Review: Scott Plasma 5 Superbike
article & images by Nick Salazar
Mar 16, 2015
Perhaps the most telling photo about a modern tri bike is the view from the front. It lets you know how much the designers cared about that clean air, and how it first contacts the bike/rider complex. I'm particularly harsh on bikes that do a bad job here, it bothers me to no end. But the Plasma 5 is exquisitely minimal from this view. The frontal profile of the Plasma 5 is absolutely tiny. Whether in triathlon or TT mode, there's virtually nothing to see; the integrated brake hides beautifully within the fork, and all cabling is hidden in the integrated stem. Few bikes achieve this level of cleanliness, and it's always really great to see a bike company put in the time to achieve it.
In the case of the Plasma 5, that profile is achieved through a combination of its integrated aerobar (a custom version of the Profile Design Aeria), integrated stem, and custom TRP centerpull brake hidden behind a fairing. We'll talk about each of these features, in the order just described.
Integrated Aerobar - Profile Design Aeria
I'm somewhat obsessed with aerobars - they're my favorite component to think about, build, tinker with, and even design myself. The aerobar is the defining feature of the tri bike, and it has enormous potential to make or break a bike. In the case of the Plasma 5, Scott brought in bar-design veterans Profile Design to make a custom version of Profile's own Aeria handlebar, exclusively for the Plasma 5. It's very much like the Aeria we reviewed in 2012, with a few key differences. First, of course, is that it mates to a custom stem, also made by Profile Design for the Plasma 5. We'll get to that in a moment. The bar also has flat hand holds compared to the Aeria's upturns - I am so glad Scott went with the flat ones - they're aerodynamically and (in my opinion) aesthetically superior. I also prefer the ergonomics of a flat hand hold, but that's a bit of a personal preference.
And the last difference with this custom Aeria is its cable routing, which is very good. Given that the bar conforms to UCI restrictions requiring no more than a 3-to-1 airfoil ratio, there's not a lot of room to route cables. This is often the Achilles Heel for tri bars - their cable routing is rather difficult. The Aeria mostly manages to avoid this pitfall, but space is still a bit tight. One brilliant stroke was to allow Di2 cable integration that puts the wires just behind the extension spacers; this means that if you change your position, you don't have to reroute any installed Di2 wires. That's a really nice feature, and one that's a bit of a pain on bars without this feature.
The bar itself is very well-designed; it has very little frontal area, and very simple installation and adjustment hardware. A pair of M6 bolts both attaches the spacer stack and secures the extension; another pair of bolts puts the arm cups on. Just four bolts per side, which is a very good, very low number. No bolt occlusion means you can get to all eight of these bolts at any time, without any hardware covering up some of your bolts. Very few bars achieve this simple, seemingly obvious feature, so it's worth noting when they do. One thing you can't do with this bar is tilt your extensions/pads up. Generally I don't think this is really a necessary thing, and athletes would be better off just finding an extension that puts their hands where they want to be, but in extreme cases, tilt might be ideal or required to hit some particular fit need. So be aware, there's no tilt on this bar.
But the Aeria does allow you to mount the extensions under the bar, in case you need to get really low. However, this requires hardware that was not included with my build, and might necessitate a call to your local Scott and/or Profile Design dealer. But the bar did come with a good deal of spacers to increase the pad stack and hit your position. You can see an example of the under-mount on Jodie Swallow's bike, which we profiled in Kona last year.
Speaking of position, I was unable to clone my preferred armrest stance width on the included cups (they were too wide in the narrowest setting). Many other Profile Design arm cups are likely compatible with the bar, but I just did a little DIY solution involving TriRig Alpha cups, and an extra threaded hole tapped into the Aeria's armrest hardware. If you run into this issue, just check out Profile Design's extensive library of arm cups, there's likely something that will fit you.
