Front Crossover Drive
 

After staring at the beautiful Alex Singer tandem that was featured for the month of May 2013 on the BQ calendar, I noticed day after day that the bicycle was set up with a front crossover drive. I have thought about this setup in the past for my tandems but haven't yet acted on the urge, however my Bilenky 650B tandem almost screams for this setup and I'm seriously thinking about making the change to the bicycle.

Is there anyone here that has a front crossover drive arrangement on their tandem? If so, do you like that setup? What drawbacks have been encountered, if any? I have already read John Allen's article so I'm aware his list of advantages and disadvantages, but I'd really like to get some real world insight from those that have actually used their tandem configured with front crossover drive before making a final decision on the change.

I have a tandem converted to 650B and considered trying front drive as you describe but have not done so. My main concern is the long chain flopping around. From John Allen's article:

John Heine has mentioned that the old French tandems used a special stronger rear derailleur spring to help keep the long chain from flopping around. This would not really be an option with a modern RD so an idler pulley as mentioned by John Allen might be a needed added complexity.

In the end I decided not to do it because of the long chain flop, added complexity and added weight. The problem of how to add a two pulley idler to a tandem not designed for one is also a problem to be solved.

I expect that the normal rear drive chain probably flops around a lot more than we know but since it is behind the stoker the movement is not noticed. A long chain's flopping would be annoyingly noticeable to both riders.

I still think about the idea because I believe the shifting would be ideal. Please post if you decide to give it a try. I would love to benefit from your experience.

As I dig back into the memory banks our old Gitane was delivered with this set-up and we didn't like it so converted to the Stokers crank. It had an idler to keep things in check but was sloppy. I do wonder how a modern derailleur system would function using this set-up.

As has been mentioned the long chain could be problematic. More so now as tandems have longer stoker compartments than they used to. You could ask on the recumbent forum what they thought of having a chain this long.

I was thinking about the extra weight of the chain as being a concern, but I'm not overly worried with weight. If I do it, I think that what I'll initially try to do is set it up without an idler to see how it works and if it is problematic, I could consider using an idler or reverting to the more traditional (rear) crossover drive setup.

Hey Paul, thanks for the input. When I read the post above from Wayne, I have the same thought about performance since modern derailleurs work considerably better than those that would have been used on a vintage Gitane tandem.

photogravity, I was pretty proud of myself for coming up with the switch back in 1984. We didn't see too many tandems in those days other then the beach cruiser type. I'm not sure why you would want to make this switch?

I'm always looking for alternate ways of doing things and I like to know what is going on with the front derailleur and chainring when I'm riding. It is difficult to know what is happening when I can't see what is going on. Additionally, I like that I'll get a vastly improved chainline that accompanies a chain of that length. The nice part about it is that the change is simple enough to do and can be put back the way it was without much work.

I know that using this setup in this day and age goes against the current orthodoxy. I just like to mess around and try different things to see how they work, and see if they fit my needs better.

On internet forums the goal is to disuss at great length the pros and cons, quote noted authorities, and never ever actually test it! :lol:

True that! With that stated, I'm getting ready to swap out the cassette on my Bilenky and I have 4 brand new Wipperman 908 chains that should be more than enough chain for my experiment. It may be a couple weeks before I get to it because I have my 1950 Norman Rapide and 1977 Jack Taylor tandem in the repair queue in front of the Bilenky. This ought to be a fun experiment.

Long chains are the norm in 'bentland - tandem synch chains are too short for many 'bents - but a chain for the proposed project would be outasite long. If the routing is reasonably staight, an idler or two, or three (!), could keep things under control. All kinds of idlers available from Terracycle (http://www.t-cycle.com/). Good luck.