Suspension systems . We have an Allsop Soft Ride System on the back of our tandem, and next to my Miyata saddle, it is the greatest addition to the bike. Stokers take a good deal more abuse, since they are over the rear wheel and can't see bumps. The Allsop clamping system is only designed for round tubes though, so an after market clamp may be necessary. We haven't tried any other suspensions, but other riders have suggested the HydraPost seatpost, Girvin FlexStems and suspension forks with disk brakes.
Tandems are abusers of components.
You will wear out chains, chainrings and freewheels at a rate, you never imagined before, especially if you ride a lot of miles. We replace our chain almost every 1000 miles, chainrings every 5000 miles and freewheel cogs somewhere in between. Part of our freewheel problems have been caused by sand and salt on snowy roads. Rims will also wear quicker than on a single, unless you are using disk brakes. Inc. All rights reserved.