Others will chime in with technical expertise, but odds are high that a P Series is slower than your P5-6. Just about everything is slower than the P5-6. You will gain disc brakes, a fresh paint scheme, and newer components.

Can't comment on fitting, but I moved from a 54cm P5-6 to a 54cm P5X. My impressions are:

• No noticeable difference in speed - PX is just as fast as the P5-6 (Cervelo and independent testing has confirmed this too...)
• No difference in weight - in fact I managed to build up my P5X lighter than my old P5 (even though every one moans that the P5X is "heavy", and the PX series is now even lighter)
• PX is slightly more comfortable (though that may be attributable to different wheels / tubeless tires), but I do feel the lack of seat stays makes the rider more comfortable.
• Just as stiff in the BB area
• better storage and hydration options than the P5.

However, the major benefit I've found, is that the PX is a lot more stable in windy conditions than the P5 - it just tends to track better and not get buffeted around as much, even with wheels that are just as deep. I also feel like it gets more of a sail effect in cross-winds. Therefore my feeling is that P5 might be slightly faster at low yaw, but the PX is definitely faster at high yaw conditions.

Disc braking is also far superior (for some people that's not an important factor)

You're not losing anything going to a PX. I would never sell my P5X to go back to the old P5.

Right, this is why I chose to not do it up until this point. I was just wondering if ST confirmed my suspicions.

I don't think the PX is an option for me. 1) I don't know if I would fit on it, even though I understand that they made a larger frame; and 2) I don't think it's even available anymore (The Cervelo website doesn't even allow you view those pages). When I asked about this bike at the Cervelo bike shop, the salesperson basically told me that this bike was a short-term anomoly/brain fart from Cervelo and there's no energy around future support for this bike, and he wasn't even confident that he could get me one if I wanted it. So, PX is moot for me, even if I thought it could be an option.

I'd guess you'd gain nothing at best........ at worst it might be slower. I've recently changed from a P5-6 to a P5 disc and I don't think there is any difference, my TT and triathlon results are the same on both bikes. The P5 disc is much easier to wrench, adjust, pack away for flying and generally a lot easier to live with which I guess would be the same on the P Series. But from a pure speed perspective you can't get much faster than the P5-6.

We took a team rider on a P5-3 (UCI legal setup) to the tunnel and vs an identical setup P5 disc there was a slight penalty to the P5 disc with no bottle, but the P5 disc was faster with the bottle installed. Some of that bottle data will be a front wheel interaction (Titan 100mm front wheel on both bikes). A P5-6 would be a little bit faster than this P5-3 although too high stack height with the Aduro made using Aduros impossible (3T Volas were used)

---

AeroCoach UK
http://www.aero-coach.co.uk

Theres a brand new XL P5x on eBay from a dealer in Singapore for a steal. It should fit if you fit on a 61 P5-6, but you can check. The fit tool for P5x on cervelos website is still live.

Are you riding slammed or with high stack? I ask because the reach difference between 58 and 61 Cervelo TT bikes is negligible. Seems they basically just make it a bunch taller at that last size step. But if you need a tall cockpit, look at Canyon. The CF in XL is a big bike in all dimensions. And their L has the same reach as a 61cm cervelo but with slightly less stack.

this is very helpful. Thanks.

My P5-6 has the highest stack that we could fit with the headset. But, I needed it just because I'm so tall (6'7"). IOW, I think it was less about "riding in slam position" or not and more about just fitting a tall person on a bike in order to get the best fit.

I'm very skeptical that the Canyon would fit. And, I'd have to buy it to find out. That's too risky. And, again to my OP, I'm not sure if I'd be any faster than my P5-6.

The XL canyon is both taller and longer than a 61 P series. I don't see how it could possibly be a problem if a 61 P only fits with maximum spacers. There's a very easy way to find out: What is your pad X and Y?

Which front brake was on the P5-3? And what would be the impact of aerobars given that in that regard the setups couldn't be identical by definition?

---

----------------------------
Need more W/CdA.

I made the same change and mostly agree with you. There is a big difference in my experience/option on technical courses. I am able to use the brakes much more precisely which allows me to dive into turns, etc with more confidence. I believe it is quite noticeable.

---

David
* Ironman for Life! (Blog) * IM Everyday Hero Video * Daggett Shuler Law *
Disclaimer: I have personal and professional relationships with many athletes, vendors, and organizations in the triathlon world.

Tririg Omega front brake - and actually the reason for the test was to determine if the rider could swap to disc brakes/potential lower stack setup without having an aero penalty, so it was a success in that regard. The aerobar setup on the P5-3 was using a downwards angled stem to achieve the drop needed.

---

AeroCoach UK
http://www.aero-coach.co.uk