hey everyone. im new to off roading in a truck. always done it in a smaller rig.
i have a 1990 f250 with one ton leaf packs in the rear for work. single cab long box standard 5 speed with a straight 6 300 under the hood. sitting on 33s 285-75 r16 kelly safary tsr tires and stock 16 inch steely rims which are 6 inch wide i believe.

when i went to a bigger tire im getting rub on my front lead springs when i turn hard. i want to go with another set of steely rims but offset front and back to get them flush or just outside the wheel well in the front they are about flush with the wheel well but far from in the back.

can anyone tell me what offset id need since the tire shops dont have a clue.

also can anyone tell me whats the best tire pressure i can go with the width of rim and weight of the truck. when i go out wheeling and crowling. where i live its mostly loose shale rock not all that much mud.

thanks
nick

 

No direct experience, but those tires are 2" wider than stock. so you want to move the tires out about an inch to be about the same as stock as far as spring clearance goes. I think the stock rims 0 offset, so I'm thinking around -25mm of offset ought to be close.

As far as tire pressure goes, I run about 15 psi for rock crawling. Lower is always better, but if you get into single digits the chance of losing a bead goes up. I don't want to take that chance, plus 15 psi works better when the trail smooths out and lets you go a little faster. You'll still want on-board air for when you get to the street though.

 

Thanks for the insite appreciate it. The back tires are about 2inches from being flush. But then again my box is beat up lol I take the truck thru small ATV roads a lot so things get smacked up but nothing a b
Hammer can't push back out haha.

15 psi seems really low for the weight of the truck I've always ran 35psi on a smaller rig. Ran 15to 7psi but that was with full Kevlar tires so they hold a sidewall until u get on rocks then mould around like play dough.

I don't have to worry so much about on board air. Once I'm on pavement I'm only 6 Kim's from my house in and direction

 

Get 16x8" rims with 3" backspacing(-25mm offset) and you should be good.

 

Stock steelies are 4" backset.
If you want to correct for a 2" wider tire you need 25mm as was mentioned (3" backspace)

If you want the rears flush, obviously you want 2" backset, but at that point you're going to need a Saginaw PS pump to turn.
The Sag is always a wise upgrade over the C2 pump anyhow...
No noise and more/smoother power.

 

An 8" wheel fills out the wheel opening nicely when it's got something less than stock backspacing, I had some 8" chrome steels on my F150 with 3.25" backspacing if I remember correctly and the tire was flush with the fender at the top of the opening.

 

I've got my friend that owns a shop he lets me use finding me new rims. Everywhere I call they just sell stock steely rims. But had a good day wheeling with my gf . Went down to 40 psi and ya I can go a lot lower. I've still yet to not get grip with the tires I have even at 80psi goin up a mega steep hill of loose rock.