D.2 ST-Ri – Lowerable parallelogram seatpost

The D.2 ST-Ri combines the advantages of the lowerable by,schulz D.1 Seat post, offering maximum riding comfort from the renowned G.2 Parallelogram suspension seat post with up to 30 mm of suspension travel with the ST variant (short travel).

The D.2 ST-Ri allows you to easily lower and raise the saddle position while riding and when stationary using a remote lever attached to the handlebars. This allows you to find your perfect driving position. The saddle is lowered or raised by operating the remote lever.

To lower the saddle height while riding or when stopping, e.g., at a traffic light, keep your weight on the saddle and press the remote lever mounted on the handlebars.

To activate the seat post extension, relieve pressure on the saddle by lifting your body and press the remote lever. The seat post now extends to its maximum height or stops and remains in its current position when you release the lever.

The speed of this function can be controlled by the intensity of the pressure on the remote lever. Low pressure causes slow extension, while high pressure causes extension at maximum speed.

The parallelogram suspension of the D.2 ST-Ri has a progressive design and reacts sensitively to light impacts and with increasing spring resistance to hard impacts. The parallelogram suspension of the D.2 ST-Ri taucht unter Belastung bis zu 18 mm nach hinten, und ca. 22 mm nach unten ab. Zur optimalen Anpassung an das Fahrergewicht und die Fahrweise, stehen leicht austauschbare Federelemente mit 4 verschiedenen Härtegraden und Dämpfungen zur Auswahl.

Inside the lowerable D.1 / D.2 A high-quality gas pressure spring is installed in the seat posts. This allows you to adjust the saddle height using a remote lever mounted on the handlebars! When the remote lever is actuated, the valve on the gas pressure spring is opened via an internal cable. As a result, the saddle lowers under the weight of the body, or extends further when the weight is removed. Wird der Hebel losgelassen, schließt das Ventil und der Sattel verbleibt in der aktuellen Höhe.

Note: Plan the installation and cable routing carefully. Ensure that the inner cable and the outer sheath are long enough for the planned routing through the frame! Remove any burrs from the seat tube of the bike. All parts must be clean during installation! Before installation, check that the diameter of the support matches the diameter of the seat tube!

1. The by,schulz D.2 The ST-Ri seat post allows the cables to be routed inside the frame. Not all bicycle frames/e-bike frames are suitable for laying internal cable runs. Für die Verlegung ist eine bereits vorhandene Öffnung für die Zugverlegung am Rahmen notwendig. The cable routing must not be kinked or crushed along its entire length! With e-bikes, it must also be possible to route the cables along the battery and motor.

2. Before installation, ensure that there is sufficient space in the bicycle frame for installing the D.2. ST-Ri seat post is available, and the seat post does not collide with other parts of the bicycle, or bends in the frame geometry, the battery, or the motor when installed!

Note: Due to the parallelogram mechanism of the suspension, the D.2 ST-Ri has a greater overall height than conventional dropper posts. Check these requirements by measuring your bike as accurately as possible in advance.

With the seat post fully lowered (measurement A), you should still be able to stand securely with your front foot on the ground (regardless of the installation depth of the seat post)!

Is the D.2 If the ST-Ri is fully inserted into the seat tube of the bicycle and this is not the case, we advise against using the support in combination with this bicycle frame.

Dimension A – Min. Installation height: approx. 135 mm
Dimension B – Installation height when extended: approx. 215 mm
Dimension C – Required installation depth: approx. 230 mm (plus cable)
Dimension D – Total length when extended: approx. 445 mm

Please also note that the individual height of your saddle must be added for the correct seating position.

Dimensions A, C, and D refer to the center of the saddle clamp. Please note that, depending on the frame for bending the cable routing, approx. 50 mm of additional installation space is required below the D.2. ST-Ri is required!

3. The diameter of the seat tube of your bicycle/e-bike should match that of the seat post. Any reduction sleeves that may be required must have a minimum length of 100 mm and must always be inserted completely into the frame.

If the frame manufacturer provides different specifications regarding the sleeve length, these must be observed. The higher value is then decisive!

You can find the by,schulz G.Shim reduction sleeves here

4. Check whether the minimum insertion depth of the seat post of 100 mm can be maintained!

This is marked on the rear of the seat post tube (STOP min. insert) below the extension scale. The production serial number is located above the scale.

5. If the frame manufacturer specifies different minimum insertion depths, these must be observed. The higher value is decisive. Failure to observe the minimum insertion depth may result in falls or damage to the seat post and/or frame.

6. The clamping force of the seat post clamp should be 5–6 Nm when securing the seat post in the frame. Exceeding the clamping force values can lead to malfunctions such as reduced immersion or extension speed and damage to components of the D.2. ST-Ri.

7. In the case of D.2 ST-Ri comes standard with a saddle clamp for saddle frames with a diameter of 7 mm. Saddle clamps for 8 mm diameters are available if required. Never combine 7 mm clamps with an 8 mm diameter saddle frame, or vice versa.

Note: Saddles with oval saddle frames must not be used in combination with this support!

8. Check that the width of the saddle frame is compatible with the head of the seat post. It must not be less than 36 mm on the inside. There are some saddles (e.g., core leather saddles) that converge too narrowly at the front of the frame and therefore cannot be combined with this support. Such use is not recommended as it can cause permanent damage to the saddle and support.