Trek’s Checkpoint SL6 gravel bike is the natural evolution of its Domane road bike and Boone cyclocross bike. In profile it could be mistaken for either, but look closely at the stealthy black frameset, and the differences become clear.
- The Trek Checkpoint SL6 is one of our Bike of the Year bikes for 2019. To read reviews of the other contenders and the categories tested across road, mountain and women’s bikes, visit our Bike of the Year hub page.
The fork has a gentle curve, with its thru-axle offset just behind the fork’s centre line to gain a little compliance, and it has mudguard and rack mounts.
The semi-compact frame includes a rear IsoSpeed decoupler, and large down tube, with Trek’s Control Freak internal cable routing system, which gathers up the cables and rear brake hose in one port on top of the tube. Beneath it, a polymer impact guard covers the lower portion of the down tube and extends along the chainstays too, punctuated only by an additional bottle cage mount.
Deviating hugely from the Boone and Domane, the Checkpoint’s rear end has a heavily dropped, intricately shaped driveside chainstay to permit extra tyre clearance and the double chainset. The square seatstays bow gently upwards, have a bridge, and well-hidden mudguard and rack mounts, and end in Trek’s Stranglehold dropouts. These feature slots and screw-in adjusters that allow the wheelbase to be altered by sliding the captive thru-axles by up to 20mm.
The lower seat tube is shaped to increase tyre clearance, which the dropouts help to tune, but if singlespeed is your bag, they’re also essential for chain tension adjustment.
Although supplied with 35mm Schwalbe G-One Allround tyres, the Checkpoint can run up to 40mm (measured) rubber, giving 4mm frame clearance. The asymmetric seat tube is offset for the front mech and Trek’s 3S chain keeper, which perches above the BB90 bottom bracket shell to prevent chain suck.
Frame sealing and storage are impressively practical. My 56cm frame has options for two bottle cages within the main triangle, as well as one below and the usual seat tube cage, and above the top tube are fittings for an easy-access storage pouch. Trek’s Ride Tuned seatmast cap means no seat tube cutting, and because the seatmast telescopes over it, it’s totally sealed against filth.
Trek Checkpoint SL6 ride impressions
What’s immediately apparent is how smooth the Checkpoint SL6 feels. With 40psi in the 35mm tyres, it glides across tarmac with road bike-like speed and feel, the closely-spaced, shallow, round tread blocks rolling almost imperceptibly, with plenty of grip.
Great frame stiffness and the light, shallow and wide Paradigm Comp carbon wheelset make for responsive, quick acceleration that help you cover ground surprisingly fast.
Leaving roads behind, the Checkpoint transitions easily to rougher surfaces, the rear IsoSpeed decoupler really coming into play. The suspended feel it gives through the saddle over washboard gravel and uneven surfaces is impressive, although the bike’s front end doesn’t quite match its ability.
The fork works hard to soak up the bumps, but the handlebar adds nearly as much, together keeping things composed and totally controlled.
The Montrose saddle proved supportive and comfy enough, and despite needing to reign the speed in a little on the slick mud and loose off-cambers, the Schwalbes coped very well.
With some 40mm tyres fitted and run tubeless, grip and off-road ability would be even greater without costing too much road speed. Trek has been quite conservative here, perhaps aiming to lure in roadies, to whom 35mm tyres are already quite a leap, but the Checkpoint’s potential is there to be tuned or exploited in a way that suits you.
Concerns that the Ultegra drivetrain might be overgeared were soon dispelled. The 50/34 compact chainset and 11-34 cassette still allow a 1:1 climbing gear, and more than enough road speed, and the gear jumps are small.
Again, it does lean towards faster terrain, which is generally a feature of American gravel riding. The British equivalent can often be slower, rougher and more fiddly, and when riding on the big ring, I often found myself with a less than ideal chainline. But despite the mud and rocks, I had no dropped chains.
Comparing the geometry to the Boone gives a further steer as to the bike’s intentions. The head angle is a little steeper, while the head tube on my model is 12mm shorter. The top tube is longer, the bottom bracket drop 8mm lower, but the wheelbase of both bikes remains the same, thanks to less fork trail and greater offset on the Checkpoint.
It’s a great balance between crisp, high-speed steering and stable, low-speed control, but always favouring quicker terrain. With its assorted mounts for drinks, spares and gear, the Checkpoint is hugely versatile and can be willingly pressed in to service as a weekend gravel racer, backroads explorer, bike packer, winter trainer or luxury commuter.
Whatever road or trail you choose, this Trek is all about speed.
Trek Checkpoint SL6 specifications
- Sizes (*tested): 49, 52, 54, 56*, 58, 61
- Weight: 8.9kg
- Frame: 500 Series OCLV carbon, rear IsoSpeed, Stranglehold dropouts
- Fork: Checkpoint carbon disc
- Chainset: Shimano Ultegra 50/34
- Bottom bracket: BB90
- Cassette: Shimano Ultegra 11-34
- Chain: Shimano HG600
- Derailleurs: Shimano HG600
- Gear levers: Shimano Ultegra hydraulic
- Wheels: Bontrager Paradigm Comp tubeless-ready
- Tyres: Schwalbe G-One Allround 35mm
- Stem: Bontrager Elite alloy
- Handlebar: Bontrager RL IsoZone VR-CF
- Headset: Integrated, sealed 1 1/4in – 1 1/2in
- Saddle: Bontrager Montrose Comp
- Seatpost: Bontrager Ride Tuned carbon seatmast cap
- Brakes: Shimano Ultegra hydraulic disc, 160mm rotors
Trek Checkpoint SL6 geometry
- Seat angle: 73 degrees
- Head angle: 72.2 degrees
- Chainstay: 42.5cm
- Seat tube: 56cm
- Top tube: 56.6cm
- Head tube: 14.5cm
- Fork offset: 4.9cm
- Trail: 6.1cm
- Bottom bracket drop: 7.6cm
- Wheelbase: 1,020mm
- Stack: 58.6cm
- Reach: 38.7cm
- Price: £3,400 / US$4,000 / AU$4,699