# Brompton M to S bars



## Squirt01 (10 Apr 2020)

I`m just about to buy a Brompton, it will be the S6L (Black edition) I have to order this through the cycle to work scheme that uses either Halfords or Cycle republic. Currently, they state they can only get the M6L (Black edition) With this in mind who easy is it to switch the bars out ?


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## Specialeyes (10 Apr 2020)

Simple enough to switch the bars, but you will end up with a super low position, as the M-type stem is about 65mm shorter than the S-Type - see pic of Mrs' and Jr's below.

Edited to add: you'd also need to cut down the cables too by a similar amount, to not interfere with the fold. They'd be shorter than S-type cables too, but nothing too tricky.


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## mitchibob (11 Apr 2020)

One thing, the newer M-Type handlebars don't rise as much as that, so may not be quite so much lower with the S-types. Also, the S-Types are wider bars, so may not need to shorten as much there either.

I switched from standard 2018 M-Bars to Joseph Kousac mid-rise bars, without a huge difference once I'd chopped them down a bit. SJScycles sell the Joseph Kousac mid-rise and flat-ish (more ergonomic) aluminium bars at a very reasonable price to be able to try both to see which you prefer.

For long distance, the mid-rise I think are perhaps the ideal for me, although I'm thinking of trying the flatter ones for commuting, as see how they go on longer distance.


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## Gunk (11 Apr 2020)

When you see them side by side like that, with the additional height of the front stem, the S Type are not actually that much lower.


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## berlinonaut (12 Apr 2020)

Gunk said:


> When you see them side by side like that, with the additional height of the front stem, the S Type are not actually that much lower.


It is a 9cm difference. I'd call this a lot, the more as I personally recognize already differnces of 1,5cm on the handlebars pretty massively.


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## Nufab (12 Apr 2020)

I’d wait for the S; changing from M to S properly will need cables, stem and handlebars, and cost a small fortune.

If they have other models in S guise, maybe consider if you need the 6 speed? I know of provides for a lot of different terrain and uses, but I went for the S2L Black Edition and I find it fine. Granted I don’t ride it far, but then I wouldn’t anyway.. they’re superb bikes but not nearly as comfy as a road bike for distance.


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## rogerzilla (12 Apr 2020)

You also can't buy an S-stem any more. It's one of the parts Brompton doesn't trust you to fit. You have to have a dealer order it and fit it for you.


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## Gunk (12 Apr 2020)

rogerzilla said:


> You also can't buy an S-stem any more. It's one of the parts Brompton doesn't trust you to fit. You have to have a dealer order it and fit it for you.



That’s crazy, it’s a 5 minute job to fit.


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## berlinonaut (12 Apr 2020)

rogerzilla said:


> You also can't buy an S-stem any more. It's one of the parts Brompton doesn't trust you to fit. You have to have a dealer order it and fit it for you.


That's true for the UK but not necessarily for other parts of the world. When they invented this policy a couple of years ago Brompton said (as to my memory) they wanted to get rid of the armada of malmechaniced Bromptons in the UK. Does this say something about British home bike mechanics?


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## rogerzilla (12 Apr 2020)

What if you live miles from the nearest dealer and have no car? You're stuffed. They must think all their customers live in London.


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## berlinonaut (12 Apr 2020)

Gunk said:


> That’s crazy, it’s a 5 minute job to fit.


If you consider this a 5 minute job Brompton has a good reason not to sell these parts to a general audience. It starts with the right tools, continues with the correct cable lengths and does not end with the correct amount of torque. I have changed countless stems and bars on Bromptons - not a single one needed five minutes an most needed a surprisingly huge lot of time until everything worked totally flawlessly as it is supposed to.


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## Gunk (12 Apr 2020)

berlinonaut said:


> If you consider this a 5 minute job Brompton has a good reason not to sell these parts to a general audience. It starts with the right tools, continues with the correct cable lengths and does not end with the correct amount of torque. I have changed countless stems and bars on Bromptons - not a single one needed five minutes an most needed a surprisingly huge lot of time until everything worked totally flawlessly as it is supposed to.



I was just making the point that it’s not a huge job. 🙄


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## roley poley (12 Apr 2020)

I love fettling out a project and learning how to do it but there are others in this world (present company excluded ) who I would not trust to sit on the loo the right way round and then sue for lack of instructions on a public toilet that anyone can enter without training.. those are the people they and many other companies are trying to stop . Its a sign of the times that it is also used against the enthusiast to make a buck .end of rant


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## rogerzilla (12 Apr 2020)

Also see Part P electrical regs. I've fixed appalling stuff done by the "professionals" - wires just twisted together, spurs off spurs off spurs, 200 square metre ring mains. Not since 2005, though.


