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by Matt Wikstrom
May 8, 2017
Photography by Matt Wikstrom
The rise of gravel bikes in recent years has helped to establish a new bona fide riding discipline but designs are still evolving. 3T Cycling’s Exploro eschews a lot of current trends in favour of a strong infusion of MTB to the point where the bike can be fitted with both road and MTB wheels. In this review, our Australian tech editor, Matt Wikstrom, takes a close look at the Exploro.
The name Gérard Vroomen is likely to be familiar to many road cyclists. He was one half of the duo responsible for Cervélo, a company that arose from modest beginnings in a university workshop in Canada to become a highly recognisable brand within the professional peloton. Vroomen’s fascination with aerodynamics would usher in a new era of appreciation for the science in cycling and give rise to aero road bikes.
Vroomen’s experience with bike design can be traced back to 1986 when he started driving and designing human-powered vehicles in the Netherlands. In 1995, he undertook a mechanical engineering project, an aerodynamic time-trial bike, in collaboration with Phil White. According to Cervélo’s company history, Gianni Bugno wanted to use the bike for an event however his bike sponsor vetoed the idea. Nevertheless, Cervélo was born and Vroomen and White quickly moved onto unveil new aero frame designs that quickly found favour with triathletes and time-trialists.
A decade would pass before road cyclists started embracing Vroomen and White’s revolutionary thinking. The original Soloist, made from aluminium alloy, stands as perhaps the world’s first aero road bike while the iconic R3 proved that composites could be engineered to create a lightweight, stiff and robust frameset that could withstand the rigours of professional racing.
Cervélo’s subsequent composite frames became increasingly aerodynamic for both the road and TT/triathlon but it was the formation of the Cervélo TestTeam in 2009 that would go on to exhaust the company’s resources and Vroomen’s energy for professional cycling. In May 2011, he announced that he was taking a step away from the company, leaving the role of CEO solely in White’s hands, and PON Holdings would go on to acquire Cervélo less than 12 months later.
At the time of his departure, Vroomen stated that he wanted to work on some new projects. He soon teamed up with Andy Kessler (a former CEO for BMC) to establish Open Cycle and the new company unveiled its first product in 2012, a carbon fibre XC hardtail frame weighing less than 900g. In many ways, Open and the new frame were the antithesis of everything that Cervelo had become, and to this day, Open’s motto remains “working hard to stay small.”
Open announced the release of a second frame in 2015, the U.P. (Unbeaten Path), which blurred the distinction between road and off-road cycling. At face value, the U.P. appeared to be a simple addition to the growing category of gravel bikes, however Vroomen engineered the bike to accommodate two wheel sizes — 700c and 650b/27.5inch — to allow an unprecedented range of tyre sizes.
The idea stemmed from the realisation that the radius of a 700c wheel fitted with 28c road tyres or 40c cross tyres was close to a 27.5inch wheel fitted with 2.1inch MTB tyres. Open eventually dubbed the thinking “GravelPlus” and it wasn’t long before the U.P. was celebrated for its versatility.
2015 also marked the beginning of a new stage in Vroomen’s career as he partnered with Rene Wiertz, the CEO of 3T Cycling, to acquire 3T outright. The engineer already had a strong relationship with 3T but the move would provide Vroomen with fresh opportunities to develop new projects without interrupting his commitment to Open.
3T’s history goes back to 1961 when it was originally known as Turin Tube Technology (Tecnologia del Tubo Torinese). Founded by Mario Dedioniggi, 3T began with a simple tube-bending machine to grow into a highly recognised and celebrated bicycle component manufacturer by the ‘80s. Dedioniggi eventually retired in 1986, and after changing hands a few times and losing its way, the brand was resurrected by Rene Wiertz in 2007.
It didn’t take long for Vroomen’s input at 3T to become apparent as the company unveiled the Exploro mid-2016. The carbon fibre frame was a first for 3T in many ways and it demonstrated that Vroomen’s enthusiasm for GravelPlus hadn’t waned. Indeed, the Exploro was the next step in the development of the concept, one where aerodynamics had become an important consideration.
