hhk25

My bike is a 2017 P6L and I never really liked the P bars. I acquired an M bar, swapped it over and everything seems to work fine. The bike folds and rides fine. The handlebar is a bit forward of a stock M but I kind of like that.

Various sources seemed to indicate I would have trouble with the fold if I didn't replace the cables. The cable bundle that goes to the rear of the bike is a touch long but not really a problem.

Did I just get lucky somehow?

Joe Remi

"Did I get lucky somehow?"

You did. My S6L came with the cables cut right to the bone for those bars..if it was possible to put a slightly lower one on, I could use the same cables. Congrats!

1nterceptor

There are 2 M bars. The older hi-rise; and the newer low rise.

hhk25

Aren't the hi-rise bars called H bars? And the extra height is in the stem, isn't it?

Anyways, not looking a gift horse in the mouth. I'm glad to make the switch with little hassle.

chagzuki

You don't have to be exact with cable lengths, so long as it works. I've changed bar configurations/height often and never had to change cables

By the way I think the set up you have is likely to ride a bit better than a standard M type; increasing the effective stem length in the traditional bike sense, i.e. the forward distance of handlebar from head tube, will stabilize the steering somewhat.

Post some pics.

fietsbob

P & M are putting the bar tops at a similar height, S is much lower ,
so of course your cables come up short, on an S to M bar swap
and the bar center clamp height is different...

I see on charts , posted online, the bend in the mast is a few degrees different ..

so a small reach change ..

specs for cable lengths can come from asking the company, on their website.





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1nterceptor

H or M uses the same bars; difference is in the mast. There was a redesign on the bar itself;
older one was very boxy in the middle. Newer M/H bars has less rise.

hhk25

Here's a few before and after photos. You can see the cables run a bit closer to the chainring than on a stock M bike. I found that the extra slack can actually loop around the chain tensioner when folded and prevent the bike from unfolding. I'm going to have to trim the cables about 2 inches I think.

The hardest part of the swap is getting the P bars off. First, if you want to save the foam grips, it's possible to cajole them off but it's not easy. Also, the handlebar clamp needs to be coaxed open just a hair to get the bars off.

Just need some grips now.

berlinonaut

No, they are not and never have been.



This ist the old M-bar which is lower than the P. The OP uses the new M-bar which is lower, thus delivering even less height. The P stem and the old M stem are about the same height. The new, current M stem is higher than the P and the old M, and the new M bars are lower, overall height is the same as the old M.

The OP is now between M and S heightwise with his bike setup, based on a P stem with the new M bar.

Using the original P cable length on a bar that is much lower obviously like the OP does works but can create a number of issues, resulting from the cables being too long. When folding or unfolding the cables may get cought at the stem hinge, resulting in issues when folding. The cable gatherer will possibly be too low now, resulting in possible issues with the fold as well like i.e. rubbing cables and paint damages as well as (with some bad luck) the chain coming off during the fold occasionally. There is a reason why the different bars have cables of different lengths. Longterm, the complexity of the Brompton will probably win. Sooner or later.

Joe Remi

Ah, you discovered the dreaded chain tensioner catch with too-long cables. Nope, you didn't get lucky, but shortening cables is WAY easier than going the other way and buying new ones.

A handy trick for opening the clamp a smidge: Take the bolt out and thread from the other side with a dime blocking the other hole. It'll push open the clamp.

fietsbob

well at least you found the graphic, (enlarged to fuzzyness)

I couldn't be bothered to..

not being Obsessed with minor differences. of what, 13mm?








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berlinonaut

If you are not botheres the least you could do is to publish wrong facts... The reality looks like that:

S bar height: 924mm
M bar height: 1013mm
P bar height: 1030mm
H bar height: 1072mm

P stem and old pre-2017 M-stem share about the same height (of the stem, not the bars!). The post-2017 M bar is lower than it's older brother. Putting a post-2017 M-Bar on a P-stem you'll end up with a bar height of about roughly 990mm, lower than a stock M-model, but clearly higher than a stock S-model. Thus ~40mm/4cm lower than the P. This is something which is clearly recognizable for the rider (even 15mm is recognizable to most people). Regarding the cable length I'd assume that the original P-cables could still just work out w/o problems - no guaranty for that.

Looking at the factory cable lengths, using the brakes as an example:

Rear brake P: 1319mm
Rear brake M: 1290mm
Rear brake S: 1250mm

Front brake P: two pieces 389mm and 485mm
Front brake M: two pieces 366mm and 485mm
Front brake S: two pieces 332mm + 473mm

So for the assumed height of the OP's "PM"-model the original P-cables would probably be about 1cm -4cm too long, depending on the cable which should hopefully still stay w/o negative effects.