Upgrading Brompton 6 speed to 12 speed using 2 chainrings

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Philip Benstead
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Location: Victoria , London

Upgrading Brompton 6 speed to 12 speed using 2 chainrings

Post by Philip Benstead »

Views welcomed
Upgrading Brompton 6 speed to 12 speed using 2 chainrings
I have a 6-speed Brompton post 2017.

I am seeking to upgrade to 12 speed

I am thinking of using the following:

SPA CYCLES RD-2 Road Cranks (pr) 170mm Silver Triple https://www.spacycles.co.uk/m8b0s109p35 ... s-%28pr%29


Chainrings 44 Used on the middle chainring position
Chainrings 34 Used on the small chainring position
SPA CYCLES Alloy Chainguard 130 BCD 44 teeth/Black (To be used on large chainring position)
https://www.spacycles.co.uk/m8b0s210p44 ... rd-130-BCD

FIRST COMPONENTS DX-30 Bottom Bracket 113mm
FIRST COMPONENTS F-2001P Bottom Bracket 113mm

SILVEROCK Alloy Front Derailleur Clamp FD Adapter Braze on 38mm to 39mm For Brompton 3SIXTY Pikes JAVA FIT Folding Bike 2 Speed
SKU: 8799018904654
https://uk.vicedeal.com/products/silver ... -BEALw_wcB

Bike Shifter Sunrace M96 Thumbie Left Hand
https://www.ebay.co.uk/itm/266742498208 ... FEEALw_wcB

Undecided yet which front derailleur is best to use, Do you have any suggestions?
Last edited by Philip Benstead on 18 Apr 2024, 10:18am, edited 1 time in total.
Philip Benstead | Life Member Former CTC Councillor/Trustee
Organizing events and representing cyclists' in southeast since 1988
Bikeability Instructor/Mechanic
rotavator
Posts: 997
Joined: 6 Jun 2016, 9:50pm
Location: North Wales

Re: Upgrading Brompton 6 speed to 12 speed using 2 chainrings

Post by rotavator »

I am using a similar set-up but with 48T and 34T chainrings. This works well enough and gives me a gear range of 23-105" which is good enough for me.

The main snag, of course, is changing gear at the front if your route includes a lot of flattish bits but also a few steep hills. Keeping a small stick handy is one bodge/solution.
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Philip Benstead
Posts: 1983
Joined: 13 Jan 2007, 7:06pm
Location: Victoria , London

Re: Upgrading Brompton 6 speed to 12 speed using 2 chainrings

Post by Philip Benstead »

rotavator wrote: 18 Apr 2024, 10:06am I am using a similar set-up but with 48T and 34T chainrings. This works well enough and gives me a gear range of 23-105" which is good enough for me.

The main snag, of course, is changing gear at the front if your route includes a lot of flattish bits but also a few steep hills. Keeping a small stick handy is one bodge/solution.
I have the bracket for a front derailleur
Philip Benstead | Life Member Former CTC Councillor/Trustee
Organizing events and representing cyclists' in southeast since 1988
Bikeability Instructor/Mechanic
Brucey
Posts: 44895
Joined: 4 Jan 2012, 6:25pm

Re: Upgrading Brompton 6 speed to 12 speed using 2 chainrings

Post by Brucey »

FWIW I'd probably gravitate towards a 8s mech because I suspect the usual brompton chain to be too wide for much else
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
rotavator
Posts: 997
Joined: 6 Jun 2016, 9:50pm
Location: North Wales

Re: Upgrading Brompton 6 speed to 12 speed using 2 chainrings

Post by rotavator »

Philip Benstead wrote: 18 Apr 2024, 10:09am
rotavator wrote: 18 Apr 2024, 10:06am I am using a similar set-up but with 48T and 34T chainrings. This works well enough and gives me a gear range of 23-105" which is good enough for me.

The main snag, of course, is changing gear at the front if your route includes a lot of flattish bits but also a few steep hills. Keeping a small stick handy is one bodge/solution.
I have the bracket for a front derailleur
Sorry I missed that bit, now you have got me thinking!
2_i
Posts: 224
Joined: 25 Feb 2020, 3:12am

Re: Upgrading Brompton 6 speed to 12 speed using 2 chainrings

Post by 2_i »

Philip Benstead wrote: 18 Apr 2024, 9:46am Views welcomed

SILVEROCK Alloy Front Derailleur Clamp FD Adapter Braze on 38mm to 39mm For Brompton 3SIXTY Pikes JAVA FIT Folding Bike 2 Speed
SKU: 8799018904654
https://uk.vicedeal.com/products/silver ... -BEALw_wcB
Such an adapter can be had on AliExpress for $7 or something. This and other adapters in the market are of poor quality, with this particular one flawed due to the material buildup under the mounting point, interfering with the derailleur's cage. Also, the finger on which the derailleur mounts is secured with a single screw underneath and can rotate over time around that screw. Maybe an adapter with a band above the mounting point, or at least one with a thinned band, could be better.
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Philip Benstead
Posts: 1983
Joined: 13 Jan 2007, 7:06pm
Location: Victoria , London

Re: Upgrading Brompton 6 speed to 12 speed using 2 chainrings

Post by Philip Benstead »

2_i wrote: 18 Apr 2024, 6:22pm
Philip Benstead wrote: 18 Apr 2024, 9:46am Views welcomed

SILVEROCK Alloy Front Derailleur Clamp FD Adapter Braze on 38mm to 39mm For Brompton 3SIXTY Pikes JAVA FIT Folding Bike 2 Speed
SKU: 8799018904654
https://uk.vicedeal.com/products/silver ... -BEALw_wcB
Such an adapter can be had on AliExpress for $7 or something. This and other adapters in the market are of poor quality, with this particular one flawed due to the material buildup under the mounting point, interfering with the derailleur's cage. Also, the finger on which the derailleur mounts is secured with a single screw underneath and can rotate over time around that screw. Maybe an adapter with a band above the mounting point, or at least one with a thinned band, could be better.
Can you suggest a better bracket?
Philip Benstead | Life Member Former CTC Councillor/Trustee
Organizing events and representing cyclists' in southeast since 1988
Bikeability Instructor/Mechanic
2_i
Posts: 224
Joined: 25 Feb 2020, 3:12am

Re: Upgrading Brompton 6 speed to 12 speed using 2 chainrings

Post by 2_i »

Philip Benstead wrote: 18 Apr 2024, 8:36pm Can you suggest a better bracket?
Litepro for Birdy has the advantage of the band above the derailleur and of not letting the derailleur's orientation change on its own

https://www.aliexpress.us/item/32568047 ... JustForYou

Is it good on the absolute scale? No, there is no satisfactory mount on the absolute scale currently on the market
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