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Which size P5 should I stick with?
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These two pictures are one month apart; the bike is exactly the same, only the shoes are different. In the bottom picture, a 70.3, I hit my power target and felt comfortable. In the top, I was 30 watts per hour off my power target (a number I have achieved in previous iron-distance races and well within what I could do based on my training.

Nothing has changed, but as you can see in the pictures, everything had changed.

Since then, I have swapped up the extensions, using my original aduro bars but inserted in the opposite way to give my hands a much higher position that feels more natural and comfortable. But I'm still struggling with whether to go with this fit or not.

I was riding a size 56 P5, no spacers, low mount. Felt super comfortable, but at 75kg, 215watts AP, 2017 Kona bike split was 5:13 ,I was giving away a lot of time due to aero. I am 5'11", 165 pounds (180cm, 75kg)

The new rig is size 51 and obviously a dramatic change. I ran well off this position and did not have any issues. But it feels a touch too short in the reach for me, and there is no way to move the pads further forward if I keep the aduro bar.

I'm asking the collective and specific wisdom of slowtwitch. Does this size fit into the "it's aggressive but maybe you can adapt to riding it well" category or is this just plain crazy? I still have the 56 size bike and can easily go back to it and can use this frame for my wife, so there are no serious financial considerations here.
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Re: Which size P5 should I stick with? [Darren325] [ In reply to ]
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what are watts per hour?

5:11 on 215w AP at Kona is not good. Were you using Gatorskin tires?

I'm a P5 owner. Be careful using carbon extension backwards to get your hands higher, they're not meant to be put in backwards and could crack and be unsafe. That said, high hands isn't necessarily the point, the point is what happens after you raise your hands up to comfort, power, and aerodynamics.

You look totally different in the 2nd pic to me, even though you say the bikes are the same. But you've got like 3cm more reach in the 2nd pic based on where your elbows are and your TT posture and IQ is much better in the 2nd pic.

I don't know what size bike that is in the pictures but I just can't see you going to a 51cm from a 56. If it were me, I'd just change your extensions to ski bends, remove the 20mm of P5 spacers, and add angled pads from AeroCoach or some other aftermarket place and you'd be good to go.

I suppose you could post a pic of you on a the 51 but I don't think it will change my mind. Switch back.

Edit: don't post race pics that you didn't pay for. Pet peeve. Do me a favor and pay that photographer for his work.

Darren325 wrote:



These two pictures are one month apart; the bike is exactly the same, only the shoes are different. In the bottom picture, a 70.3, I hit my power target and felt comfortable. In the top, I was 30 watts per hour off my power target (a number I have achieved in previous iron-distance races and well within what I could do based on my training.

Nothing has changed, but as you can see in the pictures, everything had changed.

Since then, I have swapped up the extensions, using my original aduro bars but inserted in the opposite way to give my hands a much higher position that feels more natural and comfortable. But I'm still struggling with whether to go with this fit or not.

I was riding a size 56 P5, no spacers, low mount. Felt super comfortable, but at 75kg, 215watts AP, 2017 Kona bike split was 5:13 ,I was giving away a lot of time due to aero. I am 5'11", 165 pounds (180cm, 75kg)

The new rig is size 51 and obviously a dramatic change. I ran well off this position and did not have any issues. But it feels a touch too short in the reach for me, and there is no way to move the pads further forward if I keep the aduro bar.

I'm asking the collective and specific wisdom of slowtwitch. Does this size fit into the "it's aggressive but maybe you can adapt to riding it well" category or is this just plain crazy? I still have the 56 size bike and can easily go back to it and can use this frame for my wife, so there are no serious financial considerations here.

Eric Reid AeroFit | Instagram Portfolio
Aerodynamic Retul Bike Fitting

“You are experiencing the criminal coverup of a foreign backed fascist hostile takeover of a mafia shakedown of an authoritarian religious slow motion coup. Persuade people to vote for Democracy.”
Last edited by: ericMPro: Jun 19, 19 3:05
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Re: Which size P5 should I stick with? [ericMPro] [ In reply to ]
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Hi Eric,

Thanks very much for the feedback. I did pay the photographer for this photo, but I used this version because it is a small file that I can post in ST. (Taiwan race photographers are pretty epic and charge by the image, not a package, so if you ever race in Taiwan, it's a nice bonus)

I have added a picture of me on the 56 this past October at IM Taiwan. I have ridden that exact fit for 5 years and feel very comfortable on it, but as you noted, my watts are not translating into the speed they should and I'm trying to address that without the aid of a wind tunnel.

