Cervelo's P5X with Zipp's 858 and S-900 Aero Brakes

Our continuing review of Cervelo's P5X super bike continues with a look at some new wheels and SRAM's fully hydraulic S-900 Aero HRD brakes.

| February 6, 2018 | GEAR

The Cervelo P5X with the Zipp NSW 858 and SRAM\'s new R-900 Aero HRD brakes enjoying some warmer weather in Bermuda.

The Cervelo P5X with the Zipp NSW 858 and SRAM's new R-900 Aero HRD brakes enjoying some warmer weather in Bermuda.

Photo >Kevin Mackinnon

Cervelo's P5X certainly does draw some looks, a fact I proved once again during a recent press trip to Bermuda where time and time again people either did a double take when they saw my bike or asked me what on earth it was. Those in the know had even more to look at on this trip - it served as a chance for me to test a couple of new products from the folks at Zipp (the newly released biomimicry-inspired 858 NSW) and SRAM (the fully-hydraulic S-900 Aero HRD brakes) that I couldn't test back home because of the crazy winter we've been having.

For those who find me to be far too verbose and would like to get to the bottom of the review in a hurry, I'll give you the quick answer to how they performed, then provide more details after: The bottom line is I haven't ridden a bike set up that I think is better suited to the Kona course. For those who choose to read on, here's why.

Zipp\'s NSW 858 uses a unique \"Sawtooth\" profile derived from Biomimicry.

Zipp's NSW 858 uses a unique "Sawtooth" profile derived from Biomimicry.

Photo >Kevin Mackinnon

Aero wheels

We've written about the NSW 858s before, but this was my first chance to test out the speedy wheelset launched at the Ironman World Championship in Kona last October. The 858 follows on the release of the NSW 454 wheelset that uses similar technology, but is obviously quite a bit deeper. With a shape that's similar to a whale's fin, the profile changes from 77 to 82 mm. Zipp uses a process they call Aero Balance to make the wheels less susceptible to cross winds, which allows you to spend more time in the aero position, which, of course, will allow you to go faster.

So, do the 858s perform as well as the hype? From my two days of riding on them through some pretty windy conditions, I was suitably impressed. Even with some hard, gusting sidewinds I felt quite comfortable down on the aero bars. (Although going over one bridge I plead guilty to sitting up, but even Flora Duffy seemed to be getting moved around on the road, so I'm not sure that is a knock against the 858s.)

If you've read my previous reviews of the P5X, you'll know that I've yet to come across a bike that descends as quickly, especially in cross winds. That was with the Enve SES 7.8 wheelset that come standard with the SRAM Red eTap-equipped P5X - super fast wheels, too. With the 858s I enjoyed the same, if not more, downhill speed, struggling not to surge past the rest of the group on descents (and I rarely had to pedal). The real bonus, though, was that I definitely felt the front end of the bike was less prone to getting moved around in cross winds thanks to the added stability.

In terms of straight out performance, while there weren't any super long climbs that we ventured over in Bermuda, there were certainly enough punchy, steep ascents that were enough to test the lateral stiffness and climbing characteristics of the 858s - they certainly passed the tests with flying colors.

The innovative profile makes the wheels less susceptible to cross winds.

The innovative profile makes the wheels less susceptible to cross winds.

Photo >Kevin Mackinnon

The textured carbon brake levers are comfortable and very adjustable.

The textured carbon brake levers are comfortable and very adjustable.

Photo >Kevin Mackinnon

Fully Hydraulic Brakes

The P5X, like a few other super bikes that were released in 2016, comes with disc brakes. Disc brakes provide enhanced stopping power, which means you can brake harder and later, which ultimately means you're faster. The biggest upside is you can do all that even in wet conditions. 

The original brakes that came with the P5X were a combination of hydraulic and mechanical brakes made by TRP, which perform very well. SRAM announced the new S-900 Aero HRD brakes in the summer of 2017. When I tried out the fully-hydraulic S-900s I realized that things could actually be better - braking performance just moved up a notch. The S-900s seem that much more powerful and start the process of stopping you that much quicker. (I would suggest a short ride in a parking lot and some testing to make sure you have a good feel for just how quickly you can stop before heading out for the first time.) I did have some issues with the brakes squeaking and grabbing after unpacking the bike, but quickly learned just how adjustable they are - a few minutes with a mechanic and they were dialed in. The S-900s are a much appreciated addition to the P5X arsenal. These brakes are now standard on the Red eTap equipped model and offer all the best benefits of discs, with considerably fewer of the downsides.

My lack of disc brake experience means I don't really appreciate all the benefits of these new wonders from SRAM, either. While I was able to enjoy the Reach Adjust that allows you to dial in a custom brake lever fit and liked the great feel, the word is that mechanics are likely to much happier because set up is much easier. At some point I will probably need to figure out the bleed process, too, which I was always told was a nightmare with disc brakes. That's all changed, though, as the S-900 uses "Bleeding Edge" technology to make the process quick and hassle free, according to SRAM.

Race ready

The P5X is designed for long-distance triathlon racing in mind. The entire concept is built around being able to pack all the equipment, food and drink you'll want to take along with you in a super-aerodynamic package.

In my previous reviews I have been quite open about the two things I don't like about the P5X -  the weight and how long it took me to get comfortable climbing with it. (I guess there could be a third - I'm not factoring in the price, which is certainly prohibitive for most, too.) In terms of the weight and climbing issues, though, neither was a factor at all during my rides in Bermuda as the climbs were mostly short (albeit some were steep) and I am getting more and more used to standing on the bike. Two hours into a three-hour ride I was quite happy to make my "can't imagine a better Kona setup" proclamation - the P5X coupled with the Zipp NSW 858s and the excellent S-900 brakes seem to me to be an excellent combination for a rolling bike course with lots of cross winds that requires being able to stay in an aero position for as much as possible. While you won't likely feel a huge need for the enhanced braking from the fully-hydraulic system during a ride in Kona, you will love the extra performance on more technical rides and if you are out with a group.

I'll have another go with this set up in a few weeks over some very hilly terrain in California and will provide another update then.

Kona ready ...

Kona ready ...

Photo >Kevin Mackinnon