The Stovebolt Site Forums The Parking Lot Tons 'o Fun 19.5 wheel lugs

I finally acquired 6 powder coated 19.5" wheels and 225/70 tires to replace the 3 piece 18" wheels on my 1959 38 flat bed. My truck has 1/2" lug bolts and the wheels have 5/8" bolt holes. The center hole is the correct size (4.56").

Is there a solution to the lug size difference short of drilling and replacing all the lug bolts with 5/8" ones?

The wheels did not come with mounting rings (the flat piece between the tire and lug nuts). Are these required?

Any words of wisdom are appreciated as I figure out how to use my new rolling stock.

The clamp rings are recommended. I'd even say required.
I expect the wheel is really supposed to use a 9/16" wheel studs.
With the clamp plates that use a beveled lugnut I bet you can find a 1/2" lugnut that will correctly fit the seat/bevel in the clamp plates, it'll probably have a larger than usual hex.

If you don't like that method your next choice is press out the original wheel studs and press in new 9/16" ones, and likely have to bore the holes in hub and drum larger to fit an available 9/16" stud. Might get lucky and find a direct replacement, all depends on the size of the knurled shank and what you can find.

Ah, now I know why my 19.5"s have that ring..

jose

Thanks Grigg,

I have located a set of 4 clamp plates. However, my measurements seem to indicate I may need new studs regardless. The mounting flange on the old wheels is 3/16" thick, the 19.5 wheels are 1/4" thick. If the clamp plates are also 1/4", thats an extra 5/16" thickness for the studs to go through on the front and an extra 3/8" on the rear. It doesn't appear the existing studs are long enough to accommodate this.

A potential alternative might be flanged lock nuts as listed by McMaster-Carr (p/n 90949A037). These are 1/2-20 nuts with a 1 1/8" diameter flange.

Any thoughts before I start replacing wheel studs?

Thanks,
Steve

I used flanged lug nuts on my 2 ton for a while... until I learned they were supposed to have clamp plates and put them back on.
Don't have the link handy but in the Accuride wheel catalog under the 19.5" 8 and 10 lug GM wheels they call for the appropriate clamp plates in the mounting detail, and I think also give the part numbers.

The clamp plate adds some strength to the center of the wheel that flanged lug nuts cant quite compare to.

Grigg

Grigg,

Thanks again for sharing your knowledge and experience. I will get the clamp plates.

Steve

Hey guys,

I have the 19.5 wheels on my 1 ton and don't think I've seen these plates you're talking about. Could one of you post some pics of em?

thanks,
~Dave

This is on a 2 ton but same idea, the black plate is the clamp plate.
https://picasaweb.google.com/lh/photo/RFsNMIS9lBhbuIqC2lp0UdMTjNZETYmyPJy0liipFm0?feat=directlink

Also on a 2 ton, but this is an original one. The older ones like this use a flat lug nut (the nuts with the little slits in them are original Marsden nuts), the later/modern clamp plates use a beveled lug nut
https://picasaweb.google.com/lh/photo/SlJJGfds_gFZpL2YoQzTNdMTjNZETYmyPJy0liipFm0?feat=directlink

I bought 4 clamp plates today from a shop that sells used medium duty trucks that also includes a truck scrap yard. I got the ones that use a beveled lug nut. While looking at their used trucks I noticed a F550 with 19.5 wheels and no clamp plates, only the flanged lug nuts. The owner had no opinion as to which I should use. Even though I got the clamp plates, I returned to the truck tire shop that mounted my tires and asked the owner which I should use. His observation based on changing a lot of truck tires is that Chevrolets with 16s typically have clamp plates, while 19.5s almost always have the the flanged lug nuts and no clamp plates.

Steve

A F550 ford uses different wheels than our GM trucks, the ford wheels have a lot thicker center and they use two piece flange nuts, the flange swivels on the nut.

Again, I would still use the Clamp plates on the GM 19.5" 8 lug (and 10 lug) dual wheels. There are a few step vans with the 19.5" 8 lug wheels still here where I work and they have always had the clamp plates on them.

In this tech tip http://www.stovebolt.com/techtips/wheels/ in the "Overview" section is a link to the Accuride wheel catalog. http://www.accuridecorp.com/files/2012/10/Accuride-Wheels-Product-Catalog-Summer-2011.pdf
On page 27 is all the info you need from the company that made the wheels you're using.

Grigg

Grigg,

Thanks again for providing a definitive answer. During my review of the Accuride website for information, I somehow overlooked the info you quoted from on page 27.

The good new is I now have the clamping plates. The bad news is I need new lug studs in order to use them.

