chain cross over?

[young Ed]

i have seen on loads of recumbent trikes that the chain crosses over is this necessary what purpose does it serve?
Cheers Ed

 

[bobcolover]

i have a kingcycle and a optima dingo [ two wheeled recumbents] both with idler wheels/crossovers

you may have to ask someone with more technical knowledge but i seem to remember its simply to do with not letting a such a lengthy chain [ generally at least twice the length of a normal chain] from dragging on the ground on a low slung frame. Neither the bike e or the spirit which have a frame and seat much higher have an idler to support the crossed chain.

 

[Amanda P]

On a trike, the power run of the chain cannot go in a straight line from the chainset to the cassette: the rider is in the way! So the chain has to be run underneath the rider by means of one or more idlers and maybe some tube.

The return run of the chain may also need supporting with idlers and/or tube, or it might drag on the ground.

Short and medium-wheelbase recumbent bikes usually similarly need the chain to be run over a roller to keep it from fouling the front wheel. Bikes with a very high bottom bracket may get away with a straight chain run.

 

[Aushiker]

Thanks for asking the question. I was wondering about this myself the other week as my Bacchetta Giro 20 has a crossed chain whereas my LoGo Lightning P-38 does not.

Bacchetta Giro 20

LoGo Lightning P-38

Regards
Andrew

 

[mrandmrspoves]

The cross over on my old Trice allows the chain to be deflected under the seat. Last time I changed the chain I managed to route it incorrectly so that I had to pedal backwards to go forwards!

 

[young Ed]

The cross over on my old Trice allows the chain to be deflected under the seat. Last time I changed the chain I managed to route it incorrectly so that I had to pedal backwards to go forwards!

look at
http://507movements.com/mm_002.html
Cheers Ed

 

[mrandmrspoves]

look at
http://507movements.com/mm_002.html
Cheers Ed

That's about it!