Unless you’ve been living under a rock, you’ll know that chunky gravel bike tyres are having a moment right now.
Pros are using cross-country mountain bike tyres in gravel races, new gravel bikes are being launched with ever-increasing clearance and tyre manufacturers are locked in a heated arms race to see who can release the widest possible gravel tyres.
As with any trend, though, not everyone is convinced, and one of the most common retorts you’ll see goes something like this: “If you need tyres bigger than 45/50/55mm, just buy a mountain bike.”
Naturally, we at BikeRadar love and cherish every one of our readers and viewers, and value each contribution to our comments section.
However, that doesn’t mean they’re always right, and having just bought a brand new mountain bike, I can say from first-hand experience they’re very wrong indeed.
- Read more: Simon says: don't buy a gravel bike without at least 50mm of tyre clearance – you'll regret it
Tyres are important, but they’re not everything
The crux of the argument seems to be that wanting big tyres for any given ride automatically means you’d be ‘better off’ – usually meaning faster, more comfortable and so on – on a mountain bike, rather than a gravel bike.
Yet, while it’s fair to say that wider, grippier tyres are a distinct feature of modern mountain bikes, there's much more separating them from gravel bikes than wider tyres alone.
If, for example, I compare my Kinesis GX Race to my new Trek Procaliber 8, it becomes immediately clear there’s a lot more going on than simply a few millimetres of extra rubber on the Trek.
The Kinesis, for example, is a rigid gravel bike with a narrow drop handlebar, while the Trek is a hardtail cross-country bike with a wide flat bar, a dropper seatpost and 120mm of front suspension travel.
Perhaps even more importantly, the geometries and resultant riding positions are vastly different, and small differences in tyre width don’t change that.
Even with 2.1in Schwalbe Thunder Burt tyres, riding the Kinesis doesn’t feel all that different from riding a regular road bike, except that you can barrel along anything that can be defined loosely as a ‘road'.
It is, obviously, more sluggish on tarmac climbs than my lightweight Giant TCR Advanced Pro Disc, but the Kinesis otherwise still feels very much like a ‘drop bar bike’ on the road.
You can get your head down, out of the wind, and – thanks to its tall, road-like gearing – rack up the miles with relative ease.
In contrast, the Trek Procaliber is a relative beast.
The suspension fork, low gearing and upright geometry mean it offers vastly more control on technical off-road trails, whether you’re going up or downhill.
But any time I hit a stretch of extended gravel or tarmac road, the MTB immediately has me wishing for the longer and lower geometry of the gravel bike – especially if there’s a headwind.
Both bikes have their places
Of course, there are rides that are simply too technical for the gravel bike and my limited off-road riding skills.
There are rocky descents I’ve had to walk down on the gravel bike, for example, that I’ve simply ploughed through without a second thought on the MTB.
The MTB is undoubtedly the ‘more capable’ bike, and for any rides where you don’t especially care about being fast on tarmac or gravel roads, it’s clearly an ideal choice.
But for longer, mixed-surface rides, the gravel bike is still a better choice – especially if you use big, fast tyres (such as the ThunderBurts mentioned previously) that can help close that capability gap off-road, without sacrificing too much speed on smoother surfaces.
The “just get a mountain bike” argument, then, misses the point that while there’s some small overlap between a gravel bike with big tyres and a mountain bike, the differences between those bikes – and where each excels – are much more stark than simply a few millimetres of rubber.
