Barry phoned me up the other day and asked: "what gravel tyres do I need to ride Dave?" It's a good question and one that a lot of people are asking at the moment with the increasing popularity of gravel bikes and a growing appetite for diverting away from congested roads and onto forest trails. And the answer? Well, it depends…
Before we got stuck into recommending tyres, the first thing is to talk about is the gravel term. In the US, where the gravel racing scene is hugely popular and where the term originated, races are fast and long and the gravel roads made up of fine gravel, hardpacked and dusty. By-and-large narrow cyclocross tyres are adequate.
But here in the UK, the gravel name has come to encompass so much more than finely groomed gravel roads. We're talking bridleways and byways, forest tracks, rocky chutes and rooty singletrack. That's a lot of terrain variety, and that's why terrain influences and dictates the tyre choice, and poses a much more challenging set of criteria when choosing a gravel tyre.
(As an aside, gravel really isn't the right description for the sort of riding bikes like these are being used for, but as with mountain biking it serves the purpose of getting across how these bikes differ from road and endurance bikes. We're seeing adventure and road plus being used by some brands and people to better accommodate the diversity of the riding.)
The tyre you choose will depend on a list of requirements including what type of terrain you're trying to ride over, the ratio of road to off-road usage and your riding style and the sort of riding you want to do (lunchtime blasts around the woods versus bikepacking across Europe, for example).
But why stop at just one tyre? The big attraction of the gravel bikes that are being developed, like the Parlee Chebacco, is their versatility. With two sets of wheels fitted with different tyres you can be ready to tackle any different terrain. A set of slick tyres for the daily commute and weekend club rides and another set of wheels with big chunky gravel tyres for going off-road and tackling any of the growing number of gravel events.
To a degree, a gravel tyre is one of compromise. A big wide tyre will provide a smoother ride with more grip but be heavy and draggy; a narrow tyre will be lighter and faster-rolling on hard ground and on the road, but increases the risk of punctures.
There are several factors to consider when choosing a gravel tyre, but the two key ones concern width and tread pattern.
For rougher terrain and to maximise traction and comfort, a wider tyre is best. The bigger tyre provides a bigger cushion of air between you and the trail and obstacles, isolating you from a lot of the harsh impacts and vibrations, and provides more grip on loose gravel, dirt and mud.
If you have very rough and large gravel you want to ride over, and you're riding predominantly off-road, select the widest tyre your frame and fork are compatible with. However, the downside to a wider tyre is more weight and drag, especially on the road.
So how wide? A 700c tyre in the region of 38 to 42mm width is a good option for a gravel tyre. Such a tyre width strikes a happy medium between grip and comfort on a variety of terrain whilst keeping the weight relatively low and being reasonably fast-rolling on the road. There are a lot of choices in this size range (and it's increasing all the time) and most modern gravel bikes - and even some cyclocross bikes - will accommodate tyres in this range.
The other consideration, and it's something I'll explore more in another article, is the 650b option. An old French touring wheel standard given a new lease of life by mountain bikers, and experimented in the road cycling world with the likes of the Cannondale Slate, this smaller wheel size allows a much larger volume tyre whilst keeping the outside diameter more or less the same as a 700c setup. Give or take, a 47mm x 650b tyre has the same outside diameter as a 28mm x 700c wheelset. That means the smallest of changes to the geometry of the bike (a lower bottom bracket the main change) but you benefit from a much larger tyre with all associated benefits of increased comfort and traction.
Tread pattern is important when it comes to choosing a tyre and is dicated by the type of terrain you're riding over, and how much road you might be riding to link all the gravel sections together. For fine hardpacked gravel a fast rolling tyre with a smooth centre tread section will promote a speedy ride, but if you want to ride a wide variety of terrain from dirt to mud and rocks, you'll want a more aggressive tread pattern. The amount of road riding you're using to link up the off-road trails will be a factor as well. Once again, it's all about compromise, and choosing a tyre that provides the best balance of the various attributes you need for it to perform adequately.
Many of the latest gravel tyres attempt to reach a happy balance between all these demands. A fast centre section, tightly packed side blocks and bigger shoulder knobs produce a tyre that is fast in a straight line but grips when you lean over into the corners.
Tyre pressure is the final part of the gravel bike tyre setup and generally, you'll want to run the tyres as low as you can get away with before risking pinching the tyre against the rim. A lower pressure will allow the tyre to deform and soak up the bumps and let you ride faster and more comfortably. Tubeless tyres are a great benefit to gravel tyres, eliminating the risk of punching the inner tube and much less prone to being punctured by sharp flint. But more on tubeless and tyre pressure in a future article...
The choice of tyre will ultimately be individual to you - to your riding style, your bike and the terrain you're likely to encounter. That's where we come in; at Bespoke we're all about finding you the perfect match, whether that's through bike fit or component choice.
Below are some of Dave's tried-and-tested favourites. If you want to know more, whether you're speccing up a new build or replacing tyres on an existing bike, just pop in to store or give us a shout.
The classic all-rounder, with an option for every occasion
The Schwalbe G-One tyres is a really popular choice. The tiny dimples ensure the tyre rolls fast and quietly on the road but there's sufficient control on loose and hardpack gravel and trails. It's available in various widths from 30 to 70mm and three versions; Speed, Allroad and Bite to suit different terrain requirements.
King of cornering. Pronounced side blocks make this great for aggressive riding.
The Panaracer GravelKing SK is a similar tyre with good all-round talents. It's a fast rolling tyre on tarmac and hardpack gravel but the long rectangular shoulder blocks give predictable traction when you lean the bike over into the corners.
Serious straight line speed, but with a super aggressive cornering bite
The Challenge Gravel Grinder combines a dotty centre tread section, to ensure good speed on the road and hardpack gravel, but with wide angular shoulder blocks so it still grips when you lean over into the corners.
All about the traction - great grip and low rolling resistance
WTB has put its mountain bike expertise to good use producing an interesting line of tyres suited to gravel riding. Designed for off-road trails, the Riddler has an aggressive tread pattern intended to provide maximum traction when the going gets slippery.
An adventure and gravel bike takes elements of a cyclocross, endurance and mountain bike and fuses them into a package that is ideally suited for riding over just about any...Read more
Announced today, ENVE's G Series wheels use their lightest carbon clincher rims to date. The G23 (700c) and G27 (650b) are dedicated gravel/adventure wheelsets, optimised...Read more
Mavic have brought their tubeless technology to the road. Wider rims paired with 30mm or 40mm tyres, these look ideal for gravel/adventure. Dave takes a closer look...Read more