Originally Posted by BlazingPedals
They worked for low rpm; but for higher rpm your feet spin past the dead spot quickly enough anyway.
They were designed for low RPM, and that's where they work on uprights. When they came out, it was normal to ride MTBs without toe clips and "clipless pedal systems" were considered unsuitable for the general public, off road.
BioPace helped when ridden with your feet just on plain pedals at low RPM. It was also great for non-enthusiast riders on utility bikes. However the magazine testers, who have little in common with the typical rider, found it unsuitable at their higher RPMs. So they trashed it without mercy, and drove it out of the market.
Being aimed at the enthusiast upright rider, I fear Q Rings may suffer the same fate.
Originally Posted by BlazingPedals
In addition, if used on the big ring, you have to set the derailleur spacing to the high spot on the oval, which effectively reduces the amount of teeth the derailleur will span, in addtion to degrading front shifting.
I've run it with 26-42-52 without problems (but I must have installed the derailleur post at exactly the right angle, and 26-42-53 probably wouldn't work.) They never made a 24t.
As for degraded shifting, YMMV, but I think it shifts better than round plain rings.