We have a GT Crestline tandem (don’t laugh ,just for fun riding)which has been in the shed unused for many years.My son fancied a ride now he is big enough but when we took it out the rear spindle is bent.i recall putting it into a shop to get repaired and he couldn’t get the right one so put one on that he said would work but clearly hasn’t.Any suggestions as to what I should be buying for a replacement spindle.going to strip out what’s in and get some sizes later