First of all, many thanks for your reply.
@Bruce: Congratulation for your bike: a really interesting setup!
I don't know if I like or dislike the low hanging derailleur, I guess I have to try it first to know.
@Loch: Thx for your reply! I have tested the Dual Drive twice and was twice dirsturbed by its noice. I should maybe check up my ears
The situation changed a little since my previous post: I know a little bit more about a few things but still don't know what to buy/build.
I had the opportunity to test a "velotraum": a dahon bike customized made by a german company (A Dahon Vitesse Alu Frame without "low-end" components and with whatever you like ... nexus premium, deore 9 speed, schlumpf speed-drive). I learnt the followings from this experience:
* Those Big-Apples tires are pretty good and represent a good alternative to the "short-range" suspensions of the Jetstream XP (I only fully realized it after having tested them, simply seeing their advantages in written wasn't enough)
* The Vitesse/Speed frame's form (K series Frame) is definitely the one I prefer: sticks to the street, can drive without hands without fear
Furthermore, I had the chance to test a Birdy Touring and thus the Shimano Nexave C530 (Intego) 3x8 which is an "alternative" to the SRAM dual drive. Intego offers following great properties against the Dual Drive:
* it is MUCH quieter, I feel disturbed by the noise the Dual Drive produces while "free rolling" (huh, you know the TIC TIC TIC ^^)
* it has Trigger Shifters and I can not live without it
The worrying things about Intego is that It is not a widely-spread gear system (I guess support will be difficult) and the hub has 36 holes, which will be difficult to adapt to the kinetic rims.
All that being said, I am like before still hesitating about what I should do. I am thinking of following possibilities:
a/ buy a Speed P8 (Steal Frame) and 1/ Change the twistgrip shifter with an SRAM X9 Trigger Shifter 2/ eventually add a Speed-Drive afterwards.
b/ buy a Speed Pro (Steal Frame, Alu fork, high-end components) and change the rear wheel from Dual Drive to Intego
c/ buy a Veltraum F2 (Alu Frame) with Speed-drive (approximatively 1500 euros!)
a) is the cheap variant
b) and c) are the "light weight" variants
Why does it have to be that hard to choose a bike !
Well, that's it, I am out.