older truck, what tires?

[occupant]

Ok, two part post here. First part is wheels, second part is tires.

First of all, the wheels. The truck I am buying is a 1971 Ford F-250, 3/4 ton, 2-wheel drive, old farm truck. It has the original 16.5-inch wheels on it and generic tires. So it will need the tires replaced but I'm having serious trouble finding 16.5 inch tires. TireRack certainly doesn't have many choices, I think there's a Kumho or two and a couple Firestone/Bridgestones and one Toyo. So that's not so good. Should I insist on changing over to 16" wheels before I try and buy tires?

Secondly, as for the tires, does anyone know of any 16.5-inch tires besides the handful on TireRack? If not, I'm probably going to go 16-inch and grab a set of BFGoodrich Commercial T/A's.

edit: forgot to mention usage...the truck will spend half of its time commuting me to and from work on nice paved highways. The other half will be split between driving on back roads in the county to and from markets and stores, and carrying heavy loads on the highways to and from the ranch. By heavy loads I mean 1000-1500lbs, not nearly at the bed's capacity but certainly more than just my fatness...

 

[alreadygone]

Use 16.5 wheels for boat anchors, or recycle yard material! First, I'd head to local salvage yards and attempt to locate a full set of late model 8 hole 16" wheels with good used tires already mounted and balanced!!! What size 16.5 tires are currently on wheels? There will be a 16" size with approximately the same diameter.

Bob

 

[occupant]

That's a good question, I'm pretty sure they are 8.75x16.5, but I could be wrong.

If that's the case, 245/70R16 would be the closest size.

 

[CapriRacer]

Occupant,

Just to make sure:

Look for the vehicle placard. I think this vehicle was produced before tire sizing and inflation was required to be printed on it, but it ought to have GVW and GAWR info.

What I want to be sure of is that the P245/70R16's have enough load carrying capacity. The heavy loads are a major concern. I'm thinking you need LT metric tires on this vehicle - which means you have to get rims with enough capacity. But if I have this right, Ford (GM, too!) use the bolt holes as a way to prevent folks from using a light duty rim, where a heavy duty rim is required.

For background:

In the days of bias ply tires, an overloaded tire would generally fail in the sidewall - it would crack and bulge - giving plenty of warning before it actually lost pressure.

Radial tires have a different failure mode when overloaded (or underinflated - which are functionaly equivalent). Overloading will generally cause a "belt leaving belt separation" - commonly, but technically incorrectly, called a "tread separation". When that happens the tire generally doesn't lose pressure, but the sequence of failure is this:

Small undetectable separation
Vibration that gradually gets worse
Increasingly larger bulge in the tread shoulder
Isolated Wear in the shoulder where the bulge is.
Cracks start to form in the bulge area.
The tread and top belt developes a "flap" - the start of a detachment
The tread and top belt start to detach.

This will take place of the course of 100's of miles.

If allowed to progress, the flap will damage stuff in the fenderwell as it detaches. The actual loss of the flap doesn't cause loss of vehicle control, unless the driver overreacts, such as slamming on the brakes or steering violently.

So while there is a warning, you either have to look for the bulge, or feel the vibration - and vibrations don't seem to trigger enough of a response from the operator.

So if you'll try to find the GVW / GAWR's and post them, I'll respond back with what tire you need on this truck.

 

[alreadygone]

Think what Capri Racer's tryng to say is 245/70 only comes in standard load. 245/75 is so close in diameter it'll never matter and can be had in LR-C(6pr),LR-D(8pr),or LR-E(10pr).

Bob

 

[CapriRacer]

Bob,

Uh.....not exactly.

My book says that some 1971 Ford F250's came with 9.50-16.5's inflated to 35 front 55 rear.

This means that the load carrying capacity was 1860 # front and 2650 # rear.

A P245/70R16 has a load carrying capacity of 2094 # at 35 psi - and because this is a light truck application, the load carrying captity has to be reduced 10% - to 1904 #.

So while there is enough load carrying capacity on the front - the rear is overloaded - if the vehicle is loaded to the max - which is what "occupant" seems to be implying.

We really need the GVW's and GAWR's of the truck - and to make sure, the truck ought ot be weighed as well - all 4 corners if possible.

 

[alreadygone]

It's an OLD 3/4 ton truck. My opinion is, go to a salvage yard, pick up a set of 6,8,or 10ply rating LT245/75R16 mounted on common as dirt 16 inch wheels and run it.

Bob

 

[c502cid]

First off, it's an old truck. I own a bunch of them. You might find you can't even get the thing down the road in a straight line enough to use it as a daily driver. Lots of times, but not always, they only have use as old trucks do and that certainly isn't for commuting. 16.5's are available from any tire store, forget Tire rack on this one. While not as common as they used to be, they are still all over the place in many sizes. If you find a good buy on some 8 lug x 6.5 16" wheels, get them, but they are not needed nor a must have. And also, the most inexpensive size tire which everyone runs on old trucks, trailers, and vehicles of this type are an everyday LT235x85x16 10 ply. Cheap and available!

 

[lasmacgod]

I had a '68 F250 in high school, which, save the grill, is the same as your '71. LT245/75R16's are a perfect fit. 265/75R16's will fit, but the LT245's are perfect. Watch out when buying 16" wheels. Last I knew, the center hub on 8-lug Fords were larger than the center hub on 8-lug Chevy's and GMC's. As a result, you could put Ford 8-lug wheels on a Chevy or GMC but you could not put Chevy or GMC 8-lug wheels on a Ford. Another thing to be aware of is to make sure that your lug nuts are long enough to account for the increased thickness of aluminum wheels over steel wheels. Mine were too short for my comfort with aluminum wheels, so I had to stick with steel wheels. Best bet is to "try them on" before you commit to buy.

As Alreadygone mentioned, you should be able to find some take-off wheel and tire sets for a very reasonable price. I was able to buy a set of wheel-and-tire take offs at about the same cost as a set of 16.5s. The advantages were a better selection of tires, cheaper tires in the future, and a very common, mainstream size.

Good luck with your F250. I hope you love it as much as I loved mine.

 

[Kestas]

Though it may be an old truck, for safety's sake you'll need good tires if you do any appreciable amount of interstate driving. Reading between the lines, when you say "paved highway", it looks like this truck won't see a lot of interstate driving. You'll do fine with a set of cheapy LT tires.

 

[occupant]

I got lucky. Guy who sold it to me did me a favor and swapped on 16" 8-lug wheels from an 80s pickup. Now all I have to do is call the Incredible Hulk to dispose of this split rim on the spare tire.

Thanks for all the help, I'm headed to go discuss hydraulic oil for the M. Truck is stuck out in the west side of the property and I need to get the hydraulics working on the tractor to pull it up a bit and then out.