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## 12boy (13 Apr 2020)

I have an S Brompton and I've changed from flat bars to moustache and back again with very little trouble in terms of cabling. As long as they are long enough to fold they work fine, although you may want to take a picture of the original cabling before removing it. I've found buying bulk cabling and cutting it into correct lengths a lot cheaper than buying pre cut cables.


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## mitchibob (30 Apr 2020)

berlinonaut said:


> That's true for the UK but not necessarily for other parts of the world. When they invented this policy a couple of years ago Brompton said (as to my memory) they wanted to get rid of the armada of malmechaniced Bromptons in the UK. Does this say something about British home bike mechanics?



Perhaps more on how they view their average customer? It really is a shame they wont sell certain parts to individuals and local bike shops (some with Brommie fanatical mechanics) that may or may not have the skills to do certain repairs and replacements themselves. I understand to a certain extent, but I still think it's a shame. 

Also, running an annual racing series, but not endorsing any of the 3rd party mods, or even talking about them at all, or other cool personalisations you see at these events, It just seems a little counter community. Just push the vastly expensive 3rd party luggage instead. I wonder how many completely stock Brommies have won Brompton World Championship finals? 

Saying that, it was the Alfine hub-gear that failed around 1000km in for a Brommie Transcontinental Race attempt. The standard 6-speed has gone a LONG way past that without any issues.


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## Gunk (30 Apr 2020)

mitchibob said:


> Also, running an annual racing series, but not endorsing any of the 3rd party mods, or even talking about them at all, or other cool personalisations you see at these events, It just seems a little counter community. Just push the vastly expensive 3rd party luggage instead. I wonder how many completely stock Brommies have won Brompton World Championship finals?



I find Brompton’s attitude towards customisation and personalisation very strange, if an owner spends thousands improving your product surely you would be flattered and embrace the ingenuity and take some notice.

Companies like Kinetics in Glasgow have managed to take the Brompton to another level and do the sort of stuff that Brompton should be doing themselves, rather than just producing more overpriced limited editions which are a pick and mix out of the accessories catalogue, I suppose profit comes before proper R&D on a product which is already a big seller as it is.


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## 12boy (30 Apr 2020)

I could suggest a bunch of Brompton mods, including cartridge bearing hinges for the rear triangle, or if not possible, something more DIY than the current bushings, Vbrakes , chrome moly forks, rear triangle and frame, threadless handle bar post and room for tires up to 50 mm, but I've certainly enjoyed the many hours spent on messing with handlebar and gear train mods. While I would like those kind of changes I certainly enjoy the bike I have.


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## rogerzilla (30 Apr 2020)

If you look at the original series Brompton on eBay, which has its own thread, what's remarkable is how little things have moved on in 40 years. It's a cash cow.


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## berlinonaut (30 Apr 2020)

Gunk said:


> I find Brompton’s attitude towards customisation and personalisation very strange, if an owner spends thousands improving your product surely you would be flattered and embrace the ingenuity and take some notice.


Just that in the end it is a different product than Brompton offer - they are in the business of urban transport for the masses and surely no one needs to spend thousands on top of a Brompton to achieve that (and only a tiny fraction is willing to that).



Gunk said:


> Companies like Kinetics in Glasgow have managed to take the Brompton to another level and do the sort of stuff that Brompton should be doing themselves,


Maybe in your opinion but I guess it is totally up to Brompton's owners and management what they do or what they don't do. They have been very successful with what they have been doing and how they did it over the last decade, so not so much to complain. Plus it is one thing if you build by hand a couple of one-off Bromptons a year north of 3k as a one man band and a completely different story if you produce 50.000 bikes a year with 200-something staff.



Gunk said:


> rather than just producing more overpriced limited editions which are a pick and mix out of the accessories catalogue,


This an often heard claim but still as wrong as it has always been. If you look at the special editions and calculate the usual prices of the accessories the edition comes with you'll find out that they are not a penny more expensive than their standard silblings if you would add the same accessories. They are no doubt cash-cows to a degree as they foster demand due to being limited but they are not overpriced.



Gunk said:


> I suppose profit comes before proper R&D on a product which is already a big seller as it is.


I'd agree that Brompton has become less of an engineering company as it used to be and more of a marketing and sales driven company. On the other hand that's good in a way as they have built up marketshare and financial momentum to be able to invest. Still they are a relatively small company staffwise and do R&D as well as continuous improvement each year. The profit is there but - if you look at their numbers - within a normal range. Plus: If the bike sells good enough why should they change it massively and endanger their sales and their profit? Btw: A couple of months ago I and other Brompton riders received an invitation to a questionaire by mail asking what we would like to have changed or enhanced on the Brompton. I guess it went to people that registered their bikes with Brompton or such - but maybe the request ended up in the spam-folder (it did with me and I only found it after someone else mentioned it).


