SON = Schmidts Original Nabendynamomehr Licht


SL Self-Connecting System


The electrical connection to a hub dynamo meets many requirements. It should be convenient to use, easy to fit to the cable, robust and reliable. Moreover, it should be inconspicuous yet elegant. Whereas competitive products meet the first two criteria, the blade terminals used on standard SON are far more robust but not that easy to handle.

Without doubt the most elegant way is to avoid the connectors altogether by using the areas where hub and fork touch, i.e. the contact face. The mating process is done automatically by installing the wheel, the contact pressure of the skewer protects the contacts from corrosion.

In 2009, Schmidt Maschinenbau introduced a self-connecting system where the phase contact occurs in an insulated contact plate placed on the right drop-out and the ground contact lies on the bare left drop-out (aluminium or stainless steel). The phase cable usually runs inside the fork blade to the fork crown, where it meets up with the ground cable.

SONdelux SL
SONdelux SL
SL-Contact on an Aluminum Fork
SL-Contact on an Aluminum Fork

This system is called SL (German "steckerlos" i.e. without connectors).

The benefits are evident:
- most convenient for mounting and dismounting wheels
- elegant due to invisible cables and connectors
- maximum reliability of operation

The only drawback: The fork must be specially built for SL. We decided to do without retrofitting in favour of maximum robustness. However, a standard front-wheel hub may be fitted into an SL-fork.

We offer all SON 28 and SONdelux dynamo models as SL versions together with contact parts and a small selection of drop-outs.

Meanwhile numerous renowned frame builders and bike manufacturers build self-contacting bikes. Some of them also provide individual forks.

SL Suppliers

in Germany:
idworx (
tout terrain (
Velotraum (
Norwid (
mawis (
SeLi Rahmenbau (
Poison Bikes (
Schindelhauer Bikes (

in the Netherlands:
Santos (
M-Gineering (

in Sweden:
Patrik Tegnér (

in Switzerland:
MTB Cycletech (
Hilite Bikes (
47° Nord (
Kolb Rahmenbau (
bedovelo (

in the UK:
SJS Cycles (

in Canada and the United States:
Peter White Cycles, our importer, (,
who lists many small American frame builders on his website.
Peter Weigle (

Linkhinweis General information for installation in steel forks (German)

Linkhinweis General information for installation in aluminum rigid forks (German)

Linkhinweis Range of SL Products 2017