Brompton M to S bars
- Thread starter Squirt01
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T4tomo
Legendary Member
Kell
Guru
T4tomo
Legendary Member
Kell
Guru
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...
Last edited:
berlinonaut
Veteran
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...
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.
ExBrit
Über Member
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
404 Not Found Anywhere
Über Member
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.
berlinonaut
Veteran
Not forgetting that using S bars apparently limits your front bag options. Not sure why, but that's what Brompton say - !
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.
rogerzilla
Legendary Member
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.
brommieinkorea
Well-Known Member
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" ?
berlinonaut
Veteran
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/