The Exploro shares much of its DNA with Open’s U.P. Both frames are made from carbon fibre and offer generous tyre clearance to the point where different wheel sizes can be used. Thus, the Exploro can accommodate 700c wheels with tyres up to 40mm wide as well as 650b/27.5inch wheels fitted with 2.1inch tyres.
As a tyre gets wider, it also gets taller, so the radius of a 27.5inch wheel fitted with a 2.1inch tyre (~342mm) is nearly identical to a 700c wheel fitted with a 28c tyre (~341mm). As a result, owners can swap between the two wheel sizes and use a wide range of tyre sizes without noticing an effect on the geometry or handling of the bike.
The rear triangle of the Exploro is also very similar to the U.P. due to the combination of slender seat stays and asymmetrical chainstays. The latter makes for a conspicuous mismatch thanks to the dropped right stay, but it’s a strategy that allows for a wider, and therefore stiffer, structure without compromising tyre clearance.
The shape of the right stay places some constraints on the size of the chainrings that can be used with bike, though. Thus, for 2x transmissions, the big ring cannot exceed 50T and the small ring must be 36T or smaller. Buyers opting for a 1x transmission won’t be able to use a chainring any larger than 46-50T (depending on whether it is offset or not). As for minimum sizes, the chain must be able to comfortably clear the dropped stay, so chainrings with less than 30T are likely to be a problem.
It’s the front triangle of the Exploro that really distinguishes it from the U.P. The massive down tube is the most obvious departure from the almost classic shaping of the U.P. The Exploro also features a lot of square edges, and this is where the heart of the bike’s aerodynamic performance lies.
The seatpost clamp is integrated into the top tube of the frame that is accessed from below via a tiny hole.
The down tube is actually a squared-off airfoil that 3T has dubbed “Sqaero”. The girth of the tube is large enough to catch the airflow coming off a wide front tyre. At 32km/h, 3T claims that a mud-spattered Exploro equipped with two water bottles and 40mm CX tyres suffers ~10% less drag than a road bike with round tubing and 28mm tyres. That doesn’t mean the Exploro will ever rival an aero road bike, but compared to the U.P., it promises to be a little more efficient.
Are we witnessing the birth of an aero gravel category with this bike? I don’t think so. In fact, it looks as if 3T and Vroomen are prepared to have some fun with the notion. For example, there’s the trademarked slogan, “Go slow faster”, and then there was the mud that was spattered on the Exploro for the wind tunnel tests described above. After spending so many years trying to convince cyclists of the merits of aerodynamic bike design, I think Vroomen has earned the right to have some fun while gently asserting his point that aerodynamics can assist the performance of any bike.
The Exploro is supplied with 3T’s Luteus II fork, the same fork that is found on Open’s U.P. It features a tapered steerer (1.125-1.5inch), sturdy 15mm thru-axle, and external routing for the front brake hose/cable. Interestingly, the thru-axle engages with a nut rather than a threaded dropout, so if the threads are ever damaged it can be replaced rather than the whole fork.
The same thinking is applied to the 142x12mm thru-axle at the rear of the bike. The oversized bolt threads into a replaceable hanger for the rear derailleur, locking it into the frame as the thru-axle is tightened. Just like the nut on the fork, this fitting can be easily replaced in the wilderness (a second hanger is supplied with the frame), and according to 3T, by allowing the rear derailleur to be detached from the frame, it simplifies installation of the rear wheel.
3T’s Luteus 2 fork features a 15mm thru-axle, which is a good match for many MTB wheels, but the range of road wheels using this size is much smaller.
The Exploro eschews current market enthusiasm for flat-mount disc callipers by opting for post mounts, front and rear, to suit 160mm rotors. It’s a time-proven design that Vroomen favours since there is no need for adapters to mount the callipers but buyers will find that it will limit their choices, especially for those choosing Shimano components (e.g. Shimano’s Dura-Ace disc callipers are only offered with flat mounts).
The rear brake and gear cables/wires are routed internally through the Exploro, entering the top tube just behind the stem. The bike is supplied with interchangeable fittings that are compatible with every groupset combination for a very tidy finish (and no unnecessary openings). A couple of foam sleeves are also included for wrapping the hoses/cables to prevent them from rattling within the frame.
