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Old 06-23-09, 04:21 PM   #1
Aguila281
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Brompton M-type handlebar on a P-type

Hi guys,

Today I went for (another) test ride with a Brompton, and yes I'm really falling in love with these babies.

One of the most difficult decisions is the handlebar type.
An M-type has a short reach and makes me feel I'm going to be flung over the bike doing an emergency stop.
The S-type is way too low (I'm 1m88, with 93cm inseam. This means I'll be using a telescopic seat tube. An S- is way too sporty for town.
A P-type seems te be a good compromise, more reach and good handlebar height.

Could I swap the P-type handlebar with an M-type if I wanted better grips? How do they compare in height (measured from the stem to top of bar)? How much total height would lost in this conversion?

Has anyone tried putting a handlebar with some serious rise (say about 80-90mm) on an S-type? S-types have even more reach forward. But I could do with some 5-6 cms more handlebar height for my neck

Thanks tweekers!

Luca

Last edited by Aguila281; 06-23-09 at 04:22 PM. Reason: typo in the title, butter fingers!
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Old 06-24-09, 02:11 PM   #2
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The M and P type bars are swappable. The brake cables are the same, but the gear cables will need to be changed. The S type bars are not - they require a different stem; as you mentioned it's more curved to give a longer effective top tube.

EDIT: Oh, looks like the brake levers are different for the M and P/S types. Bummer.

I don't think it would be trivial to fit, say, the M type bars to an S type stem and still retain the fold, the bars would hit the ground before they engaged the handlebar catch.

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Old 06-25-09, 03:00 PM   #3
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As I understand it, the P type gives very similar bar positions to both the M and the S. I didn't look into it too much when I bought my Brompton, because it's ugly!
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Old 06-26-09, 02:34 AM   #4
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Quote:
Originally Posted by Aguila281 View Post
Hi guys,

Today I went for (another) test ride with a Brompton, and yes I'm really falling in love with these babies.

One of the most difficult decisions is the handlebar type.
An M-type has a short reach and makes me feel I'm going to be flung over the bike doing an emergency stop.
The S-type is way too low (I'm 1m88, with 93cm inseam. This means I'll be using a telescopic seat tube. An S- is way too sporty for town.
A P-type seems te be a good compromise, more reach and good handlebar height.

Could I swap the P-type handlebar with an M-type if I wanted better grips? How do they compare in height (measured from the stem to top of bar)? How much total height would lost in this conversion?

Has anyone tried putting a handlebar with some serious rise (say about 80-90mm) on an S-type? S-types have even more reach forward. But I could do with some 5-6 cms more handlebar height for my neck

Thanks tweekers!

Luca
NO! The S-Type bars are PERFECT for riding busy streets and great for the city centre where people walk in the middle of the road. The S-type bars give the bike great agility.

I would agree though that the S-type is the “sports” version, The P-type is the tourer and the M-type is for sedate, relaxed riders.


I did try a bike with M bars once but I found the S-type far more comfortable and a dammed site better looking too.

Last edited by PDR; 06-26-09 at 02:37 AM.
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Old 06-27-09, 07:46 AM   #5
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M-Type is actually good for tricky commutes with kerb hops, potholes and lots of maneuvering, its less efficient aerodynamically so it depends what you value. Personally, i think a lower and slightly wider M type bar would suit more people and be an effective compromise. There are a couple of riser bars that would fulfill this need but they tend to be a bit swept back


. On balance - and having tried a friends S-type - I prefer speed so I'm going to convert my M to an S. If anyone is interested in the full M -type kit (stem, bars, grips and levers) for an opposite conversion then drop me a PM!
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Old 06-28-09, 08:10 AM   #6
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I found this comparison picture on www.brompton.co.uk:

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Old 06-29-09, 11:33 AM   #7
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Brompton M-type handelbar on a P-type

Hi all,

Thanks for the input so far. A pure S-type would be way too low for me. I get problems with my neck an anything longer than a few kilometres.

The thought of adding a downhill riser bar with some decent rise (like 50-70mm) to an S-type does appeal to me. Has anybody gone that way?

The sweep back is usually the prob.

The picture looks familiar . I tried comparing the options in photoshop, but it doesn't really give a good sense of height.

