Hi there!
We are right back from a 3week trip to Vietnam from which we did a 8 days biketrip in the north. It was fantastic!
Since I could't find much information before I left I thought I share some with you. First of all we found a reliable and very helpful shop, Phung, in Hoan Kiem district Hanoi where we rented the bikes, Honda Future Neo. It was very nice to ride these asia bikes and blend in. Really no need to get bigger stuff as they take you everywhere, everyone can fix the and its dirt cheap. Speedlimits are 40km/h in towns, 60 on the highway. But if you really want it you can find bigger bikes as well.
Exploring the north was an extremely good idea. It is very beautiful, with stunning landscapes, very friendly people and except from Sapa, we saw 2 other tourists.
I made a map of our route, I hope it works to put the URL here, otherwise just PM me.
As for Phungs contact, he does rentals, selling/buying and repairs:
huyphung0507@gmail.com
www.2wheelsvietnam.com
As for the driving in Hanoi, it looks difficult but since its quite slow its very do-able. Just weave in and don't stop or wait. Look at it as swimming in a school of fish
Well, enjoy your trip and stay safe!
greetzEls
https://maps.google.com/maps/ms?msa=...=m&z=8&vpsrc=1