Wear on road bikes: Tyres, chain, cranks, brakes, sprockets - how to recognise and repair wear on a road bike

Degree of difficulty: for everyone

Auxiliary materials
- Small screwdriver
- Caliper and angle gauge
- Rim eraser
- Chain gauge, e.g. Rohloff Caliber 2
- Sprocket gauge if necessary, e.g. Rohloff HG-Checker

TIPS

Test drive
A new chain can slip over individual, particularly frequently ridden, usually small sprockets. Take a careful test ride after changing the chain!

Pressure
The best protection for your tyres is the right tyre pressure. The maximum value indicated on the tyre sidewall is only relevant for heavy riders. Lighter riders give away a lot of comfort. For 23 millimetre wide tyres, the Rule of thumb: Rider weight plus wheel weight, divided by ten, minus one = adjusted tyre pressure in bar.

Noises
Scratchy brakes indicate that tiny particles have dug into the brake pads and are rubbing on the rims. On the road, short stutter braking may help to get rid of the foreign particles from the pads. After the journey, you should thoroughly clean the particles out of the pads. If this happens more often, other brake pads may help.

THE TYRES

To assess the condition of the tread, more and more manufacturers are integrating wear indicators, or TWI for short (tread wear indicator). If the rubber is so badly worn that these ribs or indentations are levelled, the tyre should be replaced.

Inspect the tyres from time to time for foreign objects and cuts in the tread. Use a small screwdriver, for example, to remove foreign objects. Check whether only the rubber tread is cut or whether layers of fabric have been severed.

The same applies to the sidewalls of the tyre. Here too, cuts in the fabric or tears mean that the tyre is no longer safe. The pressure can push the inner tube outwards through the weakened fabric until it bursts - which is associated with the greatest risk of falling.

THE BRAKE PADS

Driving in the rain is particularly hard on brake pads. Check their condition using the recesses or existing wear marks, e.g. "wear limit". If the pads are completely levelled or worn down to the line, they must be replaced.

If you wait too long to change the brake pads, you risk the threading aids of the brake pad carriers rubbing against the rim. In the best case scenario, only the decor will be scratched, but more serious damage can occur on carbon rims.

You cannot prevent normal wear of the pads, but you can prevent excessive wear - namely through maintenance. You should therefore regularly remove foreign objects and aluminium splinters from brake pads and rim flanks.

THE ROCKS

Check the rims regularly after the second set of brake pads at the latest. Place a square on the rim flank. If this has already been ground round, you need to check this more closely. To do this, remove the tyre and inner tube and take the opportunity to check whether the rim tape is exactly centred in the rim base; it must not be cracked or brittle.

Measure the thickness of the rim flank at several points around the circumference - in the area where the brake pads make contact. You can, for example, convert a caliper gauge with two small, temporarily glued-on balls. It is easier with a special measuring device. If the rim wall is only 1.0 mm thick or thinner, you should replace the rim for safety reasons.

Clean aluminium rim flanks regularly with acetone. This dissolves the rubber abrasion from the brake pads. Even better is occasional treatment with a special rim cleaning rubber. You should carefully remove stubborn build-up with sandpaper.

THE DRIVE

You should measure the road bike chain regularly from a mileage of 2,000 kilometres. The classic measuring gauge is the Rohloff Caliber 2 (see arrow). Measure at several points, it is important that there is tension on the chain - only then will the true wear become apparent and the gauge may slide into the chain links. If it does, it's time for a new chain.

The teeth of the chainrings become increasingly pointed over time and resemble shark teeth. The wear test: Place a few new chain links on the used chainring; if they do not slide into the tooth base, the wear is advanced and a new chain will no longer run cleanly.

Sprocket wear is difficult to assess visually. A technical aid is the HG-Checker from Rohloff: Place its chain on a sprocket, except for the last link. Turn the wheel backwards until the rubberised bracket touches the rear triangle. Hold the rear wheel under tension and turn the last link into the sprocket. If this works easily and at the first attempt, the sprocket is OK.

Further workshop tips can be found in the standard work "The road bike workshop" retail price 14,90 Euro

TOUR author Dirk Zedler is the owner of the Zedler Institute for bicycle technology and safety GmbH. Zedler - Institut für Fahrradtechnik und -Sicherheit GmbH specialises in testing bicycles and components in its own test laboratory. The company also develops and builds test systems and equips test laboratories for bicycle manufacturers.

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