Just for reference, here again is how some of the 700c road models of major tandem brands stack up in terms of nominal steering trail with a front tire diameter of 687mm and their OEM forks, steel and/or carbon as specified:
1.65" = Bilenky
1.65" = KHS
1.89" = Santana
1.89" = Burley w/Steel Fork
1.89" = Trek T1000/2000 w/Steel Fork (Med & Large Size w/73* head tube)
1.98" = Cannondale CAAD Design w/Steel Fork
2.01" = Trek T1000/2000 w/Steel Fork (Small Size w/72.5* head tube)
2.09" = Co-Motion w/Steel Fork
2.09" = Trek T2000 w/Carbon Fork (Med & Large w/73* head tube)
2.20" = Burley Race Package w/Carbon Fork
2.20" = Trek T2000 w/Carbon fork (Small Size w/72.5* head tube)
2.28" = Co-Motion w/Wound-Up fork
As noted in an earlier post, a larger diameter tire will increase these trail numbers by a few mm and a smaller diameter tire will therefore decrease them.
Again, how a bicycle tandem actually "feels" is incredibly subjective and while steering geometry is a major factor, it will not by itself necessarily correlate into how a tandem will "feel". Like tubing where the material itself is not as important as the diameter, butting, wall thickness specified for each tube by the builder, handling is also influenced by multiple factors and, while steering trail is a major factor, the stiffness of the fork, frame, and wheelset as well as tire selection will also influence what a team "feels" when actually riding a tandem under different conditions.
This continues to underscore why so many of us emphasise the need to test ride as many different tandems as often as possible if you are searching for a new tandem or are just curious to see how different brands and models have been "tuned" by their designers and why you also need to factor how the wheels, tires, and even tire pressure alter that "feeling". As an example, anyone who finds a tandem feels harsh might want to drop 10psi out of the tires and see how it might change that initial impression. Then again, you can ignore all of this stuff and just recognize that the average team will most likely adjust to whatever they buy.
Last edited by TandemGeek; 11-06-05 at 08:49 AM.