Originally Posted by
CEBEP
Are you sure it’s M4? Brompto and Birdy are M6 and there are lots of wheels available for them. You may try to accommodate one version or another of Easy Wheels for Brompton from, say Litepro. They have bearings so technically if you will secure them they should work. Maybe local Brompton shop/service center can give it a try.
I have checked and the diameter is 4mm. The rack is the same as the one for gen 2 birdy I think - the then adventure rack but from the mid 2000's. Here are two pictures of the bike:
Unfolded bike
Folded bike.
I think that M4 bolts would work if short. I really cannot continue to carry it around like I am at the moment.