What's the most economical way of shortening the stoker cranks on the tandem I just won on Ebay? It has Truative 170mm cranks. It's going to be brilliant fun, but my 7 year old girl with seat right down (incredibly flexible though she is).. is tending to get thrown off when I start it spinning fast. Her little Islabike must have got ~130 mm cranks and is perfect.

Crank shorteners, a few I've come across seem to be expensive. Are there any DIY solutions which have worked?

two pairs of these might do it (if number of teeth are ok)?

http://cgi.ebay.co.uk/44-tooth-junior–bike-crankset-%2f-chainset–140mm-length_W0QQitemZ280518977120QQcmdZViewItem?rvr_id=116635830923&query=ciao&fitem=280518977120&linkin_id={linkin_id}&mt_id=777&kw=ciao

[edit] Item # 280518977120 if the link doesn't work.

Yea, thanks wwaswas. It's a triple, so unfortunately that's not going to work. I am more after moving the pedal thread with a bolt-on gadget.

Highpath

Ta, I'd seen that one. I'm sure they are great. £90 though

I'd phone St John Steert cycles – they're big on tandems and would know the options. They do short tandem cranks on their website but they're £80.

I was looking at an old pair of cranks in the scrapbox and eying up the hacksaw and jubilee clips last night. Kind of looks like a DIY bolt-on option might be bodged, but getting it all square and not wobbly would be a challenge

if they're solid crankarms (rather than hollowtech 2 or something) could you just drill a hole and re-thread it?

Nice if I could source the lefthand thread (and even the RH for the at matter..) tap

"Nice if I could source the lefthand thread (and even the RH for the at matter..) tap"

Weldtite, Cyclus, Ceeway etc

Thanks, I didn't realize the taps were so easy to get. Guys at my work engineering shop might be able to drill them straight for me that for me.

Rgds