Latest News

How to convert a road bike to a gravel bike

Thursday, July 30th, 2020 4:25pm
Category: Latest News


Riding gravel has become all the rage in recent years with just about every bike manufacturer rushing to add a model to their range to cater for cyclists that increasingly want to venture off-road on drop bar bikes. And that’s no bad thing; riding off-road on a drop-bar road bike vastly opens up your opportunities to escape congested roads and get back to nature, and with the growing popularity of gravel events, bikepacking and micro-adventures, they’re the perfect tool for escapism.

Buying a new bike is an expensive business though so you might be wondering if it’s possible to convert your current road bike into one that can tackle gravel? The answer is yes and no, but mostly yes.

Let’s take a closer look at how you can turn your slick tyred road bike into a gravel munching off-roader. Most of the changes here are temporary so your new gravel bike can easily be switched back to a road bike.

The main difference between a gravel bike and a road bike comes mainly down to increased tyre clearance and slacker geometry on the former. Most road bikes can be converted to gravel bikes but some make better candidates than others. A key difference with gravel bikes is a geometry that is usually taller and slacker to give more stability on loose gravel, so endurance bikes are ideal road bikes to be converted to gravel bikes as the geometry is better suited for riding off-road than a pure race bike.


Tyres


The most important conversion to consider are the tyres. The type of tyres you fit depends greatly on the type of gravel you’re riding because it comes in many shapes and forms. If you’re riding well-groomed gravel, forest tracks and canal towpaths, a big fat slick tyre will suffice in the dry. If you want to ride rough gravel and woodland trails then you want to fit a wide aggressively treaded tyre that will give you maximum grip and control.

Gravel bikes are regularly specced with 40mm and wider tyres but you’ll be lucky to get anything like that on a road bike.

Racier bikes max out at 25-28mm while endurance bikes commonly offer space for up to 35m and cyclocross bikes closer to 40mm. For rough gravel 32-33mm is the minimum width you want to fit if you want to get good control and comfort on gravel surfaces.

Gravel tyres come in many varieties from low profile semi-slicks for summer riding to chunky blocks for winter mud-plugging, so choose the tyre to suit the conditions. A fast-rolling design like a Schwalbe G-One or Panaracer GravelKing will ensure good speed on the road as well as grip on gravel.

If space is really limited on your bike another option is a cyclocross tyre as these are typically 32-33mm wide and will fit in a wide majority of road bikes. They also come in many tread designs but most are fast-rolling and will be ideal for converting a road bike to a gravel bike.

If you’re feeling flush, with two sets of wheels you can easily switch your road bike between road and gravel setup.


Wheels


Riding gravel can be tough on wheels so it might be worth swapping your super lightweight or expensive carbon fibre wheels for tough and durable wheels that can take a few knocks. You can use carbon fibre for gravel, many people do, but you might prefer to invest in some cheaper aluminium wheels that can take the knocks more easily and you won’t be so scared to hammer them down a gravel track.

Another key consideration is the rim width. The wider the tyre the wider the rim to provide a more stable base for the wider tyre and stop it squirming at lower pressures and through corners. However, the downside is that a wider rim often means a tyre will be wider than the stated sidewall measurement, so you do need to be careful when choosing to ensure you keep a sensible amount of clearance between rubber and frame. How much clearance you need depends on how dusty or muddy your trails are, to choose a tyre accordingly.

Going to a smaller wheel size can also increase tyre clearance. All road bikes are designed around 700c wheels but gravel bikes are commonly being designed to be compatible with the smaller 650b wheel sizes, which offers the advantage of running a bigger volume tyre for more comfort and traction but the overall diameter being no larger than a 700c setup. Going down this route on your road bike could be a way to fit bigger tyres into the same space but it’s worth knowing that road bikes are not designed with this smaller wheel size in mind so there might be compatibility issues and it can impact the geometry, namely by reducing the bottom bracket height.