To make a perfect aero match with the frame, fork, brakes, and bars, Profile Design also made a special stem for the bike. And it's a beautiful match. Moreover, it attaches in a rather unconventional way, in the middle of the steerer tube, rather than right at the top. According to Simon Smart, the bike's designer, this was a very early design decision, allowing the headset bearing to sit at the top of that stack, increasing the bending moment and dramatically improving front-end stiffness. You effectively get the stiffness of a much larger head tube without needing to use that kind of tall geometry. And indeed, it *does* make the front end quite stiff. In my opinion, that's not a hugely important requirement for a tri bike, but for those who require it, this bike's front end will not give much in a sprint.
But for all the stem's virtues, it's also the source of my greatest complaints about the bike. To begin with, the stem comes in only two versions: a +0 rise and a +45mm rise. That in itself is not a problem, and I think reasonable to fit the vast majority of athletes, when combined with the adjustability of the extensions. What's a bummer is that the bike's cool tri features (the integrated hydration and storage) can *only* be used with the +45mm stem. So if you run a position too low for the +45 stem, you have to give up the integrated bottle and bento box. Well, technically you could still use the bento box, but it would be a bit out of place with its flat leading face.
I fall into the category of riders for whom the +45mm stem is too tall. I could probably get by with using the under-mount hardware and the +45mm stem, but I'm not a big fan of using multiple pieces of hardware with opposing stack functions. And to be perfectly fair, I don't mind being without the integrated bottle - I'm happy with using a standard BTA cage. I mostly lament the slick integrated storage. It'd be swell if Scott had something like a +25mm stem and a hydration and/or storage solution built for that level of rise. But I doubt it will happen.
The other slightly tricky bit here is the cable routing through the stem. In general, it's not too bad, but it could be a little easier, particularly where the front brake is concerned. Trying to route the cable into the stem's integrated cable stop isn't the easiest thing to do, and definitely involves a bit of a learning curve. To be fair, that's usually true of integrated front ends, but it makes the task no less annoying to accomplish.
It's also worth noting that because the stems only come in one length, your reach adjustment is basically limited to the pad/extension level. And the pads have virtually none. So your overall reach is more or less determined by the size of the bike, and where you put your extensions. You don't have a lot of independent control over where the pads actually sit on your forearms. This turned out not to be an issue for me, as the bike I got fit very well, but it could be an issue for others. The upshot is that you need to be sure you know your fit numbers BEFORE buying this bike.
Fork + Brake
And now we get to an area very near and dear to my heart; the aero brake. Scott made a bit of noise when this bike was launched, assuring everyone that the front brake was mechanically very different from any aero brake before it, and it was both very strong and easy to use. Stopping power, it definitely has. But in my experience, it's no easier to use than TRP's previous U-brake designs, as seen as a front brake on bikes like the Specialized Shiv, or as a rear bike on things like the Felt B2, Blue Triad SL, and many others. The TRP brake on the Plasma 5 is mechanically very similar, the primary difference being that this brake mounts to Shimano direct-mount bosses rather than TRP's centi studs.
Obviously I'm quite biased when it comes to brakes, so I won't be offended if the reader takes this section with a grain of salt. But I've never been too keen on these U-style brakes that have no independent centering control, they tend to go out of adjustment, and are rather difficult (in my experience) to install and adjust. I'm betting Scott agrees with this to some extent, as they opted NOT to use this same brake at the rear of the bike, instead opting for a new Shimano direct-mount rear brake.
But one rather amazing and brilliant thing Scott did with this bike was that on the front, in addition to the two Shimano direct-mount bosses, there is a third hole for a standard brake! Now, why would Scott choose to do this on a bike whose front end is so tightly integrated? Simple. Let's say you're traveling to a race and en route, something on your front brake is damaged. With the Plasma 5, you can easily swap out to a standard brake, no need to try and source a special part in time for race day. This is not the case with a bike like the Trek Speed Concept or Canyon Concept Speedmax. And it's awesome. Plus, it let me ditch the TRP brake, which I'm not in love with, and bolt on my own Omega brakes instead. A little dremeling of the front fairing, and I even put that back on too. Yep, if you look in the gallery closely, you'll see the Omega brake hiding underneath that front fairing. A bit self-serving, to be sure, but I honestly do prefer it.
All right, with that area more or less out of the way, let's move on to the integrated hydration and storage solutions on this mean 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.