Jim is an accomplished triathlete and endurance cyclist, and has raced in more than 35 USAT-certified races. He is also an avid trail runner and endurance gravel bike rider. Jim is a founder of Complete Tri and frequent writer on triathlon and cycling.
Bike Conversion From Road to Gravel
Many of us love the speed and efficiency of road bikes, but sometimes we crave a little adventure on unpaved paths. Or perhaps we just want more route options than the same-old road shoulders. Converting a road bike into a gravel bike is a practical way to unlock new riding experiences without buying a new bike. With some key adjustments and added gear, we can enjoy the benefits of both worlds.
Gravel biking opens up tons of new terrain while still enjoying the familiar ride of our road bike. Plus, with the right gravel setup, your bike will still be ready to tackle pavement whenever you need to — perhaps just at a slightly slower clip.
Here are the big things to know about converting a bike from road to gravel.
Key Takeaways
- Yes, you can convert a road bike into a gravel bike with a few key modifications.
- There might be some limiting factors on how much of a conversion you can do.
- Adding accessories can enhance the gravel riding experience.
Major Differences Between Road Bikes and Gravel Bikes
When we compare road bikes and gravel bikes, we see some important differences. Each type of bike is designed for different riding styles and surfaces. Namely, you will see some differences in tires and wheels, gearing, durability, and comfort.
Tires and Wheels
Road bikes usually have narrow tires that are around 23-28 mm wide. These tires are designed for smooth pavement, providing low rolling resistance, while riding at a very high PSI. This helps with speed on flat roads.
By contrast, gravel bikes feature wider tires, typically ranging from 35 mm to 50 mm. This extra width offers better traction and stability on rough surfaces. Gravel tires often have more tread, which helps grip loose dirt and gravel. Wider tire clearance on gravel bikes also allows us to tackle a variety of terrains without fear of flats. You ride a gravel bike at a much lower PSI as well, especially if you are using tubeless instead of clinchers, which is becoming common with gravel bikes.
Gearing
Road bikes often come with a broad array for a gear setup, with 2 or even 3 chainrings on the front and some heavy gears for fast riding on the back. This setup lets you really fly on those long, flat straightaways.
Gravel bikes often have a different gear range. They typically feature a 1x or 2x drivetrain. This setup allows for lower gears, making it easier to ride on steep or uneven paths. You might not have the same high gearing, reducing your top-end speed if you find yourself on a nice, hard, flat road or a slight descent.
Durability
Road bikes are generally built with lightweight materials wherever possible to maximize speed. However, this can make them more susceptible to damage when riding on rough surfaces.
Gravel bikes are usually constructed to be more robust. They often have stronger frames and components to handle bumpy roads and off-road trails. This added durability gives us more confidence when exploring diverse terrains, knowing our bike can withstand some wear and tear.
Comfort
Road bikes are designed for speed, which often comes at the cost of comfort. The riding position can be aggressive, leading to discomfort during long rides. The more the bike is built for speed, the less comfortable it is to the typical rider, generally speaking.
In comparison, gravel bikes typically offer a more relaxed geometry. This design helps us maintain a comfortable riding posture. With features like wider handlebars and a more forgiving frame, gravel bikes can make longer rides more comfortable. Of course, a good bike fitting can help you strike that balance of having a comfortable ride and one that puts out good power.
Outfitting Your Road Bike for Gravel
OK, let’s get to it. To convert our road bike for gravel riding, we need to make some important changes. This process involves checking frame compatibility, ensuring we have enough tire clearance, upgrading brakes, evaluating gearing, and modifying our cockpit setup.
Frame Compatibility
First, we should check if our road bike frame is suitable for gravel riding. Not all frames are designed for this purpose. Gravel bikes often have different geometry that allows for better handling on rough terrain.
We need to look for features like:
- Frame material: If your road bike relies on an excessive amount of carbon fiber for its build (seat post, bars, stem, wheels, plus the frame), you might find that it is not ideal for gravel, especially if you plan to do a lot of low-maintenance road or jeep trail riding. However, a carbon frame itself can absolutely work for gravel. It will just give you a little more vibration on rough gravel.
- Space for wider tires: Gravel bikes usually call for tires between 32mm to 50mm.
- Mounting points: Extra mounts for racks or fenders can be helpful.
If our bike has the right compatibility, we can proceed with the conversion. If not, we might need to consider a different frame.
Checking Clearance for Larger Tires
Next, let’s assess the clearance on our bike to fit larger tires. This is key for gravel riding, as wider tires provide better traction and comfort.
There are 3 places to examine to understand what width tire you can handle:
- Measure the current tire width and the space in the frame.
- Check the clearance between the fork, seat stays, and chain stays. You will want to ensure no rubbing of your tire on bike parts. Keep in mind that when you sit on the bike, the tires will bulge outward a bit, so you want some wiggle room.
