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This is mainly for anyone who has been running replacement flat Hummer rim centers for a while.

Are you experiencing any deflection or bending of these flat centers? I haven't looked at it mathematically, but it sure seems to me that these flat centers coupled with the leverage of hydro steering and BIG tires could result in these flat and un-supported centers bending to produce a wobble in the wheel rotation.

Just a thought I had... feel free to agree or tell me why it doesn;t work that way :p
 

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funny you brings this up DRM. when i first saw those i was gonna bash them and say how stupid a desing it is. that they were just gonna bend way to easy and so on and so on. then i decided i didn't have the time to do the research to support my veiw point and decided to just wait until people posted pics of their bent centers so i could just laugh.

my .02 is that they will bend.
 

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I had the same thought when I first saw pics of 66CJDean's Hummer wheel centers, but figured that some thought must have been put into this, plus I think his centers are quite thick, still, it would be nice to "dish" the centers a bit, or weld in some gusset "spokes"
 

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well we cheaped out and made a set from 1/4" for a zuk on 38's and can honestly say he has bent the shit out of them. we were thinking about the light weight of a zuk it would hold. we were wrong. mike
 

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jason never bent any of his hummer centers. But he made his centers out of 3/8 high strength steel. Not mild, and he is pretty hard on the wheels too.
 

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Discussion Starter · #7 ·
gunracer1 said:
well we cheaped out and made a set from 1/4" for a zuk on 38's and can honestly say he has bent the shit out of them. we were thinking about the light weight of a zuk it would hold. we were wrong. mike
Regardless of weight, I can see where the Zuk would be worse... since the smaller axles have a smaller rotor "hat" surface (or hub surface) and that means more of the flat plate is "exposed" and allowed to flex. a tall tire like a 38 only serves to add a LOT of leverage to that too.
 

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gunracer1 said:
well we cheaped out and made a set from 1/4" for a zuk on 38's and can honestly say he has bent the shit out of them. we were thinking about the light weight of a zuk it would hold. we were wrong. mike
ya but it was damn shure fun bending them .i even think gunracer spilt his beer :flipoff2:
 

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I think the worst case that could be seen is a set of 20" rims on a rig. so if this is GROSSLY oversimplified, we could say that on an 8 lug 6.5" bolt pattern, each bolt is supported by a 1/8th pie slice of the wheel disc. the capacity of the pie would increase as it widens linearly with the diameter of the wheel.

so say 20" rim, forget about all the rim crap along the outside, and that's (20"-6.5")/2 = 6.75" between any bolt and the outer rim.
the section at edge is 20*Pi/8 wide = 7.85"
at 3/8" thick, the section modulus of the pie slice is 0.184-ish.

on 60 ksi steel, that should yield at about 11 k-in.

say we toss 8k lbs on the wheel for easy math, each lug would take 1k. so 1k at 6.75" is 6.75 k-in. that's about 38% safe.

I'd use a saftey factor of 3, personally, but this is a really conservative way to run the numbers and doesn't account for any internal plate action.

if you re-run the numbers for 1/4" plate, the plate fails by about 12% on a 15" rim and about 28% on a 20" rim.

somebody please check my numbers. I've been in a slump lately doing "duh" work.
 

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Sundowner said:
I think the worst case that could be seen is a set of 20" rims on a rig. so if this is GROSSLY oversimplified, we could say that on an 8 lug 6.5" bolt pattern, each bolt is supported by a 1/8th pie slice of the wheel disc. the capacity of the pie would increase as it widens linearly with the diameter of the wheel.

so say 20" rim, forget about all the rim crap along the outside, and that's (20"-6.5")/2 = 6.75" between any bolt and the outer rim.
the section at edge is 20*Pi/8 wide = 7.85"
at 3/8" thick, the section modulus of the pie slice is 0.184-ish.

on 60 ksi steel, that should yield at about 11 k-in.

say we toss 8k lbs on the wheel for easy math, each lug would take 1k. so 1k at 6.75" is 6.75 k-in. that's about 38% safe.

I'd use a saftey factor of 3, personally, but this is a really conservative way to run the numbers and doesn't account for any internal plate action.

if you re-run the numbers for 1/4" plate, the plate fails by about 12% on a 15" rim and about 28% on a 20" rim.

somebody please check my numbers. I've been in a slump lately doing "duh" work.
what the hell did he just say
 

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My thought on this is look at a dually wheel. Yes it has a dish shape but is made of .135-188 at best. They are completly offset so the center has to take all the force and they last pretty well it seems even with 80psi tires. Ah but you say there are to fo them to take the weight.... but not in front and not if you hit a curb, rock, or hole and yet they still live. I don't doubt that it is possible to bend them but I would bet that if you did you would have bent any other wheel in that same instance.
 

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Uh me land on winch plate with Scout II, 3 footem drop. Winch plate 3/8" plate, 8" stickout, good no bend. IH motor heavy, still no bend. Me thinks 3/8" ok for wheel'em center, 1/4" not so good :D
 

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On all the 20" 2 piece wheels I make I use two pieces of 1/4" A50 steel. the bolt circle that holds the two halves together is 17.5". I think this is plenty strong, because you have a total of 1/2" of steel in the center, it is a slightly higher grade of steel, and laminated steel is stronger than non.

John
 

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JOHNS351C said:
On all the 20" 2 piece wheels I make I use two pieces of 1/4" A50 steel. the bolt circle that holds the two halves together is 17.5". I think this is plenty strong, because you have a total of 1/2" of steel in the center, it is a slightly higher grade of steel, and laminated steel is stronger than non.

John
thats how we are going to fix mine weld 2 1/4 inch pieces together .
 

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3/8" high-strength cold-rolled centers...

I have absolutely wheeled the piss out of mine, and haven't bent them yet. I just ran them out after the last trail ride I went on to make sure they weren't starting to bend, and they were still true.
 
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