I picked up a used P5 and it had the High V mount for the aerobars which made the saddle to aerobar pads drop a lot less than what I usually run for sprint triathlons. Typically I run 10ish cm of drop from saddle to the aerobar pads and with the high V mount my drop was just a little over 4 cm. I found a low mount and while I was waiting on that to be delivered I did a local course (29 miles of mostly rolling hills) with the high V mount still in place at 184 avg watts, 19.5 mph. Low bars came, I installed those which gives me a little over 8.5cm of drop, rode again doing the same course at slightly lower watts (180w) but the speed was down to 18.6 mph. This was slower than I was expecting. Temperature was the same both days, although the humidity was 20% higher on the slower day, winds were minimal both days (3mph avg wind on the "fast" day and 1 mph on the "slow" day). And to confuse things further I did have a helmet mounted light on the slower day which could have accounted for some of the drag. Otherwise the setup was really similar.

I need to gather more data but changing from high to low mount is kind of a pain! Could going from 4 cm to 8.5 cm of drop create more drag? Trying to decide if I should switch it back. Thanks.