Carbon trike wheels

[UpWrong]

I see the new Trident Trikes Gossamer SL has carbon rimmed wheels (with titanium spokes): https://www.youtube.com/watch?v=10N24JCaLyw

Great to see a volume trike manufacturer pursuing light weight. But why aren't carbon wheels being offered by ICE, Catrike etc? Lets face it, double-walled aluminum rims are heavy and most trikes use disc brakes so it's surprising that carbon rims are not more prevalent on performance models.

[[XAP]Bob]

Lateral strength?

At least uncertanties in the above...

[Marc]

Titanium spokes?! *sigh*
Why do 'engeneers' go for fancy stuff in the wrong places, when high tensile strength steel is the proper 'high tech' material for the task?
The Gossamer has way too few spokes for my taste anyway, even if they used highest quality steel spokes.

I like titanium like the next guy, but Ti is more prone to fatigue failure than proper steel and the weight savings of any light weight metal (aluminium or Ti) over steel in dynamically loaded applications (frames or spokes) isn't as much as you think.
To account for the lower tensile strenght of high strenght aluminium alloy (2.7-2.8 g/cm³) compared to high strenght steel (7.8 g/cm³), you need twice the material. If you account for the lesser fatigue resistance of alu, the weight savings deminish further. Due to its high strenght titanium alloy (4.5 g/cm³) fares a bit better compared to high tensile steel alloy, but its still less resistant to fatique.

btw, Velomo trikes have frames made from high tensile strength steel and rival (or beat) Carbon Trikes or the Gossamer in weight. http://www.velomo.eu/trikes

Great to see a volume trike manufacturer pursuing light weight. But why aren't carbon wheels being offered by ICE, Catrike etc? Lets face it, double-walled aluminum rims are heavy and most trikes use disc brakes so it's surprising that carbon rims are not more prevalent on performance models.

Thats a myth. Double walled aluminium are not 'heavy' because of the material and carbon rims are not lighter in any case.

Lets have a look at the 20"/406 rim offerings from Ginkgo: https://www.ginkgo-veloteile.de/ginkgos ... -20-406-mm
The lightest double walled alu rim weights 205g (€99), while the lightest carbon rim weights 220g (€420!). The other carbon rim weights 280g (€269).

The 26"/559 rims show a similar result: https://www.ginkgo-veloteile.de/ginkgos ... -26-559-mm
The lightest double walled alu rim weights 275g (€99), while the offered carbon rim weights 350g (€269).

Most of the other aluminium rims weight a bit more, but the higher weight comes with higher strenght.

Next is the behaviour of carbon fiber in case of a crash. It either survives or gets destroyed. Thing is, if its not obviously broken, you can't see if the carbon fiber structure is damaged and will fail from one second to the next.
An aluminium rim might get bend in a crash, but if its not obviously broken, its relatively safe to ride back home with a wobbely wheel, or fix it up.