Brompton gearing

Steve Watkin <[email hidden]> wrote:
: Anybody fitted a double with a big difference between the two sizes?
: I am thinking of trying a 22 and a 50. will it work?

No. Though have a look at Sheldon Brown's site and this thread:

http://groups.google.co.uk/groups?hl=en&lr=&ie=UTF-8&threadm=3f65e386_3%40news3.prserv.net&rnum=2&prev=/groups%3Fq%3D50/34%26hl%3Den%26lr%3D%26ie%3DUTF-8%26selm%3D3f65e386_3%2540news3.prserv.net%26rnum%3D2

Sheldon runs 28/50. 22/50 isn't going to work though.

Arthur

--
Arthur Clune http://www.clune.org
"Technolibertarians make a philosophy out of a personality defect"
- Paulina Borsook

Steve Watkin said:

Anybody fitted a double with a big difference between the two sizes?
I am thinking of trying a 22 and a 50. will it work?

Dunno, though a neater way (albeit /much/ more expensive) would be to
put in a Schlumpf bottom bracket gear. Have words with Ben at Kinetics
for more details, I'm pretty sure he's done a few.

Pete.
--
Peter Clinch University of Dundee
Tel 44 1382 660111 ext. 33637 Medical Physics, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email hidden] http://www.dundee.ac.uk/~pjclinch/

Steve Watkin said:

Anybody fitted a double with a big difference between the two sizes?
I am thinking of trying a 22 and a 50. will it work?

I know little about Bromptons (but a bit about gears). First of all, can
those rings be fitted to the double crankset? Do you know the BCD*?
Note. 24-tooth = smallest size possible for 74mm. Or are you considering
changing the whole chainset?

If the front derailleur can't cope, you could do without one! Just
manually change gears like cyclists did in the days before front
derailleurs were invented. Seriously, that could be reasonable if you
only used one of the chainrings very occasionally, say the 22 up the odd
long steep hill.

* http://www.sheldonbrown.com/gloss_bo-z.html

~PB

Pete Biggs said:

If the front derailleur can't cope, you could do without one! Just
manually change gears like cyclists did in the days before front
derailleurs were invented.

Wot front derailleur? ;-)
A pal used his Brom with a double just like this, downhill to the
station in the morning, uphill going home, one ring for each direction
(he wore that bike out completely, it's just been replaced with a new L6
though with a smaller than standard chainwheel, IIRC a 43)

Pete.
--
Peter Clinch University of Dundee
Tel 44 1382 660111 ext. 33637 Medical Physics, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email hidden] http://www.dundee.ac.uk/~pjclinch/

Steve Watkin said:

Anybody fitted a double with a big difference between the two sizes? I
am thinking of trying a 22 and a 50. will it work?
SW

A passing aquaintance has a double fitted on his Brommie but nowt lik
as extreme as you're thinking of. Doesn't use a front changer, jus
shifts the chain with a length of bent spoke using the two chainring
for two wholly seperate ranges of gears, normal and for hilly terrain

69 days until the Eco-Trip Is that a Trice you'll be on

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