# Brompton Mods



## Gandi (13 Apr 2020)

Hello,
I have searched through all 44 pages but cannot find anyone who has listed or mentioned the particular modification I am after doing.
I have a S2L but only being 165cms (5’5”) tall I want to go lower at the front. At the moment I can’t find any measurements of the different model stems (handlebar supports), I have seen diagrams and pictures showing the different overall height’s at the top of the bars but doesn’t show the stem lengths. I was thinking of fitting a “P” stem and if was too low I would fit something like a pr of Ritchie 30mm riser bars.
So does anybody know the height of the different stems.
Now for next mod, I am riding my Brompton using 44 x 16/12 and I was/am going to go to 14/12 but then this gives me a good alround every day gear and a bigger gear for tailwind and down hills, but a bit of thought I would be better making it into a 3 speed and keeping it 16/14/12 this then gives me a gear for the hills. So can it be done ?.

Cheers and thanks for looking


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## steveindenmark (14 Apr 2020)

Go on the FB Brompton site and ask. Someone on there will know.


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## berlinonaut (14 Apr 2020)

Gandi said:


> I have searched through all 44 pages but cannot find anyone who has listed or mentioned the particular modification I am after doing.
> I have a S2L but only being 165cms (5’5”) tall I want to go lower at the front. At the moment I can’t find any measurements of the different model stems (handlebar supports), I have seen diagrams and pictures showing the different overall height’s at the top of the bars but doesn’t show the stem lengths. I was thinking of fitting a “P” stem and if was too low I would fit something like a pr of Ritchie 30mm riser bars.
> So does anybody know the height of the different stems.


The P stem is about the same height as an M stem (version before 2017). You can combine either of those with an S bar and would probably be happy. The M stem is way easier to get hold of used than a P stem. The older version measures about 30cm from top of the headset to middle of the bar clamp. The newer M stem from 2017 on is slightly higher - about 2,5 cm. The H stem before 2017 has about the same height as the S (which you can measure yourself as you own it), the newer one is slightly higher - so both not an option for you.



Gandi said:


> Now for next mod, I am riding my Brompton using 44 x 16/12 and I was/am going to go to 14/12 but then this gives me a good alround every day gear and a bigger gear for tailwind and down hills, but a bit of thought I would be better making it into a 3 speed and keeping it 16/14/12 this then gives me a gear for the hills. So can it be done ?.


Yes, not a big deal. I've done the same mod on a 6-speed BWR (ending up with 9 gears) and it can be done identically with a 2-speed.


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## berlinonaut (14 Apr 2020)

steveindenmark said:


> Go on the FB Brompton site and ask. Someone on there will know.


Why? Someone here knows (and I am not on Facebook, so I wouldn't know there). What purpose does a forum have if the only answer to a question is "go on Facebook and ask there"?


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## steveindenmark (14 Apr 2020)

Because more Brompton questions are answered on the FB site. There are more Brompton owners on the Brompton FB site and therefore more experience. Brompton questions are replied to quicker on the Brompton FB site. This is not a Brompton site. It is a folding bike site

If you can find someone to point you in the right direction on here. Does that not serve its purpose?


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## 12boy (14 Apr 2020)

To answer your questions......
You can use a riser bar or several other bars such as North Roads and flip them which can drop your hand position. Both getting your saddle farther forward and using a bar like a North Road that gets your hand position behind the stem can make your reach easier. The Pentaclip saddle clamp can be reversed to make the saddle ride higher or lower and place you closer or further from your bars.
As far as gearing goes, Bike Gang sent me a proto type sprocket set with 11, 14 and 17 tooth sprockets that was very easy to swap out for the two sprocket normal set up. It works exactly as the two sprocket set, just giving a higher high, an intermediate gear and a lower low. The only drawback I can see is that the 11 tooth sprocket will wear out first and it's a one piece set, so you can't just replace it the 11 tooth.
I am enclosing pictures of my B with moustache bars to illustrate the handle bar drop and rearward hand placement.
In my mind, moving the saddle and replacing the bars with something that drops them down will be easier and much less expensive than getting a new stem and then moving everything over.
BTW, Ergon grips are nice on Bromptons as they soak up some road chatter.


