The Stovebolt Site Forums The Shop Area Engine Shop How big a tire can I use and still clear stuff&fit wheel

I want to improve my highway rpm by getting larger tires. I currently have 15" tires that are 27.5" in diam at the road. I want to get some old 16" wheels and improve my highway rpm.
I can get some 33.2" dia. which are 7.50 X 16". That would improve my rpm almost the same as a 3.38 rear end will. But, will the tires fit in the back wheel wells under load, and the front wheel wells when making sharp turns? Thanks - Scott

Assume AD 1/2 ton--original rims were 16".

thanks - yes it is a 55.1 , but original tires were narrower and not as tall either. Think they'll still work?

My recollection is that the original tires were 16x6.5--would be wise to verify. In any event, short of someone running your tire I would guess that you would have to mount one on a rim and put it on front and back and look see. If you already have the rims you might want to go to a used tire place and pay some guy five bucks to mount an old tire (of this size) for you and see if hits front or back. My guess is that height is probably not a problem unless u've lowered the truck but width could be a problem on front tie rods. Hopefully some one on this board has tried this size or is running them. Good luk.

scdascda,

If you have an Advance Design truck you could simply split the difference between what you now have (27.5) and what you would like to have (33.2) and you would have a diameter approximately equal to original tires (approximately 29").

It is interesting to note that the original 15" rim and tire (1954) was about 1/2" larger (29.7") than the original 16" rim and tire (29.1" for 16" x 6.5" wide wheels).

I agree with bznhafdzn. Width could be a problem. The sectional width of the tire (unloaded) was between 6.5 and 7.2 inches (6.00 and 6.50 x 16" tires). However, is 2 extra inches in diameter going to cause a problem?

Tim

It's all going to depend on the rims you get. Measure the setback, distance from the flange on the back to the drum face surface. Compare that with your existing wheels. Then check the clearance of your existing tire to the frame and measure the section width of both tires. With all of that you can figure if the new wheel/tire will clear the frame and the fender. One more area of concern is the wheel to tie rod end clearance if your tie rods are on the back side of the front axle, I can't recall if it is on the 55.1.

As far as the tire height, it is not a problem unless you have lowered the truck. I recently put 7.50R16's on my 3/4 ton, there is only one inch clearance to the frame. Tight, but it will be set out more when I swap rear ends.

Thanks for the tips! I can't believe some one of you hasn't done this before. I guess I'll have to look closer like you all said. - Scott

I just had a set of uniroyal laredo rib (8ply) put on our 50 truck. I was running 6.5x16 stock rims which are 41/2 inches wide. The new tires on those same rims are LT215/85r16 and 51/2 wide.
There is no problem in either the front or the rear and the handling has improved tremendously.

I have 16" wheels on my daily driver 52 1/2 since '95.
For almost 7 years I always used 235/85/16 tires.
I had to use longer bolts and 1/4" spacers for the front to clear the tie rod ends.
When turning it, just cleared the fenders.
Under heavy load the rear tires where also rubbing slightly on the bed.
I kind-a-liked the look with the big wheels. Many thought it was a 3/4 tonner.

This spring I switched to 235/75/16 radial tires and handling improved greatly, especially on the freeway.
No more rubbing of the rear tires either.
The truck is faster now getting up to speed under acceleration (great for city traffic).
The milage did not suffer significantly.
The whole truck sits lower about an inch, which looks more original and the truck hugs the road more

Bottom line: 16inch wheels with 235/75/16 radials are the way to go for a daily driver.
There are too many problems associated with the larger tires and milage does not improve significantly and make up for it.

My '51 1/2 ton had 7.50 x 16 rires on it when I bought it, and I ran them for a couple years with no interference problems. They do improve the highway performance. As long as your rims don't have extreme offset or backspacing, they should be OK. Expect your speedometer readings to change a good bit though.

By the way I still have these tires/rims out behind the garage. See Swap Meet.