Aqua Blue Sport, the 3T Strada, and the future of 1x road drivetrains

by James Huang


3T recently announced that it had signed on as the official bike supplier for Irish Pro Continental road team Aqua Blue Sport for the 2018 season. Such press releases normally don’t generate much discussion — sponsors change all the time, after all — but this one was unusually intriguing since the team will supposedly be riding the new 3T Strada, an aero road bike built exclusively around disc brakes and a single-chainring drivetrain. Does this mark a turning point in road cycling technology? Or is something else underfoot? CyclingTips US technical editor James Huang takes a look at what may — or may not — be happening behind the scenes.


The Strada is no conventional aero road bike

Incremental changes from one model year to the next are the norm in the cycling industry — a little more aero here, a little lighter there, some new feature or two. The 3T Strada, however, represents a legitimate leap away from convention.

Frame developer Gerard Vroomen — a co-founder of Cervélo — took quite a risk with the Strada. Most modern road bikes are crafted with some level of flexibility baked into the design: with just a few modifications to the mold, many frames can be made with either rim brakes or disc brakes, thru-axle or quick-release dropouts, and removable front derailleur mounts.

3T’s new Strada is one of the most progressive road bikes to be introduced in recent years. The aero frame is built specifically around wider tires, it’s disc-only, and also works only with single-chainring drivetrains.

Vroomen was so sure of his vision, however, that the Strada includes none of that engineering second-guessing.

Consider the following:

  • The seat tube hugs the rear wheel so closely and the fork crown is so shallow that neither leaves space to mount rim brake calipers.
  • According to 3T, the stays are too small to adequately handle the torsional loads of high-performance riding without the added structural benefit of the 142x12mm rear thru-axle over a conventional quick-release setup.
  • The seat tube’s cross-section down by the bottom bracket is unusually narrow so as to allow air to more easily flow through, unimpeded by the aero clutter of a front derailleur and mount.
  • The aero frame profiles are shaped with fatter tires in mind; narrower cross-sections would squander much of the frame’s claimed drag benefits.

When the Strada was introduced earlier this year, skeptics dismissed it as a somewhat of an oddball plaything for trend-following progressives with more money than sense. Such a thing couldn’t possibly have staying power, right? But while many viewed with curiosity why 3T would bother obtaining UCI certification for a frame that was never likely to see the light of top-level competition, the partnership with Aqua Blue Sport has clearly cast that move in a new light.

3T designed the Strada’s frame shape around tires measuring 25-30mm in width. That’s wider than what is typically used in road racing currently (barring the cobblestone classics), but 3T will be breaking all sorts of conventions when the Irish Pro Continental team, Aqua Blue Sport, saddles up on the Strada next season. Photo: 3T.

But is Aqua Blue Sport actually going to race such an unusual machine? There has already been widespread speculation that 3T will merely supply the team with specially modified Strada frames equipped with front derailleur tabs, but according to Vroomen, that isn’t the case.

“There is no speculation at 3T about any special 2x Strada frames for the team,” Vroomen insisted. “I’ve never believed in a team riding something different from what the consumer is riding, not even a different lay-up, and I’m not about to start now.”

Pitfalls and progression

Without question, the Strada makes a lot of sense on paper. It’s well established at this point that all else being equal, wider tires roll along the ground with less resistance than narrower ones — and when paired with the right rims, there’s no aerodynamic downside, either. While it’s true that bigger tires are a few grams heavier, it’s also commonly accepted that weight doesn’t matter nearly as much as aerodynamics in terms of rider speeds and finishing times as it was once assumed.

Especially when combined with that larger contact patch, disc brakes also work better than rim brakes in a wider range of conditions — yes, really — and single-ring drivetrain technology has progressed to the point where they’re more competitive than ever with conventional double-chainring systems.

https://cyclingtips.com/2016/08/cyclingtips-podcast-episode-9-rethinking-road-bike-tire-sizes-and-pressures/

But racing doesn’t happen on paper, and there are many questions that surround Aqua Blue Sport’s use of such unconventional equipment.

For one, the UCI still has not fully approved the use of disc brakes in competition, and riders continue to display mixed reactions to them in the pro peloton. A handful of riders used them at the Tour de France this year, but they were definitely in a minority. Bike companies continue to roll out new disc-equipped models that only barely meet the UCI’s minimum weight regulations, but none have been used in any critical climbing events. And while Specialized made a big deal of its latest Roubaix endurance bike being offered solely with disc brakes, even some sponsored riders opted for custom rim-brake bikes at Paris-Roubaix.

According to 3T, the aerodynamic cross-sections were developed based on how air actually flows across a bicycle frame, not in the straight paths that are often used in computer modeling. Either way, the profile is quite striking. Note how the down tube is crafted with a water bottle in mind, too.

More intriguing, however, is Aqua Blue Sport’s commitment to the Strada’s single-ring drivetrain.

Single-chainring transmissions are already popular in cyclocross and gravel segments, but they have been slow to gain traction on the road. Even with eleven cogs out back, current cassettes either offer reasonably close gaps between each ratio, but with insufficient total range, or a comparable level of total range, but with big jumps. This isn’t a huge issue for recreational riders out for a solo jaunt, but for riders in a peloton that want to maintain a certain cadence during a long day in the saddle and across a diverse range of terrain, the case isn’t as strong.

Perhaps the most intriguing aspect of the 3T Strada is the fact that it’s built exclusively for a single-chainring drivetrain. There is no provision whatsoever for a front derailleur, and 3T has no plans to add one for the team.