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## berlinonaut (14 Apr 2020)

steveindenmark said:


> Because more Brompton questions are answered on the FB site. There are more Brompton owners on the Brompton FB site and therefore more experience. Brompton questions are replied to quicker on the Brompton FB site. This is not a Brompton site. It is a folding bike site


So why are you here then if Facebook is so much better than any forum could ever be and a forum is worthless by definition? From my personal experience a lot of people are not on Facebook and will never be, especially the more experienced ones. Facebook on the other hand is so famous for incompetent and obviously wrong and false information in all areas that they have been forced to install fake news checker teams...


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## steveindenmark (14 Apr 2020)

berlinonaut said:


> So why are you here then if Facebook is so much better than any forum could ever be and a forum is worthless by definition? From my personal experience a lot of people are not on Facebook and will never be, especially the more experienced ones. Facebook on the other hand is so famous for incompetent and obviously wrong and false information in all areas that they have been forced to install fake news checker teams...


Because I have 8 other different bikes. Not just a Brompton. Your very strange. 😳


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## Gunk (14 Apr 2020)

Here are the different combinations of stems and bars







What you could do is to fit an “M” stem with a low rise bar

https://www.ebay.co.uk/itm/264382727766


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## Tenkaykev (14 Apr 2020)

Gunk said:


> Here are the different combinations of stems and bars
> 
> View attachment 515065
> 
> ...


Just thought I'd mention that SJS cycles and Brilliant Bikes etc has these in stock for about £20. Nowt wrong with the Ebay ones but they have to travel all the way from Hong Kong.


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## rualexander (14 Apr 2020)

I recently put a three sprocket conversion kit on my Brompton, it was the MiniMods one from SJSC

https://www.sjscycles.co.uk/sprockets/minimods-brompton-3-cog-upgrade-kit-12-14-17t/

Out of stock just now but maybe available elsewhere. Not sure about different sprocket combos.

Works well, I just got a cheap friction front changer to go with it. If you currently have a 2 speed shifter then you may be able to modify it to 3 depending on the version, otherwise a new shifter will be necessary.


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## berlinonaut (14 Apr 2020)

Gunk said:


> Here are the different combinations of stems and bars
> 
> View attachment 515065
> 
> ...


What the OP was asking for is exactly the information that is missing from this as well as from the other usual illustrations: what height do the stems have on their own, w/o the bars. So your info is correct but somewhat missing the point the OP was asking for. As I wrote several postings earlier the old M stem (as shown in your pic) is about 30cm. The old H stem is about 36,5 cm. S is about the same as the old H, P is about the same than old M, the newer M and H are more or less 2,5 cm more. 
Brompton said on it's invention 2012 the H would be ~6 cm higher than the M. The old H has the bar height from the ground at ~93cm at the clamping area (and Brompton claim 92,4 cm of height for the S bars with S-stem). So with the old M stem or the P stem combined with Brompton S-bars one should end up at more or less 86,5-87cm of bar height.


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## berlinonaut (14 Apr 2020)

rualexander said:


> I recently put a three sprocket conversion kit on my Brompton, it was the MiniMods one from SJSC
> 
> https://www.sjscycles.co.uk/sprockets/minimods-brompton-3-cog-upgrade-kit-12-14-17t/
> 
> ...


The OP was asking for 12-14-16 - not the 12-14-17 the minimods-kit offers. Furthermore the 44 Pounds for the kit seem a bit ambitious. You can simply buy Shimano sprockets and use them: 12t, 14t, 16t - alltogehter this will cost you a freaking 9€. You will need a new chain (9 or 10 speed, depending from the sprockets you are using). You will need to modify your shifter or buy a Sunrace friction shifter. You won't need the spacer from the minimods kit as you can use your existing one and you can also reuse your existing lock-ring after filing on the 12t sprocket or create one from an old spoke. So you end up with 9€ of cost instead of 44 Pounds and you have the spacing you wanted instead of what Minimods offer. For the difference in price you can buy the missing bits like chain and shifter (that you would have to buy additionally to the upgrade kit anyway) plus a couple of beers to consume during and after the conversion.


