Folding Bikes - Switching From an M to a P Type Handlebar - Where did I go Wrong?
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05-13-12, 10:37 PM
I had originally purchased an M6L Brompton. A couple of weeks later, I decided to add a P handlebar (I liked the different riding position options after trying out a friends) and a rack since its a lot easier to roll around.
Swapped the handlebar, cables and added the rack. Here are where my two issues lie.
1. I assumed the cabling(brakes,derailer,hub) for an M type bike is the same as a P type. Im guessing im wrong cuz I cant fold the handlebar stem. The cables are not long enough/snug :(
2. After adding the rack, there is a huge space between the seat pillar and the lower stop disk. :(
The gap between the LSD and the seat pillar is supposed to be about 1mm. Do I need to add more washers to lessen the gap?
Please help. Any tips suggestions would be greatly appreciated. Thanks in advance guys.
05-14-12, 01:39 AM
Have you put the bracket that the stop disk sits on, back the wrong way round ?
05-14-12, 02:09 AM
The stop disk thingy is effectively telescopic. Loosen the locknut, adjust it's position and tighten locknut.
05-14-12, 02:15 AM
I'd have thought the P bar should be fine on M stem, perhaps check your cable routing and make sure nothing is snagging.
05-14-12, 02:24 AM
The B is a masterpiece in design, I am afraid you need to understand the way YOUR bike is made before you make any changes or learn the hard way...
Each different handlebar is linked to a stem. If you want to change the handlebar you also need to change the stem- and cables.
If you do a lot of research and read up on what others have done you could maybe manage to do some DIY work that is not designed by Brompton. I suggest you (if you want to continue on your own) undo all cables where they end (by the brake calipers and gear yub/der) and look at the fold of the setup. If you want to keep it like that you need longer cables.
If you do NOT want to keep it like that put your old handlebar back and atatch the cables and ride off.
If you really want the P setup you need a P stem and longer cables. Make sure cables and housing is RIGHT, it need to be within just a few mm of what the P setup is designed for.
I have not done anything with the lower stopdisk on our bikes so i can not tell but I can not see why this should happen at all so I support the suggestion that you did something wrong when putting it back together.
Keep us updated!
A picture or two of your bike unfolded would help. I once messed up the cable routing in my B and could not fols it becouse of "short cables". Unfold it and compare with pix of other bikes or post pix.
05-14-12, 04:18 AM
AFAIK the P stem is about 5mm taller than the M so that accounts for some of the difference in handlebar height from M to P. Clearly with the P type handlebar the flat angle of the top bar means the area where brakes are mounted is higher, perhaps your cables are a bit short. If so it may only be the upper section of brake cable that secures the cable gatherer that needs lengthening so that the cable gatherer can rest a little lower down. The cables that are 'gathered' are probably fine as there's some slack in them and they're free to move a little.
05-14-12, 06:53 PM
Getting a new stem is going to be pricey, so I am trying to avoid that route. I rather replace the cables which are about $15/16 bucks a piece.
I was browsing the Brompton spare parts catalog, and apparently the brake cables for both the M and the P type are the same. The derailer and gear cables are actually different :: scratches head ::
Im gonna do some more research and keep you guys posted.
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