P3 is a waste of money in this context. Change the bars and groupset and it's the same bike as the p2. I'd personally say the p5, especially if you can throw an alpha one on that too sometime in the next couple years

P5. Always P5. That bike is the standard bearer. You have to spend like $5K in upgrades to get a P3 as fast as a P5. And, the massively upgraded P3 has to be one size smaller than the P5 to compete. The P5 is a beast.

Why does the P5 need to be a size larger than a P3?

Tririg (whom I love) did a demo study to see if they could make a P3 as fast as a P5 in a wind tunnel. They installed a butt-ton of upgrades on the P3 and got there. But the whole thing was kind of soiled by the fact that the P5 was one size larger than the P3 in their comparison.

The bars and the groupset on a second hand bike usually workout to about 1k.
P2/3 vs P5 is a tough call. P2/3 is easier to wrench and can be trivially modded up to have the front as aero as any superbike. The rear brake mount is a fucking travesty, but it is the only weak point on the bike.

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Next races on the schedule: none at the moment

You might as well get it right... It was a P2 not a P3, the upgrades were only the bars, brakes and seatpost+saddle (way less than the price of a P5), and the P2 beat the P5... by a lot. https://www.tririg.com/...mp;page=windtunnel_1

I'd much rather have that P2. If you put the Alpha One on it, it would be way ahead of the P5 in adjustability too.

Also, Jens on a comparison between his old P3C and his P5. Guess which one was the winner? : https://forum.slowtwitch.com/...r)_P6636659/?page=-1

The moral of the story is that you don't have to spend a lot on a frame; the parts are far more important. And there are after-market parts available that are better than the stuff that comes on new bikes.

Of course position and posture trumps everything else. Which is why you need bars that are easily adjustable so you can test and optimize.

I would not recommend a P2/3 over a P5 based on those two examples. The Tririg P5 was 1 size larger than the P2. That alone pretty much negates their conclusions and meaning of the data. And, Jens' P3C had a 3cm narrower Q-Factor. It was not the bike, it was his highly specialized 1x narrow drivetrain that was the difference. Oh yeah, and that was a P5-3.

Yes, aftermarket parts make a difference. But the OP was asking about three specific bikes as configured. In those examples, the P5 (assuming it is a P5-6) is likely to be faster than the other two.

Also, as mentioned above, there are a few intangibles to also consider...

• I am not a fan of the hydraulic P5 brakes. I do not have any first-hand experience, but they seem like a maintenance PITA.
• The P2/3 has dirty cable routing that need some mods to clean up.
• The P5 often comes configured more as a max bike with better wheels, crankset, saddles, etc. over the P2/3 models. The OP does not give any of the details of the other stuff, though.
• I prefer Di2 on a TT bike over eTap because it is easier to hide the install versus the eTap Blip Box which usually has to be out in the wind.
• Aesthetics: A lot of people think the P5 is one of the best looking bikes ever created. That can be a huge decision factor for a lot of people.

what was the determining factor that made the P2 faster do you think?

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Eric Reid AeroFit | Instagram Portfolio
Aerodynamic Retul Bike Fitting

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Bars and saddle? The P5 brakes should have been at least as good. A little in the frame size difference, but I don't think there's much in that; you're trading one configuration of nice airfoils for another. If frame size made that much difference, we should all be riding very low stack frames with risers to acheive stack.

Actually I think the WT results in that test are a little screwy. But I still expect that the aero-drag difference between good *frames* (and the P2 is a good frame), is tiny to the point of being insignificant, based on other evidence.

You can't do that on any of these new bikes. If it's so good then obviously you need a bike that allows narrow Q if you want to go fast, eh?

The P5 looks ok with custom paint. I really dislike the older black/red/white striped look, and the matte one with the white bottom end is hideous. The UD gloss Nick did on the P2 is perfect...;)

Eric,

Which of the 3 bikes would you choose please?

Wheels, saddles etc all the same except those listed above

Or maybe something that is not on the list?

Thank you

Is it easy to use the alpha one when building a Di2 P5-6 or does it require changing things too much?

I'd dm tririg. No idea here, I'm way too broke for either of those

Should be easy. Just possible that you have to trim the Monopost to avoid hitting the Magura “beard” fairing. But it’s ok, the Monopost is designed to be trimmed when needed.

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TriRig.com

Thank you for your post

I’ll be ordering the Alpha tomorrow

I sent an email asking if you could look at my Retul Fit numbers to make sure what size P5 I should have for the Alpha bars. I used your sizing calculator but am not sure I am using the correclt stack and reach

Always happy to help! We just sent you a long reply email with all the details on your ideal fit with the bars.

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TriRig.com

Thank you very much

Hmmmmm not happy your aero skewers will require a second order lol

Just kidding looking forward to them

Appreciate all the help

Went ahead with the order
Alpha one
2 Brakes
Extensions


Quick question. Paid via Paypal Where can we see the receipt?

Can’t find it on tririg

Thank you again

Thanks for your order! The PayPal email is the only receipt our system outputs. As long as that showed up (or your PayPal account shows the debit) your order was received. If you aren't sure, feel free to shoot an email to support@tririg.com and we will be happy to take care of you.

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TriRig.com

Thank you!

Didn’t see the email from Pay Pal even in SPAM colder. But I have a screen shot of the payment

I did as you suggested and emailed support@tririg.com