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## Gandi (14 Apr 2020)

Cheers for the replies,
Just a little bit of info I missed out on my original post, as I mentioned I have the “S” bar set up and the stem is 35cms tall/length.

Thanks.


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## Fab Foodie (14 Apr 2020)

berlinonaut said:


> So why are you here then if Facebook is so much better than any forum could ever be and a forum is worthless by definition? From my personal experience a lot of people are not on Facebook and will never be, especially the more experienced ones. Facebook on the other hand is so famous for incompetent and obviously wrong and false information in all areas that they have been forced to install fake news checker teams...


Are you for real?
Put your prejudice to one side and you’ll find there are some fabulous Brompton member sites with serious knowledge and global experience of every facet of Brompton modification and customisation. 
Jeez...You can lead a horse to water.....


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## rualexander (15 Apr 2020)

berlinonaut said:


> The OP was asking for 12-14-16 - not the 12-14-17 the minimods-kit offers. Furthermore the 44 Pounds for the kit seem a bit ambitious. You can simply buy Shimano sprockets and use them: 12t, 14t, 16t - alltogehter this will cost you a freaking 9€. You will need a new chain (9 or 10 speed, depending from the sprockets you are using). You will need to modify your shifter or buy a Sunrace friction shifter. You won't need the spacer from the minimods kit as you can use your existing one and you can also reuse your existing lock-ring after filing on the 12t sprocket or create one from an old spoke. So you end up with 9€ of cost instead of 44 Pounds and you have the spacing you wanted instead of what Minimods offer. For the difference in price you can buy the missing bits like chain and shifter (that you would have to buy additionally to the upgrade kit anyway) plus a couple of beers to consume during and after the conversion.



Yes I know the OP was looking at 12-14-16, but I was simply giving the information about what I did as a possible alternative. I did acknowledge that the sprocket combo was not exactly what they were looking at.

Where are you getting Shimano sprockets for €3 each?

The existing spacer on a 2 sprocket setup will be too wide for a 3 sprocket setup.

Not everyone wants to get involved in filing down sprockets or creating snaprings out of old spokes.


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## rogerzilla (15 Apr 2020)

If you put the "wrong" bars on a particular stem, there are a couple of issues to watch for:

1. Folding might be compromised; the bars can hit the ground, the front hub or something else.

2. You'll need to work out cable lengths for yourself if you want them to fold and sit just right when the bike is unfolded. The stock cable lengths assume a particular combination of factory bar, stem and frame length (SWB or LWB).


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## berlinonaut (15 Apr 2020)

rualexander said:


> Where are you getting Shimano sprockets for €3 each?


I linked the source in my posting. I'd assume these to be more or less standard prices. Just follow the links in the post.


rualexander said:


> The existing spacer on a 2 sprocket setup will be too wide for a 3 sprocket setup.


Strange than that my 3 sprocket setup is running with exactly that existing spacer and is has been for years.... I hope it will not suddenly stop working now that you said it would be too wide to work.



rualexander said:


> Not everyone wants to get involved in filing down sprockets or creating snaprings out of old spokes.


Everybody is free to buy a locking for the equivalent of 40 Pounds - 9€. Pretty expensive lockring I'd assume. And I also woud assume that it should be possible to buy a suiting slimmer lockring for a maximum of let's say four or five quid, if one would search for one (which I did not do as there was no need for it).


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## berlinonaut (15 Apr 2020)

rogerzilla said:


> If you put the "wrong" bars on a particular stem, there are a couple of issues to watch for:
> 
> 1. Folding might be compromised; the bars can hit the ground, the front hub or something else.


S-bars on M-stem and P-stem work and fold flawlessly - I know people who run both of these setups.


rogerzilla said:


> 2. You'll need to work out cable lengths for yourself if you want them to fold and sit just right when the bike is unfolded. The stock cable lengths assume a particular combination of factory bar, stem and frame length (SWB or LWB).


