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FTP Road vs Tri Bike
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How much of a difference do you see in FTP on your road bike vs. triathlon bike? I did a 20 minute (Zwift/trainer) test 6 weeks ago on the road bike and averaged 308 watts. If I had ridden the road bike today, I would have expected around 318 watts. Instead, I used the triathlon bike in the aero position and averaged 288 watts (so ~9-10% lower than the expected road value). Heart rate was similar in both tests. I've only been riding the tri bike for a week, though. How long would you give for adaptation and what sort of differences do you see in FTP on your different bikes?
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Re: FTP Road vs Tri Bike [triryan] [ In reply to ]
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triryan wrote:
How much of a difference do you see in FTP on your road bike vs. triathlon bike? I did a 20 minute (Zwift/trainer) test 6 weeks ago on the road bike and averaged 308 watts. If I had ridden the road bike today, I would have expected around 318 watts. Instead, I used the triathlon bike in the aero position and averaged 288 watts (so ~9-10% lower than the expected road value). Heart rate was similar in both tests. I've only been riding the tri bike for a week, though. How long would you give for adaptation and what sort of differences do you see in FTP on your different bikes?

there's your problem. give it 5-6 weeks, and the delta may narrow to 3-4%. it's okay to generate lower power as long as you are aero
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Re: FTP Road vs Tri Bike [triryan] [ In reply to ]
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Same for both.
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Re: FTP Road vs Tri Bike [triryan] [ In reply to ]
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I conducted an FTP test on my road bike a while back, then swapped out bikes. For several weeks, I had a really hard time figuring out why I couldn't hit my power targets...it turns out that my FTP on the tri bike is about 10 watts less than on my road bike. That being said, I'm WAY faster on my tri bike. ymmv
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Re: FTP Road vs Tri Bike [triryan] [ In reply to ]
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My power output on my road bike (and tri bike sitting up / not in aero) is significantly higher than when I am on my tri bike & down in aero. For me (and it sounds like for you) it's because I tend to sit up when on the trainer and not ride aero when inside (I'm working on it, but it takes time). That said, even with the differential, I'm a lot faster at the lower wattage in aero.
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Re: FTP Road vs Tri Bike [triryan] [ In reply to ]
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Just wanted to give an update in case someone searches for this in the future. I had my fit re-looked at it, and it was fine - I just started using the green body geometry insoles with more support. The fitter suggested a 3-5% drop in power from road to tri and then another couple percent from outside to inside. 4 weeks inside on the tri bike seems to have been enough for the power to come back. This was my data for the same 20 minute test (just the insoles, bike, and additional training as variables):

December Road Bike: 308 avg watts
January Tri Bike aero position: 288 avg watts (293, 282 by 10:00 w/ 176 heart rate)
February Tri Bike aero position: 321 avg watts (308, 332 by 10:00 w/ 169 heart rate)
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Re: FTP Road vs Tri Bike [triryan] [ In reply to ]
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Thanks for the update!

Are you able to do the entire FTP test in Aero position? Your HR is a lot lower during the test as well? I find it pretty tough to hold the aero position for an entire 20 min test. Also, my power is way lower on the tri bike, but it may be b/c I'm on different power meters.

Example from about a month ago:

Jan 29, 2017
Tri bike
20 min FTP - Tacx Neo/Stages: 188w
HR threshold: 158

Jan 31, 2017
Wattbike (like a computrainer and road bike position)
20 min FTP - Wattbike: 246w
HR threshold: 167

I thought my Tri bike test was off so I've actually been working out on Trainerroad at a 205-210w FTP Tri bike/Neo. I also track Stages during my intervals and find it's lower by 25-30w versus Neo. Maybe my left leg is really weak in an aero position, but I don't think it's that weak since the wattbike says I'm about a 48% left leg/52% right leg power output.

Neo and Stages have checked my power meters and say everything is fine. I may just race on the Stages and average some wattage (maybe 'low') with a decent time...doesn't matter as long as it's consistent and fast!? :)
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Re: FTP Road vs Tri Bike [tri@thlete] [ In reply to ]
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That's a massive difference in both HR and power.
They seem completely incomparable. If those results are legitimate there'd be no point in having a tri bike - you'd be faster just riding your road bike
However I'd expect something's seriously amiss here.

I wouldn't make power meter differences the prime suspect since your HR data appears to correspond with the power difference.
To my non-expert eye, I'd have said you didn't put anywhere near the effort into the first test that you did the second. If you really did try then surely your position on the tri-bike is horrific? Secondly, I see you did the two tests just 48hrs apart. I'm pretty sure if I did that, the second test would be worse. I don't think I would be properly recovered from a true all-out effort 2 days later. I've done 3 FTP tests in the last 4 months and I'm pretty sure I could feel it in my legs for at least 3 days afterwards. Even if my legs were okay, I'd want more time than that to psych myself up for another one. Done right, they hurt. I have no desire to do them more than every 6 weeks or so.
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Re: FTP Road vs Tri Bike [Ai_1] [ In reply to ]
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Thanks A.J.!

Yes, you are right. I didn't take much rest between tests, mostly b/c I was pretty pissed off from the first test and thought my Power Meters were all off. Thus, decided to do another test 48 hours later on the Wattbike. I just thought I might've been tired/sick the first time, so if I get higher numbers (which I did) on "tired" legs, then I know the first test was off.

I definitely don't have much desire in doing those tests often as well!

I did a test last Fall on a Computrainer/Quarq and did around 236w FTP, so given my training, I thought the 246w FTP jump was probably about right (also the HR effort seems better). I'll just have to try my tri bike/neo/stages test again in a few weeks.

My position is on another thread and I had my fitter change a few things, so I'm much more comfortable, mainly bringing my saddle forward/down a little (height was 180 to 175).

Position (2nd video on page 2):

http://forum.slowtwitch.com/forum/Slowtwitch_Forums_C1/Triathlon_Forum_F1/How_is_my_position%3F__P6199000/?page=unread#unread


Thanks again!
Last edited by: tri@thlete: Feb 27, 17 3:58
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Re: FTP Road vs Tri Bike [tri@thlete] [ In reply to ]
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That's a huge difference between your Tri bike and the Wattbike. I find I can push around 10w higher on the Wattbike in my 5 min intervals; I think that's mainly due to the inertia provided by an ergometer, much like turbo vs. the road for me. I always test in the aero position (or as close as I can get on the Wattbike).

29 years and counting
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Re: FTP Road vs Tri Bike [Jorgan] [ In reply to ]
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Thanks Jorgan!

I think it's a combo of things that makes the difference so large.

- Stages is left leg only and maybe mine is super weak (?), also it seems to read lower than everything else
- Neo is generally lower than Wattbike
- If I test on Neo vs. Wattbike I bet it would be closer -- Neo: 215-220w, Wattbike: 246w

I think I can push a much higher wattage on the Wattbike (10-15% more) than Neo/Stages. I suppose as long as it's consistent, doesnt' matter that much. I use Heart rate as the equalizer.
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