Sonic SX 2025

The Bulls Sonic SX is a lightweight Bosch SX powered carbon hardtail aimed at riders who want a natural pedalling feel and low weight rather than maximum power. With a 120 mm fork, no rear shock and a claimed 17.7 to 18.6 kg for the trail trims, it sits in the light assist trail category alongside the brand's full suspension Sonic AM-SX models. The 400 Wh Bosch CompactTube battery keeps the frame slim and can be extended with a range extender.

The 4,999 euro SX 1 leans on a Shimano Deore mechanical drivetrain, Shimano four piston brakes and a Shimano WH-MT620 wheelset. Stepping up to the 6,399 euro SX 2 buys a wireless SRAM GX Eagle AXS Transmission, a RockShox SID fork, TRP brakes and Mavic Crossmax XL S wheels, plus a roughly 0.9 kg weight saving. The 5,799 euro SX Dakar takes the same frame in a touring direction with a rack, kickstand, lights and Schwalbe G-One Allround tyres, which pushes it to a claimed 20.5 kg. The SX 1 low shares the SX 1 build on a step-through frame in S and M only.

Geometry is moderate and trail friendly rather than aggressive: a 67 degree head angle, 75 degree effective seat angle, consistent 445 mm chainstays and a 450 mm reach in size M. The four sizes run from a 1,158 mm to a 1,244 mm wheelbase. Buyers should note Bulls quotes the SX motor at 55 Nm as supplied, with a free Bosch software upgrade from autumn 2025 raising it to the full 60 Nm and 600 W.