Page 1 of 2

Cervélo PX5 alternative?

PostPosted: 10 Oct 2016 19:02
by King Sad
At about 1/3 to 1/2 the price .. I would look like a tw#t on it though

https://vimeo.com/182747835#at=17

http://www.diamondback.com/shop/bikes/r ... ean/andean

Re: Cervélo PX5 alternative?

PostPosted: 11 Oct 2016 19:22
by tesseract
I'm sure I saw a review of the PX5 that tested it against another bike, under as close conditions as they could manage, and it was slower. Damned if I can find the article now though...

Re: Cervélo PX5 alternative?

PostPosted: 11 Oct 2016 20:06
by King Sad
I know a lad who is a keen Time Triallist and got a P5 with the intent of smashing his 20 and 50 mile TTs. He was slower despite constant refits and eventually went back to his old bike and smashed both :ninja:

Re: Cervélo PX5 alternative?

PostPosted: 11 Oct 2016 20:21
by IanM
I think the P2 is still seen as the fastest Cervelo.

I'm quite intrigued by the new TT/tri bike from Reap - http://reapbikes.com. Designed and built in Stoke apparently.

Sent from my Nexus 5X using Tapatalk

Re: Cervélo PX5 alternative?

PostPosted: 11 Oct 2016 22:25
by Ewan
The P5x is optimised for carrying luggage so the wind tunnel data produced by Cervelo show that a fully laden P5x is marginally faster than a fully laden P5. The only problem is that they defined a fully laden P5 as 3 bottles, a toolkit and 8 gels taped to the top tube, which is hardly optimal. Someone on slow-twitch then did a bit of guesswork based on known data about the P5 and concluded that the P5x would probably test slower than an unladen P5. It's difficult though because I don't think Cervelo have told us much about their testing protocols (other than that they used a static rider!!!) so it's pretty impossible to say anything for sure.

I doubt there are any independent sources who have had time to get the new P5x in a tunnel into a tunnel to test it alongside anything else yet.

I think the P2 is still seen as the fastest Cervelo.


Citation needed. I'd be delighted if this was the case, but I thought that this was widely accepted that the old shape P3 was faster than the old P2 and that the P5 was fastest overall?

Reap does look good, but all bets are off until we see the geometry...

Re: Cervélo PX5 alternative?

PostPosted: 11 Oct 2016 22:26
by Ewan
Oh yeah...

Why call a heavy bike designed for aerodynamic speed on the flat after a high mountain range???!

Re: Cervélo PX5 alternative?

PostPosted: 12 Oct 2016 06:19
by King Sad
Then there is the https://www.dimondbikes.com/

Seems to be a trend in this design although a throwback of a design retrieved from archives and dusted off :D

Re: Cervélo PX5 alternative?

PostPosted: 12 Oct 2016 07:56
by IanM
Ewan wrote:Oh yeah...

Why call a heavy bike designed for aerodynamic speed on the flat after a high mountain range???!


Yes, I did think that whilst watching the video.

Ewan wrote:Citation needed.


It's possible I've got my 2s and 3s mixed up. I think Bussell's been on a P2 this season, and it's not like he'd be riding a bike that gives much aero penalty...

Re: Cervélo PX5 alternative?

PostPosted: 12 Oct 2016 16:58
by Ewan
It's possible I've got my 2s and 3s mixed up. I think Bussell's been on a P2 this season, and it's not like he'd be riding a bike that gives much aero penalty...


The whole question is made worse by Cervelo's naming convention where they will happily replace existing models with completely redesigned new models but use the same names.

I ride an old style P2c, the same as Chrissy Wellington did prior to switching to Cannondale. I love mine, but don't think they were ever considered faster than the famous old style P3, although the geometry did work better for some people.

Despite it's age, the classic old style P3 is the frame that I would say has very well regarded aerodynamics. However nowadays I think that is more to do with the long and low (3cm compliant) geometry than the tube shape. Also these frames were designed with frame aerodynamics as a priority and so aren't particularly well optimised for carrying multiple bottles etc. A bad thing for triathletes, but pretty irrelevant for most testers.

In 2013(?) Cervelo introduced the new style P2 and P3. The frame shapes on these are undoubtedly more aerodynamic than the pre-2013 frames, however Cervelo also targeted the new frames at triathletes and therefore followed the trend of high stack and short reach, as well as improving the integration of bottles and bento boxes etc.. While this might benefit Ironman athletes it doesn't make them ideal for CTT riders. Bussell rides one of these new style P2s so Xav has clearly found a way to make it work but many Testers will struggle to achieve an aero position while remaining 3cm compliant. The interesting thing to note is that the frame shape of the new P2 and the new P3 are identical. The only differences are in the weight (different carbon layup) and a tiny adjustment to the fork which is again apparently aero neutral but lighter on the p3. Given that there is no difference between the aerodynamics of the frame I have no idea why anyone would spend £££ on a few grams, and clearly Xav agrees.

I think both the P4 and P5 are considered very fast, but again suffer from being designed for triathletes (especially the p5). Finally Cervelo have made the final step towards integration by designing an Audax bike.

Re: Cervélo PX5 alternative?

PostPosted: 12 Oct 2016 18:04
by IanM
I bow down to your far more extensive Cervelo knowledge!

Also, bloody triathletes!