Brompton chain tensioner nut for 3 speed STURMEY ARCHER (alloy shell)

Fits to steel shell SA 3 speed

Despite the warnings that this nut is only for the alloy shell Sturmey Archer 3-speed, I agree with the previous reviewer that this one fits the older steel shell one too. The correct earlier nut appears to be no longer available, which is why I bought this one. The only thing you need to do to make this fit is to lengthen the gear change cable by about 4mm by loosening the clamp just above the tensioner, letting a bit if cable through and re-clamping, take care to adjust the cable tensioner correctly so you get all three gears, then works perfectly.

WIll work on pre 2004 models

The pre 2004 (steel) nut is no longer manufactured so this is the only option for pre 2004 bike owners. I had a long chat with Brompton about this and they sent me one of these to try
I was able to fit the alloy nut to my pre 2004 bike. The only issue I had was that the inspection hole was slightly forward from the one on steel tensioner it replaced. This made adjusting the gears a little more tricky as I could not easily see the rod as it came out of the spindle. Within 10 minutes, however, I had the gears working correctly and now my bike is back on the road.
You might want to advise any pre 2004 Brompton owners who need to replace the chain tensioner that the alloy one will work, it just needs a little more time to get the adjustment correct.