Brompton gears

[berlinonaut]

It's still a tad fiddly but I think I'll get the hang of it. I wonder why they make them so complex though; Sram manage seven gears with one handle.

A seven-gear SRAM derailleur bike has a gear-spread of ~240% at max. The Brompton has 302%, the same as a hubgeared Shimano Nexus 8.
Just that the BWR + Derailleur is 1kg lighter and furthermore fits into the 112mm rearframe of the Brompton whereas the Shimano Nexus has 135mm (and can with some tinkering brought down to 124mm). In the end it is vastly heavier, the folded package is thicker, it is more expensive and also the efficiency is lower. That's why Brompton's Halfstep approach may be a bit strange on first look but is pretty clever when you look closer.
It was btw. developed as a kind of emergency exit: When Sturmey Archer went bankrupt in autumn 2000 the only gears that fitted the Brompton was the Sachs/SRAM 3-speed. No more five gear hubs. So they developed very quickly from scratch the 2-speed derailleur system which came to the market in spring 2002 - one and a half years of development and pre-production is not very long. At that time it was combined with the Sachs hub, resulting in just 213% spread instead of the 177% of the 3-speed hub or the 226% of the five speed sprinter hub. Only when the BWR was launched in 2009 they achieved the 302%.

Once you've managed to deal with the shifting you will be ready for the next level. Either my 9-speed mod (which is a bit boring in terms of shifting) or - being in Freiburg you could mount a Schlumpf Drive from nearby company Haberstock (http://schlumpfdrive.com/). Then you end up with 3 independend shifting systems instead of just 2 now, which should keep you occupied for a while.

 

[TheDoctor]

Going OT for a moment, I'm going to do the 9 speed thing next time I replace the transmission @Bromptonaut .
Although I might put a double on too, to get 18 gears.

 

[Andy in Germany]

Going OT for a moment, I'm going to do the 9 speed thing next time I replace the transmission @Bromptonaut .
Although I might put a double on too, to get 18 gears.

And I was worried that six were overkill...

 

[Andy in Germany]

When I was buying mine, the sales guy in the Brompton store said to instead think of them as three gears with a high and low in each gear.

I tried that today, and suddenly they made sense, thanks.

 

[Andy in Germany]

These are 140mm wide. Standard grips are 130mm, so this explains the issue. Not optimal for the Brommi and even less as you seem not be able to adjust the angle of the barend part independently from the one of the grips. Probably not a good fit and will potentially lead into problems.

In this case the cables shouldn't turn out to be a problem as long as you are able to create the necessary grip space. This very much depends from the bars. With S-bars it should be possible, with M/H bars I'd have my doubts.
I'd probably go for other grips bc in my oponion there must be a lot of luck involved to get a ergonomic fit on the bars with these grips (which I consider barely possible).

I've used these grips for a while in my other bike; it takes a while to get the angle right but once done they're very comfortable. I've got straight bars on the Brompton so I'll give it another go. I think I'd also forgotten how noisy the gears are so when I tested the bike I assumed something was wrong...

 

[404 Not Found Anywhere]

I usually ran through my half step derailleur gearing in sequence, double shifts included, so the Brompton version came as second nature to me.

 

[TheDoctor]

And I was worried that six were overkill...

I don't *need* that many gears - I've gone touring on a singlespeeder in the past. 'Because I can' has always struck me as a perfectly reasonable reason for doing something quite unreasonably daft.
No-one ever talks about getting a triple onto a Brommie. I wonder why not?
*plottens*

EDIT - because you end up with a metric shedload of unfeasibly low gears and near-duplicates, that's why.

 

[T4tomo]

No-one ever talks about getting a triple onto a Brommie. I wonder why not?
*plottens*

EDIT - because you end up with a metric shedload of unfeasibly low gears and near-duplicates, that's why.

may also obstruct the fold possibly. I've never tried it, mine was used a commuter machine in the main, so 3 gears sufficed.

 

[berlinonaut]

No-one ever talks about getting a triple onto a Brommie. I wonder why not?
*plottens*

Meanwhile no one:

may also obstruct the fold possibly. I've never tried it, mine was used a commuter machine in the main, so 3 gears sufficed.

no.

 

[TheDoctor]

*approves*
3 gear levers, presumably?

 

[mountainbiker]

I'm still getting used to Brompton gears. I've noticed a couple of things that seem odd:

1: I have a six speed system, and I get the impression there's a lot of overlap between the 'lower' and 'upper' gear set; it's not a matter of using the 'lower' set and cycling up thriugh the gears, then doing the same on the 'upper' set. Is this correct?

2: I've tried pitting a set of ergo grips on the handlebars and everything was fine, except that the grips are about 2cm longer, which seemed to putt the cables too tight and (again this is an impression) seemed to meke the gears run a bit rough. Has anyone else come across this or is it just me?

Apols for jumping on this post but I'm new here and can't figure out how to start a new thread.
How do you set up a Sturmey Archer 5 speed Brompton hub? Or please direct me to instructions, preferably a video. I couldn't find anything on here. I had to take it apart to put a new tyre on. Tia.

 

[u_i]

Either my 9-speed mod (which is a bit boring in terms of shifting)

I now switched to the Brommieplus freehub for BWR* with 3 cogs + their pusher. The shifting is significantly improved over the 3 cogs on the original Brompton freehub. In fact, I can shift under tension in the rear when operating in the lowest gears in my system - must be well over 20% grade - I am at the edge of flipping backwards. Their pusher is presumably irrelevant in this, rather the better centering of the cogs. However, with their pusher I might go to 4 cogs if I can manage to make it as reliable as over 3. If it is flimsy, and that has been the case in my tests so far, suspended due to travel, I will just stay with the great shifting over the 3 cogs.

*approves*
3 gear levers, presumably?

Yes, but the third lever is in practice for changing range when the terrain changes abruptly. Again, like with the 2 original Brompton shifters, the 3 shifters become second nature with practice.

*For whatever reason the separate BWR freehub, which was just $65, is missing from the Brommieplus pages. They respond quickly over email to queries.

 

[TheDoctor]

Oh no. I see they also do a 4 sprocket conversion...
This isn't going to end well for me!

 

[berlinonaut]

Apols for jumping on this post but I'm new here and can't figure out how to start a new thread.

Should not be too difficult. Follow either of the arrows:

How do you set up a Sturmey Archer 5 speed Brompton hub? Or please direct me to instructions, preferably a video. I couldn't find anything on here. I had to take it apart to put a new tyre on. Tia.

Would be a good idea at least to mention which hub - there have been three different S/A five speed hubs avail. on the Brompton over time. A new thread would possibly be a good idea and I'd recommend using the search box (top right) before that - it is highly probable that the topic has already been disussed at least once if not multiple times.

 

[u_i]

*For whatever reason the separate BWR freehub, which was just $65, is missing from the Brommieplus pages. They respond quickly over email to queries.

Correction: The freehub for BWR is actually there on the Brommieplus pages at $65. It is the same for different Sturmey Archer gearhubs. Also, I did some measurements for the uphill ride I am currently doing on a daily basis on my Brompton. The steepest portion runs at the grade of 28% (15 degrees), but the steepest portions where I still dare to shift over the cogs run at 18% (10 degrees). And, no, I am not doing any zigzagging there - there is not enough space on the sides for that.