Widening Brompton Rear Triangle to Fit 130mm
#1
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Widening Brompton Rear Triangle to Fit 130mm
Hi there,
I'm thinking to convert my Brompton to take external gear with a 130mm rear dropout without getting a new rear triangle.
I'm thinking to take it to a local steel bicycle workshop to see if it's possible.
The bike is still on-order hence I'm here. It seems like there are only rear triangles designed at 130mm and can't see anyone converting one.
Has anyone tried and is it physically impossible to do hence there is only mod with changing the rear triangle?
Thanks,
Roland
I'm thinking to convert my Brompton to take external gear with a 130mm rear dropout without getting a new rear triangle.
I'm thinking to take it to a local steel bicycle workshop to see if it's possible.
The bike is still on-order hence I'm here. It seems like there are only rear triangles designed at 130mm and can't see anyone converting one.
Has anyone tried and is it physically impossible to do hence there is only mod with changing the rear triangle?
Thanks,
Roland
#2
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I really am not sure I understand your question.
The Bromptons I see are 3 speed hubs, so you would not have derailler hanger.
the seat stays are short which would complicating cold setting
Why try to modify a purpose built bike?
If you want deraillers get folder designed with those like a bike friday
https://bikefriday.com/product/bike-...t-folding-bike
https://bikefriday.com/product/bike-...road-bike-2019
https://bikefriday.com/product/bike-...t-folding-bike
The Bromptons I see are 3 speed hubs, so you would not have derailler hanger.
the seat stays are short which would complicating cold setting
Why try to modify a purpose built bike?
If you want deraillers get folder designed with those like a bike friday
https://bikefriday.com/product/bike-...t-folding-bike
https://bikefriday.com/product/bike-...road-bike-2019
https://bikefriday.com/product/bike-...t-folding-bike
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(looking for Torpado Super light frame/fork or for Raleigh International frame fork 58cm)
Life is too short not to ride the best bike you have, as much as you can
(looking for Torpado Super light frame/fork or for Raleigh International frame fork 58cm)
#3
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I read that it's possible through the standard technique...but naturally, all risk is yours.
#4
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#5
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I really am not sure I understand your question.
The Bromptons I see are 3 speed hubs, so you would not have derailler hanger.
the seat stays are short which would complicating cold setting
Why try to modify a purpose built bike?
If you want deraillers get folder designed with those like a bike friday
https://bikefriday.com/product/bike-...t-folding-bike
https://bikefriday.com/product/bike-...road-bike-2019
https://bikefriday.com/product/bike-...t-folding-bike
The Bromptons I see are 3 speed hubs, so you would not have derailler hanger.
the seat stays are short which would complicating cold setting
Why try to modify a purpose built bike?
If you want deraillers get folder designed with those like a bike friday
https://bikefriday.com/product/bike-...t-folding-bike
https://bikefriday.com/product/bike-...road-bike-2019
https://bikefriday.com/product/bike-...t-folding-bike
the only folder that folds in a similar compact size with similar folding time and a normal derailleur is a Mezzo/Ori but they are still bigger than Brompton when folded. The Bike Friday are too big to take on a daily commute in London and the fold is not as fast. Don't really get on with hubs, they are heavy and quite limited hence wanted more options with a normal 130mm OLD.
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Hmmm...
You'll have to be careful that you don't mess up the folding. Some of the larger internal gear hubs are even 135mm spacing.
Whatever you do, also make sure you realign the dropouts after spreading them.
You'll have to be careful that you don't mess up the folding. Some of the larger internal gear hubs are even 135mm spacing.
Whatever you do, also make sure you realign the dropouts after spreading them.
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Tensioner in a standard derailleur will have a problem collecting slack for the folded bike. I suggest living with the bike and listening to it first and not watching too much of YouTube - it could be detrimental to more than the bike alone
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the only folder that folds in a similar compact size with similar folding time and a normal derailleur is a Mezzo/Ori but they are still bigger than Brompton when folded. The Bike Friday are too big to take on a daily commute in London and the fold is not as fast. Don't really get on with hubs, they are heavy and quite limited hence wanted more options with a normal 130mm OLD.
the only folder that folds in a similar compact size with similar folding time and a normal derailleur is a Mezzo/Ori but they are still bigger than Brompton when folded. The Bike Friday are too big to take on a daily commute in London and the fold is not as fast. Don't really get on with hubs, they are heavy and quite limited hence wanted more options with a normal 130mm OLD.
as to weight you are subtracting an igh, but adding hub, cassette, derailler, derailler hanger I compared the weight of these against a sram ddr hub and in total they weigh more by about 100 grams than the igh
Brompton does offer a front shifter to get 6 speeds with the 3speed igh
you bike your choice, but overall this does no look like something that is going to be simple and work smoothly. Good luck
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Life is too short not to ride the best bike you have, as much as you can
(looking for Torpado Super light frame/fork or for Raleigh International frame fork 58cm)
Life is too short not to ride the best bike you have, as much as you can
(looking for Torpado Super light frame/fork or for Raleigh International frame fork 58cm)
#9
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Wouldn't a Shimano Nexus IGH fit within the rear triangle with no fuss? And if the OP only has a 3 speed IGH currently, then Nexus can probably put 7 or 8 speed inside the same space if the rear is 126mm spacing.
Being a folding bike, I'd hate to make it where it might not fold up properly and also I'd be worried about the DR hangar getting bent.
Being a folding bike, I'd hate to make it where it might not fold up properly and also I'd be worried about the DR hangar getting bent.
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Best advice: take your inquiry to the Folder Forum where folks know the bike, understand the question and have even done this before.
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#12
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You just need a tensioner added to the rear derailleur and a chain guide/hook at the chainring to take the slack. It's very similar to the Mezzo when folded which relies on the chain guide/hook at the chainring
#13
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#14
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Have you looked at what Kinetics do? It may give you an idea of what's possible. I would have thought, though, it would make more sense to put a different IGH hub on.
It's a folding bike, if it's messed up it only cost £70 to get another rear triangle. It's easily replaceable by undoing a bolt.
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Let's meet here in a year from now and see where your project stands.