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This letter in published in the October issue of months Motorcycle Consumer News.




I am a former MC dealer, gear head, analytical type, well read in MC engineering (just finished Tony Foales new book, thank you for printing the info on it in a prior issue) have worked as a MC mechanic and built hundreds of wheels. Regarding the letter from John Fredrikson on the failure of an aftermarket wheel, page 4 of August 2002. When I read it I wondered if this was finally a wake up call for a style of wheel that I keep seeing on Harleys that is designed so wrong it makes my skin crawl! I contacted John, he emailed me before & after photos and it is the design I had worried about! In the interest of public safety we need you to expose this to the next level.

In a proper spoke wheel all spokes are under tension only! To illustrate visualize a wheel that the spokes are made of cable! Cable will hold tension, not compression or bending forces and that is how a proper spoke wheel is designed. In a proper spoke wheel the spoke angles from the rim to a point partly wrapped around the hub with each spoke crossing the others. There are several patterns such as "Cross one", "Cross two" "Cross three” ETC., each having more angle to the spoke than the prior which wraps further around the hub and the more a sharp load pulls the hub together instead of apart! In all of those designs there are spokes going in 4 directions, clockwise angled right, clockwise angled left, counter clockwise angled right and counter clockwise angled left. When the bike is at rest a minimum of four spokes are at or near straight up and are suspending the bike thru tension! When power is applied all of the spokes that go clockwise (viewed from the right from hub to rim) are under tension and at no time is a compression or bending load applied to a spoke! That spoke angularity is crucial for coping with acceleration and braking forces!

The design that failed on John’s HD had 40 spokes ½” in diameter in a “Cross Zero” design AKA Radial (as if that was a good thing)! In such as designing the spokes are under tensions at rest but under a bending load under power or braking loads! They use huge spokes such as ½” on the subject wheel so the spoke can cope with the application of torque but as happened here it ripped open the spoke holes. That style wheel should be limited to the auto shows only but are being sold for street use. John is a mature police office with a show grade HD so I doubt he was abusing it but it should withstand anything you can do to it including most crashes anyway, it ripped the spokes out of the rim with only 300 miles of touring type use.

Engineers have worked for decades to bring the motorcycle to where it is today and someone who does not understand the design principles can endanger their customers lives by ignoring sound engineering principles and developing a product that is based on a “look”!
 

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Discussion Starter #4
Sidewalk...

I believe it is! The pictures were emailed to me the other day from a guy named Dave Hopkins that wrote the article Hippo referred me to in Motorcycle Consumer News.
 

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Highly Seasoned Rider!
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Good Thread!

DPrice said:
Sidewalk...

I believe it is! The pictures were emailed to me the other day from a guy named Dave Hopkins that wrote the article Hippo referred me to in Motorcycle Consumer News.
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Nice article, Mr. Price. Thanks.

Another issue that has been widely ignored on motorcycle spokes is the potential for hydrogen embrittlement when spokes are chromed. I understand from my readings on the topic and some prior experience in the aerospace industry as a technician that chrome plating on high stress items should be combined with a period of heat treating to normalize them and drive off excess hydrogen atoms which apparently cause brittleness in the plated metal. I wonder if heat treating is ever done on chromed motorcycle spokes?

Aircraft plating shops will place re-plated items such as landing gear struts in a heat-treating oven at high temperatures for several hours after plating and grinding. It's required by the aircraft specification.

The article mentions the "cross" of the spokes and mentions that the more spokes that were crossed the better relative to strength. I have always heard this. I laced my own wheels for my Shovelhead about ten years ago. I used chrome rims with stainless spokes and they are still together. I used stock Harley lacing with 40 spokes as shown in the Shovelhead manual with three cross pattern.

Those straight spoke wheels are pretty but I guess they aren't very safe with a zero cross.

Thanks again for the article and the pictures. They really tell a story.

NUC
 

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Thanks, D, for the article. After hearing about your trials with spokes, and seeing this bike with the radial spokes (which I WAS interested in previously), I am going back to my prior belief that billet or cast wheels are the only way to go. Thanks again.
Jerry
 

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80 Straight Spoked Wheel failure

I have a 1994 Softtail custom that I layed down 2 weeks ago. I took a ride downtown, was going about 20 mph, and my front wheel started vibrating violently. I figured it was a flat, so I began to slow down. Before I knew it, my tire started smoking, locked up, and set me over the handlebars and off the bike. No injuries, but needless to say, the entire left side of the bike is scratched up (est. $4400 so says the dealership). I took a look at wheel after I got up, and the rim metal between the spokes failed and litterally split the rim in two. If I was going faster, or riding next to any cars, I would have had some serious injuries. Ironically, it was the slowest cruising had done all day.
Progressive Ins. does not cover custom part failure, so now I am out of pocket on this. Should have looked into that before I got Progressive.
If anyone reads this, I have a couple questions and one piece of advice.