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## berlinonaut (30 Apr 2020)

rogerzilla said:


> If you look at the original series Brompton on eBay, which has its own thread, what's remarkable is how little things have moved on in 40 years.


I'd rather say this shows how brilliant the initial concept already was. Regarding changes over the years Id recommend to look a bit closer. The Mk2 of 1987 and a today's Brompton do share exactly two parts: The axle and pivot of the rear hinge and the little plastic thingy that is on the stem. Every other part has changed, many more than once. With the MK1 I'd assume there is not a single bolt that would be identical.

Following your argument you could also state that the bicycle as such lacks innovation as most today's bikes look surprisingly similar to the so called "safety-bikes" of the 1890ies when the diamond frame was invented and started to take the marketshare off the penny-farthing.

A "recent" gravel-bike race - in the 1890ies.  (picked from this brilliant picture-archives: https://wsjcc.co.uk/about-us/club-archives/)


rogerzilla said:


> It's a cash cow.


What's wrong about that? Would it be better if Brompton were strugelling and starving?


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## Hertz (21 Jul 2022)

I have M3L 2013. Want to convert to S1L. Never done bike mechanics before. By reading all your comments my lips went under my teeth. I thought it could be easy but seems not easy. I bought S bar already. So will give it a try. Not sure how to change 3 gears to one gear🤔. Or maybe it’s not possible to one gear?


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## mitchibob (22 Jul 2022)

Hertz said:


> I have M3L 2013. Want to convert to S1L. Never done bike mechanics before. By reading all your comments my lips went under my teeth. I thought it could be easy but seems not easy. I bought S bar already. So will give it a try. Not sure how to change 3 gears to one gear🤔. Or maybe it’s not possible to one gear?



Think you should be OK... you can get away without shortening cables initially, although they'll be a little too long, but if they haven't been replaced in a while, wont hurt to get some new brake cables at the correct length at the same time. 

Changing 3 gears to 1? Surely just a new rear wheel and removing the gear cable?


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## ExBrit (22 Jul 2022)

Gunk said:


> That’s crazy, it’s a 5 minute job to fit.



Rubbish - it took me at least 10 minutes 
Seriously, it's a trivial task and I'm still seeing plenty of S bars for sale on various sites.


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## rogerzilla (22 Jul 2022)

My mate wants to do this conversion but has decided to just buy an S and sell the M. It's easier.


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## berlinonaut (23 Jul 2022)

ExBrit said:


> Seriously, it's a trivial task and I'm still seeing plenty of S bars for sale on various sites.


True if you stick with the M stem and happy ending with up way lower bars than a normal S-Brompton. I'd only recommend this for very short people. And even if you want to go that low for many the P-stem would be a better choice as (like the S-stem) it offers more reach. If you want the height of an S normally one would switch to an S-stem with S bars or start fiddeling around with alternative bars on the M-stem where the Kusoac mid riser may be the easiest bet.


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## 12boy (23 Jul 2022)

A solution offered by Perennial cycles is a mtn bike stylebar with an few inches of rise. No spendier than any other bar. Another option is an Aber Hallo extension which can raise the bar and/or give an extension of a few inches.


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## berlinonaut (23 Jul 2022)

12boy said:


> A solution offered by Perennial cycles is a mtn bike stylebar with an few inches of rise. No spendier than any other bar. Another option is an Aber Hallo extension which can raise the bar and/or give an extension of a few inches.



I think the Perennial solution is (or was initially) intended for S-stems as for many people the S stem turned out to be too low. You can go up up to 10cm with the bars on an S-stem (and would then be level with M) but finding riser bars that would do that and not request more width (so leaving enough space for the grips and levers when cut down to ~52cm) were hard to find. This is where Perennial kicked in.
The Aber Hallo is indeed another option - but you'd still end up lower than S and on top of that pay a price in terms of optics, weight and mechanical complexity.


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## Kell (26 Jul 2022)

This is quite an old thread, but going down in height will not cause you any issues with cabling in terms of either gears or brakes not working. It will just be quite messy to have too much cable flapping around.

I reduced the height of my bike (from an H-type) by swapping the riser bars to some mid-risers I had lying around. Ran it like that to see if I liked it for a good couple of months before getting around to shortening the cables. Didn't encounter any problems with shifting or braking.