3T’s new Overdrive and Bailout cassettes may help, but even then there are lingering uncertainties.

The new cassettes offer the same generous 9-32T spread, which closely mimic the total range used by most professional riders already. However, Overdrive’s 9-11-12-13-15-17-19-22-25-28-32T cogs favors relatively even jumps throughout with one especially tall top-end gear for fast downhills. Meanwhile, Bailout’s 9-10-11-12-13-15-17-19-22-26-32T cogs deliver the opposite, with one big jump at the lower end.

Both are still compromises, though, and ones that I have a hard time envisioning a team with Aqua Blue Sport’s aspirations easily accepting.

According to 3T, the single-ring format is not only far more reliable than even the best 2x drivetrains, but more aerodynamic since the air has a much clearer path around the crankset and seat tube.

Those smaller chainrings and cogs would also wear faster (although that’d be of little concern to a sponsored pro team). They might be more concerned, however, with the fact that smaller chainrings and cogs generate more mechanical friction than larger ones, and the more extreme chainline angles would only add to that difference.

Nevertheless, Vroomen feels that single-ring drivetrain’s reduced complexity and increased reliability more than offset any potential disadvantages.

“I’ve been thinking about 2x on road bikes for 20 years and 1x for 10 years, so I think I understand the possibilities and impossibilities,” he said. “But even I was surprised at how few objections we got in the end, once people really started riding it. I’m not saying that everybody in every situation at every level of fitness will ride 1x, just that the usability of 1x on road is much bigger than some people think.

While there is technically room for a front derailleur to be added to the Strada, 3T insists it has no plans to do so. Photo: 3T.

“The funny thing is that every bike is a balance between advantages and disadvantages; the only difference is that this one is very visible so we get asked that question. Nobody is asking these other riders if they are prepared to deal with wasting watts on the aero drag of their second ring and front derailleur every second of every race next year. And nobody is asking Sky if they will continue to be prepared to deal with the limitations of their Di2, that require Froome to change bikes four times during the Tour de France.”

There is also the issue of neutral support.

Disc-brake wheels are already tricky from that standpoint, with different rotor sizes in play (especially up front) and extra-tight clearances offering little wiggle room in terms of pad rub. But with Aqua Blue Sport undoubtedly being the only team in any given road race fitted with 1x-drivetrains, any rider taking a neutral wheel would be saddled with a cassette that has less range than it should — a potentially disastrous situation depending on the event.

Nevertheless, Vroomen isn’t concerned.

“We have some neutral-service solutions, but I am not sure how important they are; the team certainly doesn’t feel it’s critical. You already saw that this year with other teams with disc brakes, when only 160mm rotors were supported, but [Marcel] Kittel and [Michael] Matthews rode 140mm. Personally, I’d rather avoid flat tires.”

Something is brewing

According to Vroomen, there is no question that the team is sticking to the Strada frameset as is. Moreover, the title sponsor’s business model would seem to support that fact. Aqua Blue Sport is essentially an online retailer for products the riders use themselves, and the team is directly funded by sales proceeds. If the riders race on bikes that are custom modified and not offered to the public, that system essentially falls apart.

3T will soon release two new 11-speed cassettes aimed at single-chainring road use, both with a 9-32T spread for a more generous total range than what’s normally offered in the segment. The OverDrive version prioritizes more even gaps between each gear, while the Bailout favors tighter ratios at the high- and mid-range, with the 32T cog added on for when you desperately need it. Still, neither is ideal for professional road racing.

Still, none of this directly tackles the inherent limitations of current single-chainring drivetrains. Is Aqua Blue Sport merely going to deal with the drawbacks of the system it committed to, or is something else in development?

A 12-speed (or even 13-) cassette would go a long way toward solving either issue facing 1×11 road transmissions, and seems like the most viable path. However, such a thing doesn’t exist right now – nor would it be easy to alter any of the mainstream systems currently offered by Shimano, SRAM, or Campagnolo to suit. Aqua Blue Sport raced on Shimano Dura-Ace Di2 this season, for example, and the latest versions are less amenable to hacking than earlier ones.

“With the newer generations [of Di2], Shimano has gone with a digital base, which makes doing custom stuff pretty difficult,” said Jason Woznick of Fairwheel Bikes, a high-end boutique shop in Tucson, Arizona with a long history of custom creations and one-off Di2 modifications. “The only way to make it work would be to write new firmware for the system and then create your own PCB [printed circuit board] to deliver the firmware. Shimano now obfuscates their firmware, so reverse engineering it or making changes to it is close to impossible. It can be done, but the time and cost would make it prohibitive except on the largest of commercial scales, which of course Shimano would put a stop to.”

The ultra-shallow fork crown leaves no space for a rim-brake caliper to be mounted without heavily modifying the design of both the frame and fork. It’s a similar situation out back.

Nevertheless, Vroomen hinted that while he believes in the merits of 1x, and that current offerings are well suited to most users, he also tacitly admitted the limitations. He wouldn’t offer much in the way of official details, but hinted that something is in development behind the scenes, and in a more official capacity.

“All partners will be announced in due time,” he said. “It’s safe to say the number of companies interested in partnering in this project is above-average just because it’s more interesting than average. But, of course, there are a lot of technical considerations to be made in this particular case, especially for the drivetrain. There are so many developments at 3T and at the drivetrain companies that we have zero doubt the team will be very happy next year.”

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