Titanium motorcycle wheels 1

[enghard]

Currently aftermarket motorcycle wheels are usually made of either forged aluminum, forged magnesium or carbon fibre. Weight savings increase in that order.
I'm curious if there are any technical reasons why titanium wheels are not offered anywhere. Saving rotational mass is especially beneficial on a motorcycle. Certain titanium alloys offer the highest strength to density ratio of all metals. A titanium wheel should therefore be lighter than the above mentioned forged Al and Mg wheels (maybe not as light as carbon fibre), if taking advantage of its strength in the design.

Certainly, they would be prohibitively expensive, but there are usally people who are willing to pay a premium just to be different.
Which manufacturing process and which alloys would lend themselves for titanium wheels, and which difficulties could one expect during manufacturing?

Thank you

 

[GregLocock]

perhaps yield strength/weight is not the most important characteristic.



Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[swall]

Cost is the reason. Even people with seemingly unlimited financial resources find that there are other razzle dazzle or gofaster stuff they would rather spend their money on. We found this out when we looked at titanium suspension springs for race cars. One of my previous employers looked at titanium aircraft wheels in the 1970's. They were a designer's dream. Equal strength and stiffness compared to forged 2014-T6 aluminum wheels and better corrosion resistance, but too expensive for the airlines to consider.

 

[MMcCawley]

Swall,

Correct me if I'm wrong but most grades of titanium should be both both stronger and stiffer than forged 2014-T6 (Sut of about 70ksi and Modulus of Elasticity of about 10.5 ksi)whereas titanium (6-4 for example) has an Sut of 175 ksi and Modulus of Elasticity of about 16 ksi. With that said, Ti is about 60% heavier so you have to factor that into the equation but from a strength/stiffness point I don't see how the two match up. Feel free to correct me if I'm missing something.

 

[GregLocock]

It's easier to design a part of agiven weight and stiffness in aluminium than Ti, for proportions seen in wheels. The lower density allows you to have thicker walls for a given weight, and your stiffness is increasing with t^3.



Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[Yawing]

Exactly. Same reason why magnesium is one of the best materials for wheels. even if they have a lower strength to weight ratio than ally, they can be designed to give the best stiffness. this would explain the lack of titanium wheels in racing.