Converting Your Road Bike to Gravel: Key Points to Consider

Points you must check

Is the tire clearance sufficient?

There is no clear rule that a road bike should be called gravel road if it has gravel parts, but the first thing to consider is to widen the tires. Today’s road bikes are mostly equipped with 25C tires, while gravel bikes are equipped with 35C or 38C tires.

Changing tires is the same as changing tires on a normal road bike, but the problem is the tire clearance. Tire clearance refers to the distance between the tire and the seat stay (frame), and between the tire and the fork.

“However, the “00C” on the tire size indicates the distance from the wheel rim to the outer circumference of the tire, so replacing a 25C tire with a 35C tire will usually increase the height of the tire by 1cm.

If the frame has a wide tire clearance, there is no problem, but since most road bikes have a tire clearance of about 28C, the tire will interfere with the seatstays and fork, or with the brakes if the bike is equipped with rim brakes. This is probably the reason why many gravel roads have disc brakes.

When widening the tires on your road bike, measure the tire clearance beforehand. Measure the distance between the current tire and the brake, and consider -3 to 5mm as the maximum tire size for safety.

Are there any problems with the durability of the parts?

This is not a problem if you are commuting, but if you are cycling or touring on gravel roads, you should consider the possibility of mud or other debris clogging up the chain and causing it to fall off.

Gravel components are often equipped with anti-dirt measures (to prevent the chain from getting stuck and mud from getting into the chain), but road components are designed for riding on paved roads and are not very resistant to dirt.

However, road components are designed for riding on paved roads, and are not very resistant to dirt. Even if you are not going to ride on serious mountain roads like MTB, if you are going to gravel ride on unpaved mountain roads, you should replace the rear derailleur and chainring with dirt-compatible components, as they tend to chew gravel and mud and cause the chain to fall off.

Replacing the front chainring with a narrow wide chainring will dramatically improve chain drop.

Component Compatibility

If you are going to partially replace your bike with a gravel component, you should pay attention to the compatibility of the parts.

In Shimano’s case, the gravel component is the GRX, but the compatible components for the GRX are determined by Shimano. It is not impossible to work with components outside of Shimano’s regulations, but considering the trouble of making minor adjustments, it is safer to match the official compatibility of the manufacturer.

Points to be checked if possible.

Equipment Enhancement

Unlike paved roads, where troubles are not that common or solutions to problems are affordable, the roads that gravel roads are designed to be ridden on are often in places where there are few stores and people.

In such places, you have to deal with punctures by yourself, and if you are riding on mountain roads, sudden weather changes are a daily occurrence in the mountains. Also, unlike in urban areas, if you get lost, you may end up wandering off in a crazy direction, so a smartphone navigation system is a must.

When riding in areas where gravel roads are active, it is a good idea to carry the following items.

1. Puncture repair kit (replacement tube, portable pump)
2. Rain gear
3. mobile battery and cable

It is a good idea to have a mobile battery/cable with you so that you can call an ambulance in case of emergency.

Increased load capacity

If you are going to do camping touring or long ride cycling on a gravel road, it will be more comfortable to store your luggage in the frame.

Road bikes have fewer “dowel holes” for storage than gravel roads, so you can use larger frame bags and saddle bags to increase the load capacity for a more comfortable ride.

When camping, luggage should be at least 50L, so if you are camping touring, augment your load capacity to about 50L by combining bags that can be attached to your bike.

1. handlebar bag
2. frame bag
3. saddle bag

If you are not camping touring, you can adjust the number of bags by reducing the number of bags.