ah, maybe to hold the second wheel set, where you have a screw in bolt on forks or stays, and this little widget holds the tyre part of the wheel???
That is what I was think but from the photos I have seen people seem to carry the racing wheel on the bars and if the clamp won't fit round a top tube it will not fit around the bars.
That is what I was think but from the photos I have seen people seem to carry the racing wheel on the bars and if the clamp won't fit round a top tube it will not fit around the bars.