M to H conversion

[CEBEP]

First of all I'm really happy I could find a forum with so many Brompton enthusiasts and such a friendly community. It took me some time to come here

For a few weeks already I'm proud owner of Black Edition Explore Flame Lacquer. Such an awesome bike! We have very limited availability of Bromptons in Istanbul, probably as in other areas of the world as well due to covid pandemics. So it was the only one available in this color and all models of any type or color in Istanbul were M. I'm 185cm, about 96kg and am having bad back. As far as I know my hight is at the recommended upper limit for M stems and I believe H stem will offer better ride quality for me and help with my back. Since I can't try it I don't know for sure if it will be the right choice as I will have to order an H stem + longer cables. Not a cheap drill.

My question is is there any bad sides to riding H instead of M? Any handling differences? I feel it will be the right thing to do but would appreciate any advise.

 

[CEBEP]

Cheaper alternative could probably be the handlebar extention/riser

https://www.ebay.co.uk/itm/161141554368







However there are few issues here:

1. this item is miraculously on eBay only and since PayPal is banned in Turkey I can't order it. Anyone has any idea where else this item can be ordered?

2. 25.4mm thick part of M handlebar is not all that wide, about 3cm. Then it tapers down. I'm not sure this 3cm will be wide enough for adaptor rings to grip.

Is this bad idea?

 

[Kell]

Welcome.

I'm not going to be much help here, but as far as I was aware, the M handlebars are the same as the H handlebars in terms of rise - it's the length of the stem that makes the H taller.

That was certainly the case when I bought mine, but mine's the older style (2015).

I think it's still the case now, but wouldn't swear to it.

However, I think the current style of handlebar is lower than the old style, so it may be possible to swap the new one for old to give additional rise.

Current:

Older:

@berlinonaut will definitely know. I'm certain plenty of others will too.

I have seen other people use those adapters (or ones like them) so hopefully someone will be along to give you a better understanding.

 

[CEBEP]

Apologies, I wrote in wrong. It's H stem of course. I noticed the mistake but apparently wasn't able to change the post

 

[Tenkaykev]

Welcome.

I'm not going to be much help here, but as far as I was aware, the M handlebars are the same as the H handlebars in terms of rise - it's the length of the stem that makes the H taller.

That was certainly the case when I bought mine, but mine's the older style (2015).

I think it's still the case now, but wouldn't swear to it.

However, I think the current style of handlebar is lower than the old style, so it may be possible to swap the new one for old to give additional rise.

Current:

View attachment 616863

Older:

View attachment 616864

@berlinonaut will definitely know. I'm certain plenty of others will too.

I have seen other people use those adapters (or ones like them) so hopefully someone will be along to give you a better understanding.

I was going to use the Aberhalo riser in combination with a Joseph Kuosac mid rise bar on one of my Brommies. I’d previously purchased several items from the bay which all came from China or Taiwan and it all arrived without issue or any excess charges to pay. Having read several accounts of delays and excess handling / import charges I’m reluctant now to take the risk.

 

[Schwinnsta]

I think you need H stem. Otherwise, bar too low in the folded position. You can check this by checking how much clearance in the folded position you have now. I converted my 2014 to an H .lt cost but it was worth it.

 

[CEBEP]

Welcome.

I'm not going to be much help here, but as far as I was aware, the M handlebars are the same as the H handlebars in terms of rise - it's the length of the stem that makes the H taller.

That was certainly the case when I bought mine, but mine's the older style (2015).

I think it's still the case now, but wouldn't swear to it.

However, I think the current style of handlebar is lower than the old style, so it may be possible to swap the new one for old to give additional rise.

Current:

View attachment 616863

Older:

View attachment 616864

@berlinonaut will definitely know. I'm certain plenty of others will too.

I have seen other people use those adapters (or ones like them) so hopefully someone will be along to give you a better understanding.

Great idea, thanks! As far as I know 2020 Brompton M handlebar is 53cm wide and rise is 13cm. Pre 2017 handlebars have 15cm rise which will give only 2cm difference. Joseph Kuosac full rise handlebar is even lower. However there are third party manufacturers on Aliexpress offering 170cm rise which is 4cm difference and very close to the difference between M and H type stems. Do you think I will still need to order cables for H stem to accommodate 4cm rise difference?

 

[berlinonaut]

the only one available in this color and all models of any type or color in Istanbul were M. I'm 185cm, about 96kg and am having bad back. As far as I know my hight is at the recommended upper limit for M stems and I believe H stem will offer better ride quality for me and help with my back.

