I picked up an Espresso for a song recently in the UK, and have been using it a lot as work has taken me round France and Germany.

It's bloody heavy though and as it's the only bike I actually have to pick up and move, rather than roll around it seems that a bit of light upgrading might be in order!

It runs 3x7 Tourney, shifts nicely, the original Dahon wheelset and tyres are solid but heavy, the rear rack is budget, the pedals are cheap folding ones, etc etc.

I'm thinking:

-new drivetrain. 2x10 105 with Tiagra flatbar shifters, CX70 top-pull double FD. What would be the max chainring I can run without it bottoming out on the ground when folded? Will I need a BB spacer for the chainline...?
-lightweight Syntace stem and bar
-Ergon grips - gotta have those on a flatbar
-those posh MKS 7 folding pedals, surely lighter than what's on there now
-Tubus Fly rear rack (a rack of some sort is essential)
-I have a new wheelset ready to go on, Deore hubs
-Continental Sport Contact 1.2" tyres
-Thomson seatpost - it has the pump post which I never use

Any thoughts?

The existing drivetrain can go on my son's schoolrun MTB which is worn out.

I also have a set of Magura HS11 hydraulic rim brakes but I'm not sure if the hydro lines will enjoy being folded and unfolded, plus V-brakes are adequate. Are there any light and cheap V-brake calipers and levers out there I should consider?

Thanks all!

Simon