Trek Checkpoint SL 6

Trek's first dedicated gravel bike, the Checkpoint, is late to the party but it arrives with seemingly everything such a bike needs – wide tyres, disc brakes, versatility, modified geometry – but this top-of-the-range £3,400 SL6 model has gearing that is too tall, a very stiff front end and too-narrow tyres for proper off-road adventures, stopping it from being the highly capable gravel and adventure bike it wants to be.

• Pros: Versatile, space for wide tyres, IsoSpeed
• Cons: Tall gearing, stiff front end

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Ride and handling

Ignoring those complaints for a moment, let's focus on the positives. On the road, the Checkpoint makes good progress, the low-profile dimpled G-One tyres rolling along nicely on hard surfaces. Road rides can be conducted at a speed not far off what you'd manage on a slick tyred endurance bike.

The carbon frame ensures a high level of responsiveness, the geometry provides good high-speed stability and the steering is lively enough to be a fun ride through the twists and turns. In many ways, it feels like riding a Domane (Trek's endurance bike) with fat tyres.

The geometry goes a long way to defining a gravel bike. It needs to be stable for riding over rough terrain but also reasonably nimble and lithe for easy manoeuvrability. Trek started with its Boone cyclo-cross bike but increased the stack and lowered the bottom bracket. This cyclo-cross-inspired approach works well.

It cuts a fine balance on and off-road, and the transition from smooth to rough is good. There's a good amount of stability at higher speeds thanks to the long wheelbase, but it manages to be reasonably lively when changing direction, handy when bashing through narrow tree-lined singletrack. The wheelbase length can be adjusted to suit (Trek uses Stranglehold adjustable dropouts from one of its mountain bikes – more on that in a minute); I generally kept it in the shortest setting as I preferred the extra nimbleness it provided compared to the longer setting.

Get the Checkpoint onto the sort of trails it's designed for – gravel fire-roads, woodsy singletrack with lots of roots, overgrown bridleways and everything in between – and it's a mixed bag. On the one hand, seated comfort is very good thanks to the IsoSpeed decoupler (the seat tube is separated from the frame at the top tube junction to increase saddle deflection) and 35mm tyres. But the lack of a front IsoSpeed, as found on Trek's newest Domane, means the front is hard and unforgiving in comparison to the buttery smooth rear end. Trek explains this decision away as the wide tyres providing enough cush for most people, but I think it's a missed opportunity.

Naturally, wide tyres go a long way to cushioning the blows on rough ground but even at low pressures the front of the Checkpoint just feels far too harsh. On long fire-road rides with all the holes, dips and ripples you'd expect of an unmanicured track, the Checkpoint's stiff front end becomes tedious and tiresome.

All I want is for the front to be as smooth as the back, but that's not the case here. Against the Specialized Diverge with its Future Shock, there really is no comparison, the Spesh is far better at providing a smoother ride and alleviating the fatigue from riding over rough ground for long periods of time.

And unless you want to ride a gravel bike predominantly on the road, 35mm tyres are just too narrow for today's gravel bike market. I took the opportunity to swap tyres, first to 40mm Panaracer GravelKings (an improvement), then to 45mm WTB Riddlers (much better) to eke out more smoothness.

Wider tyres improve the Checkpoint, but that imbalance between the front and rear smoothness is still apparent, though it's much more capable in the mud and on slippery trails than with the G-One tyres, which are best saved for mostly road or, at the very least, dry hardpack paths.

My overriding impression of the Checkpoint is that it's aimed at those cyclists who want a Domane that can take very wide tyres mainly for smoothing out rough roads, with the occasional foray into the wilderness. A bit like buying a 4X4 when you live in the city.

Frame details

Trek offers the Checkpoint in aluminium and carbon fibre variants. This range-topping SL 6 model is made from OCLV 500 Series carbon fibre, with a size 56cm weighing a claimed 1,240g, and 470g for the fork. On the scales, the entire bike weighs 8.97kg.

It's a well-appointed frame with some neat details. I like the plastic bash guard to protect the carbon down tube from rock strikes.

The drive side chainstay drops down to provide extra clearance and there's a metal plate for extra protection from dropped chains if the integrated chain catcher doesn't prevent that from happening.

Versatility has clearly been a big focus for Trek, with the Checkpoint frame and fork adorned with all manner of extra mounts of multiple water bottles, racks, mudguards and lunch boxes.

Tyre clearance is rated for 45mm tyres and Trek has designed the bike around 700C wheels – it doesn't recommend the use of 650B wheels. That's a shame given the rise of decent tyres and a growing interest in going super-fat for 'road plus' and gravel riding. The stock 35mm tyres look puny in the frame and fork, 45s look much better, and there's still acres of clearance.

Disc brakes are the de facto choice on gravel bikes, here with flat mount callipers and 12mm thru-axles at both ends. There's full internal cable routing, with the cables and rear brake hose all entering a single port on the down tube and concealed all the way to their prospective mechs and callipers, ideal for surviving muddy and wet riding.

The downside here, though, is the cables all splay out beside the frame far too much, which is both ugly and also sees your knees contacting them when riding out of the saddle. It could be done much better than this.

We've seen adjustable geometry on some gravel bikes (the Rondo Ruut, for example) but it's far from common. Trek has taken the Stranglehold adjustable dropouts from one of its mountain bikes which lets you slide the axles back and forth, adjusting the chainstays between 425 and 440mm. It also enables a single-speed conversion if you're that way inclined.

