Originally Posted by
fietsbob
Thing that makes the Merc lighter was the aluminum use instead of Steel , but the aluminum fatigue cracks and fails.
... as you discovered..
SJS has the main Subframe , since I see the Brommy Rear section in the picture ..
I see some SP widgets like the FD adapter bracket, in that picture, so might as well get a Brommy..
the Newer 6 speed use a hub the BWR that was designed by/for Brompton, made by the new SA sun-race company..
the older 6 speed was adapted from an Adapted Sachs 3 speed hub..
But thankfully they used a thinner 13 & 15 t 3 spline cog , which works on the older AW3 & BSR hubs too.
so you can use 3/32", 5678 speed derailleur chain . for better shifting with the double chainring set-up.
newer BWR uses a 9 spline 13,15 cog, .. as does the 2 speed hub.. 12, 16t..
I think I misunderstood this post where you talk about the new Brompton six gear arrangement. I thought you meant it was a new hub with six ratios on it, but on reading stuff on the web, it seems to be a wide ratio three speed with the same old two cog system swapped by a derailier. That is a hell of a lot less attractive than what I thought you had said and my earlier comments about efficiency must have looked mad.
I can never see why Brompton don't work with a double chain set and front changer like Steve Parry does for people. I have one of his brackets on the Merc and it works great with a really cheap front changer and an extra chain wheel. I have the big chain wheel on the outside of the spider where the old aluminium chain guard used to be and the small ring on the inside where the old 53 tooth wheel was. I am running 53/45 on the chain rings and I get 33 inches to 80 as far as I can remember.
I went on the Build Your Own Brompton pages of the B website and put together my ideal B. Six gears, fenders, M type, Raw Laquer, Shimano dynamo and lights..... Comes out at over £1100..... That's a mad price - just mad. I know a guy who is running around in a tidy little car that he just bought for £250. I need to get a ride on a Tern D7i and see what I think of it, but I don't know any dealers around these parts.