Brakes
Used road bike brakes have split into two worlds: rim brakes and disc brakes. Hydraulic flat-mount discs are standard on new bikes and stop consistently in all conditions, while rim brakes remain on millions of existing bikes and are lighter, simpler and cheaper to maintain. Your frame determines which type you can run — there's no converting between the two.
Disc or rim brakes?
Hydraulic disc brakes provide consistent modulation in rain, heat and on sustained descents — they don't fade and they don't care about wet rims. Flat mount is the road disc standard, replacing the older post mount, so check which disc mount your frame and fork use before you shop. Rim brakes are lighter, saving 200-300g per bike, more aerodynamic and mechanically simpler. For racing where every gram matters, or on bikes where simplicity is valued, rim brakes are still a valid choice; for UK riding with frequent rain and long descents, disc brakes are the pragmatic choice.
Hydraulic or mechanical disc?
Hydraulic disc brakes use fluid pressure for even pad engagement and excellent modulation, and Shimano, SRAM and Campagnolo all offer hydraulic road discs integrated into STI levers. Mechanical disc brakes (TRP Spyre, Juin Tech R1) use cables and are compatible with any STI lever, which makes them useful for upgrading older bikes. Cable-actuated hydraulic hybrids such as the TRP HY/RD and Yokozuna Motoko offer better modulation than pure mechanical at lower cost than full hydraulic. For the best braking, full hydraulic is worth the investment — budget for the cables or hosing to suit whichever route you take.
Which brands should I look for?
Shimano, SRAM and Campagnolo make both types across their groupset ranges, so most used listings come from one of the three. Third-party options from TRP, Hope and Swiss Stop fill specific niches, and modern rim brake pads such as Swiss Stop FlashPro have dramatically improved wet-weather performance — worth knowing if you are keeping a rim brake bike going rather than replacing it.
What should I check buying used?
On hydraulics, check for a firm lever feel — spongy means air in the system and a bleed is needed — and inspect hose connections for leaks. Check piston movement is even, as uneven pad wear indicates a sticky piston. On rim brakes, check pad thickness, verify the calliper arms spring back evenly, and inspect the pivot bolt for play.
Which parts are cheap to replace?
Brake pads are cheap consumables, so don't reject a used brake set just because the pads are worn. Rotors are the exception to watch: check them for minimum thickness, which is stamped on the rotor, and for warping, which shows up as disc rub when you spin the wheel.