- Take a look at your brakes, and identify if you can go much wider given the current brake setup. You will want the widest setup possible.
We should aim for at least 4mm of space on either side of the tire. This will help us avoid any rubbing, especially when riding on rough surfaces.
The diagram below notes the two major spots where issues might arise. In our experience, the seat stay and chainstay are usually the biggest limiting factors on tire size.
Tires
Now that you know how wide a tire you can handle, it is time to upgrade to a gravel tire.
You might also want to upgrade your wheelset to one that is gravel-specific, since many road wheelsets can only handle a smaller-width tire.
We highly, highly recommend using a tubeless tire setup. Why? You want to ride a gravel tire at a lower PSI than a road tire. For clincher tires, lower PSI often means more flats. A tubeless tire can be ridden at very low PSI, making the ride much more comfortable on rough gravel. (Don’t mess with tubulars on gravel bikes.)
Most road bikes can be retrofitted to handle a 32mm tire or so. If your seat stays can accommodate it, go higher, like a 35 or 38. It is unlikely that a bike originally built for roads can go higher, but if so, consider a 40 which is a great all-around width for many types of gravel.
Brakes
Looking at your brakes is another important step. Most older road bikes came with caliper brakes, which may not provide enough width for the ideal gravel tire. For the past 2-3 years, disc brakes have been the norm, which are much more forgiving in terms of tire width.
If you have disc brakes, you’re all set for a wide gravel tire.
If you have caliper brakes, see how wide they can safely be adjusted. This will be another limiting factor on your tire width.
If our bike’s frame can handle them, switching to mechanical or hydraulic disc brakes will significantly enhance our gravel riding experience. However, this switch is not an easy one, and many frames just aren’t setup to handle disc brakes.
Evaluating the Gearing Setup
Next, we should evaluate our gearing setup. Road bikes are often geared for speed, which might not be ideal for steep gravel climbs.
We like using a single chainring on the front, as some of the minimum maintenance roads we ride on tend to be a little more hard on derailleurs. Having just one derailleur (on the back) reduces the amount of road fixes required, if you do enough gravel biking.
With that said, switching from a double to single chainring on the front is a big swap, and not entirely necessary if you are just trying to keep this process simple.
On the back, we often look for a cassette that has lower gearing, because we want to really be proficient at lower speeds even if it limits us a bit at high speeds.
This adjustment allows us to tackle most of the gravel we find in races or training rides.
Cockpit Setup
Lastly, let’s focus on our cockpit setup. This includes the handlebars, grips, and saddle.
Some changes to consider:
- Handlebars: Wider, flared handlebars provide better control on rough terrain, washboard gravel roads, and other challenging sections.
- Grips: Consider adding thicker grips for comfort. Some people simply double-tape their bars to reduce vibration from gravel.
- Saddle: You might find that you want a little more padding in your saddle than you do on pavement.
- Packs: Gravel riding often has you in areas that are relatively unsupported. We’ve done 100 mile gravel rides without passing a single convenience or grocery store for refueling. It is good to ride with a top tube bag or another large pack of some sort, and plenty of water. Or you can carry a camelbak style backpack.
These tweaks help improve our overall comfort and handling while riding on gravel. By making these adjustments, we can transform our road bike into a long-distance gravel bike.
DIY or Hire a Bike Shop?
When we think about converting a road bike to a gravel bike, we face a choice: DIY or hire a bike shop. Each option has its pros and cons.
DIY Benefits
- Cost-Effective: We can save money by doing it ourselves.
- Learning Experience: We gain knowledge about our bike and how it works.
- Customization: We can choose exactly what we want without compromise, and you an continuously tweak the bike to get it just right.
DIY Drawbacks
- Skill Level: Not everyone has bike mechanics experience.
- Time-Consuming: It can take longer if we’re not familiar with the process.
- Mistakes: Errors can lead to safety issues, and safety issues while biking can have big ramifications.
Bike Shop Benefits
- Expertise: Professionals know what to do and have the right tools, and your bike will be upgrade safely.
- Warranty: Many bike shops offer warranties on their work, or the ability to come back if something isn’t quite right.
Bike Shop Drawbacks
- Cost: It can be more expensive to hire a shop.
- Less Control: We might not get the exact setup we want, or tweak the bike as you find new things you want to upgrade.
Bike Navigational Tools
One note about navigation – many of the best gravel routes are in areas where you can easily get lost. The feel or exploring that makes these rides fun is always what makes them problematic if you don’t know where you are going.
For rides where you really need to be able to take care of yourself, we recommend having a fully-charged bike computer. Remember that you often need to download your route before the ride, while you have access to good wi-fi. Then, the computer should help route you with the assistance of GPS.
As a backup, write the main turns and roads you need to look for on a cue card, and stick it in your jersey pocket. This can be your fail safe in the event that the bike computer glitches (which is unlikely.)
