An (un)controlled experiment

By now I have had the Velocite Helios for about 5 months and have put about 2500 to 3000km on it. My impressions of the frame and bike still stand, with a little update from an (un)controlled experiment.

When I built the bike, I chose the Cannondale carbon SI crank in compact. It was decently priced, relatively light, looks good, and the Stronglight Fission was not yet in stock. Little did I know that this was money badly spent: after less then 1000km, a distinctive clicking developed in the bottom bracket area. I thought it was related to my pedal axles, since the Eggbeaters I was using then were pretty worn. I changed these and it did not improve. Then I changed the bottom bracket bearings, because the Cannondale ceramics I was using are notoriously fragile and known to break. Not unexpectedly one side was running very rough, but the new, standard, bearings I installed didn’t bring any relief on the clicking.

A little later I noticed that the crank on the non drive (left hand) side was slightly loose, although the nut was securely tightened. Reason: the insert on the crank arm where the axle is mounted had cracked loose. I continued riding, with a progressively loose crank, until I got replacement. Towards the end I was able to move the crank arm about 1cm back and forth. Pretty scary. It was also β€œinteresting” to race with a loose crank, not knowing whether I would make it to the finish line or whether the crank would give up on me beforehand.

As a replacement I got some second hand Hollowgram SI crank arms. Missing a 110BCD compact spider (if anybody has one – I am still looking πŸ™‚ ), I only mounted the one on the non-drive side. The results are interesting: When out of the saddle, I can feel the pedal on the right hand side (SI carbon crank) bend down, whilst the left hand crank feels noticeably stiffer and doesn’t deflect. The frame also feels different from left to right as a result: the left side feels noticeably stiffer.

It goes to show that the Helios deserves a stiff crank set, if you want to get the most out of the frame. And the Stronglight Fission, especially now that it comes in BB30, seems a pretty good match for that.

Ride safe,