My main concern is the massive q-factor.
Looking at the videos, I feel that this might put significant angular strain on the hips on long rides, perhaps the ankles too. If the cassette faced in the opposite direction, the smaller cogs could sit above the tyre perhaps? The Cruzbike obviously avoids this issue by placing the bottom bracket at a higher point where the fork is narrower.
It seems that to some extent the large q-factor is unavoidable. We're trading a standard 70mm width bottom bracket with a wheel spacing of 130mm + fork width + return sprocket. I'm not 100% sure as the design specifics vary, but it seems that we shouldn't include the chainring in this width calculation. Another way to look at it is that we need to accommodate the 130mm wheel + two chains (over 10mm). It seems that no matter the design, the q-factor will be at least 70mm greater than with a typical BB. My guess is that 75mm-80mm would be a reasonable estimate.
A good test (for those who don't own a G4) might be to attach pedal extenders and then go for a long ride. Most shops seem to only carry 20mm versions (x2 increases q-factor by 40mm). I guess using a pair of these on each side would do the job. It seems that 30mm extenders are available at a few specialist retailers.
I would love to see a design that avoided "wheel flop" and made front wheel drive cycling more accessible to the masses. I'm not sure this G4 design is a path to toward that goal.
For now I'm very happy to carry my front wheel strap!
PS: I agree with many of the sentiments here. Great to throw these different ideas around. Thanks to
@ak-tux for the original post. Whether or not we find the next revolutionary design, I'm sure we'll develop extra appreciation for the many benefits of the Cruzbike architecture.
