Groupset choice is what most cyclists agonise over, but the performance difference between tiers is smaller than the marketing suggests. Shimano's hierarchy runs Claris, Tiagra, 105, Ultegra, Dura-Ace. SRAM runs Apex, Rival, Force, Red. Campagnolo run Centaur, Chorus, Record, Super Record. The big divide is mechanical versus electronic shifting — Shimano Di2 and SRAM AXS use motors and batteries for precise, consistent shifts regardless of cable stretch or hand fatigue. The honest truth: a well-maintained 105 mechanical groupset shifts beautifully and weighs maybe 300g more than Dura-Ace. Spend the difference on better wheels or a bike fit instead.