Power??

Hi Guys

Now this might be a very stupid question but its something that has been bugging me the last few rides.

I recently got a ceramic bottom bracket put in my Cervelo as well as upgrade to Ultegra DI2 and I have noticed that my rides have been slightly faster but my power has been way down (Measured using Garmin Vector 2 Pedals)

I decided to do a 34k loop today which includes a steady climb and not much interaction with traffic so traffic, lights wouldn't be a factor.

Todays ride my numbers were;

33.96km
123 W Weighted Average Power
25.5km/h average Speed
1:19.50 Time

Previous Ride was

34.39km
198 W Weighted Average Power
25.6 km.h Average Speed
1:20.36 Time

The bike is the same except the above changes, my weight is roughly the same but my power is quite a lot less than the previous ride.

Time is roughly the same, average speed was roughly the same. Weather conditions were roughly the same.

How come I am doing my rides in less time but power is way down?


Thanks