I use the older non-wide ratio S-RF5 on my Brompton and I have a couple of X-RF5s on other bikes (the internals are the same). I find each hub behaves differently despite there being no obvious wear/damage or difference of any sort between them. The one on my Brompton happens now to be running very sweetly and it's great. However, there are fit issues to do with the toggle chain pulley extending between the front wheel spokes when folded which can cause rolling problems. . . I think it could be fixed by using the stay hook from the old 5 speed Bromptons. Generally I'm very pleased with the performance of the hub and I don't think I'd want the dual shifter 6 speed setup.