Gravel and adventure bikes buyer's guide

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Gravel and adventure bikes buyer's guide
By Lawrence Bywater 5 June 2019 5 comments

From an inconspicuous cycling backwater in the US, gravel and adventure bikes have gone well and truly mainstream. Offering something for ardent roadies and fervent mountain bikers alike, it’s easy to see their appeal – indeed, they’re perhaps the most versatile bike you can buy today. 

Keen to hear what you thought – we asked our Facebook followers to see if they would consider a gravel bike for their next bike purchase.

A clear win for yes, then!

This guide covers all the gravel and adventure bike need-to-knows – what they are, why you might what one and perhaps most crucially, the subtle differences between models – something which should help when you’re ready to hit the button on something exciting!

What is a gravel bike?

Gravel bikes sometimes called adventure bikes, sit somewhere on a sliding scale from what is essentially a drop-bar mountain bike, to something that looks like a traditional road or cyclocross bike

Gravel bike

Let’s delve deeper with a few characteristics that are ubiquitous across all types of gravel bike.

Comfort based geometry – Most gravel and adventure bikes prioritise rider comfort over outright speed. A tall headtube combined with a slack head angle, helps riders adopt an upright position, something you’ll appreciate when riding long distances on and off-road.

Long wheelbase - Continuing the frame design thread, gravel and adventure bikes tend to have a long wheelbase. A bicycle’s wheelbase is the measurement between its front and rear axle and increasing this distance helps spread rider weight, increasing stability. When braking, rolling over obstacles or dealing with changes in gradient, a long wheelbase also helps keep things the right side of the fun line!

Low bottom bracket – A low bottom bracket (BB) is another common gravel bike feature designed to increase the stability of a gravel bike. A lower BB means the rider sits lower on the bike, reducing their centre of gravity and subsequently helping the bike feel more planted.

Generous tyre clearance – Large tyre clearance is yet another concession gravel bike designers pay to ride comfort and stability. Most models come shod with 32mm tyres but with room for much, much wider rubber.

Disc brakes – Drawn by disc brakes increased stopping power, easier modulation and reduced maintenance it’s no surprise to see bike brands use them on gravel bikes. Using disc brakes also frees designers from the shackles of caliper brakes – namely their impact on tyre clearance. Design a bike around disc brakes and it becomes easier for the frame and fork to accommodate wider tyres.

As with most bike types, gravel models tend to be unisex. By switching out contact points, or simply adjusting them, it's fairly easy to cater for riders of different shapes. That said, some brands do offer specific women's gravel bikes. Frame geometry and component selection is based around a rider of smaller form. And as another nod to the differing demands of female riders, the smaller frame sizes are more likely to run 650b wheels opposed to 700c. The theory here is that it helps maintain ride quality as well as reduce the chance of toe overlap when steering. 

Read more about women's specific bikes in this article.

Gravel bikes vs mountain bikes or road bikes: why choose a gravel bike?

Want to throw the in the odd bridleway on your favourite road loop? Don’t fancy going mountain biking, but like the idea of escaping road traffic? Dream of hopping on a train for a weekend’s bikepacking? Love road and mountain, but only room for one bike at home? Hanker after a bike that can get you to work quickly Monday to Friday, before enjoying some off-road action at the weekend? Gravel bikes fit each of these scenarios and more!

Three riders on a gravel bike ride

Gravel bike features

As with any bike purchase, it’s a good idea to take stock of the riding you are planning to do with your new bike before you jump on the first thing that catches your eye. Read the examples above, again. Do some of these sound familiar?

Thanks to ‘cross, road, touring and mountain heritage different gravel bikes will suit different riding tastes, so in the next section, we’ve highlighted certain gravel bike features which should help narrow down your options.

Gravel bike frame and fork

Frame and fork

Suspension – A gravel bike with suspension? Are you sure? Yes! Suspension is one of several attributes used to distinguish certain gravel bikes from one another. Most designs involve the use of shock-absorbing materials or elastomers in the frame to soak up the bumps, with more extreme models running a front suspension fork, albeit with less travel than a traditional mountain bike. If you’re going to spend more time off-road than and on, or if you've got a penchant for exploring the edge of grip then a gravel bike with an element of suspension will be for you.

Dropper post – Dropper post on a gravel bike? Again – are you sure? Yes, yes we are! As off-road descents get steeper and more technical, the more a rider needs to shift their weight over the rear wheel and lower to the ground. A dropper post scoots the saddle out of the way enabling the rider to tackle the descent with confidence. Whilst they’re not a common feature of gravel bikes today, we can certainly see them becoming more popular in future!

Frame mounts – Gravel and adventure bikes are the perfect partner for bikepacking trips. If you’re buying something to go on this kind of trip it’s a good idea to take stock of your chosen model’s frame mounts. Three bottle cage mounts are perhaps the bare minimum for water carrying requirements. And if you’re going to be using an extra-large frame bag which covers the traditional bottle cages, look for a bike whose forks include mounts too!

