I figure I should add my input on this one.
I am recovering from a knee injury and for the past six months - my knee had deteriorated to the point of not being able to pedal up hills.
I purchased a set of Q rings from Gary and as part of my recovery (no running allowed yet) - have been doing light spinning on the trainer with the Q rings in place. On the CT I have been able to effectively measure the difference in a controlled environment, without risking damage to my knee during my recovery. No long rides yet - but the improvements are noticeable even in short light spinning sessions.
Yes, it takes a little bit to get used to - maybe 20 minutes - as effectively - at the most elliptical point of the pedal stroke (caused by the ring shape) - you are pushing a bigger gear. The shape of the rings almost pulls your foot through the dead spot at the top of the pedal stroke.
MY knee pain on the bike is gone - and I too, have noticed my cadence is not quite as high - without a loss of power or speed on the computrainer.
At first - I pedaled with such a high cadence - that when I put the Q rings on - I bounced in the saddle - but it took only ten minutes to resolve this by slowing my cadence.
These rings are not a gimmick and should not be compared in any way shape or form to the shimano Biopace of old days.
They WORK.
They are exceedingly light - so the weight weenies (as pointed out in an earlier post) are going to love these. They also look great and get a lot of attention and positive comments - the workmanship is extremely high quality.
I had no issues with the installation - I did them myself - replacing FSA rings made for Cannondale - on a Cannondale Carbon Crankset. I use them in the number 3 position - and like rotorcranks - they have different settings to use as you become more acustomed to their use.
I did have to slide the front deraileur UP on the frame mount - per the instructions supplied - which were comprehensive and simple to follow.
I had a minor issue of the chain barely rubbing on the trailing edge of my front der at the top of the Q shape - but this was resolved by using a piece of wet and dry sandpaper on the end of a pencil - at the point of contact on the front der. It was literally a micro adjustment and caused more by the small adjustment allowed on the front der bracket - rather than the rings.
No other adjustments have been necessary and the rings are definitely not coming off the bike.
I purchased these because I could not install R/Cranks on my cannondale - so a very interesting point here for all Cannondale riders, among others.
If you want the advantage of rotorcranks - using your own cranks set - and at a lower cost than R/Cranks - PURCHASE THE Q-Rings.
You will not be dissappointed and you will notice the positive difference immediately.