Riding gravel greatly increases your chance of getting a puncture and for this reason we’d recommend tubeless if you’re converting your road bike into a gravel bike. Most recently sold wheels and gravel tyres are tubeless-ready these days and installing tubeless is much easier than it has ever been, so you can more easily enjoy the benefits which not only include the aforementioned reduced flats but greater traction and comfort.

For more info on how to install tubeless, check out this video


Gearing



Road bikes are commonly geared for high-speed road riding and racing with a focus on smooth jumps between the gears to ensure you can maintain the optimum cadence. Ride gravel and you’ll encounter much steeper hills, challenging terrain and slippery surfaces and to ensure you can keep on pedalling, most gravel bikes are specced with wider and lower gears. Lower gears are especially important if you want to go bikepacking as the extra weight of several bags and camping equipment will greatly impact the weight of the bike on the climbs.

A super easy way to give your converted road bike easier gears is to fit a bigger cassette. This will increase your range and give you the lower gears you need. Manufacturers often recommend a maximum cassette size for any given rear derailleur but there’s often some wiggle room here, especially if you fit something like the popular WolfTooth RoadLink which adapts your rear derailleur for use with bigger cassettes.

Chainrings can be swapped for smaller sizes to further increase your climbing capability. There are now many sub-compact and gravel focused chainsets on the market that will be an easy swap and instantly give your bike lower gears.


Contact Points



A popular difference between road and gravel bikes is the handlebar. Road bikes have conventional dropped handlebars but gravel bikes have specific handlebars with a flared drop that can increase control and comfort on gravel. The drop section of the handlebar is simply flared out and the angle of the flare varies from mild to the extreme so try some to see what suits you. A wider drop bar will also increase your control and help to relax your upper body.


Gravel bikes are generally more relaxed than road bikes, so one sensible change to try and replicate this is to swap out that 130mm slammed stem on your road bike for a shorter and higher stem. Bringing the handlebars closer to your body will improve your control especially when riding through woodland trails when you want an agile and nimble bike that is easy to steer. Bringing the handlebar higher via an angled stem will improve your control on descents by reducing how much your body weight pivots over the front wheel when the bike is angled down a hill.

Riding gravel can be rough and tough. If you want a little more comfort you could consider choosing a bar tape with thick padding that will provide more cushioning on gravel tracks. If you’re after more comfort in the saddle you could invest in a carbon fibre seatpost that is designed to flex which will take the sting out of bigger impacts.

If that’s not enough comfort, then how about a suspension stem and seatpost? Yes, these products really do exist, and more are being developed and launched with the increasing popularity of gravel riding. A suspension stem and/or seatpost will incur only a small weight penalty but vastly increase your comfort and control on rough gravel, and if you want to plan some long rides it could make a big difference in how fatigued you feel at the end of the ride.

You can use road clipless pedals on gravel but if you do need to dismount and walk for whatever reason, you’ll quickly trash your cleats and expensive carbon fibre shoes. Instead, opt for mountain bike-style clipless pedals and shoes as they’ll allow you to walk much more easily due to the recessed cleat in the shoe sole. Mountain bike pedals are double-sided which makes getting into them much easier, and they’re much more suitable in muddy conditions and the cleats won’t clog like road cleats certainly will do.

Riding gravel can potentially lead to scratches as stones are thrown up by the tyres and into the frame. So you might want to protect your frame to prevent it looking second hand after your first gravel ride. This is a very easy job and doesn’t cost a lot. Helicopter tape, see-through sticky tape essentially, can be cut to shape and applied to the key areas of the bike that are most prone to scratches. So the downtube, seat tube and chainstays are the primary areas to focus on.

Hopefully, these tips have given you some useful advice for converting your road bike into a gravel bike. Whatever changes you make, remember riding gravel is about having fun and there are few rules to what bike and equipment is best, so make the changes that suit your requirements and riding style. And remember, have fun!

Shop at
Chain Reaction Cycles

CRC Logo

Got a question?
Contact our editor