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2 Chainrings on Brompton

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2 Chainrings on Brompton

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Old 04-30-18, 04:55 AM
  #26  
Winfried
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Originally Posted by berlinonaut View Post
Too bad that their sales are stuck around 45.000 bikes a year for three or four years now.
Yup, it doesn't look good for the current management. Since Andrew Ritchie remains the biggest shareholder, it'll be interesting to see how things go in the coming years.

Personally, I don't care about e-Brompton, but would certainly be interested in Brompton offering new options, at lower prices than Kinetics/Vostok:
  • disk or drum brakes: I'm tired of building/buying new rims every couple of years (they wear out fast when, like me, you occasionally ride on unpaved roads: Grit and rim brakes don't mix well, as shown in the attachment below)
  • standard width rear triangle, so as to fit a Nexus/Alfine or Rohloff IGH
Is it unreasonable to expect a factory-built Alfine 11 + disk/drum brake Brompton for €2,000 ?

As for the double chainring: For close to two years now, I'ven been a happy user of the LitePro K clamp + Shimano braze-on derailleur + Sunrace M90 shifter combo. It provides the same meters development (1.79m - 7.32m, or 408%) as the Shimano Alfine 11 (409%)… at the expense of juggling with three shifters and the traditional issue of the derailleur getting stuck after riding on muddy paths.
FWIW, I changed the 50/34T to a more reaonsable 46/34T: The 50T is too big with a fully loaded bike (about 25kg), with 80-120km/day trips, and occasional 5-10% hills.

As for the bottom bracket, once the original, really el cheapo BB from F.a.g. wore out, I replaced it with a Shimano BB-UN55 in 73x118mm. I know it lacks the the asymetry provided by the original BB from F.a.g., but it hasn't bothered me and the double chainring works fine with that symetric BB.


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Old 04-30-18, 08:55 AM
  #27  
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I own a Bike Friday 'Season' Tikit now .. it takes the Brompton sized rim & has a 135 rear hub, not an 11 speed but it fits.. (has a Sram I-9)

their new Pakit is lighter than a Brompton, and they make several sizes and a long list of options on the build menu.. including Gates belt drive..

The wholesale Importer of Bromptons to Australia is Greenspeed , they re machine SA drum brakes for their recumbents and have re machined a 74 wide drum hub for Bromptons..

and Pakit/Tikits, that also use a 349 rim/74 axle front hub.
so a rear drum 4 or 8* speed SA hub is possible with Bike Friday Pakit

they're good at building with 24 spoke 349 rims and 36 spoke hole hubs too..

* SA 4 & 8 speed are 1:1 1st gear , so Ideal for small wheel bikes. 3 & 5 are 1 for middle gear and (b over a) and (a over b) ratios over and under drive..


[Been using my Bike Friday Pocket Llama all winter, on the Oregon coast]




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Old 04-30-18, 09:17 AM
  #28  
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Originally Posted by Winfried View Post
As for the double chainring: For close to two years now, I'ven been a happy user of the LitePro K clamp + Shimano braze-on derailleur + Sunrace M90 shifter combo. It provides the same meters development (1.79m - 7.32m, or 408%) as the Shimano Alfine 11 (409%)
This is good to hear. I have been worried about the finger of the LitePro clamp bearing the derailleur and getting stressed for the derailleur in the outer ring position.

Originally Posted by Winfried View Post
at the expense of juggling with three shifters and the traditional issue of the derailleur getting stuck after riding on muddy paths.
Originally Posted by fietsbob View Post
went with the 2 speed geared crank which works better with my BSR, wide range from 17~80 with 15:54.. doubled the IGH advantage As Both can be shifted at once.. and all 6 gears are in a row , no redundancies.
In practical riding, I neither mind 3 shifters nor overlap. In fact one compensates for the other. On a full size bike you have plenty of overlap between different front gear positions and it is good because you can stay for a long time without doing nothing in the front.
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Old 04-30-18, 12:02 PM
  #29  
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In practise, I don't find the three-shifter solution really annoying, as…
  1. the Sunrace shifter is easy to use since it only handles two speeds, and
  2. I only shift down to the smaller chainring every once in a great while, when I ride in hilly areas.
I wonder why I didn't think about googling for clamps before since I knew some Dahons had a double chainring, but I'm very glad I happened on this blog post that provided the solution.

