Table of Contents

Geiles Teil 4.0

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Manual Geiles Teil 4.0 stem

Thank you for purchasing tune products! Our products are designed and manufactured to the highest standards. This manual informs you about the proper handling and care of our products.


Our components are high-end parts and must always be assembled and used in accordance with the user manual. Please read this manual carefully and follow the instructions. If you are not confident with the assembly, please contact your dealer.

In case of problems with the function of the product, it must not be used. In this case, contact your dealer immediately!


The assembly instructions must be followed! Failure to follow the instructions can lead to defects and injuries! If the necessary tools for correct installation are not available, the installation must be carried out by a specialist workshop using the appropriate tools!
Technical data for the product can be found on our website in the product description and for download in the service area.
Assembly preparation

Before you can start with the assembly, the compatibility of the steerer tube and handlebar must be checked:

  1. Use a digital caliper to measure the outside dimensions of your head tube all around. The stem is designed for 1 ⅛ inch (28.6mm) head tubes. If your head tube has a different dimension, the stem cannot be used!
  2. Use a digital caliper to measure the outside dimensions of your handlebar all around. The stem is designed for 31,8mm handlebars. If your handlebar has a different dimension, the stem cannot be used!
Mounting the stem
The manufacturer's instructions for the fork and handlebar must be observed when assembling the stem!
The Geiles Teil 4.0 stem is suitable for inverted (flip-flop) mounting.
If the stem is clamps a carbon head tube or carbon handlebar, a carbon assembly paste should be applied to the clamping surfaces. The paste increases the friction and thus allows a lower torque which prolongs the lifetime of carbon components.

After completing the assembly preparations with a positive result, follow these steps to mount the stem:

  1. Loosen or remove the screws of the handlebar clamp in order to be able to insert the handlebar later.
  2. Slightly loosen the screws of the steerer clamp in order to open it all the way.
  3. Place the stem on the head tube and align it. Before the stem is tightened, the headset must be adjusted. You can find information regarding the headset adjustment in the instructions for your headset or frame.
  4. Insert the handlebar into the stem, align it and slightly tighten the clamping screws on the stem plate.
  5. Tighten the screws of the handlebar clamp alternately crosswise as shown in the illustration. Pay attention to the maximum tightening torque! The gaps on the top and bottom of the handlebar clamp must be equal!
    GT 4.0 Montagehinweis
  6. After adjusting the headset, tighten the steerer clamp screws. Pay attention to the maximum tightening torque!
Tightening torques
All screws and connectors must always be mounted with a calibrated torque wrench in compliance with the maximum torques! Non-compliance with the torque specifications can lead to defects and injuries!



Screws steerer clamping

Max. 5Nm

Screws handlebar clamping

Max. 5Nm

Intended use

Our products are designed and tested according to the current standards, which define the safety requirements and test methods for mountain bikes off-road and racing bikes for amateur use on public roads. In both cases, the standards for bikes with adjustable saddle height with a minimum saddle height of 635mm apply.

The standards mentioned do not apply to special types of bicycles such as tandems or bicycles which are used for special applications such as tough competition, stunts or acrobatics.

The standards also do not apply to bicycles with a saddle height ≤ 435mm and a saddle height between 435mm and 635mm.

Please note that our products may only be used in the amateur sector under normal conditions.

Storage & transport

When storing or transporting tune components for a longer period of time, follow these guidelines:

  • Components must be stored and transported at a temperature of 15-30°C and max. 70% relative humidity.
  • Components must not be exposed to direct or indirect sunlight. Ideally, storage and transport take place in a dark place or covered.
  • Avoid large temperature fluctuations, e.g. in a car parked in the sun. Torques must be checked again after storage or transport with large temperature differences to ensure proper function.
  • Components must be cleaned and checked for proper function before storage. Before the next operation, a new check for functionality must be carried out.
  • Wheels should be stored and transported with the tyres fitted. The mounted tyre reduces the spoke tension and thus the load on the hub flange.
  • Do not hang up carbon rims or entire bicycles, as the point load can cause permanent damage to the rim.
  • Do not hang up stored bicycles by the saddle to reduce the load on the saddle and seat post.

Maintenance & care

Depending on the conditions of use and the frequency of use, your tune components must be cared for and maintained in order to preserve their function and appearance for a long time.

You can find out more about how to care for your components here:

Here you will find information on the mandatory maintenance intervals:

Warranty & Crash Replacement

We offer a voluntary warranty on our products to protect against material or workmanship defects. For self-inflicted defects, we offer a Crash Replacement program to get you back on your bike as quickly as possible.

Here you can find out everything about our warranty:

Here you can find information about the Crash Replacement program:

Disposal & recycling

After a defect or after the service life has been exceeded, waste must be disposed of properly. Waste is a valuable raw material and correct disposal protects the environment.

Here you can find out more about the disposal of various materials:

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