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Discussion Starter · #1 ·
Hello All!

Since there are such a vast array of wheels (particularly GM Factory wheels) with 6 lug configuration, I wonder how feasible it would be to convert a B body to 6 lug wheels. Does anyone know if there are any 6 lugs rotors that would fit the B Body spindles (same diameter as factory rotors), as well as 6 lug axles/brake assemblies that would fit the rear axle housing (My B4U has the full width drum brake rear end).
 
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Discussion Starter · #2 ·
If you're thinking about Cad CTS-V wheels, for example, the answer is "maybe".

The more likely situation would be using adapters. Most new car suspension designs (certainly not the B-body) use wheels with high positive offset to provide room for "zero scrub radius" suspension geometry.

There are adapters available that allow conversion from 5 to 6 lug, but I don't know if there's room to do that while providing adequate strength to deal with the weight of the B-body. The adapter would be the critical piece, offering both a new pattern and proper spacing off of the existing hub to place the wheel correctly in the wheel opening.

Unlike the older design knuckle/spindle on our cars, new cars for the most part use unitized hub & bearing units, which are typically flat on their wheel mating face, or nearly so. The B-body has the long "snout" that has to clear an adapter/spacer and also not collide with the wheel center, cover, etc.
 
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Discussion Starter · #3 ·
I have firsthand experience with 5-6 lug adapters. They are a two piece design, are heavy as hell,and are 2 inches thick. Not the best way to do it.

Late model Astro vans switched from 5-5 to 6-5.5 is there a possibility of conversion?
 
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Discussion Starter · #4 ·
I was thinking of the wheels for the current Astro's, Suburbans, Tahoes, Yukon's, Silverado Pickups, etc. All of them are interchangeable with each other, and not long ago, all of them had a 5 on 5 configuration (in 2WD models anyways), so I figure there must be some compatibility there anyways! Anyone have cross reference guides that indicate which parts will interchange?
 
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Discussion Starter · #5 ·
Originally posted by Navy Lifer:
Most new car suspension designs (certainly not the B-body) use wheels with high positive offset to provide room for "zero scrub radius" suspension geometry.
Have you ever driven a car with "zero scrub radius"...it makes the steering feel completely numb and dead...they're shooting for close to it, but not zero.
 
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Discussion Starter · #6 ·
This is off the top of my head, but ...

Brake rotors with the desired sixlug bolt pattern that are compatible with our spindles - and an ABS reluctor ring? (I.E. Switching to Camaro front rotors which fit our spindles allows for using Camaro wheels, and maybe Wimpala wheels, etc.)

Similar axles with the desired sixlug bolt pattern

Either redrilling the rear rotors/drums, or
hope for direct compatibility between the Astrafari rear drums and the Caprice 11" drum.

That was just a guess, but should point in the right direction.
 
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Discussion Starter · #8 ·
OK, so I made an inappropriate reference, Mike--forgive me? I think my mind was probably working in the realm of high-offset FWD, and I should have stepped/spoken more cautiously.

Whether negative or positive, the direction within GM and Ford, at least has been toward less positive (or is it negative?) "scrub radius", largely due to the emphasis on FWD designs being the bulk of production.

When the C4 Corvette hit the street, it was one of the first wide rim/tire applications with high positive offset wheels and a corresponding SLA suspension design, rather than Macpherson. The unitized bearing/hub that was part of Macpherson strut FWD cars (vertually all brands) and in some GM 4WD trucks, like the S10 & Blazer (circa 1982/3) were the early GM non-FWD applications that could be considered a "Beta test" of what was used on Corvette starting in MY 1984. The AWD S10/Blazer of that era used higher (than RWD) positive offset wheels, too.

The 93 and later F-body followed suit with high positive offset wheels, very much like Corvette. How much of that was dictated by suspension design & performance targets, tires being used, etc, I can't say. It may be more a matter of making room for bigger brakes, and a high-offset wheel left plenty of room for caliper clearance.

The main point is that any 6-lug wheel that might be adaptable would have to have a large enough positive offset to accomodate the resulting thick spacer/adapter that would be needed to change to a 6-lug config. Trucks (current GM) that are 6-lug have a 5.5" BC as Kurt points out, and it's pretty much essential to keep the stock hub on the B-body to be able to have ABS function.

I'm not sure, but I do think all of the current and most recent 6-lug trucks no longer use a conventional knuckle/spindle like the B-body--the hub/bearing--and probably ABS sensor--are bolted to a knuckle/upright casting--even the 6-lug Astro. There's no commonality or adaptability of this design to the B-body. as far as I know. The only interesting thing about saying this is that the Astro and B-body had/have alot in common in the front suspension design, so it would be interesting to see if the last iteration Astro front suspension updright & hub would fit into a B-body upper/lower front control arm--I think the ball joints (5/8" lowers for sure) may be the same, but no idea of what it would do to spindle position (ie. ride height) or wherther steering arms would be compatible....
 
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