Read about bikepacking in greater detail in our 'how to' guide here

Gravel bike wheels and tyres

Wheels and tyres

Wheel sizes – Gravel bikes roll on one of two wheel sizes. Most use standard 700c road wheels, with some using the 650b (27.5”) standard. Teaming a 650b wheel with 47mm tyre is the equivalent of running a 700c wheel with 30mm tyre but with the added benefit of an increase in contact with the ground. A very general takeaway here: if you’re after comfort or traction off-road, plump for a gravel bike with 650b wheels and if tarmac is more to your taste a 700c wheeled bike will suit.

Saying that some gravel bikes are compatible with both wheel standards, enabling you to pop a pair of 700c’s in for a swashbuckling road ride, before substituting in the 650b’s for a rough and tumble hack.

Thru-axles – The majority of gravel bikes uses thru-axles. Stronger and less prone to flex over rough terrain than quick-release skewers, they’re also less likely to accidentally come loose whilst riding. A rough standard has been set, with most models using 12x142 rear and 15x100 front. The first number refers to the diameter of the axle with the second denoting the dropout width. If upgrading components in future is important to you, do take note of a bike's axle size.

Tyre clearance – To keep your riding (and tyre) options as open as possible it’s a good idea to find out each gravel bike’s maximum tyre clearance before buying. It’s easy enough to pop a pair of 28mm or 30mm road tyres on if the tarmac is calling, but if a big adventure ride calls for 42mm tyres and your bike can only take 37mm you’re going to be snookered!

Tubeless – Very much in vogue right now, a tubeless setup promises an increase in puncture protection - thanks to the sealant, more squish - thanks to an ability to run lower air pressures as well as a faster ride – thanks to lower rolling resistance. If running tubeless is important to you, be sure to choose a gravel bike with tubeless compatible wheels and tyres.

We’ve explored tubeless in greater deal in our how to go tubeless article.

Gravel bike with disc brakes

Disc brakes

Ploughing through muddy terrain, slowing on a steep descent, or pulling up short of an obstacle – gravel riding calls for disc brakes – simple! At the lower end of the market, you’ll observe that bikes run mechanically operated brakes, whilst more expensive bikes are equipped with hydraulic disc brakes.

Mechanical, or cable operated, disc brakes don’t offer the best braking feel (modulation) but are much easier to repair road or trailside when compared to hydraulic brakes – ideal then if you’re on a multi-day adventure ride. As well as offering the best braking performance, hydraulic disc brakes usually require very little maintenance once set up correctly.

Gravel bike gearing

Gearing

As road bikes continue to hold onto their double chainring gearing (2x) – gravel bikes have jumped into 1x with both feet. A 1x drivetrain consists of one single chainring up front and 10,11 or 12 sprockets on the cassette at the back. A typical cassette pattern for a gravel bike is 11-42. That largest cog will quickly become your best friend if you intend to tackle steep off-road ascents on a gravel bike. Think you’ll be spending more time on hardpacked surfaces where riding speeds are higher? A bike with a tighter cassette ratio, say 11-32 and maybe a 2x chainset upfront would suit you better.

Most gravel bike gearing uses a mechanical process to initiate a gear shift. Got deep pockets? As in mountain biking and road riding, electronic gear shifting is becoming more ubiquitous. Shimano’s Di2 and SRAM’s AXS groupsets promise reliable, easy gear shifting along with the possibility of multiple shift buttons, easy calibration and customised integration with other bike components.

Gravel bike handlebars

Handlebars

Browse our selection of gravel and adventure bikes, including Boardman adventure bikes and you might see that some models include a flared handlebar. Flared refers to the way the curve of the ‘bar moves outward, as well as around in that inverted C shape. Flared bars help handling on rough terrain whilst also allowing for easier placement of a handlebar bag – a bag perfect for single or multi-day bikepacking adventures.

There we have it, a detailed spin through the ever-expanding gravel and adventure bike category. Here's a quick selection of bikes to get your juices flowing. 

Did we miss anything? Let us know in the comments below.

Posted in: Buyer's Guides
anne 10 June 2019 at 16:45
What about ladies?
Lawrence Bywater 13 June 2019 at 15:41
That's a fair point, Anne. Thanks for taking the time to comment. I've updated the article with a nod to women's specific gravel bikes. ^Lawrence, Cycle Republic
Christopher Evans 19 June 2019 at 17:15
What about the Genesis Vagabond ??? - Lovely steel frame, chunky 29" tyres and reliable Shimano 2X with bar end shifters !!! https://www.genesisbikes.co.uk/bike/vagabond
Lawrence Bywater 20 June 2019 at 07:46
Couldn't agree more Christopher! The frameset is great value too > https://www.cyclerepublic.com/genesis-vagabond-frameset-2019.html ^Lawrence, Cycle Republic
Andrew Newman 20 June 2019 at 21:32
Just bought an Orbea Terra aluminium with Shimano 105. It has 700c wheels and 40mm tyres. I’m keen to see how it performs. Taking it out this weekend for its maiden voyage.