Brompton gears

[Andy in Germany]

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?

 

[404 Not Found Anywhere]

gearing: think half step gearing. I’ve had a few bicycles set up this way and like it.

https://www.sheldonbrown.com/gear-theory.html?utm_content=cmp-true

(Half step is mentioned… half way down)

 

[Tenkaykev]

With regard to the Ergon Grips, I have a pre 2017 M6L and had to trim about 2cm off the grips as the handlebars are a tad too narrow. Not an issue on the "S" bars, or the post 2017 newr "M" bars.
I reto fitted some Joseph Kuosac "M" bars which are wider and have a slight backsweep. I cut these to size to accommodate the Ergon grips, and cut the left side asymmetrically so it just clears the floor when folded.
2Bikes4Adventure have many excellent videos, here's one about Brompton gearing:

View: https://www.youtube.com/watch?v=7uVwMx9OZ94

 

[Specialeyes]

From lowest to highest ratio, your gears go 1-,1+,2-,2+,3-,3+. Don’t think of them as 2 sets and you’ll soon get used to when you need fo flick both shifters and when not to.

 

[steveindenmark]

There is little doubt that the Brompton gears are awful compared to a df bike. It is a case of working with what you have. But you do get the hang of them quite quickly. I usually just go up or down one gear at a time. Going from +2 to -2 is a big jump unless you come to a hill. I would go from +2 to +1. You just need to practice.

 

[Andy in Germany]

gearing: think half step gearing. I’ve had a few bicycles set up this way and like it.

https://www.sheldonbrown.com/gear-theory.html?utm_content=cmp-true

(Half step is mentioned… half way down)

This makes sense: I assume you are referring to this passage:

With half-step gearing, the larger shifts were made with the rear derailer, and the front was for fine tuning. This allowed an 8- or 10-speed set up to have a reasonable range with fairly close spacing of the gears.

So I use the three speeds as my gears, but step up a bit with the two speed shifter, then drop down again before going up into the next step on the three speed. As Brown says:

Cyclists would then use the gears as if the bike were set up with crossover gearing, and wind up enduring unpleasantly large rear jumps.

This is what I was doing with the results described, which was plain weird.

From lowest to highest ratio, your gears go 1-,1+,2-,2+,3-,3+. Don’t think of them as 2 sets and you’ll soon get used to when you need fo flick both shifters and when not to.

That makes sense now, thanks. I'll try this out on the next ride. I was assuming the system worked like the 3/8 derraileur system on most of my bikes.

There is little doubt that the Brompton gears are awful compared to a df bike. It is a case of working with what you have. But you do get the hang of them quite quickly. I usually just go up or down one gear at a time. Going from +2 to -2 is a big jump unless you come to a hill. I would go from +2 to +1. You just need to practice.

It does seem an odd combination, especially for someone who buys a Brompton as their first 'proper' bike and may not be interested in cycling, just wanting a good bike to help commute to work. I'll have to try it and see if I warm to the system.

 

[tinywheels]

Brompton gears are weird as feck, but so are the owners

 

[Andy in Germany]

Brompton gears are weird as feck, but so are the owners

Is that a qualification or a result? Either way my aquantances will tell you I fit the picture...

 

[berlinonaut]

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?

The way ho to shift the halfstep has been outlined already. This is what it looks like and what it looks like if you ad a 3rd sprocket and this way end up with a 9-speed:

https://ritzelrechner.de/?GR=BBWR&K...lopment&GR2=BBWR&KB2=44&RZ2=12,14,16&UF2=1330

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?

Sounds weird. Which bars and which model of Ergon grips are we talking about? If the grips are longer the shifters should sit further inside on the bars and thus have more cable slack - the opposite of being too tight.

 

[simongt]

Brompton gears are weird as feck, but so are the owners

Yup, we're definitely a breed apart - !

 

[Andy in Germany]

Sounds weird. Which bars and which model of Ergon grips are we talking about? If the grips are longer the shifters should sit further inside on the bars and thus have more cable slack - the opposite of being too tight.

They're bog basic Contec parts from our wholesaler. "Tour DLX Pro Kork" apparently; they have a screw on both ends so can't be shortened.

I got the impression they were forcing the cables to turn too tightly. I'm a bit cautious about Brommie cables as they're a bit of a rat's nest anyway, so I didn't want to do them a mischief.

 

[berlinonaut]

They're bog basic Contec parts from our wholesaler. "Tour DLX Pro Kork" apparently; they have a screw on both ends so can't be shortened.

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.

I got the impression they were forcing the cables to turn too tightly. I'm a bit cautious about Brommie cables as they're a bit of a rat's nest anyway, so I didn't want to do them a mischief.

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).

 

[Kell]

I think any issues with gears stem from thinking of them in any way like a front and rear derailleur.

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.

It still takes a bit of getting used to, but soon becomes second nature.

 

[TheDoctor]

TBH, I'd be wary of over-thinking the entire 6 speed Brommie thing. It rapidly becomes second-nature.

 

[Andy in Germany]

I rode the Brommie to work and back today and tried the gears out as described: it makes vastly more sense used as reccomended here, so many thanks.

TBH, I'd be wary of over-thinking the entire 6 speed Brommie thing. It rapidly becomes second-nature.

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.