Road bike brake calipers, rim or disc

What is a brake caliper on a road bike?

The caliper is the part of the brake that clamps. On a rim brake, its two arms pinch the sidewall of the rim through the brake pads, actuated by the cable from the lever. On a disc brake, a body fixed to the frame or fork houses pistons that push the pads against the rotor. Replacing a caliper is justified after a crash, when an arm is bent, when a piston leaks or sticks, or to gain power and lose weight by moving up to a higher-end model.

Rim brake calipers: dual pivot, direct mount and reach

The vast majority of road bikes with rim brakes use a dual pivot caliper fixed with a central bolt: its two arms pivot on two separate axes, which gives more power than a single pivot. Two details matter for the central fixing: the recessed nut, housed in the frame or fork, is fitted to most modern bikes, while the nutted fixing, visible at the back of the fork, is found on older frames.

A direct mount caliper is fixed with two bolts to dedicated mounting points, on either side of the wheel. Stiffer, it also leaves room for wider tyres; at the rear, it is often mounted under the chainstays, near the bottom bracket. It can only be fitted to a frame designed for it.

Then there is the reach, the distance between the mounting bolt and the centre of the brake pad. Standard road calipers suit modern frames, and their maximum reach often appears in their reference, such as 51 mm on Shimano models. An older frame, a bike designed for mudguards or a smaller wheel needs a long-reach caliper, such as the Tektro R559.

Disc brake calipers: flat mount, hydraulic or cable

On road and gravel bikes, the disc brake caliper is fixed in flat mount, flat against the chainstay or the fork; post mount, an older standard, remains the norm on mountain bikes. A hydraulic caliper forms a closed circuit with its lever: it must use the same fluid, mineral oil at Shimano and Campagnolo, DOT fluid on Sram road groupsets, and be bled after fitting. Some manufacturers offer the same caliper for several brands of lever. A mechanical caliper, operated by a cable, is fitted with conventional levers and adjusted without bleeding; check that it is designed for a road lever, whose cable pull differs from that of an MTB lever. Road calipers generally have two pistons, compared with four on many MTB models.

How to adjust and maintain road bike brake calipers

A rim brake caliper is centred so that both pads touch the rim at the same time: a small centring screw or a slight rotation of the caliper on its bolt is enough. The cable barrel adjuster takes up pad wear, and the small quick-release lever opens the arms to remove the wheel: always close it before setting off again. On a disc caliper, rubbing is corrected by loosening the mounting bolts, squeezing the lever and then tightening the caliper again; pistons that no longer retract are cleaned and pushed back with a plastic tool, never with a screwdriver.

Brake pads, cables and levers: the related parts

A new rim brake caliper deserves road brake pads suited to your rims, aluminium or carbon, and brake cables and housing in good condition. Complete systems and rotors are presented with road disc brakes, and controls with road brake levers. For a bike made for tracks and trails, see gravel brake calipers.

Which brake caliper brands to choose?

Tektro, a braking system manufacturer focused on everyday durability, offers rim brake calipers here such as the R539 and R559, the latter with long arms, in nutted or recessed versions, and mechanical disc calipers such as the MD-C550.

Sram, an American group based in Chicago, supplies the flat mount calipers of its Red and Force eTap AXS hydraulic road groupsets, as well as rim brake calipers such as the S900 direct mount.

Shimano, headquartered in Sakai, near Osaka, covers every road range: dual pivot rim brake calipers in Sora, 105, Ultegra and Dura-Ace, front and rear direct mount versions such as the BR-R9110, and flat mount disc calipers such as the Dura-Ace BR-R9170.

Campagnolo, the Italian maker of groupsets for road, gravel and track, is present with its Super Record, Chorus and Centaur rim brake calipers, its direct mount calipers and its hydraulic disc calipers.

Formula, an Italian manufacturer of brakes and suspension, offers its Cura Road caliper in flat mount for Sram or Campagnolo hydraulic levers.

Miche, which designs and makes its components in its factory in San Vendemiano, near Treviso, offers a pair of direct mount calipers and the Performance caliper.

Brake calipers on sale and new arrivals

Calipers whose range is changing go to our road braking clearance, a good lead for upgrading a rim-brake bike; recent models are in new arrivals. The seasonal sales and Black Friday are good times too.

Frequently asked questions

How do you know if your bike has direct mount calipers?

Look at the fixing: a conventional caliper is held by a single central bolt through the fork or the frame's brake bridge, a direct mount caliper by two bolts placed on each side of the wheel. At the rear, a caliper located under the chainstays, near the bottom bracket, is almost always direct mount.

Can you switch from rim brake calipers to disc brakes?

Only if the frame and fork have mounts for a disc caliper. You then need wheels with disc hubs, rotors, calipers and suitable levers, hydraulic or cable. On a frame designed only for rim brakes, conversion is not possible.

Why does my brake not release after braking?

Most often, the cable is dragging in dirty or damaged housing: replace them. Also check that the central bolt is not overtightened and that the caliper spring is not bent. On a hydraulic disc brake, it is often dirty pistons that retract poorly: clean them.

Do you need to bleed a hydraulic brake after changing the caliper?

Yes: disconnecting the hose lets air into the circuit. Bleed it with the fluid specified by the manufacturer, never another, following its procedure, or leave the job to a workshop.

Do older rim brake calipers work with newer levers?

Usually yes, but the feel may change: manufacturers have changed the lever ratio over the generations, and a mix sometimes gives a less progressive brake. For consistent braking, pair calipers and levers from the same generation.