Going to give the Kojaks a try I think. Still running the Brompton kevlars on my 2017. Just had an accidental breakage of a tube. Not used my bike for 2 months and while removing a large pump end (fiddly)from the front tyre valve I managed to use enough force to rip a hole where the valve joins the tube! I'm sure I'm not the first to do this?. Spare tube is the right one for Kojaks (28/***) and has a valve ring which the original tube didn't have which should hopefully stop this from happening again as it will keep the valve in a non-flex position. Anyway, going to stick on some kojaks and give those a try.