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.

I suppose the pulleys rolling on cartridge bearings is a gain.. metal pulley teeth bound to be a quite bit Louder..

My M3L got Tacx pulleys , nylon quieter than the stock Plastic or the metal ones on my touring bike..

Thats so nice. WOW! great bike bro

Thanks for posting the before and after because it really adds impact. It looks great, I am glad you treated yourself.

That's impressive!

I like it. I want one. I love that raw lacquer.

Nope, they're very, very quiet, in fact I can't hear them at all, either riding the bike or hand pedaling it with my ear close to the cogs.