This does not compute at all.

I am recovering from Pneumonia and I am finally able to ride my bikes without stopping every few yards to breathe.

Yesterday I rode 19.7 miles on my Kestral Tri bike. It took me a pathetic 1hr 54 minutes. I averaged a terrible 10.3 mph.
This morning I rode 28.8 miles on my Fixie. It took 2hrs and 7 minutes, for an average speed of 13.7mph.

My Kestral is a carbon fibre Aero thing that is seriously fast. There were also a lot of people on the circuit that I rode and it was fairly warm (80-85F). I also rode around the lake, which is busy. But my fastest mile was 3.04. Most of the miles were around 4:46.

My Fixie is a steel framed mish-mash of part. I rode it further and faster, my fastest mile was 3:18, but the vast majority of my miles were under 4 minutes - the slowest was 8:04 where I stopped to refill my water bottles.

I **think** this is comfort related, but I am not sure - I am taking the fixie on a group ride tomorrow - I think I am fast enough on it now....