Probably not worth it. You would be better off and less bothered to sell your bike--they sell pretty well--and start over with a six speed, one in a color you prefer.

The pictures I got are from facebook. It is a closed group and in Chinese. He didn't say too much but just sharing the pictures.
Two chain rings or mountain drive are probably easier to get the job done. There are quite a few videos on youtube if you need reference. Personally I like mountain drive better.

Thank you. Yes, mountain drive and similar solutions are "cleaner" but I fear heavyer. I`ll start riding what I have done so far and look into if I need more range.

The Schlumpf Mountain drive is 1: 2.5 so the two-chainring equivalent might be 54/22. Does the tensioner even have the capacity for that much chain wrap? The Schlumpf is best used with the BSR rather than the BWR to avoid gear duplication. The old Sachs 3x2 6-speeds worked well with the Schlumpf using a 54t chainring which gave you 12 evenly-spaced gears and no overlap (you could use up to 60t, IIRC, but you lose practical low-end gears that way.) They are heavier than a two ring (without a FD).

First of all I said "mountain drive and similar solutions". Maybe I should have said "front mounted internal gears with only one visible chainring (no derailing of the chain)". There is more than one on the market and what they have in common is that you see/use only one chainring but there are gears innside that gives you the effect of two or more chainrings, just like what happens in a rear hub with one sprocket and internal gears. This is why chain wrap is not an issue!

And about overlap: Did you ever calculate the overlap on a regular 9x3 bike?? Some times you may want to find the same gear in more than one place on a bike for easyer shifting.

The Schlumpf Mountain Drive and Speed Drive from Harris Cyclery

Schlumpf Service

About weight: Yes, I said "cleaner" but I fear heavyer" but sometimes you are willing to pay the price right? Also there are some seriousely heavy steel cranksets around (some of them even with three chainrings) so what do you knoew about comparing weight?? Some peopel choose a Rolhoff hub and do not care about the weight.

You may want to read up before posting...

Perhaps I was not clear to your reading. My comment about chain wrap pertained to an actual 54-22 double, not to the Schlumpf Mountain Drive. Having owned a Brompton with such a driveset now 10 years, I am aware how it is constructed, and its weight and operation. But thank you. As far as overlap on a 9x3, I have seen those gear-inch calculations and am well aware of the redundancies in those setups. But those have 27 steps from which a sequence can be selected to make reasonably even progression without excessive cross-chain stresses. With 12 "gears" across 550% gain (thinking the Brompton with a standard 3x2 + Schlumpf) avoiding redundancy is more important if you want to keep the spacing between gears reasonably short and even (the way other IGHs do--thinking Rohloff and Alfine 11 or 1x 9-12 setups do.)

There is a lot of "if`s" in your post. I am writing about my brompton and my setup. At present it is 5x2, going towards 5x2x2 with two chainwheels at the front and greasy finger shifting.

If I for some reason do not like the setup in the front I may look into gearbox instead of a der setup. I hope that is ok with you.

This is to remind you all about the option of several positions for the SA three and 5 speed thumb shifters. I have used the 5 speed thumb shifter for some years on my B. I could not find a good place for it so it ended up on the left side of my M bars. Then I started the process of converting to 2x5 so I decided to follow the standard of having the 2 speed shifter on the left side and the hub gear shifter on the right side and therefor I have been back to scratch trying to find a place for the 5 speed shifter.

I want the shifters below the bars so I can place the bike upside down standing on the bars and saddle. I do not want the shifters to get in the way when folding.

After several days of tinkering and thinking I suddenly remembered that these shifters can be adjusted to the position you want. You loosen the hex cey bolt on top of the shifter (not too much) and twist the top part of the shifter into the position you want. I remember reading abut this a long time ago- but then i forgot.

In the long run I am planning to upgrade the brakes and brake levers to the 2017 model with integrated shifters. I am thinking of making my own spacer for the shifter and hope to be able to fit the 5 speed thumb shifter to the brake lever where the 3 speed should have been.

https://www.freemanscycles.co.uk/medi.../l/sls50-t.jpg

I could not find the data sheet for the new shifter/brake lever on the Brompton support site but it can be downloaded from here (bottom of page): https://brilliantbikes.co.uk/brompto...ake-lever.html

I saw this video on Riv bikes site.https://www.rivbike.com/collections/...fter-left-side

The video is at the bottom of the page, so scroll. It looks helpful.

That's basically what I did with SWMBO's Brompton. Put in a 5 speed wheel and the shifter underneath. But I had to modify it.

Pix of shifter?

I have a out of stock plastic Brompton 5 speed shifter that I have been thinking of using but it is plastic.. it is a HSJ968 SLW5N Thumb Shifter.

I have been looking at the option of using a bar end shifter too. Anybody did that on a M bar B?

A bar-end won't fit in the end of the bar.

Too big? In that case it should be possible to grind it down- just in case? I`l try to atatch a shifter to the new brake handle first.

The Tube ID has to be bored out Its done on the Nitto Aluminum bars, and The Guy , Ryan who made a great LWB recumbent

took a Bar End and bored it out , for the shifter, that then pointed up, on his under seat steered bikes..

It's theoretically possible, but the inner ID of my 2016-model M bars is quite small. I'd much rather have a bar-end attached to a Paul Thumbie than go to all that trouble for an ergonomically awkward location.

Sticking out too much

Can not see what you posted (only that it is pix). Should I uppgrade something? Could you post links? Thank you.

Try again? Saved them at photobucket this time. I often fail at using google photos.

Working now, thanks. This is what mine looks like now. Still need to test if mine is easy to use when riding (if my thumb is long enough and strong enough).

I recived a 2 speed shifter today, bought from Ebay, sent from Singapore. Suntour make. Blackish and slim, staying close to the handlebar. Looks good but the weight!!

102 grams. For now I`ll just keep using the one I installed until I can take a closer look at the new Brompton one, hoping they still make them in plastic The heavy one I may eventually put on my sons B..