That's obvious but not too hard to figure out. Especially if the OP sticks with the S-bars or at least with a similar width it is more or less 1cm less cable length per cm lowered bars. A bit too long cables do not hurt during experimenting and testing and 2-3 cm too long cables are not a real issue in practice (while massively longer may start to be annoying and get in the way). Personally I am i.e. running the new H bars on the old H stem, so overall height is more or less what P used to offer. Still using the original cable-lenght w/o issues. Before that I had an S-bar with a riser on the same old H-stem, again using the original cables. This was clearly too long with the consequence that sometimes cables would get caught by the hinge on the stem when unfolding and rarely the rear brake cable managed to throw the chain off the chainwheel when unfolding due to being massively too long. Apart from that no real issues in practice - still I wouldn't recommend running with way too long cables.


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## rogerzilla (15 Apr 2020)

"S-bars on M-stem and P-stem work and fold flawlessly"

That's useful to know. M-bars on an S-stem wouldn't fold at all, I suspect. One grip of an M-bar already grazes the ground with an M-stem.


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## Pale Rider (15 Apr 2020)

Fab Foodie said:


> Are you for real?
> Put your prejudice to one side and you’ll find there are some fabulous Brompton member sites with serious knowledge and global experience of every facet of Brompton modification and customisation.
> Jeez...You can lead a horse to water.....



The purpose of posting answers on here is two fold.

Help the OP, but also maintain and build the CC community.

There is a judgement to be made, but simply shunting posters elsewhere may achieve the former, but it does nothing for the latter.

We do have expertise in Brompton bits on here, so there's no valid excuse to bat away the inquiry.

Ebikes is another example.

A few years ago it was only me and Emma - @voyager - who knew anything about them.

Some inquiries were just sent to the Pedelecs forum and the threads stopped there, but we now have a decent handful of posters who can answer ebike queries.

Thus we've achieved both aims, the OPs are answered and the CC community has grown.


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## berlinonaut (15 Apr 2020)

rogerzilla said:


> "S-bars on M-stem and P-stem work and fold flawlessly"
> 
> That's useful to know. M-bars on an S-stem wouldn't fold at all, I suspect. One grip of an M-bar already grazes the ground with an M-stem.


Short overview about the topic: Typically you won't run into issues if you go lower than than the stock configuration that is delivered from the factory. You typically will if you want to higher oder wider, with the S-stem being an exception from the rule. With the S you can go 10cm higher if you maintain the widht, if you want to go wider you can't go as high. H, P and M outlast the possible height and width limits already with the factory bars. You will however gain a cm or two if you have a rear rack mounted to your bike as this lifts the bike a tiny bit higher on the bar side than the L configuration w/o rack does.
Obviously bars of other shape like bullhorns, racing bars, Jones bars or alike won't work with the fold if you do not implement a kind of quick-release as an additional folding possiblity to them. Still they may or may not work and almost always supersize the folded package considerably.
Risers like the AberHallo can only applied to S-bars (on any stem) or third party bars as the M/H bars lack a wide enough clamping area for those (no matter on which stem), furthermore even if if was possible on M and H stem with riser and M/H bars of the same generation you'd hit the ground when folding.
Third party bars that offer considerable rise and at the same time enough grip width and can still be folded are not that easy to find - the Joseph Kusoac ones are the easiest to go for (available in two sizes). I found one bar on ebay from Asia that is available in 8 and 10cm rise that fits as well. Apart from that you are basically limited to MTB bars which in most cases limits you to about 3cm rise to maintain enough grip width once the bar is cut at it's sides as the rise on MTB-bars is typically way less steep than on Brompton bars.


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## rogerzilla (15 Apr 2020)

Oddly, given that Brompton have never offered such things, stubby bar-ends on an S-type don't interfere with the fold at all!


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## berlinonaut (15 Apr 2020)

rogerzilla said:


> Oddly, given that Brompton have never offered such things, stubby bar-ends on an S-type don't interfere with the fold at all!


They did, on the New York Edition:






But indeed this was the only time until now.


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## Fab Foodie (15 Apr 2020)

Pale Rider said:


> The purpose of posting answers on here is two fold.
> 
> Help the OP, but also maintain and build the CC community.
> 
> ...


None of which means we shouldn't be able to direct people to other sources of knowledge that we have found useful or be castigated for daring to do so....


