wheels after crossmember swap?

[63whoopie]

Ok, it's lesson time again; I need to be taught a few basics.

I am looking into doing a crossmember swap from a pre- 1/2 ton '87 onto my '63 C10 to give me discs and the 5x5 bolt pattern. I see 5x5 advertised on wheels that say BOP (Buick, Olds, & Pontiac)... does that mean this will fit a truck hub? I also see 5x4.5 advertised for Chevy's- is that a car lug pattern?
Also, can someone explain the "unilug" phenomenon to me? Best I understand, one size fit's more than a few hubs w/ some sort of lug nut or special shim; dosen't sound too terribly safe...
(I am not even going to waste your time with backspacing and offset and all.... I'm looking it up online.)

Thanks in advance..

[markeb01]

Yes, essentially anything with a 5 lug 5 inch bolt circle will fit on the 5x5 Chevy truck pattern. Buick, Oldsmobile, Lincoln, later Chevy big cars will all fit. From about 1949 until the 70's Chevy passenger cars all had the 4 3/4" bolt circle, while Ford passenger cars and Mopars had the 4 1/2" pattern. Most would interchange, but Mopars and Fords used different interference angles in the lug nut seat, so some combinations could be a problem in staying tight. At one time I ran mid 50's Buick wheels on my GMC. In the 60's these were the poor mans reversed rims.


Any of the 5x5 wheels will work so long as the center hole is big enough to clear the hub. If they are going on disc brakes, you'll need to check for caliper clearance if you're using wheels from the 50's.


Unilugs started out on ET mags back in the 60's or early 70's. The wheel has a recessed area for an oval washer which has an offset lug hole. An example can be seen at the following link:
http://cgi.ebay.com/ebaymotors/20-ET...Q5fAccessories

Here's what the washers/lug nuts look like installed. They wheels came in slot mag style, 5 spokes like American Torque Thrusts, and big window as shown:
http://cgi.ebay.com/ebaymotors/1969-...sQ5fLiterature

They were actually very nice wheels, well made with good offsets. The washers came in two sizes, 4 3/4 for Chevys and 4 1/2 for Fords. If you rotated the 4.5" washers 180 degrees in the seat, they now produced a 5" bolt circle. I believe there are other versions of unilug wheels now, but these where the type I used to have.

[Slow Build]

You don't have to swap the crossmember to get disk brakes and 5 lug pattern.

[63whoopie]

markeb01-
Thanks for the very informative and thorough response; that confirmed all my beliefs. Questions- what is the sizing and all on your American 5-spokes, and what tires are you running on them? I would like to know to get an idea of what things look like under a stock-height truck.

Slow Build-
I know you don't, but if all it takes is bolting up 4 bolts and only having to fudge two of them, I may as well take the whole thing, it's the same price anyway. Thanks for watching my back, though.

[Tx Firefighter]

It's not 4 bolts, it's 14 bolts that hold the crossmember to the frame.

[markeb01]

The wheels in the recent pictures are the American TTO version with the 5x5 bolt pattern. The fronts are 15x5, with BFG Radial T/A's. Tire size is 215-70R-15, and are about 26.5" tall (off the truck) with a tread width of approximately 6.5".


The rear wheels are 15x7 with Firestone Firehawk Indy 500 tires size 255-70R-15. They are 28.75" tall off the truck, with a tread width of 8.5".


I prefer the way they look for back tires since they have more of a square shoulder and look beefier. They're mounted with the white letters on the front side, since I didn't care for the design on the blackwall side. I colored out the letters with a chisel point Sharpie, and seal it with ArmorAll Extreme Tire Shine Gel. It lasts about a year before needing any touch up. It would have been easier to mount them blackwall out, but I've always been a bit nuts about wheels and tires. If I ever make another change it will be to swap out the front wheels for 15x7's. I'd still mount the smaller tires for a staggered look, but they would appear deeper and probably look better than the 5" rims.

15x8 TTO's will fit just as well, but I don't like the design of the wheels. They have an extra machined space in front of the spokes that just doesn't look right to me.

The 5 spokes on the front of the truck in the picture with the Buick wheels on the back, are 1968 era 15x6" Dragmaster mags. I was surprised they fit over the disc brakes very nicely with just a tad of light grinding on one of the calipers.