Review: Scott Plasma 5 Superbike
article & images by Nick Salazar
Mar 16, 2015
In general, there's been quite a bit of convergence in the design of various UCI-legal frames. That is, TT bikes are starting to look a lot alike, and some of this design cohesion has spilled over into tri-specific frames as well. Specifically, a lot of new frames sport dropped down tubes to better hug the trailing edge of the front wheel, and have large gussets behind the head tube, above the BB, and in a sort of parallelogram at the seat tube cluster. Truncated airfoils are everywhere, saddle clamps are often wedges, and the Ritchey SideBinder post has become rather popular. The Plasma 5 has ALL of these features, executed very nicely. To say that it ticks these boxes is to take nothing away from the fact that it is a unique bike with a lot of nice and well-thought-out features. It just also happens to conform to the current "best practices" in design.
Let's start with that down tube; as mentioned, it perfectly hugs the trailing edge of the front wheel. There are no funny gaps or weird shapes here, and it's easy to see why this design tests faster than previous solutions at the fork crown; it's simply a better way to move air around without creating a drag-inducing vacuum. The gussets in the main triangle are very much like those on the Cervelo P5, particularly the one behind the seat tube. As Damon Rinard once said, Cervelo didn't create it - the UCI did. That parallelogram is a result of the UCI's very specific rules regarding tube shapes, and both Scott and Cervelo are basically maximizing the area allowed within those rules.
The down tube of the plasma 5 uses a truncated airfoil shape that has become such a popular design choice since Trek introduced it with the Speed Concept. But Scott's airfoil opts for softer corners on its truncated rear half than those Trek uses. In Trek's kammtail white paper, they found that the sharper edges were generally faster than soft ones, but I'm sure Simon Smart and Scott did their homework and wound up with a shape that doesn't compromise on aerodynamic speed. And another benefit of the slightly rounder-shaped cross section is that the tube is amazingly stiff. It's evident that Scott was interested in wowing their UCI-riding pros with sprint-worthy stiffness, because this bike feels as solid as anything I've ever ridden, particularly at the front end.
All the little details have been given their due attention. For example, the wedge-actuated seatpost clamp uses a very LONG three-piece wedge, allowing for greater clamp force at lower torque. The cable covers for the brakes are light weight and easy to use. I was even able to modify them to run Omega brakes front and rear. The BB uses Shimano's BB86 standard, which definitely isn't my favorite, but it works fine as long as you're cool with stock cranks from Shimano, SRAM, or Campagnolo. A crank with a 30mm spindle doesn't usually play nice with BB86. You can do it, but the bearings you have to use are rather thin, and will likely require replacement a bit sooner. I wish everyone would use BB30 or PressFit30, which is my favorite standard by far.
The dropouts in the rear are horizontal, which allows you to really tuck the wheel into the seat tube cutout, at the expense of being slightly more difficult to swap wheels. I have to say I generally prefer vertical dropouts, but the horizontal ones aren't too much of a hassle.
Cable routing through the frame is very basic and generally easy to work with. Cables go in the big port at the top tube, and come out at the BB, or go all the way through to the rear derailleur in the case of a Di2 wire. Assembling the bike does require a bit of wire fishing expertise, but it's nothing too rough, especially if you make sure to keep the crank out while running cables. Full disclosure, I didn't get the chance to build up this bike from scratch, it came to me already assembled. But I did cut all the cables and reroute them to get a sense how it all worked. As mentioned on the page about the front end, the front brake wasn't the easiest routing, in particular because of the sharp angle the cable has to make to get to its stop in the stem. But other than that, the cables weren't too bad. I'd say rather par for the course on tri bikes these days. Not too tough, nor spectacularly easy.
Hit the jump and we'll get to the last words on this beautiful machine.
Complete Bike - Tri Mode
The Scott Plasma 5 is one of the latest generation of superbikes to feature a whole lot of integration up front. In its debut year, it was ridden to a World Championship victory by Sebastian Kienle, Scott's marquis athlete. This section shows the bike with its +45mm stem and the integrated bottle/storage unit that go with it.
Complete Bike - Low-Stack TT Mode
The Plasma 5 can also be built with a lower-stack +0mm stem for those who need a lower position. However, in this configuration is cannot use the integrated bottle or storage mode. But it's VERY clean, and I really like the look in this mode.
The Plasma 5 uses an integrated version of the Profile Design Aeria bar, and an integrated stem to match. The stem is available in the stock +45mm version, or a +0mm version that can be purchased separately, but the low version isn't compatible with the bike's integrated aero bottle.
The integrated bottle is a very slick and usable aerodynamic feature, and something triathletes have wanted to see for years. The only real downside is that it's not compatible with the low-stack stem. The bottle has a number of somewhat difficult-to-install rubber pieces (I wish they were all just one piece), but once on the bike it's a really cool feature.
The integrated storage unit forms a perfect aero match with the rest of the front end, and has quite a lot of space to store gels, tools, tires, etc. Even better is that Scott used the industry-standard boss spacing, so that you could optionally mount any other top tube storage unit you wanted. This could be nice if you run the bike in low-stack TT mode, because then you could put on a storage box with a rounded leading edge, like some of the units from XLAB, or the carbon unit we featured from Glen Alden.
The Plasma 5 uses custom integrated TRP centerpull brakes that completely hide from the wind. These brakes are built on the Shimano Direct-Mount standard. But in an awesome and very thoughtful move, Scott also included a standard brake boss on the front of the bike. This means that if, for example, your brake gets damaged in travel, you could easily bolt on a standard brake as a last-minute replacement. In my case, I installed a TriRig Omega, which even fit underneath the aero cover after a small modification.
More shots of all the beautiful pieces of this very clever bike.