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## berlinonaut (15 Apr 2020)

Fab Foodie said:


> None of which means we shouldn't be able to direct people to other sources of knowledge that we have found useful or be castigated for daring to do so....


Agreed. But as a lump-sum first answer to a concrete question in a forum where this question is totally on topic to redirect someone "to facebook" is no concrete advice and in my eyes intimidating for a forum. I also consider it insulting towards the other members of that forum as they are obviously considered to be incompetent by the person posting such an answer. Different story if one says: For your specific question there's this thread, this blogpost, this bit of information or this person somewhere else who might be able to help. Or to redirect someone who has a really esoteric question and after some time there has been no useful help or advice for him.


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## u_i (15 Apr 2020)

steveindenmark said:


> Because more Brompton questions are answered on the FB site. There are more Brompton owners on the Brompton FB site and therefore more experience. Brompton questions are replied to quicker on the Brompton FB site. This is not a Brompton site. It is a folding bike site
> 
> If you can find someone to point you in the right direction on here. Does that not serve its purpose?



I do not know what is meant by 'Brompton FB site' but I found 'Brompton Hacks Public Group' there, that topped popularity. I scrolled about 50 Page Down worth of material there and found that I must be particularly dense as I could not identify a single significant passage of useful information. (There was quite a bit that I knew to be wrong and/or trivial.) After 50 pages my browser choked up and I went to another browser and after a comparable amount of scrolling it choked up too. Yes, obviously people can post as well here as there and elsewhere, but FB seems to lack structure it filtering out useful info, with Post-It tacked to a Post-It to a Post-It, sort of like my table. I communicated with other people to figure out whether it is the problem with me or FB and they seemed all to lean to the fault being there. I guess ideas need criticism, alternatives, discussion tweaking and cataloging and not all platforms work equally well.


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## cyberknight (15 Apr 2020)

Heres me expecing a chap in a parka with a load of wing mirrors


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## steveindenmark (15 Apr 2020)

u_i said:


> I do not know what is meant by 'Brompton FB site' but I found 'Brompton Hacks Public Group' there, that topped popularity. I scrolled about 50 Page Down worth of material there and found that I must be particularly dense as I could not identify a single significant passage of useful information. (There was quite a bit that I knew to be wrong and/or trivial.) After 50 pages my browser choked up and I went to another browser and after a comparable amount of scrolling it choked up too. Yes, obviously people can post as well here as there and elsewhere, but FB seems to lack structure it filtering out useful info, with Post-It tacked to a Post-It to a Post-It, sort of like my table. I communicated with other people to figure out whether it is the problem with me or FB and they seemed all to lean to the fault being there. I guess ideas need criticism, alternatives, discussion tweaking and cataloging and not all platforms work equally well.


I have not been on Brompton hacks. Just London Brompton Club and Brompton Folding Bikes and so cannot comment.


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## Fab Foodie (15 Apr 2020)

berlinonaut said:


> Agreed. But as a lump-sum first answer to a concrete question in a forum where this question is totally on topic to redirect someone "to facebook" is no concrete advice and in my eyes intimidating for a forum. I also consider it insulting towards the other members of that forum as they are obviously considered to be incompetent by the person posting such an answer. Different story if one says: For your specific question there's this thread, this blogpost, this bit of information or this person somewhere else who might be able to help. Or to redirect someone who has a really esoteric question and after some time there has been no useful help or advice for him.


It was good advice well meant. Get-over yourself.


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## Schwinnsta (16 Apr 2020)

12boy said:


> Bike Gang sent me a proto type sprocket set with 11, 14 and 17 tooth sprockets that was very easy to swap out for the two sprocket normal set up. It works exactly as the two sprocket set, just giving a higher high, an intermediate gear and a lower low. The only drawback I can see is that the 11 tooth sprocket will wear out first and it's a one piece set, so you can't just replace it the 11 tooth.



Is it alloy or steel?


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## 12boy (16 Apr 2020)

It is steel. At this time of year, with 20 mph headwinds very common, having some gear inches between 85 and 55 (67) is very nice. 85 is very nice with 20 mph tailwind and 55 on a 5% grade with said headwinds is good, too.


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