Road and gravel rim brakes

Although the market is massively switching to disc brakes, rim brakes still have their irreplaceable place in this segment. While road bikes use calipers for aerodynamics and stopping power, gravel and cyclocross have had to use cantilever or V-brakes due to the need for space for wider tires.

Road rim brakes - caliper brakes

This is the most classic type of brake, which has dominated the Tour de France for over half a century. They are compact, lightweight, and aerodynamic.

Single Pivot brakes

Usage: Standard on old bikes (Favorit, old Campagnolo).
Design: The brake arms pivot around a single common centre bolt that attaches the brake to the frame. When the brake cable pulls one arm toward the rim, the mechanical connection at this single pivot point causes the other arm to react by pulling on the opposite side, clamping the rim and braking.
Advantages: Low price, light weight, simplicity and higher tolerance for wheel throw.
Disadvantages: They are difficult to centre and have a weaker braking effect because the lever is not optimal. Today you will only find them on the cheapest bikes.

Dual pivot brakes

Usage: Today's standard for quality road bikes with rim brakes.
Design: In addition to the centre bolt, there is a second pin that changes the leverage ratio. This means that the same finger force will exert much more pressure on the rim.
Advantages: Excellent braking power, easy centreing (often just a hand turn) and great modulation.
Disadvantages: Higher price and weight, limited wheel clearance and susceptibility to wheel spin, more complex design

Gravel and cyclocross rim brakes

Gravel as a category was born in the era of disc brakes. Before that, however, off-road riding was done with rim brakes, which could not use road “shoes” (they did not fit the tire and mud). Therefore, they used the following solutions:

Cantilever brakes

Use: They are used in cyclocross (CX), older/cheap MTB and gravel bikes.
Construction: Two separate arms. A cable pulls them from above through a central bridge.
Advantages: Huge clearance. There is a lot of space between the jaws, so a wide tire (35-40 mm) can fit there, and even mud deposits won't block the wheel.
Disadvantages: Complex adjustment (so-called “triangle of death” - cable geometry), weaker braking effect compared to V-brakes, and frequent squeaking or vibration of the fork.

V-Brakes (Classic Linear Pull)

Use: They are used in trekking and city bicycles, in older and recreational MTBs, and children's bicycles.
Construction: They have long arms, which gives them enormous leverage. The cable runs horizontally from one arm to the other through a rigid metal tube called a “noodle”.
Advantages: High braking power, wheel clearance and sufficient space for tires, low price
Disadvantages: Sensitivity of adjustment and more complicated wheel removal

What is the widest tire I can fit in road caliper brakes?

It depends on the design and type of brake:

Older brakes (around 2010): The limit is usually 23 mm or 25 mm.
Modern Dual Pivot (Shimano 105/Ultegra R7000/R8000): Can handle 28 mm without any problems.
Direct Mount Brakes: Often accommodate up to 30 mm or 32 mm (if the frame allows).

Always check that the tire is not rubbing against the bottom of the brake caliper.

Is it safe to use rim brakes with carbon wheels?

Yes, but:

You need to use special brake pads for carbon (typically yellow or cork). Regular pads will ruin the carbon.
Beware of heat: On long descents (Alps/Tatra Mountains) you have to brake intermittently (“pump”) to cool the rim. If it overheats, it can delaminate (deform) or the tube can burst.
Rain: Braking on wet carbon is significantly weaker and the onset of braking force has a delay (until the water is wiped off).