[DeTomaso] Wheel weight

[Ken Green]

The wheel making I talked to mentioned that some failures are because the rims are too stong.  If the rim is ridged, when the tire hits something, all of the shock that gets to the rims is directly passed to the center.  He said a properly engineered wheel distributes shock between the rim and the center.
 
I overheard one conversation between a wheel seller and a potential buyer.  The seller said he gets the wheels from China and they cost only a little more than the material and shipping.  I had the feeling that he had no idea of the soundness of a design or the metalurgy in the wheels he sells.  He was much cheaper than the US wheel maker.
 
It seems like there is a lot more to wheel design than appearance.
 
Ken

--- On Fri, 11/6/09, JDeRyke at aol.com <JDeRyke at aol.com> wrote:


From: JDeRyke at aol.com <JDeRyke at aol.com>
Subject: Re: [DeTomaso] Wheel weight
To: julian_kift at hotmail.com, detomaso at realbig.com
Date: Friday, November 6, 2009, 11:35 AM


In a message dated 11/6/09 6:16:08 AM, julian_kift at hotmail.com writes:

> just because there are documented cases of Hall Ultra Wheels cracking it 
> doesn't call for sweeping across the board statements. When were Hall Ultra 
> wheels made? In the 80's probably, we are now 2 decades on, no one's doing 
> stress calcs on the back of envelopes anymore.
> 
Hall Ultra 2 wheels aren't the only brand that has failed on the street; 
there are several others. Street car owners by and large do NOT rigorously 
maintain their cars like racing machines. So noting that truth, bolt-together 
3-piece wheels on street cars are generally a bad idea. Sure, Hall wheels 
were built in the mid-'80s- and some are still on street cars today, which only 
proves my point. In the case of the Hall wheels, we don't even know the 
alloy used- the actual manufacturer has passed away as has the seller, Gary 
Hall. I seriously doubt if ANY stress analysis was ever done but we'll never 
know. 
Work hardening, stress cracks, bolts or rivits loosening, centers cracking- 
most 3-piece problems are not noticed until air pressures start dropping. 
The most common result of loss of air pressure? GLUEING the rim halves 
together so it doesn't prevent the car from being driven. In the Ultra 2 case 
described in my post, ONE rim-half out of a set of 8 failed. In racing, that's 
entirely acceptible, but not on the street.
Bottom line: these are RACING wheels and should be treated as such; not 
doing so is ultimately at the owner's risk. Most 3-piece wheels made today come 
stamped 'For Racing Use Only' and I find that significant. I'm as lazy as 
anyone else in regard to routine maintenence, so for me the risk is just too 
high, the financial hit of discarding them after a short period of use is 
too much, so I feel that warning non-engineer street car owners of the hidden 
costs of some adapted racing parts is responsible reporting. 
On your personal cars, I assume you will be carefully watching your modular 
wheels for potential problems, and posting any problems you find. They 
might or might not show up right away so keep your harnesses tight (also 
something some street-car owners still don't do). Good luck- J Deryke 
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