Gravel guides
Gravel or road bike — which one suits you?
If more than a quarter of your riding is on gravel, forest roads or rough tarmac, choose a gravel bike. On smooth roads it costs you 1–2 km/h at the same effort; everywhere else it is faster, more comfortable and safer. Choose a road bike only if you race on tarmac or ride almost exclusively on good asphalt.
What actually differs
The two bikes share more than they differ: drop bars, similar frame weights, similar groupsets. The differences are tyre clearance (28–32 mm on a road bike, 45–58 mm on a gravel bike), geometry (a gravel bike has a longer wheelbase, slacker head angle and often a higher stack for stability and comfort), and gearing (gravel groupsets have a wider range with lower low gears for steep, loose climbs).
Mounts are the quiet difference. Gravel frames carry bags, extra bottles and sometimes a rack; road frames usually do not.
Speed on tarmac
A gravel bike with 40 mm slick or semi-slick tyres at the right pressure rolls almost as fast as a road bike on good asphalt — the difference is mostly aerodynamics and a kilo of extra rubber, roughly 1–2 km/h at the same power. On rough or wet tarmac the wider tyre is often faster because it loses less energy to vibration and holds more grip in corners.
Speed and comfort on gravel
On gravel the comparison flips. A road bike on 28 mm tyres bounces, punctures and slides; a gravel bike on 45 mm tyres at 2 bar floats over the same surface. The longer wheelbase and slacker front end keep it calm on loose descents, and the lower gears let you sit and spin up steep forest roads instead of grinding.
The Norwegian case for one bike
In most of Norway the good riding is on a mix of surfaces: a tarmac approach, a forest road, a mountain pass with broken asphalt, a gravel loop. A gravel bike with two sets of tyres — a fast 38–40 mm for the road and a 45–50 mm knob for the mountains — covers all of it. That is the bike we designed the Eryx to be: fast enough on the road, built for everything above the tree line.
When a road bike is the right answer
If you race on tarmac, ride in a fast group on good roads, or simply never leave asphalt, a road bike is lighter, more aerodynamic and more precise. Buy the road bike — and borrow a gravel bike the day your friends suggest a forest road.
Frequently asked questions
Is a gravel bike slower than a road bike?
On smooth tarmac, by about 1–2 km/h at the same effort with fast tyres. On rough tarmac, gravel or wet roads the gravel bike is usually faster and safer.
Can I use a gravel bike as a road bike?
Yes. Fit 35–40 mm slick or semi-slick tyres at the right pressure and it will keep up with road bikes on most group rides.
What tyre width should I run on a gravel bike?
38–40 mm for mostly tarmac and smooth gravel, 45–50 mm for forest roads and mountain gravel. The Eryx clears up to 58 mm for rough tracks and winter.
Do I need a gravel bike for GravelBirken?
A gravel bike with 40–45 mm tyres is the right tool. A road bike with 32 mm tyres can finish it, but you will be slower and more tired on the descents.