The Stovebolt Site Forums The Parking Lot Big Bolts Wheel and tire Tech Tip, long awaited, and finally here!!!

I know it has been quite some time now that John asked me to help with a Wheel/Tire tech tip for our AD trucks, finally it is available for viewing.
http://www.stovebolt.com/techtips/wheels/

There are a bunch of other new tech tips listed in the March news page, click "News" at top center of this screen.

It's not completely finished, as the plan is to cover your options on some of the newer trucks before it is all done.

I have been warned that if I ask for opinions and corrections I will be overwhelmed and wish I had not asked.... So, any obviously wrong or misleading info in the new wheel/tire tech tip?

Thanks,
Grigg

Fascinating. Thanks! well done!

pretty well lays it out, looks great, lots of info, thanks

This is good stuff. Thanks Grigg, & John.

Thank you very much, Grigg and John. Great job.

There is an error in how metric tire sizing works. The second number is the % of the section width (first number) that the hight of the sidewall is. In the example given, a 75%, the sidewalls are 75% of the section width. It isn't 75% sidewall and 25% tread. On lower profile tires, if the section width remains the same, the width increase will not be very great, so a 50 series tire with the same section width will be considerably shorter, but the width will be almost the same, perhaps within a 1/2" of the taller tire's dimensions. If properly plus sized to keep the same diameter, then the width will be increased greatly.

Bill, would you be willing to re-write that portion?

Thanks,
Grigg

Hey Grigg, the big trucks didn't come with diesel right?, i found this one on ebay, thought you might find it interesting http://cgi.ebay.com/ebaymotors/1950...3133QQcmdZViewItem?hash=item280204583133

GMC did offer the Detroit Diesels factory with big trucks, I believe 450 size and larger, starting with a 3-71.
That Cannonball appears to be factory (and should be), it is a little unusual in that it has a 4-71, as many of them had 6-71's.

I was all set to buy a Cannonball with a 6-71 a few years ago, but was quickly talked out of it by an older friend and fellow GM truck and Detroit fan. He too likes the looks of them, but has some experience operating and working on them...

Thanks,
Grigg

Great tech tip, Grigg. Wish I'd had that several months earlier!!!

You should check your linked pictures of the clamp plates, though. They both reference the 10-hole rear plate. Do you have any idea as to their purpose? Added strength? Or why the 19.5 wheels from P30's and 3500HD's have clamp plates with chamfered holes and conical lug nuts? Since they're hub centered, I would think you could just use washered lug nuts directly on the wheels like you show on your 22.5 wheel.

Also, as for the metric tire sizes....the way I understand it (and I'm pretty sure I'm correct), is that in your 245/75R22.5 example, the 245 refers to the tread width in millimeters, the 75 is the aspect ratio, R is radial, and 22.5 is the wheel size in inches. (Why they combined standard and metric is beyond me).

The aspect ratio means that the sidewall height is 75% of the tread width (75% of 245mm is 183.75mm). 183.75mm is about 7-1/4 inches. So, you add twice the sidewall height to the rim diameter to get the overall height of the tire----- 22.5 + 7.25 + 7.25 or about 37 inches. Again, why they combined standard and metric is anybody's guess.

So, that means that if you switched to a 245/50R22.5 low profile tire (if there is such a size), the tread width is still the same (245mm), but the sidewall height is now only 50% of the tread width, so the tire is much shorter. To maintain the same overall diameter, you would move to a larger rim size.

One more note...The 8R19.5 tires on my donor truck measure 33-1/2 inches tall. The old 6.50x20 are also 33-1/2 inches. 7.50x20 are about 34-1/2 inches. So, for some folks with smaller original tires, the 8R19.5 might not be such a bad swap (if they clear the brake drums).

Hope this helps,
Bob

Oh, and it's spelled "Dually", too.

-Bob

Bob,
Thanks,

The pictures for the clamp plates are identical, but they show both plates, 10 hole, and in the background the 5 hole.

