Bulls Sonic AM SX: suspension setup & specs

Manufacturer data retrieved on 26 September 2026 · 3 builds · RRP €5,999 – €9,999 · Bike type: Full-suspension e-MTB

The Bulls Sonic AM SX is an e-MTB for trail and touring with 140 mm of fork travel and 130 mm at the rear. It is powered by Bosch Performance Line SX (Smart System) 25/55 Nm. Below you will find all 3 current builds with fork, shock and shock size, plus SAG values in millimetres and a tyre pressure table.

Calculate the setup for your Bulls Sonic AM SX →

All builds

Fork, shock, shock size (eye-to-eye length × stroke) and rear travel, motor, weight and price according to the manufacturer. Wheel size: 29.

How it compares

At 140 mm, fork travel is 10 mm shorter than the median of the “e-MTB for trail and touring” category (150 mm, 101 bikes). The rear offers 130 mm, 10 mm less than the front. On travel, it slots in between the Bulls Sonic SX and the Bulls Sonic AM in the Bulls range. The frame is made of carbon.

The lightest build, I, weighs 18.9 kg according to Bulls – about 4.5 kg less than the category median (23.4 kg across 49 bikes with a stated weight). Within the range, weight varies by 1.0 kg. The starting price of €5,999 (1) is roughly in line with the category median (€5,500). For the I build, Bulls asks €9,999. For suspension, Bulls combines components from RockShox and SR Suntour. The fork line-up ranges from the BULLS Lytro 34 SL to the RockShox Pike Ultimate. It is powered by Bosch Performance Line SX (Smart System) 25/55 Nm. Bulls specifies a maximum system weight of 130 kg. Subtracting roughly 20 kg for the bike leaves about 110 kg for rider, clothing, backpack and luggage.

Setup notes for this spec

• Air fork (RockShox Pike): the air valve is on top of the left leg under a cap. Change pressure in small steps (about 5 psi (0.34 bar)) and cycle the fork a few times afterwards so the air chambers can equalise.
• Rebound: on RockShox suspension the rebound adjuster is red. Always count clicks from fully closed (clockwise to the stop) so you can return to any setting.
• Shock (SR Suntour Edge Plus 2CR): get on the bike in your normal riding position, step off carefully and read the O-ring. Always cycle the shock a few times after pumping.
• e-MTB: because of the extra weight, start with slightly more tyre pressure – the surcharge is already built into the table below.

Target SAG for the Bulls Sonic AM SX

SAG is the share of travel your weight already uses in the riding position. The table gives it straight in millimetres – read the O-ring on the stanchion and on the shock shaft and adjust the air pressure until it matches. Any figures from Bulls take priority.

140 mm fork (all builds)

How to measure SAG is explained in our guide SAG setup.

Tyre pressure starting values

Basis: 2.40″ tyre width, tubeless, trail casing, including the e-MTB surcharge. If you run tubes, add about 0.2 bar (2.9 psi); with an insert, about 0.1 bar (1.5 psi) less is enough. Stock tyres: SCHWALBE NOBBY NIC EVO, Folding; SCHWALBE NOBBY NIC Perf, Folding.

Air pressure in the fork and shock

The sticker on the fork (or on the shock) and the manufacturers’ setup charts give you a first pressure. Our calculator is more precise and suggests rebound too – always check the result via SAG.

Sources

• Sonic AM SX 1
• Sonic AM SX 2
• Sonic AM SX I

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