Wire spokes on sport bikes

[MonkeyPainter]

Wire wheels are associated with tubs and usually put on dirt bikes, dual sports, supermotos, and certain cruisers. And they usually have inner tubes,and are maintenance intensive, but there are manufacturers out there that have made advancements on the design to run carefree and tubeless. (

http://www.alpinaraggi.it)

Cast wheels are on everything else.

My question is why? And are there benefits or cons with either type of wheel?

Is it that the wheel would experience deflection on higher performance bikes? (i.e. axle twisting relative to the rim.)

I know the downfall of wire rims on cars are that they deflect excessively under lateral loads. But I don't think a motorcycle rim would ever see that kind of lateral force.

Is it just a style/trend/manufacturing ease thing? Are there any reasons wire spoked rims wouldn't work on sport bikes?

 

[MikeHalloran]

Wire wheels worked just fine for decades.
Alloy, once the bugs were worked out, was cheaper.


Mike Halloran
Pembroke Pines, FL, USA

 

[swall]

Only advantage I can think of for wire wheels are that they are more damage tolerant in impact situations. This is a good feature for dirt bikes and dualsport bikes. Also, wire wheels are a little bit lighter. Only other reason you see wire wheels is strictly for style.

 

[BrianPetersen]

Motorcycle wheels see lateral force when going over bumps. Also, with modern wide tires, when leaned over, the contact patch is significantly away from the centerline of the wheel, which means there is a lateral component to the force on the wheel.

Also, it may be non-technical, but wire wheels look old skool, and just don't fit in with modern styling on the rest of the bike. I've seen pictures of otherwise modern-looking small bikes in Asia with wire wheels, and they just look wrong, it doesn't fit with the way the rest of the bike looks.

 

[swall]

I would guess that the widespread adoption of radial tires to motorcycles affects the spoke vs cast wheel decision.

 

[drwebb]

Wire spoked wheels are labor/cost intensive to manufacture to equivalent dimensional tolerances of cast wheels. Yet most bicycles still use spoked wheels, so perhaps sport bikes passed some power density point on the strength/weight/cost triangle that sent them to cast. This may be supported by the observation that modular wheels (i.e. comstar) saw employment during the transition.

Lateral forces are a concern with high performance MC wheels- 5-10 years ago some designers recognized they had developed chassis that were TOO stiff, as MCs need some lateral deflection for suspension when leaned way over in turns. So now they design controlled lateral flexibility back into high performance frames. The question makes me wonder whether they considered wheel flex- maybe not as racing wheels are sometimes developed out of house, so that wasn't a lever they could easily adjust.

Might be a good student design project.

 

[pennswoodsed]

Could a solid tubeless rim be mounted on a float type hub with shock absorption ? the spokes could be capable of compression and extension ? Could this be done in a cost effective modular,repairable manner ? Lateral and radial compliance could be tuned .
Regards,Ed

 

[MonkeyPainter]

Ed,

I would think that as soon as the wheel hit a bump and threw the wheel off center, all hell would break loose.