Artic

Ar(c)tic^*) A special project we've finished recently is a expeditionbike for Marco Geurts. Marco wants to cross Siberia, climb over the icepack in the Bering straight, hopefully meet not too many polar bears (Cyclist in Alaska are described as Meals-on-Wheels (TM) ) and subsequenty drop down towards South America to warm his bones. Because well- maintained cycling routes in Siberia are scarce, Marco plans on navigating frozen rivers. Cycling through the snow with a full load puts special demands on equipment. Here you can follow Marco on his exploits, hoping to reach Siberia before global warming takes over!

	Double rims To be able to ride on snow each wheel gets two additional demountable rims. Yes, just like a tractor, but then two per wheel. So you can't use rimbrakes, which explains the disk
	The central tyre is taller than the two others, creating a rounded profile for cornering
	Another rimdetail
	Bracketaxle If you run 160 mm wide tyres, you need a bracketaxle to suit. Otherwise you end up with the crankset hitting the tyre and the chain running through the wheelrim. This one is 145 mm, and the bracketshell is wider as well. Still not enough for the bike in snowmode, so then we will resort to a two-stage driveline
	Fork The forkcrown is 28 cm's wide, not very standard.....
	Frame Subtle isn't really Marco. But then the wrecking service being 2 meters tall (72cm frame) might have something to do with it. So he is not getting a subtle frameset: 55 mm downtube and 35 mm toptube is heavy. But with 200 kg sledge behind him and not a cyclingshop for the next 4000 kms this must be a comforting thought.
	Chainstays The 175 mm wide reartriangle (forks are 600 mm long) wasn't built in a day
	Seatstays The seatstays in proces. The tube will tahke the excentric bottombracket for the twostage drive.
	The frame taking shape It is slightly more, do you mind dear?
	The rack A standard solution wasn't on. The tow-hitch is a bolt on and not shown
	Rear hub The rearhub widened to 175 mm and with a (for now) floating caliper and the sprocket for the dual-drive
	Fitting At last it looks like a bicycle and Marco can offer his Polar boots (these must have been on the mind of Nancy S. ) and bikebags (usefull as a bathtub if it wouldn't be freezing) up for fitting
	Testing At last, it is a bicycle! Here with the drive in normal terrain mode, without botllecages and without the towing eye. Paintjob is temporary tractorpaint (continuing the theme), so we can still do modifications (apologies for the midnight picture quality, which is wat it was)
	Testing2 Front derailleur on a extension (normal ones are not meant to be used with a 145mm axle) and lenghtened brakecable
	Testing3 The much relieved polar traveller, who now can ride (not in the picture the much relieved framebuilder, who gets fed up with this kind of 'over budget & time' projects ;))
	Snodrive 1 View from the left with the triple tyres installed and the drivechain going down. The derailleur is nicely tucked away and barely visible
	Snodrive2 The intermediate axle consisting of freewheel, adapter (reworked crankarm), standard square bracketcartridge and again a reworked crankarm with the inner ring in a very outside position.

*) Ar(c)tic: n. 1) Articulated Lorry, 2) Bitter cold.