Geiles Teil 4.0

The most memorably named Tune item

from 94 gramm

Geiles Teil 4.0

"Geiles Teil" literally means "Horny Piece"

So naturally, it’s super-stiff and available in many lengths…

But it’s also as reliable as it is beautiful, and as firm as it is elegant.

A bonafide superstar amongst the aluminium stems of the world, it’s currently in it’s fourth iteration, benefitting from next generation youth, and all the lessons learned from our experience of previous versions.

Each one is artfully milled by our new CNC machine (with a milling time of 25 minutes per unit) from a single piece of the highest quality aluminium.

The conical shape, both inside and out, corresponds exactly to the variations in force running through the stem, making it as light as is possible, and as strong as is necessary.

Continual evolution and optimisation has turned the original ‘very good’ stem, into an almost perfect product, proved by the VR-3 Max stress test (the toughest in the world).

At just 112g, and 85mm in length, our titanium screw equipped version offers the best combination of stiffness, weight and safety.

The precise and balanced clamping of carbon fibre bars and fork shafts means that both are held firmly and evenly, but adjustment is also precise and easy.

The geometry is ideal for 29er and 650B mountain bikes.

So perfect in fact, that mountain bike World Championships – and Olympic Games were won with our „Geiles Teil 4.0“!



The flip-flop mounting of the 8-degree version on the road bike results in an angle of approx. 0 degrees to the ground.

Geiles Teil 4.0Geiles Teil 4.0







Geiles Teil 4.0 – Black Forest shorty: Download

Wallpaper: Geiles Teil 4.0. How short is not too long?: Download

The 50 mm “short” stem has a Special design, unique to its small size.

The 50 mm “short” stem has a Special design, unique to its small size.   Tune-Geiles Teil 4-2__04_02_Lenker__04_02_Vorbau Available in numerous lengths, anodised in the most beautiful TUNE colours, and laser-etched.


Länge (mitte-mitte) OV (31,8 mm)
50 mm 94 g
60 mm 96 g
75 mm 108 g
85 mm 112 g
95 mm 117 g
110 mm 126 g
120 mm 131 g


Specs Geiles Teil 4.0

Material aluminium 7075, Titan TiAI6V4 (Schrauben)
Finish CNC machined, anodized, laser marked
Handlebar clamping 31,8 mm (Oversize)
Hight 40 mm
Head tube diameter Ø 1 1/8 Inch
Length 8° (middle-middle) 50/ 60/ 75/ 85/ 95/ 110/ 120 mm
Road 100
Marathon 100
AllMountain 100
Enduro 70
Downhill 50
Geiles Teil 4.0

Tune Vorbau Geiles Teil 4.0 – In the most beautiful colors anodized and laser-inscribed. The conical shape, inside and outside, exactly corresponds to the flow of the flow.

Download Geiles Teil 4.0