Not necessarily - especially if you have a bad back when cycling it is important not to put all the weight on your lower back but distribute the weight between bars and saddle. In general, a too upright riding position should therefor be avoided. To do this will also help with building up muscles in your back an this way lower the pain. I am slightly taller than you (just) and find a H-model clearly too high for me. On the other hand I did not like M and clearly not S for longer rides.

Since I can't try it I don't know for sure if it will be the right choice as I will have to order an H stem + longer cables. Not a cheap drill.

The H stem is best for using and trying out different handlebars. As the folding hinge is slightly higher you can use bars of different heights and widths with it.

My question is is there any bad sides to riding H instead of M? Any handling differences? I feel it will be the right thing to do but would appreciate any advise.

As said above I am not sure if a stock H will suit your needs. Alternative bars may.

Cheaper alternative could probably be the handlebar extention/riser

You cannot use this with a M stem as the bike will not fold any more and furthermore the AberHallo will not fit an M/H-bar as well.

Is this bad idea?

Unfortunately yes.

the M handlebars are the same as the H handlebars in terms of rise - it's the length of the stem that makes the H taller.

That was certainly the case when I bought mine, but mine's the older style (2015).

I think it's still the case now, but wouldn't swear to it.

still true. Just the height ratio between stems and bars changed slightly but not the overall height and M and H bars are still identical.

On most of my Bromptons I do use the older H stem before 2017 along with the newer M/H bars from 2017 on. This way I do achieve a height between stock M and stock H which I like. After using this setup for years already I am now into a new experiment: On one of my Bromptons I do use the new H stem (2017 onwards) along with a slight riser bar that is way wider than stock. Overall height is ~110cm, so about what M offers. buth width is ~60cm, so massively wider than stock. I like - at the moment my most ridden Brompton. However: With the M stem you are locked into the factory bars if you do not want to go lower. Going higher and/or wider hinders the fold.

 

[CEBEP]

I think you need H stem. Otherwise, bar too low in the folded position. You can check this by checking how much clearance in the folded position you have now. I converted my 2014 to an H .lt cost but it was worth it.

You mean H stem has pivoting mechanism higher than M stem? If that's the case adding spacer or handlebar may end up handlebar ends hitting the ground?

 

[CEBEP]

@berlinonaut
Many thanks, very valuable info. I'm appy I didn't make mistake buying that extender. It's also clear that if I want to experiment, I'll need to invest into the H stem + cables. Different handlebars are widely available.

 

[berlinonaut]

You mean H stem has pivoting mechanism higher than M stem?

Yes

If that's the case adding spacer or handlebar may end up handlebar ends hitting the ground?

With the M stem an the original bars, yes. But it will not fit the original bars anyway. You can use the Aberhallo or similar risers with straight bars like i.e. the Brompton S-bar. But this will not lead to your desired outcome of a bar higher than M.

 

[CEBEP]

Not necessarily - especially if you have a bad back when cycling it is important not to put all the weight on your lower back but distribute the weight between bars and saddle. In general, a too upright riding position should therefor be avoided. To do this will also help with building up muscles in your back an this way lower the pain.

Do you think suspended saddle mount will help bad back too? They will have much wider range of motion than Bromptons suspension. If yes what could be the disadvantages of installing it? Thanks.

 

[rogerzilla]

Can you buy an H stem in Turkey? We can't buy the part in the UK - we can only pay a dealer to supply and fit one. It is, apparently, too difficult a job for mere mortals.

 

[berlinonaut]

Can you buy an H stem in Turkey? We can't buy the part in the UK - we can only pay a dealer to supply and fit one. It is, apparently, too difficult a job for mere mortals.

As said many times before: This seems to be an almost exclusive UK issue for the time being.

 

[berlinonaut]

Do you think suspended saddle mount will help bad back too? They will have much wider range of motion than Bromptons suspension. If yes what could be the disadvantages of installing it? Thanks.

I'm not a huge fan of suspended seat posts either. They will eat up power (that then cannot be used to push you forwards) and - as with a suspended seat post the distance between saddle and pedal varies - they are an ergonomical nightmare. "Bad back" can mean a lot of things and have a lot of root causes. With some a suspended seat post may be able to linder pain, for most it is just counterproductive. Thus I would consider them as a kind of last exit if nothing else helps. Before that I'd clearly have an ergonomic bike fit and a bit of training to build up muscles. In most cases this will not only be sufficient and in many cases also help to get rid of the back pain also when not on the bike (through the building up muscles in the back when sitting on the bike ergonomically correct). A suspended seat post won't help you with that but at best linder pain when on the bike. So it deals with lindering symptoms only and at a price instead of making things better.