It's a relatively easy procedure but by no means a trailside alteration, requiring a few tools and 5-10 minutes of your time. It works well enough, though, and offers the opportunity to tailor the wheelbase length to suit – long for extra stability for a bikepacking adventure, short for playful riding – but the long bolts protruding from the frame in the longest setting are ugly in my opinion.

It could be something you change all the time, or, I suspect, it's a set-and-forget. I tried both settings and settled on the shorter option for most of my riding, as it's plenty stable enough in this setup.

Build

Starting at £1,450 and topping out at £3,400, there are seven bikes and three women's models to choose from in the range. The pictured test bike is the range-topping SL 6 which combines an OCLV carbon fibre frame and fork with a full Shimano Ultegra mechanical groupset and lots of Bontrager equipment.

All bikes in the Checkpoint range use Shimano groupsets, and because the Japanese company doesn't (yet) make a dedicated gravel groupset, that means it's 2x11 setups across the range.

On this bike, that means a compact 50/34t chainset and 11-34t cassette, which would be fine were it a road bike, but the gearing was very often too tall for steep off-road climbs (even forcing me off on a number of occasions) and just not as simple to use as a 1x setup on the usually rapidly changing terrain of off-road riding. I'd like to see a sub-compact chainset like a 46/30 to lower the gearing range please Trek, and even a 1x option in the range would be nice.

No complaints about the brakes, though, with the Dura-Ace-inspired Freeza disc rotors and hydraulic callipers providing plentiful braking power with easy one-finger control all of the time. They bedded in quickly and worked consistently in a range of conditions.

Wheels and tyres

Moving on to the rest of the equipment, and it's a full house from Bontrager, including the Paradigm Comp wheels. It's a 1,685g wheelset comprising aluminium hubs with Centerlock disc mounts and aluminium rims.

The rims are tubeless ready, but you'll need to invest in tubeless tape, valves and sealant should you want to ditch the inner tubes. I made the conversion and it worked well, with easy installation and good air retention. The rims measure 19.5mm internally, which is on the narrow side for the wider tyres the Checkpoint is designed for.

The 35mm Schwalbe G-One Allround tyres have had many thousands of positive words written about them, and they are excellent tyres. The low profile dimpled tread pattern is fast on the road and reasonably grippy for riding off-road, provided the trails are dry and not too loose.

If you're going to want to ride a lot of off-road trails and gravel paths in the UK, with all the mud we have to deal with, I'd consider a tyre upgrade. Something wider, for extra suspension, and grippier to prevent washouts on loose corners.

Finishing kit

The Montrose Comp saddle is a good shape with a pressure-relieving channel, and sufficiently padded for bumping across rutted tracks. The carbon seat mast it's attached to is easy to adjust for angle and fore-aft, with 20mm of offset.

The IsoZone handlebar is made from butted aluminium (why there's no carbon bar on a bike of this price I don't know) with recesses for vibration-absorbing pads, providing extra cushioning underneath the bar tape. It's a nice touch and is a good alternative to double-wrapping bars and does provide a bit of extra comfort when riding on the tops.

The handlebar has a short reach and compact drops and is a nice shape for long rides. Some companies are dabbling with flared drops for increased leverage and control when riding technical descents, but for all but the most demanding tracks I was just fine with the lack of flare.

The Elite stem is aluminium and according to the Trek website comes with computer and light mounts, though I didn't receive those to test.

Built up with all this equipment, our 56cm test bike came to 8.97kg. That's a fair chunk heavier than the similarly priced Merida Silex 9000 at 7.98kg.

Conclusion

There's a lot of hype, buzz and excitement around the whole gravel and adventure bike thing right now, and it's clear that despite our lack of wide open gravel roads like they have in the US, here in the UK people are tapping into the versatility and capability of these bikes for a wide variety of uses, from exploring and adventure bikepacking to commuting.

This is reflected in the rapidly growing choice, but it's interesting that it's mostly the smaller brands really leading the way: the likes of 3T, Open, Lauf, Kinesis, Rondo and Bombtrack to name a few, the one exception being Specialized. These are interesting and exciting, with some really cool ideas about what a gravel bike should be.

> Buyer's Guide: 19 of the best gravel and adventure bikes

The Checkpoint just doesn't cut it. It does get a lot right: if you want a bike that is comfortable and provides space for wide tyres for mostly road riding, with lots of versatility whether for winter training and commuting or touring and bikepacking, the Trek is a good choice. But it's not the most capable bike when the going gets rough and bumpy.

Sure, the rear IsoSpeed decoupler works its magic, filtering out the harshness and giving your bum and back a smooth ride, but the front end is simply too harsh in comparison. Not fitting wider tyres and a lower range drivetrain shows either a failure to be bolder in the spec or a lack of appreciation for the demands of riding what is essentially a road bike off-road.

It's a shame. Trek is a company with a strong record in innovation, and it could have brought something truly compelling to the market and knocked everyone else out of the park. But it's played safe and the result is a bike that just lacks a bit of sparkle compared to some of the rivals I've already mentioned.

> Cyclo-cross bikes vs gravel/adventure bikes: what's the difference?

There's a lot to like – the stiff carbon frame packed with versatility, wide tyres, IsoSpeed rear – but a lot that holds it back, such as the stiff front end, too-narrow tyres and tall gearing. And that makes it hard for me to honestly recommend the Checkpoint.

If you are only going to ride it on the road and occasional smooth and flat dirt roads, the Checkpoint might be for you, but if you're looking for a highly capable gravel and adventure bike, there are better choices.

Verdict

Sadly disappointing gravel bike debut from Trek, though fine if you want a fat-tyred road bike