The purpose of the clamp plates are to add strength at the center of the wheel. The wheels are designed to use the clamp plates. I have used big washer face lug nuts without the clamp plates, but am switching back to using the clamp plates now that I know better. Mine are at the powder coater now, should have them back by the end of the week.

Ford uses the same bolt pattern and they use swiveling washer face nuts, but the center part of the wheel is nearly twice the thickness of our wheels, so they are designed to use nuts only, no clamp plate.

The original AD clamp plates have flat surfaces around the holes, and use tall nuts with flat ends, similar to what is used on the spring U-bolts.
The new style do have countersunk holes, and use chamfered lug nuts. I don't have an explanation as to why, other than it accomplished the same thing, but I do know they have no part in centering the wheel itself.

Someone else helped with the metric tire size part, and truthfully I have a general idea how it works, but I never bothered to really learn, as I don't plan to use any of those tires.
Sounds like I need to get edumicated and correct that part of the tech Tip... I know I have read a good simple and short explanation somewhere, now to find it again..

Grigg

Grigg, Those 22.5 red wheels you got have a 5.25 center,right?
Are you going to put in ring to make these fit your hub ?
Hey , Thanks for all the effort you put into this, it's too bad there aren't more options out there to cure this 2 piece wheel nightmare.
22.5 wheels are a great way to go but thats a heavy price for the tires when you have good 20 inchers already.
I had been out there looking for a 20 in rim,thinking that if I found a rim I could punch out the centers from my old wheels and weld them in the new rims. The idea worked great with some 26 in tractor wheels I made last summer.
Ya know with all this talk about how dangerous these 2 piece wheels are I was gettin scared to take them off my truck,but I'm still here and they're off the truck ! thanks again
Dan

Dan,
Yes, the 22.5" wheels I have from a 56 1.5 ton have 5.25" center holes.
I have axles from the mid 90's under my truck, so they already have the 5.25" hub (they changed from 4.75 to 5.25 over 1953/54)
You can find stock 20" three piece wheels no problem, most every AD 1.5 and 2 ton truck has them.


There is a mentality out there that any wheel with more than one piece is a "widow maker" and that all these wheels are a huge problem, no one will work on them, and every last person that tries to gets killed in the process.
This is not true! With this Tech Tip John and I have tried to educate people about wheels and that most multi piece wheels are truly OK to use. Check out the last three "definitions" in the tip.
The "Split Rim wheels" definition, click the link to the Budd wheel catalog. The wheel shown at the bottom left is the one to avoid, all the rest are reasonably safe if the wheel is in good shape and treated with respect.

Grigg

Grigg, I appreciate the effort you guys have put into this.

Id love to see what you come up with when working with 5 lug wheels. I know my Gmcs hubs are a lot bigger then Chevys and they can range from 4-6" on the larger trucks, also the studs are quite a bit bigger as well. My Gmcs hub is a bit over 5" and is hub piloted.

Keep up the good work.

Jeff

Thanks Grigg and John and everyone that added info. Great tech tip!! Only one small addition as it relates to AD 3/4-tons. The standard wheel seems to be 15" - 15x5.50F semi-drop-center - of 2-piece design: a wheel with one bead flange/rim and a separate locking ring/rim. 7.00-15 tires in 6- and 8-ply were supplied. That applies to all three AD 3600's I have owned. Good Work!

From your (all of you) suggestions above I double checked some things and rewrote a few parts. Then John made the changes online, a number of little things as well as fixing the metric tire size info.

Again, the Tech Tip can be found here
http://www.stovebolt.com/techtips/wheels/

Grigg

Great work guys!! Although the main focus was on AD era wheels, it has plenty of information that I can use with my Art Decos.

I printed a copy to put in my shop.

Thanks for all the hard work.

John

Great Tech Tip.

Here is a link to a few pictures of some of the wheels discussed.

http://rides.webshots.com/photo/2095006560033981030mrRXGI