Brompton for beginners questions

[e-rider]

My inclination would be get the M and then change the bars to something lower. This is because you have the longer cables and can cut them to fit. Its more of a pain going from flat bars to riser bars. Going from high rise to low rise is easier.

Also the new m bars are around 3cm shorter than the old ones and may feel better.

yes but the handlebar extension is much shorter with M bars, so changing to striaght bars would give an ultra-low position, much lower than the normal S bars so I don't think that would work very well at all

 

[reppans]

This is what Brompton mentions about the new 2017 M bars:

Evolved handlebar shape: a shallower handlebar rise and longer stem assembly combination provides a stiffer, more modern looking front end with increased grip area, whilst maintaining the original riding position.

 

[fivelittlefish]

S version with mild riser bars is what worked for me...

 

[samsbike]

That would be logical but I guess they issue would be that the by doing that one of the bars would be too high or low.

Is the longest stem on the S version then?

 

[cheys03]

Yes I think so. But remember it bends forwards which restricts which bags you can 'officially' fit, though most will fit with a bit of modification or care.
I'm tempted to go H with risers on my next B for this reason like Kell.

 

[srw]

Why do they make the S with a longer stem than the M, and then put the risers on the M to make it higher? Why not have a common stem and less rise on the M bars

I thought that the 2017 stems were the same.

 

[Kell]

I'm between M or S - the H will defo be too high. I will see if I can try both before deciding

This is exactly where I was.

Preferred the look of the S, and found it OK on a test ride, but with a dodgy back I figured it was probably too low. The M was more comfortable, and would probably have been the route I went down, had I not spoken to the guy in the Brompton junction who said that some people buy the S and put small risers on them.

A little googling led me to this site and I then found out about the H type, which I figured would be better for what I wanted to do. If you look back at my pictures, you'll see the cables ended up being way too long, but I figured it would be easier to shorten long cables, than have to buy new cables if going from an S to a slightly heightened S made them too short.

As it turns out, it's not that simple with a Brompton (few things are), but I got there in the end.

I didn't know the stem heights had been changed for 2017, but that might make your decision a little easier.

 

[Kell]

The other thing to consider is the real estate on your bars.

Flat bars mean you can line up all your 'bits'. M bars means there's not much space for attaching speedometers/lights/Garmins/phones etc.

 

[samsbike]

Ok for the sake of science I went and measured everything and voila
Measured from just above the headset widest ring stem length/ grip height


p stem 31cm. Top bar 48cm
s stem 37cm
Old style m bars 32cm , bar height 45cm
New style m bars 35cm, bar height 45cm
H bar 38cm, bar height 50cm

Hope this helps. TBH I forgot to check which year they were but I don't think stems are the same height.

Looking at them the H seems the best with that long stem and then fit short risers.

 

[mitchibob]

2. handlebars - how low are the straight bars? As a tall person, the saddle will be quite high so will the flat bars then be too low? I generally don't want a 'sit up and beg' position, but...... not too low either

I rode a brompton bike hire model for a few months, which are M3Ls, plus took an S2L for a test ride. For me, with a slightly dodgy back, the ride position of the S bar was a little uncomfortable. But the S bar did feel better for steering, and you can get more gadgets on it more easily if you need to do that. However, with the M-bar, you get a better choice of luggage options at the front, and I'm always amazed how much I can carry in the touring bag when riding home from the supermarket. For the flexing, they do sell a cross-brace thing that stiffens bar and makes gives it a longer life, although I couldn't find one in stock last time I looked.

3. gear ratios - I was thinking to pay the extra for 6-speed, but there are different sized chainrings available - is the 'standard' size suitable for general riding or do people find it generally quite low or high?

When I was first looking at Bromptons, I assumed I'd need a 6 speed, but actually, it really depends on where you are and how you're using it. I commute about 8 miles to work in London on mine, and after riding the 3 speed for a few months, and trying a 2 speed, I went for the 2 speed and haven't been beaten by any hills in London yet. I found I was only really using the higher two of the gears on the 3-speed anyway, plus it's quite a bit lighter to carry folded.

Also, with the single or 2-speed, if you do need to remove the rear wheel for a puncture or anything, it's less fiddly, as although you have to remove the chain tensioner, you don't have to re-adjust the hub gear.

For me, the 2-speed felt more efficient than a bike withe a hub gear, but I can envisage wanting a 6 speed as well, and as others have mentioned, it's not exactly a cheap upgrade. But I don't miss the ticking of the hub gear. If it's making a noise while I'm pedalling, surely it can't be converting all my energy into forward movement?

 

[TheDoctor]

That ticking noise is endemic to hub gears. It's the non driven parts for each gear ratio freewheeling past the driven parts (gross oversimplification alert!) It's not a significant power loss, especially compared with the unaerodynamic element in the saddle ie us

 

[12boy]

I have read that a broken in (not down) SA 3 speed with oil instead of grease lubrication, approaches 99% efficiency. This is comparable to a clean, properly adjusted derailleur. Apparently the SA 3 speed design with the aluminum shell is also the lightest and reliable 3 speed choice. The 3 speed I am referring to is the standard 177% model but I don't know why the 256 % Brompton wide range would be different. SRF3 at 970 grams.

 

[simongt]

In Frank J. Berto's book 'The Dancing Chain' a very detailed tome about the history & development of the derailleur, he did some rigorous testing of many drive trains; hub & derailleur and concluded that the derailleur is about 3 - 4% more efficient than an oil lubed 3 speed SA hub gear. The modern hubs are a little less efficient because of the custom of 'packed for life' grease lubing. However, he says that 7 speed hubs are 'significantly less efficient' than 3 speed hubs.

 

[12boy]

A drawback for dérailleur on small wheel bikes is that to be able to shift a big gear range they hang down to close to the ground. Brompton are the exception because they have a chain mover and the chain tensioner stays pretty close to the chain. I am considering putting an IGH on my 20 inch for winter when it would drag through the snow

 

[simongt]

One reason why three of my five bikes have hub gears; 3 spd., 5 spd., & 8 spd Sturmeys. In colder winters, I've experienced ice building up on the cassette which then makes shifting difficult - unless you frequently clear the ice which on a longish commute is a pain.