Now that modern fat tyres, like Bigger Apples, have much better rolling resistance than in the past.... do 305 rims have a place on some Bromptons?
( standard Brompton rims are the larger 349mm size)
For more suspension or also (like in a past AtoB magazine experiment) knobblys for 'off-road' muddy rough tracks etc.
Presumably brakes would need to become V-brakes or hub brakes* (a pity as avoids quick wheel comparisons / swaps ).... Nevertheless, some people have fitted V brakes neatly.
*cos very long reach calipers would be rubbish.