I'll cut and paste some of the info from the not quite finished yet tech tip:
Most of the information I have is about the 10-lug wheels used on our AD (Advanced Design 1948-1954) trucks. Much of what I have learned comes from experience with AD trucks and reading the Accuride catalog, found here:
http://www.accuridewheels.com/completeversion.pdf of particular interest is page 28 with the 10 lug on 7.25" circle and 5.25" center hole. This is the exact bolt pattern used on late AD 1.5 and 2 ton trucks. Earlier trucks have the same bolt pattern but a smaller 4.75” center hole, because of this the new Accuride wheels are not a direct replacement for trucks with this smaller hub diameter, we’ll get to the details and solutions later.
As a side note, Ford used the same bolt pattern with a larger 5.46" center hole on the F-Super Duty trucks from 88-97, available in a 16" rim. Because of the larger center hole these wheels are not directly useable on our Chevy trucks without bushings in the center holes, as the wheels are hub-piloted and it is important that the center hole fit snugly on the hub. Also different are the Ford wheels/hubs use 9/16” studs, while our AD Chevy trucks use 5/8” studs.
We will focus on the available different newer wheels and tubeless tires. Note that 19.5” tires are only to be used on 19.5” wheels, same goes for 20” wheels and tires, 22.5” wheels and tires, and all other wheel and tire sizes too; they must be an exact match.
20” tube type tires are easily available to fit the original 1.5 and 2 ton two or three piece “locking ring” wheels. 7.50X20 is a normal size. 8.25X20 can often be used although with a slight decrease in turning radius because the rear edge of the front tire will rub the springs in a hard turn, most people don’t consider this a problem.
New tubeless and radial tires to fit our 1.5 and 2-ton AD trucks seem to only be available in 19.5" tubeless, as found on the Chevy P30 chassis, 3500HD and other trucks in the 80’s and 90’s. Again, 19.5” tires can not be used on 20” wheels; new 19.5” wheels must be used. The tallest tire available (without being really wide) in 19.5" is an 8r19.5, and they are about 32" or 33" tall. I think they are intended to be a replacement for 7.50X17, although I am not 100% sure on that. If you replace your stock 7.50X20 tires with the available 8R19.5 tires (and new wheels) they will be smaller. Some people don't mind, I personally think they look much too small on a 1.5 or 2 ton truck. With smaller tires you will also lose road speed, not good for our already slow trucks. On the plus side, smaller tires give increased braking performance.
19.5" wheels may have brake drum interference problems in some cases, and as the case with all non original wheels, should be test fit before purchasing.
8X22.5 is the tubeless direct replacement (approx same OD, and approx same tread width) for 7.50X20. The replacements for 8.25X20 tires are 9R22.5. This info is on page 45 on the Accuride catalog. There are lower profile 22.5" tires that you may use; they will be labeled as 245/75R22.5, or some such mess of numbers. I don't know the details and sizes as to what replaces what for those.
Now that you know about tires let’s talk about your wheel choices to fit them.
So, now you say "why don't I get some 22.5" wheels and use modern tubeless tires on my AD truck?" Well, easier said than done. To start with, 8X22.5" tires are very hard to find these days. On the plus side, the 9R22.5 tires are made and easy to get at any truck tire store.
I've looked long and hard and have yet to find any "new" 22.5" wheels made with the small bolt pattern we use. I have found that, in 1956, Chevy used that bolt pattern with 22.5" wheels on the 1.5 ton trucks. As far as I know it was only 1.5-tons, as the 2-tons had 6 lugs. As for the years, right now I can only confirm 1956, they may have been used a few other years, possibly through 59? That makes the wheels somewhat difficult to find. Although I have seen a few trucks with them, and I have found a set of 7 for my '48 2-ton.
1.5 & 2-ton -- Originally, these trucks used locking ring 20" wheels. Be sure to check the center hole diameter before you buy new wheels, the earlier wheels have 4.75" and later wheels have 5.25" center holes. New 10-lug 19.5" wheels (with a 5.25" center hole) from the larger size 1977-05 “bread truck” should work look for Accuride part number 27775 or 29667, the second number is a newer and slightly stronger wheel, either should be fine. (See note below). These wheels fit the 8R19.5 tries also, but they are several inches shorter than the original tires. I think they look too small on a 1.5 or 2 ton. If you want aluminum wheels the only aluminum wheels I know of are Alcoa or Accuride 19.5" wheels for use on a Chevy 3500HD or P30 chassis with that same bolt pattern. They can be bought new. I have never seen 20 or 22.5" aluminum wheels with the 10 lug on 7.25” bolt pattern.
The other, and in my opinion, most desirable option, is a set of 10-lug 22.5" wheels from a '56 Chevy 1.5 ton. Same deal with the 5.25" center hole. They are not real easy to find, although prices are generally fair if you do find some. Many tire choices are available, and 9R22.5 is probably a good one, comparable to 8.25X20.
Note—10 lug wheels with 7.25” bolt circle--- The one problem you may have with the new wheels is the wrong center hole size. To start with you need to know what size center hole your original wheels have, actually measure it, or get an idea from the list of years and bolt patterns below. All the new style tubeless wheels have a large 5.25” center hole (except for the larger ford 5.46 center hole wheels). The problem comes when you want to use these new wheels on an older (generally pre 1954) truck, as there is a ½” difference in hole size. Because these wheels are hub-piloted and it is very important that the center hole fit snugly on the hub as designed. To allow you to use new wheels on the older trucks a set of simple spacers may be needed. For the front these spacers/bushings would be just less than the thickness of the wheel measured at the stud holes, a shrink or press fit on the hub (nominal 4.75”), and a slip fit in the wheel (nominal 5.25”). If you used the original cover ring that has only 5 lug holes and covers the other 5 the adapter bushing could be a slip fit on the hub, as this cover would keep it from falling out. The rear spacers/bushings would be similar to the front, but twice the thickness to allow dual wheels. If it was not a press fit you could again use the cover like on the front, but with 10 stud holes (I believe these covers are stock). Some loctite and frequent inspections may also work to hold the bushings in.
1.5 & 2-ton Bolt pattern:
1954 & later – depending on the year stock wheels are 20" and some 22.5”, the bolt pattern is 10-lugs on 7.25" circle. The center hole is 5.25". Studs are 5/8-18. Some later trucks used 6 studs, I don’t have experience or information on those, but I do believe they are stud piloted Budd wheels and new tubeless 22.5” wheels are available, some even came as 22.5” stock.
1948 -1953 – stock wheels are 20", the bolt pattern is 10-hole on 7.25" circle. The center hole is 4.75". Studs are 5/8-18
Pre 1948-- (I am not 100% sure on these older trucks, please correct me if I am wrong.) Stock wheels should be 20"; the bolt pattern is 10-hole on 7.25" circle. The center hole is 4.75". The studs are smaller than the later trucks, probably ½-20 or perhaps 9/16-18.
See if any of that helps,
Grigg