So nobody has tried swapping a P with an M-type bar? Personally I don't really care for the looks. That's something to get used to.

Bye

Luca
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Old 06-30-09, 01:43 AM   #8
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Luca,

I'd like to know the answer to your question too. In the mean time, check this thread: Some Brompton Mods (56K Warning)

He/ she swapped an M-bar for a mountain riser. Anyone sure this can be done with an S-stem too?

Wim
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Old 07-07-09, 03:40 PM   #9
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Tried it today and it seems to work... so I ordered!

Hi all,

Long story short: It will work!

Over the weekend I did a lot of internet research, some calculations, even tried pasting the M-type handelbars on a P-type in photoshop. The theoritical conclusion was that the M-type bar would fit on a P-type stem, ending up with a total height of about 1cm lower than the P-type stem and bar combo (the original). The P-type handlebar is 16cm above the stem clamp and the M-type 15cm. The P-type stem is about 1cm higher than the M-type, leading to the 18mm more height in total, assuming the foam of the grips is equal in thickness.

So today I went back to the store and yes! my theories seemed to work in real life. I held a spare M-bar next to a P-type and it worked out just as I had calculated. The package remains 100% foldable. BTW you need the 1cm less height to make up for the bit of added width (M-type bar is 53cm as opposed to the P-type, meaning it comes closer to the ground because of the added 1,5cm). In the end it all evens out to the same ground clearance as the original P-type.

So I bit the bullet and ordererd a P-type with an M-type bar. The dealer was reluctant at first, but after actually holding the bar next to the bike he was finally convinced. Shouldn't that be the other way round? Now, let's wait and see what Brompton say when they get that order.

When the bike arrives, I'll post some pics.

BTW, I even believe there will be room for some ergons. Since I've got them on another bike I can try that myself.

Oh yeah, some may wonder: why go to such lengths? Because that's just me. And because I want as much height as possible together with some extra top-tube length (long arms and legs, so I'll still be riding with the bars well under the seat, without getting neck pains though). The P-type bars were too flexible in my opinion. The M-type bars are a lot stiffer and it just feels safer. Plus you can add bar-ends if you like.

Sorry for the rant. But maybe this can spark some ideas for other people who are discouraged by relactant dealers. No disrespect to them or Brompton in any way. The package of the bikes is already beautifully optimised for each type of handlebars. But what would the world be without some customisations...

Bye

Luca

Last edited by Aguila281; 07-07-09 at 03:43 PM.
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Old 07-08-09, 03:02 AM   #10
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Hi Luca,

Very interesting post for tall people.

"because I want as much height as possible together with some extra top-tube length"
>>> any idea how much that is?

With all your calculations, you probably also know the distance from the ground to the handlebar?

I thought S-type with risers was the way to go, but maybe P-type with M-bar is a better idea. Especially if they can do it in the factory. Any difference in top-tube length between the P-stem and the S-stem?

Wim
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Old 07-08-09, 03:20 PM   #11
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Update on the process

Quote:
Originally Posted by wim View Post
"because I want as much height as possible together with some extra top-tube length"
>>> any idea how much that is?
No, sorry. Dealers don't like people with tape measures in their showrooms I'll measure everything up when I get the bike and post some pics.Top tube length also varies with how far your seat is up and how far it's back on the rails. When you're tall you may find that the original saddle is too far back even at the extreme forward setting. That is using the "knee over pedal" rule. And since I value my knees, I stick to that. A Brooks could cure this, as you sit more to the front automatically to avoid the metal frame.

Quote:
Originally Posted by wim View Post
With all your calculations, you probably also know the distance from the ground to the handlebar?
Ground to handlebar on a P-type is 1033mm, M-type 1015mm, P-type stem with M-type bars should be bang in the middle, that's about 1024mm (calculated, not real measurements!). The stem is 30mm more to the front at that height, compared to a pure P-type. This can be adjusted a little by tilting the bars forwards or backwards.

