Ford Ln700 tires

[Dairy Feeder]

I recently bought a 1980 Ford LN700 with a 20ft livestock box on it. It had very good bias ply tires on the rear and I put new radials on the front. Empty the truck is great, I hauled 1 load of cows and when it was loaded it went all over the road! Is that caused from mixing bias ply and radial tires?

 

[Nordic]

Are all the tires inflated to the same and proper pressure? If they are...the going all over the road should not be from having radials on the front. You didn't happen to have rambunctious cows in the load? LOL. I guess if you have done cattle hauling a lot you know what to expect.

 

[Destroked 450]

I have had some tires that made a truck pull from one side to another on rough patchy roads, but most times there's a issue with the steering.
How much free travel is in the steering wheel, it should have less than a quarter turn, 1/8 turn is better but it does need some free travel. Check the free travel in the shaft next to the steering box as there's a couple of ujoints in the steering shaft between the steering box and steering wheel that can give a false reading.
If the steering wheel has to much free travel check these.
tie rod ends
drag link
Steering box adjustment

I've worked on, owned and driven several Ford L series trucks and have replaced more worn drag links than any other part on the steering.
ujoints in steering shaft
slop in telescoping shaft

If steering is tight check these
king pins, jack up the front axle then pry up on the tire to check for movement
alignment, should be toed in 1/8 inch
wheel bearing tightness
spring eye bushings and pins
spring shackles and pins

 

[Destroked 450]

(quoted from post at 08:46:39 11/04/16)
I have had some tires that made a truck pull from one side to another on rough patchy roads, but most times there's a issue with the steering.
How much free travel is in the steering wheel, it should have less than a quarter turn, 1/8 turn is better but it does need some free travel. Check the free travel in the shaft next to the steering box as there's a couple of ujoints in the steering shaft between the steering box and steering wheel that can give a false reading.
If the steering wheel has to much free travel check these.
tie rod ends
drag link
Steering box adjustment

I've worked on, owned and driven several Ford L series trucks and have replaced more worn drag links than any other part on the steering.
ujoints in steering shaft
slop in telescoping shaft

If steering is tight check these
king pins, jack up the front axle then pry up on the tire to check for movement
alignment, should be toed in 1/8 inch
wheel bearing tightness
spring eye bushings and pins
spring shackles and pins

The part about working, owning and driving was supposed to be at the bottom, not in the middle.
This forum needs to have one way to view and make it where one can edit mistakes.

 

[hd6gtom]

What kind of tires do you have on the rear? If they have a very very aggressive tread on them it can cause this problem. Speaking from experience here. In the 22+ years I owned a tire shop, I saw lots of straight trucks with radial on the front and bias on the rear with no drivability problems. As stated, jack up the front end one side at a time and check for loose parts.