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Hello and technical question

adam2020-06-17 12:21:18

Hello !

I've just bought a cheap tandem and getting familiar with the differences between this and my other single seat bikes.  My bike is an Omega Sport Tandem (looks fairly old) and I'm unsure what the double jokey wheel set up half way along the front drive chain. I assume it's somthing to do with tensioning but then most tandoms don't seem to have them ?  There seems to be very little techincal information online, or not that I can find with a google search anyway. Any feedback much appreciated :-)

John Little2020-06-17 12:38:03

Welcome to tandeming!

Yes the jockey wheel is for tensioning - an alternative is tensioning the chain via an excentric front bottom bracket. Providing your current set up is working I wouldn't worry about it - enjoy the ride

adam2020-06-17 12:52:47

That's wonderful thanks for the reply.  I assume if the chain is a little loose then there is a screw to turn to make the chain travel further.  Is there an official name for it ?  It just looks like a deraillier to me !  pic attached :-)

adam2020-06-17 12:56:10
adam2020-06-17 12:56:28

Would you say these are about 20 years old ?

John Holiday2020-06-17 12:57:27

Yes,almost certainly a chain tensioner for the front section .

Make sure that it is spinning freely & that spring is working properly. 

Enjoy & safe cycling. 

John Holiday 

North Wales 

adam2020-06-17 13:00:22

Thanks John - very excited to pursuade the Mrs to trust my captain skills :-)

John Little2020-06-17 13:02:15

That looks to me like that might be a standard rear derailure put to a new purpose...As long as there's not too much resistance and the chain stays on I wouldn't worry about it.

adam2020-06-17 13:13:09

I've been reading on the Sheldon Brown website that Eccentric brackets are the 'norm' and this system tends to be on the lower end/homebuilt tandems.  I can't complain as the bike is in mnt condition and only paid £147 for it, just want to undertand the workings so I have a better chance of 'road side fix' if we get a mechanical.  For example if the pulley/derailleur came off the frame (quite a bit of play where the fixing bolts threds into the frame).

Stuart Hibberd2020-06-17 17:33:07

Just to say that you only need a single pulley to tension the chain. It does need to tension the chain. Allowing the derailleur to take up the slack does not work so well. When the front rider stops pedalling, the rear rider does not stop immediately this transfers any slack in the bottom of the chain up to the top and this can result in the chain coming off. I have done this. See photo showing position of pulley.