The p5x has marginally lower drag. The p3x/PX are stiffer in BB and head tube. They are also a bit lighter. Stiffer and lighter would probably outweigh the lower drag on a sprint course where you are more likely to be "attacking" the bike leg more, such as accelerating out of corners and any short inclines?

No idea re: bike choice.

For all-out speed, get an 808 or similar on the front, not the 404. Disc wheel in back, not the 808.

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Dr. Alex Harrison | Founder & CEO | Sport Physiology & Performance PhD
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I think aero will still trump stiffness and weight even on the most technical and undulating sprint tri course. I have no data to support my intuition here.

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Dr. Alex Harrison | Founder & CEO | Sport Physiology & Performance PhD
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Not worried about the wheel choice. Just want to make sure I buy the frame set will be the fastest between the 2.

As stated will probably go with the Enve 7.8 and SES disc.

That was my thought also.

But, how much faster is the P5X? Similar position on both bikes, so it all comes down to the frame set.

Oh! I misread! Sounds like wheel choice is going to be on point.

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Dr. Alex Harrison | Founder & CEO | Sport Physiology & Performance PhD
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As of 2 weeks ago, Cervelo did not have the P5X on it's dealer site, so not sure you will have a choice unless you know of existing stock.

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Kiwami Racing Team

dude you're over thinking the bike. You're splitting hairs which at the end of the day are going to be seconds, and not a ton of them.

I'd be willing to bet you $25,000 that if you set up both bikes exactly the same, within the mm and did 10 runs on each over a 10 mile course the differences between the averages would be so trivial it wouldn't matter.

Most people aren't going to be able to have so consistent a position over that many runs that you're going to be able to tease out which bike is actually faster. I've seen thumb position change drag by as much as 8 watts...for the worse. Thumb position was > any clothing or helmet difference. Think about that then think about your dire situation of choosing between bikes.

Now for the front wheel you can find faster wheels than the Enve 7.8 That's going to matter more than what bike between those two that you buy.

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Brian Stover USAT LII
Accelerate3 Coaching
Insta

Found a chart that averages the yaw and the p5x saves between 17g and 27g depending on number of bottles. So for sprint the lower figure which is what, one or two watts? As Brian has said it's so negligible to be almost irrelevant. But the stiffer bike likely to track better in corners which could make up more time. It all depends on what your sprint courses are like. P5x has slightly less tyre clearance as well which may or may not be a factor.

LOL.

I like to overthink. I would hate to buy a $12,500 bike plus extra $ for my mods and realize I could have bought the other X model and be a tad faster.

I do appreciate the feedback.

What wheels would you choose. I just likeEnve wheels. I have about 8 sets of them on various Road, TT, Gravel and MTB's. I have never had an issue with any of them in the past 4 years, and I am rough with my bike stuff. Usually if it can be broken, I end up breaking it.

Also was thinking the Aerocoach wheels and disc.

I too think you are over thinking it.

I've gone from an S-Works Shiv to a Trek SC to a P5x.
I will say it does feel like the p5x is better at keeping higher speeds. Be it due to drag or just belief.
But it is heavier and thus slower up to speeds or accelerations. Noticeable - not really. Stiffness - no issue also not exactly noticeable.

I've lightened mine with dash combo and cut posts and the likes, integrated it with a bladder etc. I really love the bike.
I do still feel its a little heavy though. Everything aero says it doesn't matter.

Realistically there's virtually zero difference between the top end bikes. Purely down to preference or integration that you like etc.

Now, ironically I'm in the process of adding a P5d.
Why? Largely as I love the bike and had an opportunity to pick up the last one in Sunweb colours in my size.
I will test against the p5x and keep whichever I prefer most.
I expect there to be very little time difference. More down to preference be it feel or weight or drag or integration or colour!


My answer is go with your preference - colour/integration/availability whatever.

If you love it you will train more or better on it and be happy. That is what counts.

Also - Enve wheels all day long. I liked Zipps when I had them, then picked up Enves and realised they're just better overall particularly in wind and seem to be stronger also.

Enjoy!

Short answer: P5X < PX < P3X (lowest to highest drag, according to Cervelo's data)

Long answer: they're all within like 1-2W of each other, so get which one you like the most or the cheapest. I got a 2019 P5X over the P3X/PX mainly because I think its the coolest and the front wheel cutout looks better then the spares pod on the newer models. And it is faster. Just. ;)

Ps. weight of the P5X is really no issue. I built mine up ~150g lighter than the P5-six I had before, and i didn't even resort to getting fancy combo seatpost/saddles etc.

As for wheels, the HED Vanquish are truly phenomenal. I ride the V8 and in combination with the P5X are SOOO stable and fast. Only had Zipp 808NSW before so cant compare to the Enve.

 

hold up ... to hell with frames ... can we please discuss optimal thumb position?

I also like the look of the P5X with the down tube closer to the front wheel. Only thing I do not like is the integrated derailleur hanger.

I bought the PX.

Cervelo is out of stock of PX's, frame sets and forks. They only have a couple P3x's in stock also. Are they discontinuing the X series? I hope it's just a color change and they are not doing any revisions or updates to the frames. Any one have info on this?

hahaha she changed her thumb position one run and the #s came back waaaaaaaaay higher. We were like wtf. Then started comparing head, back, hip, wrist, elbow positions from the previous run. Suddenly it was "look at her thumbs" Then "come on you've got to be kidding me".

We ran it thumbs in the slow position and it repeated. Thumbs in the fast position and sure enough something like 8-10w faster. Had we had beer in there we would have drank several thinking thumb position??? One of the biggest drag additions/reductions?? W........T........absolute............F????? and downed another.

In the past I've tested thumb position before for a few riders pre and post this test and it was not as consequential as for this rider.

I've seen some weird crap where you think this is going to make them as slick as a rocket. Turns out they are about as aero as a brick. Or times where you think I bet that adds 5-8w of drag and sure enough it subtracts 5-8w of drag. \_O_/

Sometimes it's the tiniest or least consequential detail that can make a huge difference, sometimes it's pretty obvious. That's why you test though.

Which reminds me, need to start working on putting together testing session for April where you can test, get a bike fit, or do both all at the tunnel.

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Brian Stover USAT LII
Accelerate3 Coaching
Insta

this is why I always tell my athletes and clients they are fighter pilots, not helicopter pilots. AeroFit athletes don't have issues with thumb position, it's all about trigger fingers baby.

E

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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.”

 
funny!

i wish there was a way to do some kind of quasi-empirical testing online over video. we used to have an outdoor track but it was torn down a few years ago.

There was some software that could measure your CdA at some point out there. Used an xbox kinetic then you sent it to them they modeled it. IDK if they are still around. I know microsoft is 2-3 gens past the kinetic.

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Brian Stover USAT LII
Accelerate3 Coaching
Insta

A friend has the Bio Racer software here in Madison. Not sure if that's what you were looking for....

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Kiwami Racing Team