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Old 08-01-08, 10:37 PM   #1
CrimsonEclipse
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Are there new bromptons with deraileurs?

I'm looking for a wide gear range with at least 2 rings up front and the normal 7-9 on the rear.
I would prefer to avoid the internal hub.

Why? Because I said so. :p

CE
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Old 08-01-08, 10:49 PM   #2
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Talk to Steve Parry
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Old 08-01-08, 11:20 PM   #3
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If money is no object, you can do almost anything.
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Old 08-02-08, 01:19 AM   #4
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This is all folding bikese for "no". Brompton don't supply such a thing, and because of the design of the rear triangle it's apparently difficult to upgrade. If you can afford to pay the Grand Wizard of Brompton, you can have it, but the result will be too low geared (unless he employs a 58/68 front chainring setup), and have the most vulnerable rear derailleur since records began.
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Old 08-02-08, 01:35 AM   #5
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You can do almost anything to a brompton, not everything is useful. If you are absolutely booked on it, check this thread here:

Best looking brompton I've seen so far.

And here:
Terrific 18-speed brompton MOD
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Old 08-02-08, 02:13 AM   #6
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Originally Posted by Sammyboy View Post
This is all folding bikese for "no". Brompton don't supply such a thing, and because of the design of the rear triangle it's apparently difficult to upgrade. If you can afford to pay the Grand Wizard of Brompton, you can have it, but the result will be too low geared (unless he employs a 58/68 front chainring setup), and have the most vulnerable rear derailleur since records began.
Might be "better" to use a Schlumpf Speed Drive instead of 2 huge chainrings. Schlumpf cater specifically for Brompton.
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Old 08-02-08, 03:11 AM   #7
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I pesonally think the hub system on the Brompton is very efficient. It's the shifters that need improving. Of course if you want more gearing then adding front and rear derailleurs is the way to go. Real Steve Parry stuff that.
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Old 08-02-08, 03:24 AM   #8
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That's a good point, Jur. Forgot about Schlumpf. Expensive (again) though.
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Old 08-02-08, 03:48 AM   #9
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I am not so sure if the Schlumpf really is a better option. Compared to the wish of 7-9 cogs in the back (widening triangle, bigger fold) the 2 chainwheels in the front is a quite straight forward and lightweight modification that doesn't interfere with the fold. The Schumpf is sure heavier than 2 chainwheels plus front derailler plus a lightweigt bottom bracket and crancs. You have limited choice of cranks if you don't want to go with the Schlumpf cranks. And because of the fixed percentage (-2,5%, +1,65, +2,5%) of up/downgearing you can end with quite odd gearsteps.

But having said that, I think the Schlumpf is a technical candy, very nice and if really wide gear range is the first aim and even spaced gear steps can be resigned then go with the Schlumpf high speed drive for flat or with the mountain drive for ultra low gears.
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Old 08-02-08, 03:51 AM   #10
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That's a good point, Jur. Forgot about Schlumpf. Expensive (again) though.
Yes, hence the quote marks around better.
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Old 08-02-08, 01:32 PM   #11
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Quote:
Originally Posted by somnatash View Post
I am not so sure if the Schlumpf really is a better option. Compared to the wish of 7-9 cogs in the back (widening triangle, bigger fold) the 2 chainwheels in the front is a quite straight forward and lightweight modification that doesn't interfere with the fold. The Schumpf is sure heavier than 2 chainwheels plus front derailler plus a lightweigt bottom bracket and crancs. You have limited choice of cranks if you don't want to go with the Schlumpf cranks. And because of the fixed percentage (-2,5%, +1,65, +2,5%) of up/downgearing you can end with quite odd gearsteps.

But having said that, I think the Schlumpf is a technical candy, very nice and if really wide gear range is the first aim and even spaced gear steps can be resigned then go with the Schlumpf high speed drive for flat or with the mountain drive for ultra low gears.
I recently had a chance to test out a schlumpf and in this particular case it felt very inefficient (just as inefficient as a Sturmey-Archer 8-speed). Is that also your experience or was there something wrong with the bike I tried?
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Old 08-02-08, 04:28 PM   #12
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Originally Posted by CrimsonEclipse View Post
So, does that require a special hub?

CE
What do you mean by special? Raxel said in each thread the wheels of the white brommi and the black are built using American classic hubs.

Hi makeinu,
I like the idea/concept of the schlumpf and the (inner) looks of it. I seem to have a bias for a little bit odd things. And I rode the Schlumpf only for a shorter testride and it felt fine...but then I admit, am also happy with my Sturmey Archer 8-Speed...so probably your feeling of in/efficiency is much finer tuned then mine is

BTW: I plan my next Folder to be a CarryMe. (Yes poor me is infected). I want the pink or orange one from the website...I tried to contact them. I called twice but no English speakers and the contact formula doesn't seem to work? Any ideas for me?
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Old 08-02-08, 04:35 PM   #13
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Why not a Strida Somna?
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Old 08-02-08, 05:01 PM   #14
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Why not a Strida Somna?
Sorry for OT...Mulleady you got a pm...its me Somna
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Old 08-02-08, 05:32 PM   #15
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Originally Posted by somnatash View Post
BTW: I plan my next Folder to be a CarryMe. (Yes poor me is infected). I want the pink or orange one from the website...I tried to contact them. I called twice but no English speakers and the contact formula doesn't seem to work? Any ideas for me?
Accordig to an email from Max Yeh (Pacific Cycles, Inc.) from June, the CarryMe distributors in Europe are:

United Kingdom
Airnimal Europe Ltd.
Tel: +44-1223-523973
info@airnimalfoldingbikes.com

