Always try to improve Brompton supermarket shopping experience, here are some thoughts.
Up till this moment. the only choice you have is brompton rear rack with easy wheels installed (R version).
[R version Brommie in action]
Easywheel extender with mudguard wheel upgrade can also act as light version solution, if you pay more attention on the balance.
We did the shopping test on S2LX the other day with Valeria's Brompton basket. This was the first time shopping experience with L version of B with miniMODs easywheel extender installed. The roll is OK, quick as smooth as Rack version. Balance is good without load, but tend to tilt sideway if the load started to pile up, this was due to the lack of two rear easywheels (now only mudguard wheel) to balance the load, and the load is now 70% on the fender. Strong as it is, might not be a good idea. We will say easywheel extender is ideal for L verison B to balance itself and to be pushed or pulled by the rider switching transportation mode, but only for some easy shopping.
[What a basket, Valeria's]
Q: Will the load break the extender?
A: The basket won't hold up 30Kg items to break the extender, 10 to 15 kg maximun in practice, and the load is not fully on the ezwheel extender. Mudguard will bend first before extender is affected.
[How easy wheel extender works without any load]
Issues : Any accessory that put the load on the mudguard will not help you with the shopping situation. If you just want balanced fold and walk your B, you can use easy wheel extender and upgrade the mudguard wheel. This will let you push around the B without any issue. As for really satisfied shopping with B experience, either add the Brompton rear rack, or wait for our QR rear eazy wheels fixture to come out.
[Mudguard easy wheel upgrade]
Oh, we also tested the Colorplus Kickstand on B with load. Thumb up!