Kona was using continental GP 4000 clinchers, Zipp 808 front and back, 2017 so moderate wind, but nothing serious. These pictures have DT Swiss ARC 1100 80, I will be using the 62 size for the front wheel and the 80 rear this year at Kona. (Riding with tubeless setup on the DT Swiss, latex tube with Zipp)

Both of the pictures in the original post are riding the size, 51, and the set up was exactly the same, even though I'm sitting on the bike in entirely different ways. The aerobars here are Zipp Evo 110, which just aren't high enough. You are absolutely right; the second picture was a much better ride from power and comfort.

So what I did in that position was slide my elbows further forward on the pads so that my hands would not be oriented so high. I am wondering if I should just get rid of the angled pads and try the position with the 3T extensions in their normal ski jump orientation and just "make up" for the lack of reach with larger pads such as the ones from speedshop 51 that would allow me to ride with my elbows further forward and my hands flat.

The only comfort issues I have on the size 51 is increased strain in my forearms. No back or neck issues, and I ran well off this position. I am less 'planted" in this position compared to the size 56 and it makes it more difficult to make the power, but I'm not sure if that is just an adjustment/training issue, or if this new position is simply too aggressive and unrealistic for me.

And thank you so much for the already very valuable feedback. I'm feeling a little lost as to how to get the bike feeling right again.




ericMPro wrote:
what are watts per hour?

5:11 on 215w AP at Kona is not good. Were you using Gatorskin tires?

I'm a P5 owner. Be careful using carbon extension backwards to get your hands higher, they're not meant to be put in backwards and could crack and be unsafe. That said, high hands isn't necessarily the point, the point is what happens after you raise your hands up to comfort, power, and aerodynamics.

You look totally different in the 2nd pic to me, even though you say the bikes are the same. But you've got like 3cm more reach in the 2nd pic based on where your elbows are and your TT posture and IQ is much better in the 2nd pic.

I don't know what size bike that is in the pictures but I just can't see you going to a 51cm from a 56. If it were me, I'd just change your extensions to ski bends, remove the 20mm of P5 spacers, and add angled pads from AeroCoach or some other aftermarket place and you'd be good to go.

I suppose you could post a pic of you on a the 51 but I don't think it will change my mind. Switch back.

Edit: don't post race pics that you didn't pay for. Pet peeve. Do me a favor and pay that photographer for his work.

Darren325 wrote:



These two pictures are one month apart; the bike is exactly the same, only the shoes are different. In the bottom picture, a 70.3, I hit my power target and felt comfortable. In the top, I was 30 watts per hour off my power target (a number I have achieved in previous iron-distance races and well within what I could do based on my training.

Nothing has changed, but as you can see in the pictures, everything had changed.

Since then, I have swapped up the extensions, using my original aduro bars but inserted in the opposite way to give my hands a much higher position that feels more natural and comfortable. But I'm still struggling with whether to go with this fit or not.

I was riding a size 56 P5, no spacers, low mount. Felt super comfortable, but at 75kg, 215watts AP, 2017 Kona bike split was 5:13 ,I was giving away a lot of time due to aero. I am 5'11", 165 pounds (180cm, 75kg)

The new rig is size 51 and obviously a dramatic change. I ran well off this position and did not have any issues. But it feels a touch too short in the reach for me, and there is no way to move the pads further forward if I keep the aduro bar.

I'm asking the collective and specific wisdom of slowtwitch. Does this size fit into the "it's aggressive but maybe you can adapt to riding it well" category or is this just plain crazy? I still have the 56 size bike and can easily go back to it and can use this frame for my wife, so there are no serious financial considerations here.
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Re: Which size P5 should I stick with? [Darren325] [ In reply to ]
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Darren325 wrote:

Both of the pictures in the original post are riding the size, 51, and the set up was exactly the same, even though I'm sitting on the bike in entirely different ways. The aerobars here are Zipp Evo 110, which just aren't high enough. You are absolutely right; the second picture was a much better ride from power and comfort.

OK, if the original post is you on a 51cm, then you should not be on a 56. I'd keep the angled pads and get some big ski bends like USE Tula alloy extensions and then just focus on posture.

Money no object you should probably be on a 54 though...

Eric Reid AeroFit | Instagram Portfolio
Aerodynamic Retul Bike Fitting

“You are experiencing the criminal coverup of a foreign backed fascist hostile takeover of a mafia shakedown of an authoritarian religious slow motion coup. Persuade people to vote for Democracy.”
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Re: Which size P5 should I stick with? [ericMPro] [ In reply to ]
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Thanks Eric.

I'll get the extensions and see where I am at.

I got this frame and fork brand new for $1000usd and 100% legit Cervelo from a close friend. You are right, though, the extra few mm of reach would have made a big difference, but I think I'm still better off than when I was on the 56.
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