Rim brakes on small diameter wheels like on the Brompton have specific problems:
- rims become hot much faster than on a bigger diameter rims.
- rims wear faster than bigger diameter rims.

It is a well known issue on fast small wheels bikes like for instance recumbent with a ETRTO406 front wheel (in case of downhill, there were exploded tires due to overheating).

And Brompton double wall rims wear quite fast (faster than the previous single wall rims) because of the poor quality aluminum alloy they are made of.