I don't know whether it has been done before,
but yesterday I witnessed at an LBS, my friend's brompton, converted from 3 speed internal gear,
to an 8 speed nexus 8..



would love to try to test ride it, but alas, he carried it straight to the trunk of his car.

well, maybe some other time...

That is a major addition of weight, the main reason that Brompton dont supply them as standard.

previously it was a sram t3 IGH. 911grams
nexus 8 is 1550 grams
the additional weight will be around 600grams?

FYI.
https://www.flickr.com/photos/cycleologist/2272585286/

The chainring is kind of small ... isn't it?

so are the wheels... its all about ratios.

That is precisely my point. With the Nexus rear, direct drive is ... 4th gear? Consider the small wheel and a lot of those eight gears are very low.

What is the smallest cog available for the Nexus hub?

Then again, the chainring might be bigger than I first thought.

Why Brompton don't fit Nexus gears has nothig to do with the weight of it compared to a 3 speed..it is because the management of the company have their heads buried in the sand and believe they don't need to develop a good product..into a first class one...
Besides..a Nexus hub has a width of 130mm..the 3 speed hubs are only 110mm...but again..all down to shortsighted management..Once Britain made wonderful motorbikes...exported all over the world...but didn't invest in new product development ..and they had the same type of management as Brompton have..today..blind..!

I think it's running a Sturmey 8spd .. that would have 1st gear 1:1 and everything else overdrive... that would explain the small chainring ...

in my friend's case, if he wants to stick with the original chainring, I think he might put a 16T cog, and probably get a wide range of gears, rather than only 'lows' and not much 'highs'

Adding a Schlumpf Mountain drive crank for Bromptons works well for me,
54 x 15 on an AW3 planetary low is 21,6t equivilent.
range is: 77.1, 57.9, 43.4, 30.8, 23.1, 17.4 ,

range could be higher with the 13 or 14t on the hub.

flicking the trigger shifter is quickly done, to switch both range, heel button,
and gear, at the same time.

The Brompton on that photo had a decent range with a 30T ring and 19T sprocket using the Sturmey 8


INCHES
8------- 81.4
7------- 63.5
6------- 56.1
5-------49.5
4-------43.8
3-------38.6
2-------34.1
1-------26.7

Seems more likely that Brompton want to stick with British components where possible so import SA hubs from Holland

They don't need to change anything since they sell every bike in production! I don't find the gearing bad at all and I only wish for one more smaller gear that's smaller. You don't need an 8 speed hub and quite frankly, a four speed would be ideal and five is enough!

My first bicycle was a three speed Dahon Piccolo and I was able to ride that bike for over 5 thousand miles climbing hills of all sorts! And walking up others!

That would make a huge difference.

Sturmey-Archer hubs have been manufactured in Taiwan since 2000.

Officially 16T, but if you use an 11/128" (10 speed) chain and an 11/128" sprocket and remove the dustcap then you can fit a 13T.

I so happen to have a 13T Brompton sprocket which I shaved down to 11/128" and mounted on a Nexus for this very purpose. Alas I decided not to go through with the project (it wasn't for a Brompton).

So I'm looking to sell my custom 13T Nexus sprocket at a discount if anyone's interested (I hate to waste it and those Brompton sprockets aren't the cheapest).

That gear cable arm looks like a Nexus to me.