Bionx rim failures
I've now encountered two Bionx rim failures. The rim came apart at the sidewall wear indicator, peeling like a banana. The first I put down to extreme usage, on a recumbent tandem with two larger riders, but the second was the rear wheel on a tadpole trike, hardly an extreme use. In both instances the tire pressure was 100 psi. Both were 350W units with less than 6 months usage on them. The tandem was equipped with a disc brake, and the trike was not equipped with a rear brake (front discs), so the sidewalls had no brake wear on them. I dropped the tandem rim off at a Bionx dealer so he could send it to Bionx for analysis. Haven't heard anything. I would hope they would be concerned as their website has advertised Bionx units as suitable for tandems.
I rebuilt the unit from the tandem onto a Sun Rhyno Lite rim and there have been no problems, and I'm doing the same with the trike.
I know this is a reply to an old post and the original poster probably has figured out the answer to his question but this is my answer.
I was a bike commuter in Milwaukee for about 25 years and in my opinion, you need to match tire width to rim width. I'd be very careful about putting wide tires on narrow rims and then inflating the tires up to 100 psi. I know, the rims broke just like you described.
We had a Ryan Duplex recumbent tandem and the rear rim failed. Sorry to say, we are a heavy, 400 pounds, couple. I replaced the rim with an appropriate Sun Rhino Lite XL rim and had no further problems.
Now I'm riding a BionX equipped TerraTrike Tour II and I try to run a maximum pressure of 80 psi in the Schwalbe Durano rear tire.