I've indulged my Brompton again by replacing the OEM tension arm assembly and cogs with parts from BikeFun of Taiwan.

OEM:




BikeFun parts as received:




BikeFun parts as installed:




The new parts are beautifully machined and finished, and I managed to convince myself that, being metal, they would have a much longer service life, especially for the cogs, than the plastic parts, so it wasn't ALL for the looks. I probably added some weight, but I'm not really concerned with weight.

Regarding BikeFun, although their parts are marvelous it can be slightly difficult to place an order. English is not their first language (and Tawianese is not mine), but their website is understandable and with care in emailing back and forth I was able to order/receive exactly what I wanted. The parts came with exactly zero installation instructions, but by taking photos of each disassembly step I was able to remove and install with no trouble. Better mechanics than me wouldn't need the precaution of photos.

Now I'm lusting after their chain guard, extendable easy wheel arm, and copper suspension.