Myrdal-Flam by Bicycle

Have you looked at this site? It's all about bicycling this route.
http://www.rallarvegen.com/index.php?m=home&lang=en

I don't know what your descriptions have said, but if you like mountain and nature scenery it sure is beautiful.

Myrdal is 867 meters above sea level. Flåm is at sea level. It is downhill :)
Finse and Hallingskeid are also popular places to start bicycling. Those are also in the mountain, Finse at 1222m, Hallingskeid at 1110m, varied between up and down.

Taking the bicycle on the train: http://www.nsb.no/luggage/bike_and_rail/taking-your-bicycle-on-the-train-article24873-2783.html
It says 150 NOK, but the same page in norwegian says 175 NOK, so I suspect the english one is not updated.

If you plan to take a bike on the train do book early i you are leaving at popular times. The trains do not have unlimited boke slots.
The whole trip is really beutiful, i did it myself last fall from Finse. But if you go early in the season from finse you will have to check the snow leavels.
My photos from the trip : http://www.flickr.com/photos/margit86/sets/72157622415624016/
I like the high up montain scenery the best with lots of mountainlakes/waters.
but the Flåm valley from Myrdal to Flåm is also beutiful and a nice trip.

From Myrdal station you have to start by wheeling your bicycle down a steep path for a short distance, perhaps 500m or something, and through a gate onto the track where you can start riding. We had fully loaded bikes for camping and I recall it being a little tricky. Once you get on the track, it is not very steep but well graded and well surfaced for cycling down very fast. If you are coming up from Flam on the train with a bike, I think there is a halt before Myrdal which connects to the track more easily.

Since the most beautiful bit of Norway is the bit where the sun is shining, and the most horrible bit is where it is cold, blowing hard and tipping down with rain, it can be anything from lovely to horrible. For me, there were more special places to ride a bike. But they were much harder work.

And biking down, you will have to be very cautions of hikers, as this is mainly hikers domain. Lots of bends, not so much visibility in some parts.

Thanks everybody ,
This is what I was looking for ..

You do get a lot of people walking down the Flam valley, and often in summer you will see them doing the 'Norway in a Nutshell' tour doing as we did, getting off the train and walking the last bit to Flam to catch the Ferry.