However, as others have stated (for the benefit of anyone reading the thread late) is that while all Bromptons appear to look the same to the untrained eye, it's not as simple as just swapping handlebars out as the stems are different. I've not yet come across a diagram that shows each of the stem heights, *but *if you know the rise of the bars, I guess you can work backwards to find out.


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## berlinonaut (26 Jul 2022)

Kell said:


> I've not yet come across a diagram that shows each of the stem heights, *but *if you know the rise of the bars, I guess you can work backwards to find out.


Speaking of the models before 2017 basically M + P do have the same stem height (not counting in the bars) as do S + H. P + S do have more of an forward angle in comparison to M + H and thus more reach. The H does have the folding hinge 3 cms higher than the other stems, thus allowing more overall height (including bars). The H stem is 6 cm higher than M and does have a total height (top of the headset to top of the bars at the clmping areaa) of ~37,5cm.
For 2018 Brompton changed stem and bars on M + H; the stems got slightly higher, the bars slightly lower to maintain the same overall height. The new H-stem has in total about ~40,5cm (again top of the headset to top of the bars), so a 3 cm difference to its older sibling. The same ~3cm got added to the M, too, while S + P stayed as before (and P vanished from the lineup completely about two years later).

As a consequence these are the about heights of the different stems (*not* bars):
M (before 2018): 31,5 cm
P: 31,5 cm
M (after 2018): 34,5 cm
S: 37,5 cm
H (before 2018): 37,5 cm
H after 2018: 40,5 cm

For the T-line the world is different again: There are only a M and a S model available - however: Both are using the same stem. So only one type of stem avail. on the T-Line. Did not measure it's height until now as I forgot to do it when I had one in my hands a while ago.


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## Kell (26 Jul 2022)

So that's all their lengths... how does that translate to height? i.e. from the ground?


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## T4tomo (26 Jul 2022)

Kell said:


> So that's all their lengths... how does that translate to height? i.e. from the ground?


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## Kell (26 Jul 2022)

T4tomo said:


> View attachment 654499



Stem height. Not bar height.


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## T4tomo (26 Jul 2022)

Kell said:


> Stem height. Not bar height.



www.google.co.uk


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## Kell (26 Jul 2022)

T4tomo said:


> www.google.co.uk





Kell said:


> I've not yet come across a diagram that shows each of the stem heights, *but *if you know the rise of the bars, I guess you can work backwards to find out.



The whole point is that I've never seen anything that on Google or elsewhere that shows the stem heights. Given that the OP was trying to determine what would happen if you put flat bars on an M stem it would be useful information.

If it did exist on Google (in an easily digestible form), I'd imagine that someone would have linked to it in one of the many, many threads about bar heights and bar swaps.

In fact it was that information that I was trying to find when working out my approach to buying (and modifying) my bike back in 2016. I never rode it as an H-type as I knew that I was always going to go for the mid-bars. 

There was someone on here that had made an S-Type higher with mid riser bars. I was interested in buying the H-type and making it lower - due to the way the stem folded higher up etc and the longer cables, but still couldn't find the information I needed. In the end I took a leap of faith...


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## berlinonaut (26 Jul 2022)

berlinonaut said:


> As a consequence these are the about heights of the different stems (*not* bars):
> M (before 2018): 31,5 cm
> P: 31,5 cm
> M (after 2018): 34,5 cm
> ...





T4tomo said:


> View attachment 654499





Kell said:


> Stem height. Not bar height.



Despite @T4tomo obviously not haven got the topic it is easy to fulfil your desire:
The S-stem is 37,5 cm and this results (with straight S-bars) in 925mm bar height. Which teaches us that to each stem we have to add 925mm-375mm=550mm = 55cm to get the overall height of a given stem on the Brompton.

M (before 2018): 31,5 cm -> 86,5cm
P: 31,5 cm -> 86,5cm
M (after 2018): 34,5 cm -> 89,5cm
S: 37,5 cm -> 92,5cm
H (before 2018): 37,5 cm -> 92,5cm
H after 2018: 40,5 cm -> 95,5 cm

However, the height from the ground will differ slightly depending from which tyres you mount. It is not a too helpful measurement also as you rather want to know the difference between pedal height and bar height if you want to do a bikefit and this depends from the height of the bottom bracket and the length of the cranks...



Kell said:


> The whole point is that I've never seen anything that on Google or elsewhere that shows the stem heights. Given that the OP was trying to determine what would happen if you put flat bars on an M stem it would be useful information.
> 
> If it did exist on Google (in an easily digestible form), I'd imagine that someone would have linked to it in one of the many, many threads about bar heights and bar swaps.


