FTP Increase but slower overall time

Hi, I’ve experienced a strange result on Zwift and wonder if anyone can contribute as to why it might have occurred.
As part of my personal training plan, in order to make sure I spend plenty of time in zone 4, I frequently ride time trials; usually 10 or 25 milers. Not actual Zwift events, just pick a relatively flat course, hit ride and keep an eye on the clock when I hit the desired mileage.
Generally over the last few weeks my times have been quite consistent (on the same course). My last attempt however was a bit odd.
The nuts and bolts: I used a higher gear than usual (I only ever use one gear as I ride fixed on the road), my ftp increased by 8 watts, my time was almost a minute slower than my previous best.
So I’d previously used a lower gear, higher average cadence but lower power and rode a faster ride!
Is this simply a case of ‘spin to win’ or is there something else at play? Opinions?

If we’re talking about a free ride and not an actual FTP test, and you’re not using the TT bike, it’s possible to have a faster time with lower overall watts if you spend enough time drafting a fast rider.

Ah yes, I’d not thought of that. I don’t use the TT bike and have never intentionally drafted anyone but I suppose if it just ‘happened’ by default it would explain things.
I intentionally keep bias and difficulty set on 100% and haven’t used the TT bike. Didn’t realise until now that you couldn’t draft on the TT bike so will give it a try; that should level the playing field. Thanks.

But then you still can be slower with an higher wattage :wink:

Sorry I don’t understand your wink. It’s the how and why I’m interested in, is there another way this could have happened?

The difference in your times isn’t as big as you think. Looking at your last two 10+ mile rides on the Watopia Flat (31Jan and 5Feb), your time to the 10.0 mile mark on 5Feb was only 23 seconds slower than on 1/31. The rest of the difference in elapsed time comes later (i.e. the time it took to stop the ride clock differs. (you also climbed a few feet more and rode 0.1 mile further on a (slight) incline on 5 Feb before the clock stopped).

If you’re going to compare time to distance, make sure you’re looking at the same distance both times.

Re: the 8 or 9 watt diff in average power that accompanied the slower time? Could definitely be from drafting on 31Jan and not as much on 5Feb (as mentioned), or even something as basic as using different bike/wheels/whatever on different days.

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It matters when you apply the wattage. If on one day you are doing more on the climbing and less on the downhill you will be faster than the other way around, even though the average wattage in the second attempt was higher.


Fantastic; thanks a lot for looking at this. I think I know where to go from here.
I just completed a workout based on the new ftp and found it quite easy so hopefully things are moving in the right direction. Cheers.