Sonic SX 2024
How current the bike is — newer chassis, motor and battery score higher. 10 = brand-new, 0 = legacy.
The Bulls Sonic SX is the carbon hardtail in the Sonic family, built around the lightweight Bosch Performance Line SX motor (rated 55 Nm, with a free firmware upgrade to 60 Nm and 600 W offered from autumn 2025) and a slim, expandable 400 Wh battery. It sits below the full suspension Sonic EVO SX and Sonic EVO AM SX models, trading rear travel for low weight and a clean, simple ride. With 120 mm of fork travel front and rigid at the rear, it is pitched as a sporty light assist eMTB for cross country and all mountain tours rather than aggressive descending.
Two trims were offered. The SX 1 (4,999 euro) runs an SR Suntour Raidon 34 Air fork, Shimano Deore 12 speed cabled drivetrain, Shimano MT420 brakes and Shimano WH-MT620 wheels at a claimed 18.6 kg. The SX 2 (6,399 euro) is the clear step up: a RockShox SID fork, wireless SRAM GX Eagle AXS Transmission, TRP brakes and Mavic Crossmax XL S wheels drop the claimed weight to 17.7 kg. The extra outlay buys electronic shifting, a lighter fork and a more capable wheelset, which is where the value lies for riders who want the lightest, best equipped build.
Geometry is moderate and trail friendly rather than slack: a 67 degree head angle, 75 degree seat angle and 445 mm chainstays across all sizes, with reach growing from 420 mm (S) to 490 mm (XL). That makes it an easy handling, efficient climber suited to flowing terrain, consistent with its light assist positioning.
The Sonic SX is discontinued as a 2024 model. Bulls has since moved its lightweight Bosch SX range forward under the Sonic EVO naming, so the simple SX hardtail is best viewed as a one off lightweight option in that line.
Geometry · hover a row to highlight the measurement on the bike
| S | M | L | XL | |
|---|---|---|---|---|
| Reach | 420 mm | 450 mm | 470 mm | 490 mm |
| Stack | 629 mm | 638 mm | 657 mm | 666 mm |
| Seattube | 400 mm | 440 mm | 470 mm | 510 mm |
| Chainstay | 445 mm | 445 mm | 445 mm | 445 mm |
| Headtube Angle | 67° | 67° | 67° | 67° |
| Seattube Angle (eff) | 75° | 75° | 75° | 75° |
| Wheelbase | 1158 mm | 1192 mm | 1220 mm | 1244 mm |
| Headtube | 100 mm | 110 mm | 130 mm | 140 mm |
| Front Centre | 713 mm* | 747 mm* | 775 mm* | 799 mm* |
Trims · 2
SX 1 | SX 2 | |
|---|---|---|
| Motor | Bosch Performance Line SX · 60 Nm · all trims | |
| Battery | Bosch CompactTube 400 · 400 Wh · all trims | |
| Travel F/R | 120/? mm · all trims | |
| Frame | Carbon · all trims | |
| Fork | SR SUNTOUR Raidon 34 Air, 120 mm travel | RockShox SID, 120 mm travel |
| Headset | ACROS AIF-531 1.5" · all trims | |
| Stem | RUMBLE Altimate · all trims | |
| Handlebar | RUMBLE Altimate · all trims | |
| Grips | Bulls Proxim | Prologo Proxim Cush |
| Saddle | SELLE ROYAL SRX | Prologo Proxim 400 wide |
| Seatpost | LIMOTEC Alpha Series A1-UH ultra lite, 125 mm dropper · all trims | |
| Brakes | SHIMANO BR-MT420 hydraulic disc | TRP C2.3RX Trail / Slate caliper, hydraulic disc |
| Rear derailleur | SHIMANO Deore RD-M6100 | SRAM GX Eagle AXS Transmission |
| Crank | SAMOX EC40 | SRAM GX Eagle |
| Shifters | SHIMANO Deore SL-M6100, rapidfire+ | SRAM EC AXS Rocker |
| Cassette | SHIMANO Deore CS-M6100-12, 10-51T | SRAM GX Eagle T-Type, 10-52T |
| Chain | SHIMANO Deore CN-M6100-12 | SRAM Eagle GX |
| Drivetrain | SHIMANO Deore RD-M6100; SAMOX EC40; SHIMANO Deore SL-M6100, rapidfire+; SHIMANO Deore CS-M6100-12, 10-51T; SHIMANO Deore CN-M6100-12 | SRAM GX Eagle AXS Transmission; SRAM GX Eagle; SRAM EC AXS Rocker; SRAM GX Eagle T-Type, 10-52T; SRAM Eagle GX |
| Wheels | SHIMANO WH-MT620, tubeless ready | MAVIC Crossmax XL S |
| Tyres | SCHWALBE NOBBY NIC Perf, Folding, 29 x 2.40 · all trims | |
| Weight | 18.6 kg | 17.7 kg |
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Other eMTBs with the closest geometry to this one.
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