New to tandems - drivetrain solution needed please

HebdenBiker

OK here goes. I'm considering getting a childback tandem frame, and want to cannibalize my current touring bike (converted MTB) for parts. This opens up a world of pain as regards chainset options, compatibility, etc.

So I'll try to keep this very simple...

I am running 8spd XT shifters and mechs, on LX hubs, and a Spa Cycles XD2 chainset with 170mm cranks. What is the minimum I need to buy to fit this to a tandem and make it all work?

Anyone able to provide a specific shopping list will earn my everlasting respect and admiration!

Thanks in advance

marcusjb

The slight weakness in your plan is the chainset to a degree.

You obviously need a timing chain setup for a tandem.

You will be able to use the right crank from your chainset on the rear of the bike - but then you'll need the three tandem specific cranks (front right, front left (with timing chainring) and rear left (with timing chain ring).

You will find it hard to buy those 3 without buying the 4th - so you might as well just use the whole tandem chainset so everything matches.

Have a look at SJS and see what they have for tandem cranksets. Edit - http://www.sjscycles.co.uk/chainsets-ta ... pt891_pg1/

Beyond that, the weird and wonderful bits are minimal - two bottom brackets, extra long cables and that's it.

Wheels - assuming your lx hubs have a decent number of spokes, they should be fine for a child back tandem (tandem wheel sets are often 40 or even 48 spokes, but that is for hefty touring applications). Further edit - check dropout width on you chosen tandem - might be a wider hub than you have currently.

Good luck with the project

HebdenBiker

Thanks for the reply. Re cranks - would I simply be able to use a couple of pairs of these? http://www.spacycles.co.uk/products.php?plid=m2b0s109p2003

Oh and how important is an eccentric BB?

marcusjb

They have to be tandem specific cranks - you can't use regular cranks, the wrong way around (the pedal threading will be wrong etc.)

Spa have a crankset at reasonable cost http://www.spacycles.co.uk/products.php ... 2b0s109p15

You need to have an eccentric as part of the setup - otherwise you can not tension the timing chain correctly.

HebdenBiker

Other than pedal threading, is there any other reason why cranks must be tandem specific? Only I've read that it's easy to rethread them, and not having to buy a whole new chainset would really keep the cost of the build down...