The last major specification to take note of is the bottom bracket, which is the oversized and threadless BB386 EVO format. It is a highly adaptable bottom bracket that can accommodate both 24mm and 30mm crank axles, but that doesn’t mean every crank will fit the Exploro. For example, any BB30 crankset will be too narrow for the 386 EVO bottom bracket.
The Exploro is available is four frame sizes, as shown in the table below:
Unsurprisingly, the geometry of the Exploro resembles that of the U.P. though the stack of the bike is ~5mm lower due to a shorter headtube at each frame size. At 415mm, the chainstays are also shorter for the Exploro (the U.P. has 420mm chainstays). The same bottom bracket drop (70mm) and fork rake (50mm) is used for every frame size.
A 3T seatpost shaped to suit the Exploro’s aero seat tube is supplied with the frameset. The zero-offset design is a good match for the slack 72° seat tube angle, though riders that require small amounts of saddle setback may have trouble with this combination.
3T’s DiffLock saddle clamp may also cause some problems. Comprised of a pair of ratchet rings, the clamp is virtually slip-proof, but the saddle must be removed before the amount of tilt can be adjusted. The mechanism is somewhat counter-intuitive because inner ratchet must be rotated in the opposite direction to the outer ratchet to provide the promised 0.5° increment.
For those riders that are unaffected by fine adjustments, DiffLock should work well to keep the tilt of the saddle locked in while providing quick and easy setback adjustment. Riders that depend upon more precise positioning of the saddle are likely to end up frustrated though, since there is no fine adjustment for the clocking of the ratchet rings. I fall very much into this category and had to compromise on the tilt of my saddle when setting up the bike. The bike was rideable but my sweet spot fell somewhere in between each 0.5° increment, and as a result, it influenced my comfort during long outings on the Exploro.
3T’s DiffLock saddle clamp offers very simple setback adjustment but the entire clamp must be disassembled before the tilt can be adjusted. Even then, adjustment is dictated by a pair of coarse ratchet rings.
Given the proprietary shape of the seatpost, there are no aftermarket remedies to address these issues. For those that already understand their dependence on fine adjustments, or have been frustrated by 3T’s DiffLock in the past, then it might be wiser to consider the U.P. instead because it uses a standard 27.2mm seatpost.
The seatpost clamp is integrated very cleanly into the top tube of the bike but with a reasonably deep and blind corridor to access the head of the bolt, adjusting the height of the saddle was an unnecessarily time-consuming process. I also discovered that the clamp mechanism had a habit of pulling the post into the frame as it was tightened.
It may have only been ~1mm, but when combined with the difficulty of accessing the bolt head, it took me a lot longer to get the saddle height perfect. With that said, once set, there wasn’t a reason to revisit it, though riders travelling with bike will need to remember that the clamp will fall out of the top tube and into the depths of the frame once the seatpost is removed.
The Exploro is available in two versions: the Team model reviewed here, which is painted white, and the LTD model, which is black. The difference between the two versions is more than just the colour because a different blend of carbon fibre is used for the LTD to save some weight (~200g), but it adds a lot to the cost of the frameset.
The Exploro Team frameset supplied for review by 3T’s Australian distributor, Echelon Sports, was a size M assembled with a SRAM Force groupset (50/34T cranks, 11-32T cassette), Prologo saddle, and an alloy 3T cockpit. Two sets of 3T wheels were supplied with the bike, Discus C35 Pro fitted with 700x33c Challenge Strada Bianca tyres and DiscusPlus C25 Pro fitted with 27.5×2.1inch Maxxis Pace tyres. Total weight for the bike was 8.41kg with the 700c wheelset and 9.04kg with the 27.5inch wheelset (excluding pedals).
The recommended retail price for the Exploro Team frameset is AUD$4,099/US$3,000/€3,000, which includes the frame, fork, seatpost, 15mm thru-axle for the front wheel, and fittings for the axles. There is also a two-year warranty against defects that can be extended to five years if buyers register the bike via 3T’s website within 30 days of purchase. For more information, visit 3T Cycling and Echelon Sports.
With a choice of wheelsets on hand for this review, I opted to started on familiar ground and fitted the Exploro with the 700c wheelset fitted with 33c tyres. This combination proved to be quite versatile allowing me to ride both paved and unpaved roads with plenty of speed and confidence.
