Tandem conversion to BBSHD - advice needed

Hello - been reading a lot about mid-drive kits -to install on my 1990 Santana tandem that I bought used a few years ago. I use it to ride with my autistic daughter who does NOT pedal. As she is getting older and heavier and I am hitting mid-40s I want to think ahead with electric assistance so we can do longer rides without getting crushed by hills and riding back into strong winds - thinking I want to go with a BBSHD and a 52V 24ah Panasonic battery triangle that I will mount in triangle behind front seat post. This seems like more that enough power considering I am 200lbs with 125 but growing daughter + bike - we ride on trails or slower streets no off-road mountain slogging. Will probably add thudbuster seat post in stoker ( back ) and maybe front posts as bike does not have suspension. My issue is what to do with chain drive - I discussed this briefly with Court - he suggested that I switch Captain drive to Right hand side and run it clear back to the cassette in back - eliminating the stoker crank as it is not used - I know I would have to use some chain tension accessories - I looked on t-cycle.com at idler's etc. - but as shown on Court's tadpole project that long of chain run is not an issue- just need to nail down my parts list. My questions are - should I convert rear cassette to an IGH ( Sturmey Archer 3spd ) ? This would result in a straight chain run and I would probably only need 3 speeds with 1500w power supply .. correct ? + my gear cables run along bottom of frame where the BBSHD will reside so I would have to route those cables differently anyways ... worried that old cassette is not sufficiently strong to handle the torque of new BBSHD. Have original rim brakes too - do you recommend switching to a disk on back? if that is even possible ? Would I have to specify a stronger chain to handle the power of BBSHD ? Any advice you can offer would be great ! Also will update tires to schwalbe big ben 2.15's. Working on my ordering list. Thanks in advance. Chad
upload_2017-6-6_10-59-24.png

upload_2017-6-6_10-59-43.png

upload_2017-6-6_11-0-5.png
upload_2017-6-6_10-59-24.png upload_2017-6-6_10-59-43.png upload_2017-6-6_11-0-5.png
 

flymeaway

Well-Known Member
should I convert rear cassette to an IGH ( Sturmey Archer 3spd )

I'm a big fan of IGH's. The only concern is to make certain the IGH can handle the additional torque. The Rohloff 500/14 can and I know some posters have used the Afine hubs so hopefully they'll comment on it's torque requirements.

I don't think the chain length will be an issue. If you find there is too much sag and you want to give some support you can add a chain guide at the Stokers bottom bracket, or the down tube between the two BB's.

It should be a relatively straight forward conversion. Keep posting, and if you need some help I will do my best to provide assistance.

Court J.