For many years, hardtails were the unshakeable basis of the mountain bike market. If you wanted to cycle quickly and cheaply off the beaten track, there was no getting around the hardtail. By the beginning of the new millennium, however, suspension forks and full-suspension bikes became more widespread. Technical progress made suspension systems better and better. However, the move away from the motto "stiff and light equals fast" took a long time. BIKE also conducted decades of basic research and today we know that in mountain bike terrain, fullys are faster than hardtails in almost all cases.
Rigid-tail bikes have almost completely disappeared from the Cross Country World Cup and the first manufacturers, such as Canyon and Scott are no longer labelling their hardtail models as race bikes, but as all-rounders for everyday use and adventure. Isn't that exactly what gravel bikes are supposed to be able to do? Is it all just marketing? Has it all been done before? We wanted to find out which approach would be better for bikers in 2025 and asked hardtail and gravel bikes to compare concepts.
Gravel bikes continue to boom
"Bad bikes with narrow handlebars and slippery tyres already existed in the past" was our sceptical headline in 2020, when the gravel trend was really taking off. And yet, in parallel to the dwindling importance of the hardtail, a completely new bike genre was able to develop, which is now in full bloom. Among sporty bikes without an electric motor, no category is currently selling better than gravel bikes. However, a lot has also changed technically in five years. Some gravel bikes now have wide tyres, suspension forks and even dropper posts. According to manufacturers, the range of use is on roads, gravel and easy trails - a spectrum that appeals to many cyclists and that MTB hardtails can also cover.
When it comes to off-road use, the versatility of mountain bikes almost always exceeds that of gravel bikes. Ultimately, the intended use of the sports bike and personal preferences determine the requirements in terms of seating and grip position, handling and the importance of aerodynamics. As if the relativisation wasn't enough, there are now also Mountain bikes with drop bar and Gravel bikes with flat bar. To shed some light on the situation, it helps to take a look at the facts and figures.
Seat position in comparison
If you put the geometry drawings of hardtail and gravel bikes side by side, you can see clear differences. On our example bikes Propain Terrel CF Trail (gravel bike) and Bike Ahead The Frame The seat tube length in size L is an impressive 75 millimetres. While gravel bikes compensate for the shorter fork with a longer head tube and therefore often end up not far away from the hardtail in terms of stack value, the reach difference of our candidates is a considerable 43 millimetres.
Here, too, the devil is in the detail: the gravel bike gains a lot of length thanks to a longer stem and racing handlebars that extend forwards. The grip position is also decisive for the riding position. Whether hoods, lower or upper handlebars stretch, compress, raise or lower the body position on the bike. It is therefore impossible to make a generalised statement that a gravel bike is more comfortable or sportier than a hardtail. The only thing that can be said is that a drop bar offers more grip options. Especially on long distances, the variance can take the strain off your torso, shoulders and arms.
Handling: Gravel vs. MTB
Beyond tarmac and fine gravel, no gravel bike can hold a candle to the hardtail, even with the best riding technique. While on a gravel bike the hands are positioned clearly in front of the front wheel axle when the handlebars are positioned on the hoods, on a straight MTB handlebar the imaginary plumb line is behind the axle. On trails that are fun for mountain bikers, gravel bikes reach their limits early on, and not just because of slippery tyres. Especially when the gradient becomes steeper, the rider on a gravel bike hangs so far forward that the feeling of rolling over quickly sets in. In addition, most models have a rigid seat post, a high top tube and a significantly steeper steering angle. Flat forest tracks may still be the gravel bike's habitat. On trails, however, gravel bikers unfortunately have to push much more often, even with wide tyres, suspension fork and dropper post. The steeper the incline and gradient, the more likely you are to fall off the saddle.
In addition, the wheelbase is a good 70 millimetres longer with a comparable chainstay length on the size L hardtail. In theory, this gives the mountain bike a smoother ride. In a straight line, a hardtail is more stoic on the track and is less likely to be thrown off course by obstacles. In contrast, the frame geometry of a gravel bike promises more agile handling and more turning pleasure in tight bends. However, long stems and front-heavy grip positions on the cockpit significantly restrict more direct steering behaviour.
A hardtail is therefore easier to keep under control off-road than a gravel bike. However, there are also significant differences within the gravel bike category. Bikepacking models, which are designed to cover long distances with a high system weight, are typically closer to the smooth-running geometry of a mountain bike than sporty race gravel bikes.
Major differences in aerodynamics
The aerodynamic differences between gravel and mountain bikes are measurable. The rider is responsible for around 75 per cent of the aerodynamic drag, while the bike only accounts for around 25 per cent. Even on a mountain bike an efficient sitting position with inner bar ends the lion's share of the air resistance. Nevertheless, the gravel biker can duck even deeper into the wind in the lower handlebar position.
At 45 kilometres per hour, wind tunnel measurements show differences of around 90 watts between aero road bikes and mountain bikes. Depending on geometry and equipment, gravel bikes fall somewhere between the two extremes. Incidentally, the wheels account for around eight per cent of the total air resistance. Between a 30 millimetre wide road bike tyre and a 42 millimetre wide gravel tyre, the aerodynamic advantage is around 20 watts in favour of road tyres. In terms of aerodynamics, the gravel bike has an advantage over the hardtail.
Initial conclusion on the comparison of the two wheel types
Gravel bikes have their advantages on tarmac and fine gravel, mainly due to aerodynamic and ergonomic arguments. A quick after-work ride across the fields? Perfect for a gravel bike! The more the area of use deviates from mostly flat rides with high average speeds on firm surfaces, the more sense an MTB hardtail makes. If the terrain becomes only slightly more technical and the gradient only slightly steeper, bikes with drop bars can no longer keep up. Even with off-road-compatible equipment, the riding position is too front-heavy and the handling too indirect. A hardtail with a classic flat bar provides a greater sense of security in all situations. When planning tours through unknown terrain, it often happens that a steep descent or a short trail suddenly opens up in front of the bike. With a versatile hardtail, there are fewer nasty surprises in store.
Jan Timmermann
Editor
