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This guy has a 1500 and wrote in about using a CT on his bike. Below is the guys answer.

I went down to my local tire store with a caliper and started measuring beads.There is some variation but they're all pretty close to each other, right around 14mm. Motorcycle tire beads are considerably thinner, roughly 9 to 11 mm. The rims themselves have similar designs but are sized accordingly. The tire bead, when fully seted, site between the outer rim bead and an inner bead. If the wider car tire bead doesnt fit between the two beads of a motorcycle rim, it could fail under cornering loads. Some of the engineering diagrams I was able to find online show some very specific radius and angle dimensions for both inner and beads. Machining the stock rim s would not be practical. It would be better to replace the wheel with something made for the job.

Thats it. I would say this guy is concerned about cornering and the bead issue. Can you fit a car wheel in there?
 

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I don't know where you would get a car tire that would fit a 1500.

Keep in mind, when you are cornering a motorcycle, you are pushing the bead against the inside of the rim - not where the bead seats, but the rim itself. When you corner a car, you are pulling the bead away from the outside edge of the rim. You can pull the bead off the rim on a car (BTDT) but you aren't going to pull the bead away from the rim on a motorcycle. On the motorcycle, you never but any substantial strain on the bead.
 

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Discussion Starter #3
Tom, I was doing some thinking. We all know how the rear wheel on a 1800 is barely seen without getting down and looking at it. What if we could find a wheel that would look hald way decent and fit in there. I think that would make more people comfortable with the idea of using a CT. I know its not your concern about how people feel, but there are benefits pf using a CT and more people would be able to use this benefit. After reading that article I was just doing some thinking..... Now my head hurts!
 

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tomfranken said:
I don't know where you woul dget a car tire that would fit a 1500.

Keep in mind, when you are cornering a motorcycle, you are pushing the bead against the inside of the rim - not where the bead seats, but the rim itself. When you corner a car, you are pulling the bead away from the outside edge of the rim. You can pull the bead off the rim on a car (BTDT) but you aren't going to pull the bead away from the rim on a motorcycle. On the motorcycle, you never but any substantial strain on the bead.
Did you actually read your response??? Yes, MT do press against the center of the rim because they are round... I'm assuming you are accepting that the beads on a car tire/wheel have different dimensions...
Here, let me spell it out some design FACTS for you...
* A radial car tire tread is very stiff and wants to be flat (part of the design to keep a maximum amount of rubber on the road)
* Bike leans, tread tries to remain flat and pulls on outside sidewall
* Stress induced in outside bead...

Does this make sense or is there some scientific testing you've done that disproves this?? I have done NO testing and I don't know if it would be enough force to be of concern for a motorcyclist running a CT..
I'll admit that I'm ignorant and assuming you are equally ignorant of the actual forces generated on the bead or the force required to break a bead of a car tire on a motorcycle rim..
 

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Toyo said:
Tom, I was doing some thinking. We all know how the rear wheel on a 1800 is barely seen without getting down and looking at it. What if we could find a wheel that would look hald way decent and fit in there. I think that would make more people comfortable with the idea of using a CT. I know its not your concern about how people feel, but there are benefits pf using a CT and more people would be able to use this benefit. After reading that article I was just doing some thinking..... Now my head hurts!
There's a couple of 175/55R16 tires that might fit. The 1500 rim is much smaller than the 1800. You'd want to double-check how well everything fit together. If you could find a 15" rim, you would have a few more options.

I think the CTOM issue gained prominence once it became reasonably possible on the Valk and then the more popular GL1800. If it was doable on the 1500, it would have been done!
 

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PunkinWing said:
A radial car tire tread is very stiff and wants to be flat (part of the design to keep a maximum amount of rubber on the road)
* Bike leans, tread tries to remain flat and pulls on outside sidewall
* Stress induced in outside bead...
I was thinking about that outside sidewall. We know the inside sidewall flexes in a corner. If the tread were 100% rigid across the tire, the outside sidewall would FLEX just as much; i.e whatever happened to one side of the tread would have to happen to the other side. However, we know - from experiments and observations - that the tread is not rigid across the tire. Several people have reported looking at the trail left by cornering with wet tires. Between two and three inches of tread stay on the ground. Plus, in the video, we see the inside sidewall flexing and the outside not doing anything. If the stress to the outside sidewall was trying to pull the bead out of the rim, the outside sidewall would be stretched.