Steve

I have a 52 1 ton dually with the original 18" wheels. I found a 69 Chevy 1 ton dually with 19.5 one piece tubeless wheels and they have the same center diameter and same size lug holes as the 52's 18" wheels and even have the same flat lugs with the slits on both trucks. These 19.5 wheels do not have clamping plates and should not have them because they are basically hub and lug centric, correct? Are these style 19.5 wheels difficult to find? I was planning on trying to find an extra 1 or 2 for spares but have not seen any more of these anywhere. Just thought I would ask a few questions since most of the knowledgeable 1 ton guys seem to be posting on this thread, thanks.

It sounds like you have found a great set of wheels that will work for for application. After buying my 19.5 wheels, I found I'm not near as knowledgeable as I need to be. This simple? wheel change has resulted in needing: clamp plates, replace 1/2' studs with longer 9/16" studs, add a spacer plate to the rear because the inside wheel presses against the edge of the brake drum, and adjust front turn stops to correct interference with drag link. Also, it looks as though I will have to trim a bit from the lower edge of the flat bed flange directly above the outside tire because the 225/70-19.5 tires are, of course, wider than the original 7.00-18s.

On the plus side, it should look and drive great when I'm finally done.

Yes, I think I got lucky finding the wheels but then after finding them, I found 5 700-18 6 ply Denman tires with the tiddies and mold marks still intact for $300 shipped to me with tubes and flaps. I really like the look of the original 18's so I will probably look for a couple more decent 700-18's and at least have them for my truck even if I do decide to put the 19.5's on.

52Torpedo,

Sounds like a good plan. I have 4 never mounted 7.00-18 Kelly tires just in case. My 19.5 wheels apparently came from a P30 chassis ( bread van) and seem to have more offset than the one ton 19.5s like yours. I would love to know the back spacing (measurement from the flat inner mounting surface to the rim lip) on your rims to compare to mine.

Thanks

The backspace looks to be about 8.25", give or take a little as I measured with the tire on. I am guessing that the wheel width is 6" but may be less, I did not measure that but I will. I am putting 16's back on the 69 and I was going to measure them as well to see if this BS measurement is about the same on them. I also have 17.5's on the 52 as rollers right now that I can also measure, but only 1 on each rear facing out because they would not clear the rear brakes either.

I quoted myself because I wanted to update as I answered one of my own questions. I couldn't believe it but I found another single tubeless 19.5 wheel at a salvage! It is identical to the 6 that were on the 69 1 ton so now I have a spare! I am not sure what these would have came on originally because my 69 said on the glovebox sticker that it originally had 18" wheels and tires. I know 73up duallys had 9/16 studs so these wheels would have to have been made 72 and earlier because they just fit on the 1/2" studs perfectly. I will keep an eye out for more but I have a feeling they are a relatively rare wheel.

I agree, they are rare. I recently found a 1956 one ton flat bed with what appear to be factory 19.5 wheels. The wheels have 1/2" lug bolts and use the same lug nuts as the 18" wheels. I tried to buy the truck, but the owner owns several old vehicles and apparently doesn't believe in selling, only buying.

yes, I've seen a number of the 19.5" 8 lug dual wheels with the small bolt holes for the old 1/2" wheel studs.

Grigg

Were the wheels tubeless type? The 19.5's I have are tubeless. Also, I finally dismounted one and they are exactly 8" backspace.

19.5" wheels, like 22.5", and 24.5", and even 17.5" will always be tubeless. It's the whole number sizes that were originally tube type, then the half sizes came out as the tubeless wheels. This is still true for the wheels and tires we're interested in for our old trucks.

These days car and pickup tires with whole inch rim diameters are also tubeless. That's an exception to the old rule of half size wheels being tubeless and is no help for our old wheels and tires.

Grigg

What years would have had the 19.5, 8-bolt wheels with the smaller holes for 1/2-inch studs?

I'm needing 2 for my 1959 Chevy to complete the set with a spare. I was lucky enough to find someone junking out a 59 GMC and found four usable rims. Could have had all six but the lugs had run loose and reamed out the holes on two of the wheels: one's good enough for a spare, but the other was too far gone in my opinion.

56 is about as early as you'll find them, and I don't recall when the studs changed form 1/2" to 9/16", but that's the later cutoff point.

No reason you can't use the later wheels with 9/16" stud holes and still use the original clamp plates and nuts.

9/16 studs started with the new 1973 body style. My 70 1 ton had my 19.5 wheels so it obviously has the 1/2" studs and I saw a 72 1 ton that also has 1/2" studs.

My 19.5 wheels on the 70 did not have clamping plates. They used the same slotted flat lug nuts as my 52 18" wheels. These are hub and lug centric so I guess they do not need the plates. I also looked at the stud length on both trucks and the studs are not long enough to use a clamping plate. I have some from a 70's/80's dually and it is just will not work.

This looks like the 19.5's that I have:

Ebay link