Mallorca's climbs and coastal roads concentrate strangers into peletons of 40+ at peak season. The unwritten rules: ride two-up max, point out hazards, brake early before hairpins, and shout instead of swearing.
Article 36 of the Reglamento General de Circulación allows cyclists to ride two-abreast on most roads — but you must drop to single file on bends with limited visibility, descending fast roads, and any time the road is narrow enough that you would block a vehicle from passing safely. Mallorca's mountain roads are mostly the "drop to single file" category. See [[cycling-law-group-riding]] for the full text.
Most casual groups break up on the first 5% gradient — that's healthy. Stronger riders should not surge at the front: it shells the group and leaves slower riders riding alone in traffic. Agree a regroup point (the next saddle, the next café) before you start the climb. On Sa Calobra and Sa Batalla, the single-lane sections force single-file regardless — never half-wheel a descending rider here.
The Tramuntana descents are technical: tight hairpins, broken tarmac, and tour buses cutting the corners. Brake before the corner, not in it. Look 30 metres ahead through the apex. Stay on your line — do not surprise the rider behind. If a bus is coming up, hold your hand out flat to signal "slow" to your group and pull as far right as the verge allows.
Point with a flat hand at any pothole, gravel patch, or glass. Tap the small of your back when you are about to slow or stop. Wave your right hand behind your hip to signal "car back" along the line. None of this is in the law, but every Mallorcan cycling club uses it — fall in with the convention. See [[cycling-law-hand-signals]] for the legally required signals (turning, stopping).