

Any input is appreciated as always

R. J.

 

[Agnem]

Won't the bumper be an issue? The body lift is a good idea, but beauty is in the eye of the beholder if you go back to the smaller tires. I don't think a 2" lift would make that big a difference visually.

 

[Dirtleg]

My truck has 315/75-16 tires on it now. They will fit the stock wheels (16x8).
You will need the 2" from the body lift. Mine clears stock but it's a 350. I have read that the 250's don't. You may also have to adjust the stops on the steering knuckles to keep them from rubbing the leaf springs.(easy)

I have 3.55 gearing and have averaged 16.5mpg on a 1400 mile trip. With 4.11's I think you'll be fine as my truck could use a little more gear than it currently has. Although, in 4LO, it seems to have plenty of useful torque offroad for crawling up rocky trails.

You can also recalibrate the speedo to work with the larger tires I have read but have yet to try it myself. Someone here could probably point you to a link for this. I think I saw it on Pirate 4x4.

Good luck.

 

[Mr_Roboto]

The stock wheels (92+) are 7" wide. You need to measure between the beads, NOT the outsides of the wheel.

 

[kcw12]

Youd probably have to cut the bumper, but i dont see any need for the 2 inch lift (on my truck) and i already rub with 285s, and im used to it. Fords......Cut the wheel until they rub

 

[4x4TruckinGirl]

I think you'll need the 2" lift. Your tires won't be so "stuffed" in then. The ride of a 35" tire isn't too much different, i have 315/75/16 BF Goodrich Mud Terrains on mello now, and when hes running, the ride isn't too awful.

If for some reason your stock wheels won't work, a new set of wheels for 35's aren't too expensive. And, if you hate them you can downsize and a 2" lift isn't the end of the world

 

[TLBREWER]

Although I've seen 315's mounted on the stock 16X7" wheels, it's not recommended by the tire manufacturer and you run a bigger risk of rolling a bead in my opinion. Too much ballooning on the sidewalls. I would bet that a reputable tire shop won't even mount them for you. BFG recommends an 8.5" rim for 315's. I'm toying with that idea myself. Or I may just go up one size to 295/75-16's. Kind of an oddball size, and have to be ordered, but a little bigger.

As far as the 2" body lift. I'd like to do that too, especially since I'll be installing a turbo soon (hopefully). My hesitation is with the bumper alignment as Mel mentioned. Can't find the 2" lift brackets and they look goofy with the bumpers low.

Tom

 

[Double-S-Diesel]

I have 35s on mine but using 8' wide wheels, stock 350 with 3" body lift.
only rub the springs.

 

[fsr7]

I just finished the 3" body lift on my dually and have 315 70 r 17s on 7" wide dually wheels - almost identical tire dimensions to the 315 75 16. No problems with the bead on the narrow rims, and it rides great/ plenty of power. A warning about the body lift, however - This is the second IDI I've put a 3" body lift on, and its the second one that I've had problems with the cab coming into contact with the motor. There is an indentation in the firewall where the back of the driver side head sits, and when you lift the body off of the chassis the head contacts the section of the firewall below this indentation. It is a real PITA to modify that part of the firewall with the motor in the truck! Lots of time with a hammer, a prybar, and a lot of dirt in your eyes. Re-mounting the bumpers is a breeze compared to this. I don't know if it would be a problem with a 2 inch kit... never done one, maybe someone else will chime in. Its a sad moment when you start the truck thinking you're done with the lift and it sounds like your sitting in the engine when you're in the cab of the truck...

 

[lotzagoodstuff]

Thanks for the input. I have heard that a 2" lift gets around the dreaded firewall interference that makes the truck a giant echo chamber. I will figure out how to move the bumpers up, and it sounds like I should be looking for a a wider set of wheels.

Thanks again for the input, I will report back on what I do to make things fit.

R. J.

 

[apextrans]

I may have missed something here, but why not just do a 2" suspension lift? Just some springs & blocks and you have the clearance with out disturbing linkages, brake lines, & bumpers. I had a 2 or 2.5" suspension lift on my IDI & it was very livable. I was running 285's but had plenty of room to run bigger tires. If your looking at a body lift just to ease the install of a turbo, IMHO you could create more problems than you cure for the downpipe space. 3 sawzall cuts & a digging bar will get you more room than you need to drop a downpipe through. Just my .02

 

[Darrin Tosh]

I didn't read all of the post but here is my .02.

The 315's will fit fine on the factry alcoas. Wider wheels "Look" better in my opinion but are not necessary.

A 2" body lift won't do you any good and you don't need it for cleareance. The only cleareance problem you will have is the front bumper. You can shim out the bumper a couple of inches, and/or trim off the corner with a sawzall.

Another remedy is what Scott said, suspension lift, You can get an add-a-leaf from JC Whitney for the front for under $100.00 That will get you about 1.5 to 2" of lift, and level out the truck. Will still need a little bumper trimming of shimming. Then get factry 4" lift blocks from a F350 and that will ad 2" in the rear by replacing the F250 2" ones.

315's will fit better on 87 to 91' body style because there is more bumper clearence.

Hope this helps

 

[lotzagoodstuff]

As always, thanks for the input. I have already put an add a leaf in my front spring pack and it definitely leveled the ride height. I believe that I am going to mount the 315s on the stock Alcoa's as I have an extra set and it sounds like several folks have done it successfully. I am definitely going to shim the bumper out a couple of inches and if I'm unhappy with all of this I will go back to my 285s.

Thanks again for everyone's input as it's nice to tap the experience of others prior to making changes (read mistakes).

R. J.

 

[apextrans]

here's my 285's on OEM Alcoas. Could have gone considerabley bigger without a problem.

 

[Diezel_Cowboy]

I know this may be diggin up bones but R. J. do you have any pictures of how the 315's worked out? Did you have to shim the front bumper? I am thinking of going bigger now and would like to hear how/see how it went for you.