I notice that no-one (including me) has actually answered the question of why more people aren't trying the step up rides. I think part of the issue might be the length/difficulty of the step up ride itself. Even if you are quite comfortable with (say) a fairly flat 40mile ride at 16mph, you might still be unwilling to risk a 50+mile ride which is a bit hilly, and will probably be going at 16.5+ - so I think the route chosen should be perhaps a bit less taxing than is the norm.
Even those who don't think they can go in the faster group on a regular basis might welcome the opportunity to push themselves a bit harder than normal occasionally.
@johnclucas
I notice that no-one (including me) has actually answered the question of why more people aren't trying the step up rides. I think part of the issue might be the length/difficulty of the step up ride itself. Even if you are quite comfortable with (say) a fairly flat 40mile ride at 16mph, you might still be unwilling to risk a 50+mile ride which is a bit hilly, and will probably be going at 16.5+ - so I think the route chosen should be perhaps a bit less taxing than is the norm.
Even those who don't think they can go in the faster group on a regular basis might welcome the opportunity to push themselves a bit harder than normal occasionally.