With reference to the Jones racer, in the April 2019 issue of TCM, Dennis Jones did indeed make his own front wheel but it was not a disc.
The front wheel he made is in fact still in the Supercharged four he also made.
This was unusual, in the fact the brake was operated through the wheel spindle.
The wheel fitted to the twin in your feature, I picked up at Netley Marsh autojumble years ago.
It came from some of Maurice Cann’s stuff. I believe it is an experimental Italian hub, though I may be wrong.
Read more of this letter and other reader letters in the June 2019 issue of TCM – on sale now!
Enjoy more The Classic MotorCycle reading in the monthly magazine. Click here to subscribe.