The Exploro was very stable in terms of its handling with steering that was close to neutral. On paved roads, I found it was easy to take a tight line through sharp bends and roundabouts, and while there was a mild inclination towards understeer, it wasn’t difficult to push the bike around. The 33c tyres hampered the agility of the bike a little in this regard, but overall it was a competent road bike.
With ~50psi in the tyres, I could make the transition onto unpaved roads and tracks with a certain amount of ease. The tyres offered a reasonable amount of grip despite the dry and dusty conditions that prevailed throughout the review period. While I never felt like I could push the bike deep into dusty corners, I had a lot more confidence on the Exploro than a road bike fitted with narrower tyres (e.g. 28c).
I was able to tackle some reasonably rough terrain with the 33c tyres however they could only do so much to protect me from ruts, rocks and holes. Nevertheless, I found the Exploro easily matched the performance of a cyclocross bike, albeit with a more aggressive feel to the bike thanks to the reasonably low front end and short chainstays.
Swapping out the 700c wheelset for the 27.5inch wheelset and fat 2.1inch tyres had many of the expected effects on the off-road performance of the Exploro — namely, big gains in grip and comfort — but I was still surprised by the transformation.
What started out as a reasonably confident gravel bike was transformed into a rock-gobbling beast with an insatiable appetite. The wide tyres added enormously to the stability and grip of the bike and I had a lot more confidence to tip the bike over in dusty corners. The steering was agile enough to negotiate technical singletrack at slow speeds, yet it was forgiving too, allowing me to drift through puddles of deep sand.
At higher speeds, the Exploro was very steady, and as long as I had some room, I could hold a fast line through tight bends and corners. In this regard, the Exploro couldn’t quite rival the performance of an XC bike, but there were definitely some of the same elements present.
Unsurprisingly, the fat knobbies were slow and cumbersome on the road. I had the choice to work hard to maintain a high pace, or ease off and pass the time until I hit the dirt. Given the amount of fun that I could have on the dirt, I always chose the latter.
Perhaps the most impressive aspect to the performance of the 2.1inch tyres was the way they could soak up the worst rocks and ruts I’ve ever traversed on a “road” bike. On unpaved roads and tracks where I’ve had to take carefully pick my way through the rocks and holes, as if they were land mines, to preserve narrower tyes, I found I could aim for them on the 2.1inch tyres without any consequences.
It was an exhilarating experience, and one that has redefined my expectations for a gravel bike. The amount of comfort that the 2.1inch tyres offered was as extraordinary as the extra grip and sure-footedness, and I found myself looking for longer routes into areas that I would have abandoned out of fatigue on any other gravel or CX bike.
For those readers that split their time between road and MTB, the performance of the 27.5×2.1inch tyres won’t be any kind of revelation. In fact, some may be quick to sing the virtues of even wider tyres and the so-called “plus-size” MTB that have been designed around this notion. Put simply, wider tyres expand the capabilities of any bike, allowing the rider to tackle more challenging terrain, with or without suspension.
So is there a place for a bike like the Exploro (or U.P. for that matter) when there are MTBs with even greater capacity to handle rough terrain? Yes, I think there is, simply because MTB can’t offer the familiar position and touchpoints of a road bike. At face value, this may seem something of a novelty, but as I spent more time on the bike, it was something that I came to treasure.
Any time that I have ridden a MTB, I’ve been distracted by the tall front-end and the bounce of a suspension fork. By contrast, the Exploro was extremely familiar to me, offering a choice of the same three hand positions that I’ve become accustomed to whilst making the most of a riding position that has been honed by years of practise. Of course, the value of such a position for true MTB riding is questionable, but for gobbling up the miles on wide-open gravel roads, I’d rather be on the Exploro with 2.1inch tyres than a MTB.
After spending a week on each set of wheels, I compared my times for an undulating and dusty 8km trail. Having ridden this trail on a few different gravel and CX bikes, I’ve found that it’s a good 20-minute test that demands a high level of concentration to maintain speed and avoid colliding with the bushes and trees that line the route.
In terms of performance, I preferred the 27.5×2.1inch setup because I felt like I was able to attack the course with a lot more confidence thanks to extra grip. And while this wheelset added to the weight that I had to carry up the inclines, I was convinced it would be a minor penalty, easily offset by the extra speed that I could maintain on the descents and through the many corners of this course.
