Re-centering wheels with aluminum

JDodd · Jun 20, 2016

I'm needing some custom offset wheels and wanted to see if anyone has tried welding on a ring and bolting an aluminum center to it. If so what thickness did you use?
I did some simulations on my computer and using a .5" center and a 15,000 lb force there was .000629" distortion from a straight on force and the same 15,000 lb force applied to the side had a distortion of .001306".
From these simulations, .5" looks to be fine but personally it seems thin to me. So what do yall think, is it enough?

patooyee · Jun 20, 2016

I think way too thin. Most aluminum wheels are much thicker than that with contouring in addition to material thickness that increase rigidity. 15,000 lbs doesn't seem like a lot of force either. Don't know how much your rig weighs but say it weighs 5000 lbs. I would think adding a vector to that mass would increase resultant forces exponentially, not just 3x. I have no clue how much but I would guess 100,000 lbs or more.

TBItoy · Jun 20, 2016

Re:

1/2" 7075t6 should be decently strong. And expensive

3/4 7075t6 I wouldn't worry about at all.

I wouldn't use 6061

Rockwells607 · Jun 20, 2016

My raceline rockets are .75 thick almn.

patooyee · Jun 20, 2016

Rockwells607 said:
My raceline rockets are .75 thick almn.

They're not flat though, are they? They have some dish / contours to help strengthen them.

TBItoy · Jun 20, 2016

Re:

The high dollar Weld racing wheels are 2 piece with center welded into a shell. (Also how all the high end billet center hot rod wheels are made) Many of these aren't 3d patterns, so they are essentially a flat plate center

I doubt anyone makes a one piece billet wheel

617_Racing · Jun 20, 2016

What size wheel? I'm sure the height of the center will play a huge factor.

patooyee · Jun 20, 2016

Re:

TBItoy said:
The high dollar Weld racing wheels are 2 piece with center welded into a shell. (Also how all the high end billet center hot rod wheels are made) Many of these aren't 3d patterns, so they are essentially a flat plate center

Unless I am mistaken as to what wheels you are referring to, none of those are meant to hit rocks at high speeds. All the cast and forged beadlocks that I see any rock rigs using are all way beefier than what you mentioned.

patooyee · Jun 20, 2016

Try this. Use your same center only change the material to 1/4 steel. Apply force increasingly until it deforms / gets destroyed. (Since people do commonly bend 1/4" flat centers.) Now apply that force to your aluminum center and see what happens.

(I'm not being sarcastic. I'm genuinely interested to see the results.)

TBItoy · Jun 20, 2016

Re:

People commonly bend 3/8 steel flat centers too, but I think a lot of it has to do with material selection.

Usually not enough emphasis was/is put on material selection in our hobby.

Regular ol hot rolled plate, vs XT100 (or other high yield impact resistant steel)

6061 vs 7075 aluminum

JDodd · Jun 20, 2016

patooyee said:
Try this. Use your same center only change the material to 1/4 steel. Apply force increasingly until it deforms / gets destroyed. (Since people do commonly bend 1/4" flat centers.) Now apply that force to your aluminum center and see what happens.

(I'm not being sarcastic. I'm genuinely interested to see the results.)

Theses are going on a Toyota pickup with 40's so it's definitely not going to be seeing any crazy impacts, but I'll see that the 1/4" steel comes out to later tonight.
I just plugged in these values in real quick to see, first set is 100,000 lbs and the second is 200,000 lbs. I think 200 is about the limit on what they could take.

TBItoy said:
1/2" 7075t6 should be decently strong. And expensive

3/4 7075t6 I wouldn't worry about at all.

I wouldn't use 6061

You're hinting at why I started testing the strengths, the thinner I can make them the cheaper they are. Right now I'm looking at $400 to just cut the centers and another $250 for the blank rims.

Rockwells607 · Jun 20, 2016

The racelines have some contour not a flat plate . They are also one piece wheels

TBItoy · Jun 20, 2016

Re:

I'd run a solid, flat, 3/8 7075 plate center and never think twice about it. (On my Toyota)

It'll be stronger, tougher, and more resilient than standard hot roll plate steel. And 60% lighter.

Of course you have to add the bolt ring and hardware, so you lose some weight savings there.

patooyee · Jun 20, 2016

I was kind of assuming bouncer. If we're talking about a DD / trail rig then my requirements go way down and are more inline with Weld Racing-type of wheels. JDodd also never said the material he was considering or how it was going to be cut. Any heat-treated aluminum is going to lose a good bit of its treatment if it is flame or laser cut I would think. Water jet or machined would be prefered.

TBItoy · Jun 20, 2016

Re:

Oh yeah,

I assumed you are looking at doing a steel wheel shell with an aluminum center, correct?

Besides just being different, why? (Since you can order custom offset factory built steel wheels very easily)

I guess you could change your offset by bolting the center on either side of the ring...

JDodd · Jun 21, 2016

patooyee said:
I was kind of assuming bouncer. If we're talking about a DD / trail rig then my requirements go way down and are more inline with Weld Racing-type of wheels. JDodd also never said the material he was considering or how it was going to be cut. Any heat-treated aluminum is going to lose a good bit of its treatment if it is flame or laser cut I would think. Water jet or machined would be prefered.

They are going to be 7075 and cut on a water jet.

TBItoy said:
Oh yeah,

I assumed you are looking at doing a steel wheel shell with an aluminum center, correct?

Besides just being different, why? (Since you can order custom offset factory built steel wheels very easily)

I guess you could change your offset by bolting the center on either side of the ring...

It is going to be a steel rim with aluminum centers. I guess the main reason is just to be different, and I haven't decided on the size yet but I can get 20" steel rims and if I use them everyone knows 20's need some bling in them.

JDodd · Jun 21, 2016

For the strength of steel vs. aluminum, I used .25" mild steel and .375" 7075 in the simulations. Weight-wise they're are virtually the same once you add the fasteners and steel ring to the aluminum.

.25" mild steel had .0519" of displacement at 300,000 lbs
.375" 7075 had .0526" of displacement at 300,000 lbs

This is .0007" difference between the two materials, then you can consider the caricaturists of 7075 vs. steel I think it would hold up fine.
The price will determine if I go with .375" or .5" but since the centers will be removable if I crack or break one they should be easy to replace.

patooyee · Jun 21, 2016

JDodd said:
For the strength of steel vs. aluminum, I used .25" mild steel and .375" 7075 in the simulations. Weight-wise they're are virtually the same once you add the fasteners and steel ring to the aluminum.

.25" mild steel had .0519" of displacement at 300,000 lbs
.375" 7075 had .0526" of displacement at 300,000 lbs

This is .0007" difference between the two materials, then you can consider the caricaturists of 7075 vs. steel I think it would hold up fine.
The price will determine if I go with .375" or .5" but since the centers will be removable if I crack or break one they should be easy to replace.

Thanks for reporting. But if no weight is saved why bother? If this is just about the bling, chrome the steel centers. Or make multiple sets and powder them different colors for every day of the week.