There are bicycles for rent at our S-Bahn train station here in Duerrnhaar. Check the availability on your mobile app “MVG more”, reserve required number of bicycles (max. 15 minutes in advance) and walk the 7 minutes over to the train station. To start the rental enter the PIN code from the app. Per minute the charge is EUR 0,08, the maximum is EUR 12 per calender day. You can drop the bicycles at any other bicycle station. Get more info here: www.mvg.de/rad (german only, but the flyer is also in English).
The bicycles network covers the entire Munich city and outer area. So basically you can take a bicycle and ride it to Downtown, drop it of there and come back by S-Bahn train. Drop off points in the city are anywhere, in the outer area on defined spots. Munich has a huge range of bicycle lanes and allows you nearly to get everywhere without going on public roads. Riding with a helmet is recommended, but not mandatory. If you need helmets you can ask us, as we also got a few.