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Tennessee Wheel and Tire \  Running 4 Alcoa 19.5's on back of 3500HD (GMT400)

Running 4 Alcoa 19.5's on back of 3500HD (GMT400)

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following 3
someotherguy   +1y
Hey Trevor, got what is probably a "milling" question for you, so please feel free to PM me with a quote if you think it's necessary or would even work. Seems like it might be removing too much material from the wheel, dunno.

I've got a whole pile now (8 total) of 19.5x6 Alcoa's, the 761001/761002 part number, 10 lug x 7.25 bolt circle, for fitting the old GM-platform Class A motorhomes, and GMT400 ("OBS") 3500HD's. As far as I know these were never actually offered on the 3500HD's but are the same pattern, as well as the larger P30 stepvans with the same pattern, etc. but I have only ever seen them as optional equipment on the big RV's of the 80's/90's.

The Dana 80 on my '95 3500HD has enough wheel stud, no problem, plenty of it - but of course these are hub pilot wheels. The flange on the hub is only wide enough for two steelies, not two aluminums. The steel wheels have a roughly 19/64" thickness at the flange, where the Alcoas are 9/16". I'm sure I could get away with running a steel inner and an unmodified aluminum outer. I reaaaaally wanna run two aluminum on each side for the weight savings, about 30lbs each wheel.

The guy I bought 6 of them from actually had all 6 on his motorhome, which surprises me, dunno what axle they had but I would have assumed it was also the Dana 80.

I measured the wheel studs and they're 5/8" thick; the holes in the wheels are about 41/64". I don't think I would trust them to not flop around and tear themselves up since they are NOT stud pilot.

Here's another thought, a hubcentric ring that I could just clamp-fit behind the OEM clamp ring and lug nuts? That's how guys are getting away with running these wheels with the 5.25" hub bore on the 40's heavy trucks that have a 4.75" hub. " target="_blank" target="_blank

One aluminum installed, takes up the whole hub flange:

Two aluminums installed, stud holes pretty much line up but I don't trust it:

Plenty of stud length though for everything including clamp rings if I run them:

Amount of hub flange left if I run a steel inner:

The more I look at it I guess the older trucks those guys are talking about must have a small bore on the clamp ring because when I look at mine, there's no way it could sandwich in a hubcentric ring because the hole on the clamp ring is large, too; looks like the full 5.25"

Post was last edited on Dec 26, 2011 08:12. This post has been edited 2 times.
lockone   +1y
Will send a pm over.
lockone   +1y
For some reason it will not let me post or pm my reply to your question. The site just sits and trys to load the answer.

Richard if you want to give me a call we can talk this over in further detail. 931-308-6994 is the easiest way to get me during the day if no one answers at the shop.
someotherguy   +1y
Thanks Trevor I'll give you a shout tomorrow and see if I can catch you while you're not too busy.

someotherguy   +1y
Hey Trev, tried calling a couple times and couldn't get through. Didn't wanna hassle you...if you don't mind posting up any ideas or PM'ing them to me I'm still interested in trying to run all four across the back. I just had them all polished up, ordered new Alcoa-badged center caps, and I guess the only two piece washer style nuts available for these damn things (Haltec/Alcoa) other than the tall chrome ones which I don't really like. Can't believe how much the damn lugs cost, gotta be similar to what y'all get for semi lugs. Stupid 5/8" thread...

Anyway, eye candy:

byecorp   +1y
are those rims for sale?
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