First an update!

I have wanted to drive my 78 to our lake cabin as long as I have owned it, and finally made the trip last weekend! 600 miles round trip plus a lot of exploring I would never do in my 14 Sierra (fire/log roads, gravel, woods)

WHATS DONE:
-Rear brake are done
-Rear lines from Jeff's Bronce Graveyard (very impressed with these and would recomend them if anyone is looking for
prebent lines)
-Master cylinder, wheel cylinders, drums and shoes plus the hardware kit
-33" Toyos mounted
-New sending unit so my gas gauge works
-New steering stabalizer

TO DO:
-Front brakes / lines
-Lift kit
-Steering box
-Electric fan
-Dyno / chassis tune

QUESTION:

I have OEM 15" wheels on the 33x12.50s and they rub the radius arms at full crank, what options do I have that to fix this? Wheel spacer? New radius arms?

My lift didnt come with new radius arms or drop brackets (bought it used), will the stock work with the 4"?

Any ideas on either question would be appreciated.

PICS:

Nice pictures and a very nice truck! Is there a reason you have to stay with the 12.5's? 10.5's will do lock-to-lock with no issues.

What Doug said about the 10.5's....otherwise you will have issues. You will have to do something with the radius arms for the lift...either a drop bracket or different arms...otherwise you will have serious steering/axle geometry issues.

fatherdoug said:

Nice pictures and a very nice truck! Is there a reason you have to stay with the 12.5's? 10.5's will do lock-to-lock with no issues.

Click to expand...

I wanted 10.50s but I ended up finding these used for a steal, and the 10.50s I found (BFGs) were too agressive.

Well it sounds like I am going to have to make some radius arms and fix it!

33-12.50's are fine for your truck. All you have to do is adjust the steering stop bolts out a little bit. There is one on each side of the front end located on the knuckle. They just look like a bolt threaded into the knuckle and when you turn full lock the head is supposed to make contact with the axle tube to stop the wheel from turning any further thus eliminating undue stress on the steering box.

Just adjust them out slightly to lessen the steering turn radius untilI the tires have enough clearance against the radius arms. This is common when putting bigger tires on these trucks.

The tricky thing about big tires is the backspacing. If you get enough backspacing, the outer edge of the tire may hit the lower corner of the fender-well when turning or especially if hitting a bump while turning.

Being as you are wanting to do a lift, the bigger tires will look good anyway so for now adjust the stops and live with the worse turning radius. One thing to keep in mind is the more backspacing you have the more load you put on the bearings. Not an issue really if 33's is about it but going really big will definitely shorten the life of the bearings, ball joints, etc.

So adding some backspacing to the wheels to net tighter turning radius with bigger tires works well to a point but it's a balancing act.

I'm not a fan of compromising the ability of the truck to 'solve' a problem, so I wouldn't make any adjustments to the steering. Lifting it isn't going to fix anything, because it's a width issue, not a height issue. As nate stated, the key is in the rim backspacing...and 3.75" seems to be the magic number. Numerous folks across the innernets have fit 35x12.5 on stock height rigs with no rub, with the right offset and backspace. Given, it's a Bronco, but it's the same front end set up. Lifted 4' with 36x14.5" TSL's, with no rub...even on ther RA's...not at lock, but it works:

I am trying to figured out if 17x8 wheels with a backspacing of 4.5 wrapped in 255/75r17 would work on my stock 78 f100 custom. any advice?

jgonterm158 said:

I am trying to figured out if 17x8 wheels with a backspacing of 4.5 wrapped in 255/75r17 would work on my stock 78 f100 custom. any advice?

Click to expand...

Assuming this is a 2wd. That's about a 32x10...on a stock rim, it'll work...not sure on 4.5" BS though.

Thanks for the advice. For now I am going to have to stick with the stock rims and cheaper tires. No point in spending money on great tires when there is such a long road ahead in way of repairs.