E-Motion camber question

[chasmengr]

Below are two excerpts from Frank Mobility's E-Motion's wheelchair Compatibility Chart. Notice the superscript behind TiLite's chairs notes that e-motions on all TiLite chairs (rigid and folding) must have zero camber. The same is also true for several KI chairs, but it's not true for many other manufactures & chairs. Does anyone know why?

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I am considering working on obtaining e-motions for my reinforced AeroZ, but I love having 4-degrees of camber.

[MillsWheels]

I hadn't thought about this, we were looking into e-motions, but decided to hold off for a bit. I'd also hate to lose my camber (I have 3*). and assuming reversible camber tubes aren't an option, since you can't put emotion wheels on any chair without the special housing for it. they're so darn heavy wish they could be lighter but understand why they aren't.

[cheesecake]

I have always been told ZERO camber. The change in the anti-tippers is new in the last 18 months, no one can answer why however.

I personally liked the 0 camber because it makes it easier to maneuver and get through doors.

[takenaback]

Don't really know why it should possibly vary between wheelchair makes but I have had 3° camber ever since I have had E-Motion wheels. It wasn't a problem with the M12s but it is possibly a cause for concern with the new M15 wheels. I have broken many spokes and have had both wheels completely re-spoked, I also have two friends who are also suffering from broken spokes and one thing we have in common is 3° camber. I suspect it is a problem with the M15 wheels rather than being as a result of the 3° camber as I had no problems with the M 12 wheels. To this end I would like to know whether others have suffered with broken spokes?

Anyway I have in front of me at this moment mounting instructions in German which were for my M 12 wheels and it states <40 kg max 8°, 40-50 kg max 6°, 50-60 kg max 4°, >60 kg max 2°.

Cheers

[Patrick Madsen]

Perhaps changing over to double butted stainless steel spokes would help with the breakage. They are much lighter and stronger than those cheap spokes they Emotion and Magic wheels use.

[takenaback]

Patrick

According to my local bike shop there is no problem with the quality of stainless steel spoke fitted on the E-Motion wheels, he believes they just weren't thick enough. Instead of the 2 mm spokes he believes they should be 3 mm but this would require the hub being drilled out and I am not about to risk that without being absolutely positive there would be no permanent problem caused by stronger spokes.

The spokes were breaking in exactly the same spot on the butt curve. This is also the case for the two friends I have with E-Motion M15s. I have no experience with double butted stainless steel spokes but for future breakages I am interested to know how these might help considering the spoke butt can still only be 2 mm the same size as the spoke currently fitted.

One of my friends in particular is at his wits end so perhaps I can mention doubled butted spokes. I guess the idea is that the spoke itself would be thinner therefore allowing more Flex and taking pressure off the butt curve? Is that your understanding?

Cheers

[chasmengr]

What about using triple-butted spokes (http://sheldonbrown.com/wheelbuild.html)? Then you'd not have to drill your hubs to use stronger spokes:

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[takenaback]

Very interesting