Interesting. Geoff Duke would have had to change his style to ride a modern bike round any circuit. Unfortunately he was always adamant that HIS was the correct style. Who could argue? He had won six World Titles, and six TTs.
Anyway, such was his skill, if he was born in the modern era, he would just adapt the current style, and like any top rider, he would be on the pace. As I've mentioned earlier, the course is easily 2 minutes faster from 1937. From 1955 the difference is about 1 minute 45 seconds. Take one minute 45 seconds off 22m 39 (it was 39 not 38 KF), you get 20.54. That's about 108mph.
Interestingly, I reckon the MV's were doing around 110/111 at the Classic TT (20m20s)
Well if you put modern tyres and disc brakes and better suspension onto Geoff's 1955 bike, I reckon 112 is about right.
Discuss.