It's just the final bit that's bad isn't it........ did it in a 42x21 last time I went up - some years ago....have a 39x21 now, but guess I'd need a 39x23 after a number of miles...
I generally only do up to 50 miles as I get bored on my own, and it's usually a very hilly circuit, so could possibly stretch to the 97 mile one ???? Or might be safer with the short one....