Indeed this information as to my knowledge does not exist. We tried to collect it for quite a while in the former Bromptonauten forum and once we were more or less done Brompton introduced the new stems 

But now you have it at your convenience, H-stems (old and new) measured by your's truly today and derivated the other values from there based on historical knowledge about their relations.


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## simongt (26 Jul 2022)

Not forgetting that using S bars apparently limits your front bag options. Not sure why, but that's what Brompton say - !


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## ExBrit (26 Jul 2022)

simongt said:


> Not forgetting that using S bars apparently limits your front bag options. Not sure why, but that's what Brompton say - !



Some tall bags interfere with the low bars making it hard to turn. I have to be careful to have the side pocket covers tied down or they will catch the brake levers as I turn


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## 404 Not Found Anywhere (26 Jul 2022)

> Kell said:
> 
> 
> > There was someone on here that had made an S-Type higher with mid riser bars. I was interested in buying the H-type and making it lower - due to the way the stem folded higher up etc and the longer cables, but still couldn't find the information I needed. In the end I took a leap of faith...



that might have been me - at any rate my 2009 S6L now has handlebars at M-height. Joseph Kurosac mid-rise bars from SJS cycles along with M-length cabling. Whilst I was at it I updated the brakes and shifters to the current versions. I'm very pleased with the change - I can ride without my neck complaining loudly every 20 minutes or so. Plus the newer controls are much slicker and more solid than the originals - especially as the shifters no longer rattle furiously. Handlebars are a mite wider too - I chose to compromise a little on the fold to achieve this, it sits on my Cane Creek bar end when folded.


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## berlinonaut (26 Jul 2022)

simongt said:


> Not forgetting that using S bars apparently limits your front bag options. Not sure why, but that's what Brompton say - !





ExBrit said:


> Some tall bags interfere with the low bars making it hard to turn. I have to be careful to have the side pocket covers tied down or they will catch the brake levers as I turn


As far as I know this is no longer true for a couple of years already. When Brompton invented the S-Stem in 2005 they also invented the S-Bag, that had a somewhat lower frame than the other bags. At that time it was the only bag officially compatible with the S-Brompton. All the others had the larger frame and the plastic grip of that larger frame was endangered to interfere with the steering or catch the cables in the worst case and thus rendering the steering useless.
In practice it was always possible to use the larger bags on the S- model as well with a bit of caution or slight modifications.

However: When Brompton overhauled their bag line two or three years ago they got rid of the plastic grip on the frame and replaced it with some textile handles on the bag. Since then, as far as I know, there are officially no issues with the S-model any more.


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## rogerzilla (30 Jul 2022)

For what it's worth, my friend has decided he doesn't like the S- type much as, being 6'2", the bars are too low for him. I'm 4" shorter than he is, and an S-type is just right for me.


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## brommieinkorea (28 Dec 2022)

berlinonaut said:


> As far as I know this is no longer true for a couple of years already. When Brompton invented the S-Stem in 2005 they also invented the S-Bag, that had a somewhat lower frame than the other bags. At that time it was the only bag officially compatible with the S-Brompton. All the others had the larger frame and the plastic grip of that larger frame was endangered to interfere with the steering or catch the cables in the worst case and thus rendering the steering useless.
> In practice it was always possible to use the larger bags on the S- model as well with a bit of caution or slight modifications.
> 
> However: When Brompton overhauled their bag line two or three years ago they got rid of the plastic grip on the frame and replaced it with some textile handles on the bag. Since then, as far as I know, there are officially no issues with the S-model any more.



Ugh... so does the "M" handlebar have a 120mm rise ? Which in turn means if you were to replace it with a bar with a 30mm rise you would end up at the same height as an "S"? How much farther forward is an "S" than an "M" ?


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## berlinonaut (28 Dec 2022)

brommieinkorea said:


> Ugh... so does the "M" handlebar have a 120mm rise ? Which in turn means if you were to replace it with a bar with a 30mm rise you would end up at the same height as an "S"? How much farther forward is an "S" than an "M" ?



The actual M/H handlebar has a rise of 10cm (if you measure at the inside of the high area of the bars) or ~13cm (if you measure at the outside). If you put a 10cm riser bar on the S you end up at M height (and that's the maximum possible with the S stem). If you put a cm riser on the M bars you end up with S height.

Regarding the forward angle this pic may help despite referencing to the older stems and bars before 2017/2018:





I did a writeup about the topic in the German forum, Google translate may be able to get the content:

https://bromptonauten.cc/threads/basiswissen-kleine-lenker-und-vorbaukunde.182/


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