The image shows the optimised Cannondale SuperSix Evo Hi-Mod 2 built for the Ras Tailteann stage race with Aerocoach Ornix bars, Parcours Chrono wheelset, Continental GP 5000 S TR tyres, Classified Powershift hub, Miche Pistard Air crankset with Pyramid Cycle Design chainrings, and CeramicSpeed OSPW Aero.

Optimising a SuperSix Evo: A 60-tooth chainring and a 28-watt gain

Re-building a bike for the Ras - "Keep the frame, aero-optimise the rest."

Ronan Mc Laughlin
by Ronan Mc Laughlin 06.12.2023 Photography by
Ronan Mc Laughlin
More from Ronan +

A few weeks back on the Geek Warning podcast we discussed what and how the Escape Collective tech crew tinker with review bikes we are sent. We dial in our preferred fit, and quite often, we’ll change a saddle or tyres, we swap wheels in and out, and the odd time we might change a stem length. None of us mentioned a complete strip-down and rebuild with an almost entirely new set of components, but that’s exactly what I did with the recently reviewed Cannondale SuperSix Evo.

The bike arrived to me in late April, just weeks before I was due to ride the Ras Tailteann, Ireland’s premier, and legendary, stage race. I had planned to race my S-Works Tarmac SL6 with mechanical Record 12 speed, rim brakes, and Hunt 50 mm clincher rims. A fine bike, my own bike, but not a modern so-called “superbike.”

The Evo had landed and the lure of racing the latest iteration of a do-it-all premium bike was 1) too much to resist and 2) exactly, I told myself, how I should use the bike to ensure a thorough review.

That’s not quite what happened, though. I’d decided I’d race on the Supersix Evo, but where’s the fun in racing it if I don’t also “optimise” it? This was, of course, to be “my last Ras,” and so I wanted to give myself every opportunity to perform well. I knew the Evo was a great race bike, but I could make it faster.

Nothing was off limits, although I didn’t bother to consider changing the shifting elements of the groupset, the time and effort spent in upgrading Ultegra Di2 could probably be better spent training a little extra. Everything else was fair game, though. Narrower handlebars, lighter (and TT-specific) saddle, deeper rims, and the pièce de résistance – an aero-optimised drivetrain.

I will delve into the exact components and spec list in a moment, but before I do: the results. The results at the Ras were not what I’d hoped for, but the bike certainly delivered the gains. Everything considered, the optimised version of this Cannondale SuperSix Evo did balloon a bit in weight to 8.1 kg, but in return aero testing of the frankenbike versus the SL6 I was due to ride suggests an aero saving of around 28 watts! That’s practically a .4 watt / kg increase in threshold power. And the testing was done at 32 km/h, so chances are the savings are even greater at race speeds, especially when attacking.

Due to the logistics of building/rebuilding the SuperSix Evo I wasn’t able to do same-day aero testing comparing the two versions, nor did weather cooperate with an attempt to test the SL6 against the stock SuperSix Evo. So we don’t have a direct comparison of savings between the two versions of the Cannondale. But we do have a significant savings to the Tarmac SL6, already an aero-focused frameset, built with similarly high-quality but not aero-optimised parts to the SuperSix. I also tested against a Ridley Falcn RS and found slightly smaller but still impressive gains.

How did we find a 28-watt saving? Read on to find out.

That was my optimised Ras bike. Sadly it has been stripped down and rebuilt again since, and the Evo now sits in its original state, ready for collection for return to Cannondale.

As for that 28-watt saving, that is real and measured. As listeners to the Performance Process podcast episode on aero testing will know, I have quite a detailed protocol to ensure accuracy. Truth be told, that level of attention to detail isn’t entirely required for most testing, but what I didn’t mention on that episode was that I was testing different bikes rather than smaller changes in equipment, helmets, or clothing. As such, and with all the potential pitfalls that could scupper bike vs. bike testing, I believe this attention to detail is required.

Long story short, I used my trusty Tarmac SL6 as the baseline setup and tested against the optimised Cannondale seen here and the new Ridley Falcn RS. The bikes were mounted with Aerosensor’s new aero meter, with a mount on each bike, meaning I could simply switch the sensor from bike to bike from run to run.

I normalised the tyres, pressures, and weights across all three bikes (although the Ridley was fitted with Hunt 32 mm rims, a much lower profile than the rims on the other bikes), used the same power meter, adopted the same “standard, upright riding position on all three bikes (although with the Ornix bars being so narrow the standard upright position was inevitably more aero) , and completed six out and backs on each bike. In fact, I did an additional six out and backs on the Tarmac SL6 between Ridley and Cannondale runs. So if the Specialized is bike A, Ridley is bike B, and Cannondale is bike C, I did ABACA testing, with six out and backs for each run. It was a lengthy process.

Testing complete, I sent the anonymised data to Aerosensor, who ran the numbers, not knowing which bike was which or even the doubling up on baseline runs.

The results were pretty clear, the SL6 with exposed mechanical cables and a six-year-old frame at this point, was the slowest. The Ridley (with the lowest profile wheels) was 8 watts faster. The optimised Cannondale? Well, it tested 28 watts quicker than the SL6 and 20 faster than the Ridley! Ideally, I’d have liked to complete the tests again to double-check such a huge gain. There was some drift through such a lengthy test, but with such a large gain, we can be sure the Cannondale was signifcantly faster. And, of course, a large proportion of that gain was likely down to the narrower position (not to mention the significantly deeper wheels), but that’s the very point. I didn’t fit the narrower bars and the narrower and shorter crankarms to stay in the same position; I fitted them to go faster. With that 28-watt gain coming with just a 595-gram weight gain, it was mission accomplished at least as far as the bike is concerned.

What did you think of this story?