"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.
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.
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