By contrast, I felt quite sketchy when riding the 700x33c setup. I didn’t have the same kind of confidence to attack the corners and kept my speed in check for the descents. In fact, my run on the 33c tyres was less exhilarating and more terrifying as I tested my nerve and the grip of the tyres.
In the end, the time difference was much smaller than I expected — just one second — and it was in favour of the 700x33c setup. Given the choice, I’d still opt for the wide knobbies, though, for the extra grip, comfort and confidence they provided.
I tested the performance of a set of 25c road tyres during the review period, and the experience taught me a couple of things about the Exploro. Firstly, the chassis was quite stiff and very much like a race-tuned road bike, so the wider tyres were doing a lot to improve the compliance and comfort of the bike. And secondly, I started to notice the weight of the bike.
That’s not to say that the Exploro was a particularly poor performer on the road; rather, I simply expected more from it based on my experience with other road bikes. At the very least, I found myself wishing for a lighter wheelset and quicker steering to rev up the bike’s performance at high speeds.
This last point was enough to convince me that while Exploro can be used for road riding, it is best suited to off-road riding because that’s the realm where the bike’s geometry and handling really shines. And while the grip and performance of the bike varied with the different wheels and tyres, the Exploro had an aggressive poise that always encouraged me to bend my back and reach for the drops.
As for the effectiveness of the Exploro’s aerodynamics, this wasn’t something that was ever obvious to me. I don’t have any quarrel with 3T’s claims but when placed into the context of total drag on a cyclist, the minor reduction (~10%) described for the Exploro amounts to a very small saving of ~2% (estimates attribute ~30% of all aerodynamic drag to the bike, one-third of which involves the wheels. Thus, 10% reduction in the aerodynamic drag of a frameset will provide, at best, ~2% reduction in total aerodynamic drag).
Ride the bike for long enough and this kind of saving will add up, but I doubt it’s something that the rider will ever feel or appreciate. Nevertheless, the saving is there, more or less, for buyers to enjoy on one level or another.
Throughout the review period, I found myself thinking a lot about the groupset and components I’d use to build an Exploro. SRAM’s Force groupset was excellent choice, however a few incidents of chain-suck had me thinking that a 1x transmission with a wide-range rear cassette might be the better choice. SRAM has yet to create a road lever version for its 1×12 off-road groupsets but I’m starting to hope that they will.
Finally, a note about the thru-axle fittings: I like the fact that the threaded portions aren’t fixed in the frame so they can be easily replaced when damaged, but they always fell out when the axles were removed. Buyers will have to take care not to lose the nut for the front axle when packing the bike in a car and should expect to get their hands dirty when re-fitting the rear derailleur. I can see this becoming something of an annoyance for those that have to remove the wheels on a regular basis, but I doubt it will be a deal-breaker.
Besides, there are more important concerns for potential buyers to worry over, where the asking price would have to be counted as the most significant. The Exploro is clearly a high-end product, and in many regards, it offers the kind of performance that justifies the expense, but I hope Vroomen’s GravelPlus thinking trickles down to more affordable bikes in the future.
At face value, the Exploro is an opulent frameset that seems to ask a lot of the buyer. Not only is it expensive, there is the prospect that multiple wheelsets will be required to make the most of its capabilities. Considering that there are well-equipped MTB bikes that sell for less than the cost of an Exploro frameset, most shoppers would be forgiven for thinking that there are more economical ways to quench their thirst for off-road riding.
I have no strong argument against such pragmatic thinking, and depending on the expectations and ambitions of the rider, a dedicated MTB may be a better buy. But that doesn’t mean the Exploro doesn’t have much to offer because it is an enormously versatile bike that allows road cyclists to preserve their position while exploring the benefits of much wider tyres for off-road riding.
With the capacity to accommodate standard road tyres as well as cyclocross and true off-road tyres, the Exploro has the potential to serve triple-duty for some buyers. In this context, a second set of wheels might be easy to justify, but it’s worth noting that in terms of performance, I think the Exploro is best viewed as an off-road bike that can be used on the road, because that is where its greatest strengths lie.