Hi Peter, credit to you for this as I have been watching your posts on this for probably 3 years.
I had intended to change the tyres at the beginning of next year when the tyres would have been 4.5 years old. However just this weekend I had the bottom scrape over a sleeping policeman, so I decided to do it now rather than wait until next year.
At the weekend I used a 4inch diameter coffee tin to identify the low points under the Morgan. There were 3 points which were up to a half inch lower. The gear box, and two at the gearbox cross members. I can get the 4 inch tin under these points with the new tyres. I am very happy with the result,
I will look out for you at Thrill on the Hill so you can have a look for yourself.