So I need a spare tire that will fit between the frame under the bed. The tires that were on the truck were 215/75-B15. Yeah, see that B instead of an R? That means bias ply. Searched online and they don't exist. I tried fitting a radial tire of comparable size under the bed but it was too fat and the bracket could not be secured.

Here's some questions up for discussion:

1) I simply can't fit a tire with the same diameter under the bed compared to what I'm running. Is this a problem at all for an open differential?

2) I run radials, and was reminded by the tire guy (who has a good used 7.00-15 Bias ply trailer tire) that radials and Bias are dangerous when ran together, but I'd be just fine if used as an emergency "get-me-to-safety" spare tire. Just how dangerous is this combination?

 

If you look for a pre 1972 Ford of your type that use radial rim they would fit. I replaced my rearend from a 1972 F250, I could use either my old rims to look period perfect or run with a set of radial on my newer rims.


If replacing rear you would also only have to change the pinion angle. I used a machined 8 degree wedge.

 

I just reread, your asking about a spare tire holder. At truck show that may have your type truck, look at the bigger trucks. I originally was using a spare tire holder for an F1. I was able to find one that was used on the F2 and larger trucks. Its flater than the F1 type. My radial tire fits fine when I get home I take a photo.


Means I'll have to dig it out. Its not outside it's in the garage. My family and yes, I did it too. Put too much junk around it.

 

I think if you got a flat on the rear, and were running a bias-ply spare on one side, I'd limit speed to maybe 35. Not so much for running but for braking. The difference in rolling diameter would be an issue if you drove for 100's of miles with an open diff, not so much if you just need to get to a tire shop.

You could always put the bias spare on the front and move a front to the rear, but braking would still be an issue (maybe worse).

 

Hmmm, so bias ply tires brake differently than Radials? Never thought of that!

 

I got a spare tire hanger with drop down cable gear from pick-n-pull but my truck has 235/75R17s and a Class 4 receiver tow hitch between the frame rails so there is less than 24 inches between the differential and the hitch cross member. The spare is in the bed.

 

For my F-1 I used an OE 16x4.5 wheel and mounted one of those temporary donut spare tires on it. They come in lots of diameters, just went to the junkyard and dug through the pile till I found one the right size. Dismounted the tire and put it on my wheel.
You can also buy the temp spare tires new, but they are spendy.

 

I had that thought once, Scott, but I was hung up on bolt patterns on Temporary wheels. How does OD come out with your setup?

 

Do the OEM 16x4.5" wheels work OK with tubeless tires?

 

I found a tire shop with a 7.00-15 Bias ply tire available. It got stuffed up under the bed for now. We'll see if it holds air in the long term though. Stem is accessible and I will check it monthly.

 

The one I found is within an inch or so.....close enough for a temp spare.

The front wheels on my truck are stock non radial(15") with tubeless radials on them.....been running them for years with no problems. Just make sure they are in good shape and not pitted where the tire mounts.

 

Just buy a good, compact, 12v air compressor. That will work for most flat tire incidents. It also works if your wife's car has a flat.