Since 2018, the Santa Cruz Syndicate have been racing and developing prototype versions of Santa Cruz Reserve
rims that use carbon nanotubes
to increase strength. The technology is called NAWAStitch
and it's essentially a layer of vertically aligned carbon nanotubes in-between the layers of carbon fiber and at right angles to them. The idea is to "stitch" the carbon fiber layers together to prevent them shearing apart, or cracks developing in the rim. NAWA refer to this layer as "nano-Velcro".
NAWA is a company headquartered in France with a second location in Dayton, Ohio. They use vertically aligned carbon nanotubes
for ultra-capacitors, battery electrodes and carbon composites, like these rims. They claim that in their own tests, "NAWAStitch-reinforced carbon fiber composites have shear strength increased by a factor of 100 and shock resistance by a factor of 10." Apparently, this results in a rim that is "not only more resistant to strike damage... but has far greater shear strength too. NAWAStitch has the potential to dramatically reduce the number of wheel failures experienced by the team over a competitive season by 80%."
According to Nic McCrae, Senior composites engineer at Santa Cruz, "NAWAStitch has made the wheels much stronger, we believe by increasing the buckling resistance of the inner surface of the rims during high compressions [from an impact]... We’ve had far fewer wheel failures as a result. What’s more, NAWAStitch does not affect the way wheels respond to the riders’ inputs... our Reserve wheels are without doubt the strongest rims on the circuit."
The rims have been in development with the Santacruz Syndicate since 2017 and raced on since 2018. NAWA becomes an official "key partner" of the team in 2021.
The rims are competition-only for now, but the aim is to use NAWAStitch in mass-production Reserve wheels in the future.