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Engineered & Designed by Rocker Parts
An Ahead stem clamps the protruding steerer tube from the outside. Requirement: no external thread on the steerer tube.
Will your stem fit my bike? (handlebar & steerer dimensions)
Our stems fit 1⅛" (28.6 mm) steerer tubes. Handlebar clamp sizes: 31.8 mm or 35 mm. Please check both diameters.
Not compatible: fully integrated cable routing through the stem/head tube – please be sure to check our ICR cable routing.
Is the stem approved for e-bikes?
Yes, for pedelecs up to 25 km/h within the intended area of use. Not approved for S-pedelecs (45 km/h).
When pivoting sideways, FlatFit™ keeps the handlebar flat. This allows the bike to fit, for example, into a camper van rear garage – tool-free.
Due to the angled fork, the handlebar rises when pivoted. Our geometry automatically compensates for this by 10° – depending on handlebar width, this reduces the height increase by up to approx. 7 cm – achieved with the patent-pending FlatFit™ technology.
To ensure your stem is secure, the quick-release lever must be set with the correct preload.
We recommend the two-finger rule: the lever should just be possible to open with two fingers.
With only one finger it must not be possible → preload too low.
With more force than two fingers → preload set too high.
This ensures your stem clamps reliably while remaining tool-free and comfortable to operate.
LiftFix secures the height easily and tool-free. The locking mechanism prevents unintentional adjustment of the height setting.
All stems are prepared to easily retrofit accessory mounts (adapters to follow).
Some manufacturers say “rotating,” we call it pivoting – technically it’s the same principle: the handlebar is moved sideways to save space.
What can I do if there are noises (creaking or cracking) from the stem?
Under unfavorable conditions, noises may occur at the joint components. In this case, a light spray of chain lubricant (bicycle/motorcycle) into the pivot joint helps restore quiet, smooth movement. Apply sparingly and avoid brake surfaces.
6061: proven, robust lightweight alloy.
7075: high-strength aerospace-grade alloy for maximum stiffness at low weight. We use each material according to component requirements.
Our assembly paste increases friction between stem and steerer tube as well as between stem and handlebar. This ensures everything sits securely and stably without unwanted twisting. At the same time, it protects surfaces and makes later disassembly easier.
We manufacture on modern 5-axis CNC machines for precise fits.
Edgeless means: no sharp edges at the handlebar clamp, but chamfers/radii – reducing stress concentration and protecting the handlebar.
SLS uses a safety latch in the quick-release lever and a dual fixation of the steerer clamp. This prevents unintentional opening and increases operational safety.
Approved: road, gravel roads, forest paths, light off-road.
Not recommended:
– Jumps > 50 cm
– Downhill, bike parks, trick riding, demanding singletracks
– Large handlebar bags > 2 kg / heavy front racks.
We exclude installation on carbon steerers because carbon is more sensitive to localized clamping loads. Our stems may generate higher or point loads that could damage the carbon steerer (e.g., due to height adjustment or extension length). For safety reasons, we recommend aluminum steerers only.
There is no legal CE requirement for bicycle components and no TÜV testing as in the automotive sector. Our products undergo strict quality checks and are suitable for the stated area of use. We align with ISO 4210.
Account holder in lowercase and one word, e.g. maxmustermann.
We review and label reviews transparently (e.g., order reference/verification). Details can be found in our review information.
We reduce plastic as much as possible; where necessary, we use recycled materials.
An Ahead stem encloses and clamps the protruding steerer tube from the outside. The steerer tube must not have an external thread.
A proven, high-strength aluminum alloy, primarily used in vehicle construction.
A very high-strength aluminum alloy, used especially in vehicle construction as well as in aerospace. Ideal for highly stressed components.
Distance from the center of the steerer tube to the center of the handlebar clamp.
The backward angle of the handlebar grips relative to the handlebar center axis. It influences handling, for example by promoting a relaxed elbow and hand position. Optimal range: 5° to 8°.
Information on the authenticity and verification of our customer reviews.
CNC machines (Computerized Numerical Control) manufacture components with the highest precision. Our parts are produced on modern 5-axis machines.
An e-bike is powered exclusively by an electric motor (without pedal assistance). Helmet and insurance are mandatory.
Universal accessory interface on all RocStem stems for lights, bike computers, navigation devices, and action cameras. Retrofit-ready on all models.
“Edgeless” means there are no sharp edges at the handlebar clamp, but rounded transitions. This reduces stress concentrations and protects the handlebar.
Our patent-pending FlatFit™ technology ensures that the handlebar remains flat when pivoted. This allows the bike to fit better into low spaces – without modification or tools.
Height adjustment refers to the one-time, tool-based setting of handlebar height during installation.
It is not a quick adjustment for daily use – only the pivoting function of the handlebar is tool-free.
With this design, brake and shift cables run directly through the headset into the frame. This creates a clean look but can restrict handlebar movement with pivoting stems.
Rocker Parts’ ICR cable routing guides the cables kink-free past the pivot area, allowing the handlebar to remain fully movable.
We avoid plastic in our packaging whenever possible. Where necessary, we use recycled materials.
Common handlebar diameters in the stem clamping area are 25.4 mm (1"), 31.8 mm (1⅛"), and increasingly 35 mm. The grip area is usually 22.2 mm.
The LiftFix system prevents unintentional adjustment of the height setting.
The steering angle of a bicycle causes the handlebar to rise when pivoted. Our special geometry (FlatFit™ technology) compensates for this by 10°, reducing the height increase by up to 7 cm depending on handlebar width.
For SEPA direct debit: enter the account holder in lowercase and as one word (e.g. maxmustermann).
Designation for our stems featuring the patent-pending FlatFit™ technology.
Special grease with microparticles used on stems and handlebars. It increases slip resistance, protects surfaces, and makes disassembly easier.
An electrically assisted bicycle. Propulsion is provided by a combination of human power and motor. Maximum assisted speed: 25 km/h.
There is no legal CE requirement or TÜV approval for bicycle stems as in the automotive sector. However, our stems undergo strict quality testing and are developed in accordance with ISO 4210.
Rise describes the vertical offset of the handlebar. It allows the cockpit height to be adjusted. A higher cockpit results in a more relaxed riding position.
A quill stem is inserted into the steerer tube and clamped from the inside. The minimum insertion depth must be observed.
Safety mechanism of our pivoting stems. An additional locking latch prevents unintentional opening, and the dual steerer clamp increases stability.
A pedelec with motor assistance up to 45 km/h. Requires an AM-class license as well as insurance and a helmet.
Stem
A stem connects the handlebar to the steerer tube and determines reach and cockpit position.
The upward angle of the handlebar grips. An optimal range of 3° to 8° promotes an ergonomic wrist position.
…wir bei Rocker Parts sprechen dich direkt an – klar, unkompliziert und ohne Schnickschnack. Uns geht’s nicht darum, Wörter zu verbiegen oder in Watte zu packen, sondern ehrlich miteinander zu reden.
Dabei steht für uns eines ganz oben: Respekt. Jeder ist willkommen – egal ob Frau oder Mann, jung oder alt, unabhängig von Herkunft, Religion oder sexueller Orientierung. Wir glauben an echtes Miteinander, nicht an Schubladen.
Und weil wir unsere Energie lieber in gute Produkte stecken als in Sprachdebatten, verzichten wir bewusst auf kompliziertes Gendern. Denn am Ende zählt nicht die perfekte Formulierung, sondern das, was wir tun: Qualität liefern, offen sein und fair bleiben.