Switzerland
Simpel GmbH
Tel: +41 44 768 27 53 Fax: +41 44 768 27 48
Alte Käserei, Dorfstrasse 58, 8933 Maschwanden
www.simpel.ch

It's also on http://www.pacific-cycles.com/ but the links are Java based so there's no way to put here the direct link. Check PRODUCTS--CARRYME--DISTRIBUTOR INFO

Last edited by Carlos71; 08-02-08 at 05:37 PM.
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Old 08-02-08, 08:53 PM   #16
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Originally Posted by somnatash View Post
I am not so sure if the Schlumpf really is a better option. Compared to the wish of 7-9 cogs in the back (widening triangle, bigger fold) the 2 chainwheels in the front is a quite straight forward and lightweight modification that doesn't interfere with the fold. The Schumpf is sure heavier than 2 chainwheels plus front derailler plus a lightweigt bottom bracket and crancs. You have limited choice of cranks if you don't want to go with the Schlumpf cranks. And because of the fixed percentage (-2,5%, +1,65, +2,5%) of up/downgearing you can end with quite odd gearsteps.
I admire the depth of your tech knowledge.

I have installed Schlumpf Speed (x1.65) on my Yeah folder; combined with the 11-34T rear cluster it gives me 510% range. The equivalent chain wheels sizes are 40-66T. This is with 406 wheels.

With 349 wheels, the euivalent chainwheels would be 46-75T. 75T might interfere with the fold (I don't know), but it is difficult to get and expensive, plus I don't know if a front derailer could handle a chainwheel that size plus the 19T difference. The rear derailer would need to be long cage and would be preciously close to the ground.

The whole derailer system was designed for large wheels; applying it to small wheels reveals its limitation.

Combining the Schumpf with the SA hub would give an almost identical range of 510%, albeit with reduced efficiency in the high gears, and the requirement of a tiny chainwheel.

My Schlumpf's efficiency feels very good in the 1:1 ratio, almost no drag; more drag can be felt in the 1.65 step-up ratio. Some of that drag is due to the thickish grease that was used in it; I am thinking of washing it out and replenishing with a thinner molybdenum grease. One day when I have nothing to do and the internet is dead.
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Old 08-02-08, 10:10 PM   #17
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Oribike, Neobike, Tikit, Birdy all have derailleur gear system with the same as or slightly larger wheel size than bromptons. Japanese folder shop sells custom rear triangle with 130mm spacing AND hanger. They sells FD mount too. Many users here MOD their brompton with derailleur system and are very happy with them.

Personally I don't need any reason to use hub gear systems at all, except for some very abused downhill bikes. Hub gears are heavy, noisy, very inefficient (Or it just feels so) and expensive in general. :[
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Old 08-02-08, 10:25 PM   #18
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And I'm sure they are happy with them... just that for my personal prefs, I need a gearing system (eg for touring) that has a 510% range. I like to crawl up steep hills while being able to spin and I like going fast downhill while pedalling slow, to rest the legs. My Swift has a 304% range with just 11-34T cluster, and a gearing of 32-99", that's good enough for the Swift and its intended use.

For a loaded Brommie I would like to have gears in the low 20s as well, that gives about a 500% range. A road bike can have gears in the range of 305% (same as my Swift) with 2 chainwheels; that can be extended to 420% by using the most extreme cases available while using a double chainring.

So it doen't matter which way you cut it, the Brompton simply can't have that sort of gearing unless you used internal hubs with a Schlumpf. It's not a case of having derailer just because you can, it must also have a suitable range. With small wheels that becomes almost impossible.
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Old 08-02-08, 11:40 PM   #19
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Don't forget that there are capreo cassette for smallwheelers. Capreo 9-26 cassette with 53/42/30 Road triple crank gives 510% range.
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Old 08-03-08, 09:13 AM   #20
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Originally Posted by somnatash View Post
BTW: I plan my next Folder to be a CarryMe. (Yes poor me is infected). I want the pink or orange one from the website...I tried to contact them. I called twice but no English speakers and the contact formula doesn't seem to work? Any ideas for me?
Maybe try a different web browser for the contact form. I have lots of problems with viewing the Pacific Cycles website in Firefox.

Quote:
Originally Posted by jur View Post
My Schlumpf's efficiency feels very good in the 1:1 ratio, almost no drag; more drag can be felt in the 1.65 step-up ratio. Some of that drag is due to the thickish grease that was used in it; I am thinking of washing it out and replenishing with a thinner molybdenum grease. One day when I have nothing to do and the internet is dead.
Hmmm, then the one I tried must have been maladjusted because even in 1:1 there was a lot of drag. Searching the net it seems I'm not the only one complaining about drag in the 1:1 to which I found the following response:
Quote:
Originally Posted by David M. Eggleston, VelomobileUSA, LLC
The Schlumpf Mountain Drive must be installed with constant reference to
the manufacturer's instruction manual, which is very detailed. At the time
that Timothy tested it, the drive was only temporarily installed and no
final adjustments had been made.
When we made all the proper adjustments, the drag largely vanished. There
was little drag left in either position of the end-cap armature.
It takes some time to become familiar with installation of a Mountain
Drive. We found our 3 mm thick aluminum BB shell to be too weak to withstand
the spreading load of the 45 deg. chamfered gear case when tightened to the
Schlumpf specification. We had to exchange the mechanism with no torque arm
for one with a torque arm. Installation in a steel BB shell or a thicker
aluminum shell should be possible without resorting to a torque arm.
However, the torque arm adds little weight and provides quite a robust
system for counteracting the back torque exerted on the BB shell.

Last edited by makeinu; 08-03-08 at 10:04 AM.
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