To pull the outside bead off the rim, the tread belts would have to pivot on a point in the center going across the tire. I'm guessing the belts deform a bit so they have a bow in them. (I know the belts can deform because a car tire going over a rock smaller then the width of the tire will wrap itself around the rock. Aren't the belts just a tightly woven bunch of cables?) I'm also guessing the belts pivot inward on a point at the outer edge of the belt. These two dynamics would keep it from pulling with any real force on the outside sidewall. 'Don't know how to test to confirm that.

I went back to look at all the bead failures with CTOM to review what actually happened. Problem is, I can't find a single case to review.
 

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PunkinWing said:
Did you actually read your response??? Yes, MT do press against the center of the rim because they are round... I'm assuming you are accepting that the beads on a car tire/wheel have different dimensions...
Here, let me spell it out some design FACTS for you...
* A radial car tire tread is very stiff and wants to be flat (part of the design to keep a maximum amount of rubber on the road)
* Bike leans, tread tries to remain flat and pulls on outside sidewall
* Stress induced in outside bead...

Does this make sense or is there some scientific testing you've done that disproves this?? I have done NO testing and I don't know if it would be enough force to be of concern for a motorcyclist running a CT..
I'll admit that I'm ignorant and assuming you are equally ignorant of the actual forces generated on the bead or the force required to break a bead of a car tire on a motorcycle rim..
You may want to reconsider your own question. You say "the tread tries to remain flat". What force is there that makes the tread try to remain flat? Gravity? Yes, but hardly significant in this instance. The force that is trying to make the tread remain flat is the same force that is acting upon the tread whenever the tire is mounted on a rim and inflated - internal air pressure. It remains so when the tire is leaned over in a turn. And what is keeping the bead sealed against the rim? The bead bundle, a bundle of steel cables that keep the bead from stretching and coming loose on the rim. If you've ever seen the residue from a burned steel-belted radial tire you can see that the steel cord in the belt is a fine, very flexible steel, whereas the steel in the bead bundle is larger, stiffer, and not intended to flex to any appreciable degree.
As far as lateral force that could unseat the bead - on a motorcycle the weight of the vehicle is virtually always perfectly parallel to the height of the tire; on a car, especially one that can attain high cornering forces, it can be at an oblique angle as much as 45° with 1g of cornering force.
Also take a look at the amount of force required to unseat a bead. Have you attempted to remove a tire from a rim lately - especially a car tire from a GL1800 rim? As you should know, it takes quite a bit of concentrated force applied directly to the bead area to do so. Even if the GL1800 were to be equipped with an outrigger, or sidecar mounted, so that it could make a left hand turn while being held straight up (thereby having force applied at an oblique angle as with a car) it would probably experience no more than a couple hundred pounds of lateral force at most, and that would be transmitted through a very flexible sidewall, spread over a broad area around the bead. From my experience with the CT on the Wing, and extensive experience with tires in general, I'd lay odds that you could drop the tire pressure down to 20 psi and still be unable to unseat the bead on that rig regardless how hard you cornered.
Getting back to the CT mounted on a standard Wing, in a turn, as ArnButtBill noted in his description of Tom Franken's bike as he followed it through turns, the inside sidewall flexes when the bike is leaned. Again, this force is applied parallel to the height of the tire. In effect, this reduces the loaded radius of the tire toward the inside of the turn, mimicking the smaller radius of a rounded m/c tire when the tire is rolled onto its side in a lean.
While the contour of the bead profile on the GL1800 wheel may differ slightly from that of a car rim, it is not enough to keep the tire from: a. Sealing properly, b. Staying on the rim in turns, c. Failing to slip on the rim under power, even at drastically reduced inflation pressures.
Naysayers have gone to extreme lengths to theorize why the CT cannot possibly work on the GL1800, rather than looking at what is working and trying to understand it.
Someone (nedro perhaps?? - can't find the post right now) mentioned that there is but an infinitesimal (my word, not his) fraction of riders who have reported mounting a CT on a Wing. What is that saying about "...lies, damn lies, and statistics." ?? He is neglecting the fact that virtually 100% of those riders are reporting the same things regarding improved performance in certain areas, and no one has reported a failure such as one of those predicted by naysayers.
One last "old saying" that sums it up for me - "The proof is in the pudding". :D
 
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