I purchased this tandem during the 1990's in hopes that I could get my wife to go riding with me.  It didn't work and the bike has been stored in our storage shed.  The Captain's seat tube is 22" and the Stoker's is 19".  The complete specifications can be found by searching Nashbar 1000rt specifications,  The tires and tubes have deterated while in storage.  The bike has Shimano 21 speed click bar-end shifters and an additional rear drum break.  The bike is located in Oberlin, Kansas which is in this year's Bike across Kansas route.  You can contact seller by calling 785 470 7024 or by text.