Hot Rods Minimum flange thickness on alum. wheel question

I bought a set of american rodmaster wheels at a swap a year ago. The problem is it doesnt have enough backspace. I know I can have the back milled but how much is safe? The car is going to be a family truckster not a corner carving autocrosser. The last photo shows two lines, the black line is where the backspace is on the steel wheels, at that line I have 3/4 of meat left in the flange area the blue line at the back is probably what I could probably get away with, that would leave me 7/8 to 15/16. So whats your guys thoughts?

 

The counter bore go the lug nuts looks like it could be a problem. I think you need to measure the depth of them subtract that measurement from the overall thickness then subtract how much more back space you want. Post that thickness and you will find a better answer. Brian

 

how thick is the wheel at the lug nut holes? Looks like they use conical nuts, and there is not really any extra meat for you to remove and still have the lug area strong enough. But your picture is at slightly the wrong angle, so we can't see the lug nut seat very well.

 

when you are at the machine shop and the back space is where you want it drill the lug holes out and find some old washer and shank lug nutz- just sayin

 

Ill have to have the wheel redrilled because the counter sink on the lugs. Ill run a knockoff to cover the old holes.

 

I've went down to 1" thick on Halibrands. I have a pair of Hal 15x4.5's that are at 3/4" thick as shipped. Yes, you will have to re-drill your bolt pattern in between the tapered holes and use plates or knock-offs.

 

Balcom did more than one pair and took them down to 1" or so with no issues. You should be fine Tim.

 

Got a picture of the backside of the wheels?
Do they use tapered faced lugs, or flat faced nut/washers?
Are they hub centric with your set up?

As others asked, How thick will the floor of the counterbore be after machining the mounting face?

The attached image suggests there Won't be a lot of material left if you generate a rotated hole pattern and include the original large counterbore.

I'd be thinking along the lines of enlarging the counterbores diameter ~3/8" but to a shallow depth, and making some thick goofy steel washers so the nuts would be clamping the thick part of the wheel.

 

The wheels as they sit have tapered lugs and are not hub centric.I could have the machinest make a ring and then they could be hub centric. I was thinking that I wouldnt do a counterbore just drill and taper on the face of the wheel. Or would it be better to use a shanked lugnut so no taper would be used?

 

Shanked lugnut. And an old Halibrand was a lot thinner than an inch when it left the factory. Not saying that your new wheel is as good as an old Halibrand though.

Having a full face cover as part of that "knockoff" would also add strength. Do you have those parts already or do they still need to be purchased? Can you tell us how thick the steel backer/threaded plate is?

 

Dont have knock offs yet.

 

Tim,

I would not use the tapered lun nut holes after thinning up the wheels. The best solution is to redo the pattern with the proper bore for standard shank nuts. Your machinist will know how much clearance based on the nut diameter. I've had them done many times. He will pick up the bolt circle off another true surface. We have been running wheels concentric to the studs for years and I personally have not run into any problems. Make some polished aluminum 1/8" flat plates to go under the shank nuts and washers. Sometimes Real Rodder has them in stock but they aren't hard to make with simple tools. If you want some knock-offs the Speedway ones are well made, nice and sturdy. About $325 or so for a set of four.

Charlie