On September 25 a small group leaves Incheon for Busan on the cross-country cycling road, four days on the bike. One of them rides a 2025 Trek Domane SLR 7 Gen 4: Bontrager Aeolus Pro 37 carbon wheels, 32c road tires, Shimano 105 Di2. It's a good road bike, and it came in to become a good cross-country bike. This is what changed.

Tires: 32c road to 40c gravel

The Gen 4 Domane has the room, so the 32c road tires came off and a pair of Hutchinson Caracal Hardskin 700×40c went on, tubeless, tan wall. Hardskin is the reinforced casing in the Caracal line, the version built for cuts and long days rather than for the last few watts.

Why 40 instead of 32? The cross-country road is paved almost end to end, but it isn't smooth end to end. There's worn concrete, brick, cracked tarmac around the dams, and short stretches where the path turns to dirt. A 40 at lower pressure takes the edge off all of that, and on day three that matters more than it sounds like it should on day one.

What it costs: on clean tarmac a 40c knobby tire is slower than a 32c slick, and it's heavier. That's the trade. For four days of mixed surfaces with a load on the back, we think it's the right one. For a fast Sunday loop on good roads, it wouldn't be.

Rack: Topeak Zi:RAK Essential with Quick-Mount

[Photo: rack parts on the bench — rails, thru-axle, strap clamp]

This Domane has no rack eyelets, so the rack is Topeak's new Zi:RAK Essential in the Quick-Mount version. It mounts in two places: a strap clamp on the seatpost and a replacement thru-axle at the rear wheel. No eyelets, no clamps on the carbon stays, and it comes off the same way it went on.

The rack is aluminum and rated for 6 kg on top. It's a minimal design, two rails and a top loop, which is what you want when you're adding weight to a bike that was bought for being light.

Bag: the U-Shell and drybag, instead of panniers

Instead of panniers, the rider is running Topeak's U-Shell for Zi:RAK Essential, a 154 g carrier plate sold separately, with the matching 10 L U-Shell DryBag strapped on top.

The point of this setup is weight and width. A roll-top drybag on a plate weighs a fraction of a pannier set, sits centered behind the saddle, and doesn't hang out past the wheel. The U-Shell locks to the rack with one pull and releases the same way, so at the guesthouse the bag comes off the bike in a few seconds without touching the rack.

The trade: 10 L is enough for four days if you pack like you mean it. It is not enough for a two-week tour. If the packing list grows, the Zi:RAK takes side loads too, and panniers can go on later.

Handlebar bag: Route Werks

[Photo: Route Werks bar bag from above — lid mount, bungee, stub]

Up front is the Route Werks Handlebar Bag. It's a rigid-lid bag on a quick-release bracket, and the reason we like it for long trips is what bolts onto it. The lid takes a computer mount, so the head unit sits on top of the bag where you can read it. The sides take machined stubs for a light or a bell. The top has a bungee for a jacket or a map. On a multi-day ride you end up wanting all of those things somewhere, and this bag gives them one place.

The finished bike

Same frame, same wheels, same drivetrain. Wider and tougher tires, a rack that took ten minutes and no eyelets, a bag that comes off in one pull, and a bar bag that carries the small stuff and the electronics. It's still a road bike when the trip is over; the tires and the rack come off and it's back to what it was.

No setup does everything. This one gives up some speed on smooth pavement and adds some weight, and in return it's a bike that can go 130 km a day for four days on whatever surface the river path hands it. That's one reading of what a cross-country bike should be. If you're planning the same ride and want to talk through your own bike, come by. We'll go through it part by part.