Quote:
Originally Posted by wim View Post
I thought S-type with risers was the way to go, but maybe P-type with M-bar is a better idea. Especially if they can do it in the factory. Any difference in top-tube length between the P-stem and the S-stem?
I've played with the idea of getting an S-type and fit a BMX type bar myself to get about 100mm rise. Theoretically this can be done, as long as the bars don't sweep back too much or rather very little. And as long as you cut them to the right width. But finding a bar with more than 50mm rise that fit the bill is not an easy task. I didn't want to take that risk.
Top tube length on a P-type is 30mm more than M-type, S-type is 50mm more to the front. That's measured at the height of the handlebar which is lower to the ground (935mm). Take a look here, this is where I got he figures:http://www.greenspeed.com.au/brompton/ride.html

Today I called the dealer to hear what Brompton had replied. They strongly advised against fitting an M-type bar on a P-type stem because of safety reasons, warranty issues, compromising the fold, etc etc... Even the dealer wouldn't do it in-house (he's an A-dealer, so he'd better listen to B) Personally, I understand they don't like anybody eperimenting with the integrity of the bike. But the safety issue is completely idiotic. The M-bar is a lot more sturdy than the P-type. The stem clamp is the same. The leverage (height) is even sligtly less than in the original design! I accept the possibility that the folded bike may be a few millimetres wider. Ah, never mind.

So I'll order a P-type with an extra M-type bar and just do it myself. For a moment they actually thought they had talked me out of this...

Even though this mod will result in more top-tube length, you don't really get more height. That is impossible without REALLY compromising the fold. And that's just the essence why I'm buying a B. So In my case (1m88cm and 93cm inseam) that means that even then the top of the bars will be about 6-7cm under the top of the seat. That's quite sporty, but still ok for longer rides. Even then top tube will be on the short side.

To be continued.

Wim, are you Flemisch or Dutch? If so, and if you live near Antwerp, you can come and have a look at the result if all this works out (That's in 6 to 8 weeks from now+some time for the mod)

bye

Luca
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Old 07-08-09, 03:50 PM   #12
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Hi Luca,

Thank you for your elaborate reply. Your membername made me think you were Italian, from the city of L' Aquila. I am Flemish (Gent). And I have about the same measurements as you at 190cm.

Although I am a very happy Dahon owner, I need something that folds smaller for my traincommutes, so looking for a Brompton that fits. Bromptons are more difficult to mod than Dahons (or at least for me they are) so I like your approach: only Brompton parts.

Thank you for the invitation, just not sure I am willing to wait that long to order my own! :-)



Wim
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Old 07-09-09, 04:22 PM   #13
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Hi Wim,

As you are a Dahon owner you can compare the top tube of the Brompton to that. The P-type is about the same, a tad shorter. Dahon tend to be fairly long in top tube(with the saddle set for our height).

A week ago I had some rides on my Batavus folder near the seaside (it looks very much like a Dahon Mu, come to think of it some original parts actually have "Dahon" on them...). The handlebars on the P-type Brompton are about the same height as the Dahon's set on 1 inch under the maximum insertion mark (with the standard flat bars). In the picture below that means the height of the handle bar clamp (should be about 103cm from the ground). The saddle would be set 2-3 cm too low for you. Top tube is a bit shorter, hard to tell how much exactly. I had them side by side last week at the dealership.


One of the reasons why I'm buying the Brompton is the more compact fold. The Dahon looks petite untill you load it into the trunk of your car together with some bags and a cooler box. All of a sudden it takes up a lot of space! The compact fold is also a lot easier to carry up stairs etc. There's not much of a weight difference between a 20 inch Dahon and a fully equipped B. But the compactness makes all the difference. But even then I wouldn't want to carry either for more than 50 meters.

But they are very comfy and fun bikes to ride and easy to mod (you can even fit suspension seat posts etc.). Brompton's can not be modded that easily. Lots of proprietary parts

The best advice I could give you is to take your Dahon to a dealer and put it next to a Brompton for P-type for comparison. The ride of the Brompton is surprisingly comfy, considering the smaller wheels and narower tyres, when compared to the 50mm wide front and 47mm wide aft tyres on the Batavus that is. If you ride the standard tyres on the Dahon, you won't feel much difference in ride quality or comfort. Good points for Brompton there!

Happy hunting!