How can I find out who made the wheel and where can I find the part number on the wheel? People tell me it looks like American Wire. I am the 3rd or 4th owner, and I can't get into contact with the guy that put the wheel on. However, I do know the guy's name and where he had the wheel put on.

If I address it with the company (if I find out for sure who made the wheel), is there any potential for damage cost reimbursement? I was reading an entry about American Wire going out of business.

Can I take this to small claims if the company takes no responsibility?

Advice: If you have one of these straight spoked wheels, do not ride another mile on it. Change it our ASAP, or you could really do a number on yourself and whoever is riding with you. This whole experience really changed my outlook on the dangers of riding. I won't feel 100% comfortable ever again controlling myself on the road. Also, If you have Progressive insurance, and you have functional custom parts that are integral to your bike staying on the road, cancel your policy and pick up someone else.
 

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OLDBOY
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Radial Spoke Safety-

This issue is of great interest to me and should be of great interest to all motorcycle enthusiasts. If the integrity of a common type of motorcycle wheel is in question it is of the utmost importance that this be made aware to the motorcycle community.

Radial or straight laced spokes have been around for many many years. They were a very common factory upgrade on many early European and American luxury cars. Today they and are manufactured for every make of car, bicycle, and motorcycle. They are sold by the thousands for one reason… their unique and desired appearance over cross laced spokes.

Cross laced spoke are a much more advanced feat of engineering no doubt, as told very accurately in the lead post that describes the “suspension only” design of a cross laced spoke. However, it can not be interpreted from that description that Radial Spokes are dangerous in design. What is true is that Radial Spoke wheels require different engineering than cross laced. Rims, spokes, or hubs engineered for cross laced wheel assemblies do necessarily not make them suitable components for a radial spoke wheel. The forces generated by a radial spoke design are entirely different than those generated by cross laced spoke and the components must be and should be engineered differently. In the same manner, a 3 spoke billet wheel creates the same type of compression forces that a solid billet wheel does, but, the 3 spoke creates much more powerful forces on specific parts of the wheel. This does not make the 3 spoke billet wheel unsafe or dangerous compared to the solid rim, but it does require completely different engineering and tolerances.

As long as the radial laced wheels components are engineered specifically for that type of wheel assembly they should be no less safe than a properly engineered cross laced or even a stronger billet wheel.

But obviously there is (or was) a problem in at least 2 or 3 of the cases cited in this thread,

The question is what caused the problems?

One possibility- I have read that some radial spokes do require much closer attention to spoke tension. I have read that they should be checked and tightened to the correct tension every 300-500 miles. Is this procedure required? Did the wheel mfg make sure the buyer knew this procedure? Could this maintenance have been overlooked?

Another possibility- Piss poor engineering by a particular mfg. Perhaps there is one mfg that uses components only engineered for laced spokes on radial wheel assemblies. This would be criminal! Unfortunately, as with any unsafely manufactured product, legal action taken against the mfg by the consumer would be the only way to bring this dangerous situation to light. I strongly wish and recommend this course of action be taken in efforts to protect us all. There must be safe engineering standards for any type of wheel.

Looking at the pictures of the rim above it appears to have 40 3/8” radial spokes, the only mfg I know of that offers a 40 3/8” radial spoke is American Wire. Fat Daddy’s have a 50 3/8” radial spoke, and Hallcraft have a 47 3/8” radial spoke. However there may be many others mfgs I am not aware of. The other post where the author had an 80 radial spoke failure, he states they could be American Wire, American Wire does make 80 spoke radials, but so do many others.

I have tried many times through many searches to find more information on the safety record of radial spokes but have found this thread to have the most information available and to have the only cases of recorded failure I can find. I guess that’s good news considering the 1000s and 1000s sold every year.

I’m sorry for the long winded post but I am a big fan of the radial spoke look. I would hate to find out that there are some being sold that are unsafe. I would also hate to have the general opinion of radial spokes tarnished unnecessarily when in all likelihood they are probably manufactured to be perfectly safe.

I encourage anyone, fans or not, to post any credible information they can find regarding radial spokes and their safety in this thread.

Manufactures responses especially welcomed.

-Greglal
 

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Total Nutcase
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TacomaWA12 said:
I
Can I take this to small claims if the company takes no responsibility?

You can take it to small claims court, but depending on your state, your award might be limited. Around here, I think the maximum amount that small claims will award is $1500. If I were you, I'd find an attorney. The wheel manufacturer could have killed you and may have killed others. They have liability insurance. If these wheels are dangerous, they need to be taken off the market or sold with a disclaimer.
 
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