Still, if Brompton or someone else offers an affordable way to add an Alfine 11 IGH (and non-rim brakes), I'll consider selling my B and getting a new one: Handling all the gears with one shifter + solving the derailleur issue (mud) would be great. Besides, I love how silent the Alfine 11 is on my regular bike.
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Old 04-30-18, 12:09 PM
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That some one is Ben Cooper in Glasgow Scotland, but you are wanting cheaper than his cost of doing business.

He will ship a completed bike to you with that new fork & rear section, powder-coated to match , as I understand, as a Dealer He has to Buy the complete bikes from London, and resells the original parts ..

Bike Friday Ships (Pakit and new NWT) around the Globe, From Oregon..
those 2 are able to function without a chain tensioner..



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Old 04-30-18, 01:11 PM
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Originally Posted by fietsbob View Post
That some one is Ben Cooper in Glasgow Scotland, but you are wanting cheaper than his cost of doing business.

He will ship a completed bike to you
I am amazed you are able to open his website. I hope that the website is not representative for the quality of his bike work - shiny when I catch a glimpse but not usable.
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Old 05-01-18, 01:58 AM
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I know several people who bought modified Bromptons from Ben Cooper and are very happy with them.

I, however, am not willing to spend that much money to get non-rim brakes and/or a wider range IGH.

Hence my suggestion to Brompton to offer those as options when ordering a new bike from them. It could only be cheaper than making and replacing those parts after sales.

But considering the vast majority of people only use the B for its intended purpose, ie. riding a few kms/miles in the city… I'm not holding my breath.
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Old 05-01-18, 08:57 AM
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Invest in the company, as a Shareholder they may hear you.
I doubt it matters otherwise.
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Old 05-13-18, 11:06 AM
  #34  
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Adapter Update

After nearly 4 weeks from order, another derailleur adapter arrived, shown in the photos below. When a brand is indicated for this adapter it is mi.xim and the product identifier is NC-100. It is marketed for Dahon Speed P8 often as a 'disc' adapter and the latter seems to stand for chain ring.

Ebay Link
AliExpress Link
AliExpress Link 2

The adapter can be had for $8, 1/4 of the price of Litepro, it is heavier than Litepro, 74 vs 54g, and cruder. By being more bulky it is stiffer than Litepro and flexes less when the shift cable is tensioned. Also it is easier on the cable, see the photos. When using Litepro on Brompton, the cable gets awkwardly pinched to the seat tube on its way to the derailleur arm. Because the adapter is cruder, it is harder to adjust to arrive at best shifting than Litepro.



On the Scale


On the Bike


From Above
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Old 05-14-18, 06:37 AM
  #35  
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Originally Posted by 2_i View Post
The adapter can be had for $8, 1/4 of the price of Litepro, it is heavier than Litepro, 74 vs 54g, and cruder. By being more bulky it is stiffer than Litepro and flexes less when the shift cable is tensioned. Also it is easier on the cable, see the photos. When using Litepro on Brompton, the cable gets awkwardly pinched to the seat tube on its way to the derailleur arm. Because the adapter is cruder, it is harder to adjust to arrive at best shifting than Litepro.
Not sure what you mean. The LitePro K clamp doesn't flex when I pull the derailleur cable:


Ideally, the cable should head straight for the derailleur, but I haven't had any problem in the almost two years I've been using this setup.

Also, I notice Ben Cooper now sells the Alfine 11 for 1,550: If I had to get a new Brompton today, I wouldn't bother with adding a doublechainring to the six-speeder and juggle with three shifters, as the Alfine 11 provides about the same gear inches.

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Old 05-14-18, 11:28 AM
  #36  
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Originally Posted by Winfried View Post
Not sure what you mean. The LitePro K clamp doesn't flex when I pull the derailleur cable:
When I pulled the cable I saw the finger of the LitePro adapter lean against the seat tube. However, this might have been early on when the bolts securing the finger might have not been yet tightened up. I.e. you may have a point there, especially that if the finger flexed so much it might have been broken by now. Still the finger of LitePro looks a bit scary with relatively little material for the task. Mi.xim uses more material and you may need to switch to a longer holding bolt for derailleur, but that is not a big deal.

Thanks for the photo.
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Old 05-14-18, 11:57 AM
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The Steel one I got from CM Wasson won't win the least grams competition, Vs Aluminum
but it incorporates the housing stop and a Italian style (most common type) FD mount..
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