Bye

Luca

PS: Luca is my nick (as in Ray Luca in Crime Story)
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Old 10-22-09, 02:20 AM   #14
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Hello,
I have just bought an S-type, and being a taller rider need extra reach. I've just ordered these
http://cgi.ebay.co.uk/Spank-Tweet-Tw...item33561e4418
70mm was the highest rise I could find, and I think will make all the difference.
I'll post a picture when they turn up and are fitted.
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Old 05-11-12, 05:13 PM   #15
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I joined your club: P stem with an M bar, as per advise of capproblema shop in Barcelona. I am quite tall 1,92m (6feet 6") so I have gained about 5 cm forward. I tested it yesterday and hell yes now I can press the pedal to the metal! Those guys are the best brompton specialist I have known so far, selling exclusively BP since year 2000.

I took your idea and we tried in the workshop. Now I'll go for the world championship with a racing machine!


Thanks,

Monskton

Last edited by Monskton; 05-15-12 at 04:22 AM.
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Old 05-13-12, 12:56 PM   #16
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I used the SAP, on my Mk2, it is a pin that is made to put the saddle closer, but,
I used it on top of my steel extended seatpost, pointed back, ,
to give me more setback, which also took weight from my hands to my bum.

It,P riser, to my eye, has more kink bent to it than the M riser..
New this year is the H riser, they added 3cm to both sides of the hinge,
so bar will not strike the ground , when folded down. +3,-3 then.. but +6 when up.

I would look also into the Non Brompton , Trekking bar from Modolo,
their Model 'Dumbo' has worked in place of the P/M bar as its a very adjustable
setup of wings on a U shaped piece that would be held by the 1" clamp on top of the folding riser.

SJS had them, ask if they have been discontinued, or is just a stocking issue, at present.

the clamp setups that create adjustability are not weightless.

Last edited by fietsbob; 05-13-12 at 01:07 PM.
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Old 05-16-12, 06:51 PM   #17
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Monskton, could you post a pic please? I'm curious to see how it looks and how the bars are angled. Plus clearance from the ground when folded (I was advised the bar would hit the floor, though with rack and easy wheels that probably wouldn't be the case).
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Old 05-16-12, 09:36 PM   #18
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Quote:
Any difference in top-tube length between the P-stem and the S-stem?
Toptube is the distance between the centers of the seat post and the fork steerer.

the mast that goes in the fork , to put the handle bar upon,
makes no change in the one frame they make.

Is that your concern?
the P steering Mast does appear to have a slightly different bend in it,
than the Mast for the M..
but one likely has to Own Both to insure the method of measuring is consistent.
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Old 05-23-12, 01:09 PM   #19
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Quote:
Originally Posted by chagzuki View Post
Monskton, could you post a pic please? I'm curious to see how it looks and how the bars are angled. Plus clearance from the ground when folded (I was advised the bar would hit the floor, though with rack and easy wheels that probably wouldn't be the case).
Hi chagzuki, some pics of my P-type with M bar and the single-SPD well go pedals:


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File Type: jpg Camera Effects-1336819677696.jpg (87.7 KB, 84 views)
File Type: jpg Camera Effects-1336819789471.jpg (63.1 KB, 54 views)
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Old 05-23-12, 04:43 PM   #20
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Thanks Monskton. It's interesting, it has the effect of greatly lengthening the effective stem length, if one is thinking of a stem in the traditional sense, i.e. as forward reach. It ought to stabilize the steering and slow down the response, both of which are desirable.

I see you've no rack there. I take it the end of the handlebar doesn't hit the floor when folded?
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Old 06-01-12, 04:03 AM   #21
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Quote:
Originally Posted by chagzuki View Post
Thanks Monskton. It's interesting, it has the effect of greatly lengthening the effective stem length, if one is thinking of a stem in the traditional sense, i.e. as forward reach. It ought to stabilize the steering and slow down the response, both of which are desirable.

I see you've no rack there. I take it the end of the handlebar doesn't hit the floor when folded?
At the end it has the same height as an M type, no hitting on the floor.
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Old 10-16-12, 11:27 PM   #22
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1st post here....

Found something interesting while researching a near purchase of H-type with S-bar replacement.



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File Type: jpg brompton stem angle.jpg (56.3 KB, 77 views)
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Old 10-17-12, 07:11 AM   #23
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Similar diagrams here, and a few more, that might help someone -

http://groups.yahoo.com/group/Brompt...61368/pic/list
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