Right now, the pro models that dealers are stocking are the new GX line, which is the new version of the "R21" series. In fact, it uses the same case. We're also retrofitting older engines with the new parts, for those that need to rebuild.

Keep in mind though that when replacing the crank with the new one, you need to replace the conrod as well. The reason for this is that the new rod has a slightly larger eye on it for the new conrod.

Also, from what we're seeing (per my team drivers) the new Ti Nitride-coated parts are showing awesome anti-wear results!