why not the 8 speed instead. you'll be glad you have the extra gears. you'll be working on it anyways. you just need some elbow grease but it will work. some people on this forum had experienced on the internal hub but if i were you i will get the 8 speed one.
everything is possible
however, when you done with all the swapping around, new wheel builts etc... will you let us know how much money the mods have eaten up......
A boardwalk (224 shipped) + 8-speed hub upgrade (150 + labor) would put me over budget - enough to buy a better bike in the dahon lineup :-)
Rohloff 14 speed hub. That would be awesome on a boardwalk. My old boardwalk was set up with a flip flop hub, I wish I had never sold it...
I believe forum member folder fanatic(?) had this done to her boardwalk. She went with 3 speed and was happy with the results. If you search these forums you might find her posts regarding her experiences.
Perhaps for you, it might not be the best option. How about just riding the bike around for a while and see if you need the extra gearing. If you do, go ahead. If not, pocket the money.
I thought that boardwalks were mostly s1, single speed.
but some time ago, a friend bought a d7.
for a reason I don't know, he decided to convert his bike to a 3speed internal hub.
(so it happens I got his freehub, sprockets and shifter, that I put into my d6 vitesse)
he has to keep his rear derailer to act as a tensioner.
to the threadstarter, I think it would be great if you have the singlespeed version, with the horizontal dropout, so chain tension would be no problem, while giving you the oportunity to use the coaster brake version as well.