Brompton 2/3 speed hub on a any bike?

XE007

Regular
Hi all,
I am planning on having a bike frame built through a third party and have considered using a brompton hub or aftermarket. You will as ask why?

I like the simplicity of 2 or 3 speed bikes without investing heavily on expensive setups. Unfortunately, the market likes to push toward more gear$ and complex setups but I enjoy the simplicity of low maintenance bikes. I have single speed but since I am looking at building a 451/406 wheelset,

I would like to know if this is possible?

Are the holes in the hub smaller/bigger etc?

I do know that the hub is 112mm spacing and 10mm axle but is there anything else necessary for such a setup?

Thank you for help and any assistance.

Xavier
 

12boy

Veteran
Location
Casper WY USA
You can get Sturmey Archer 3 speed hubs in several widths but these are the 177% range, not the wide ratio found on 6 speed Bromptons. The issue here is how wide the hubs on your current bike are. How wide are your current hubs? If you are set on the wide ratio hub it may be necessary to get a different axle and Sturmey Archer axles are flat on 2 sides, so finding the right axle may be difficult.
 
OP
X

XE007

Regular
You can get Sturmey Archer 3 speed hubs in several widths but these are the 177% range, not the wide ratio found on 6 speed Bromptons. The issue here is how wide the hubs on your current bike are. How wide are your current hubs? If you are set on the wide ratio hub it may be necessary to get a different axle and Sturmey Archer axles are flat on 2 sides, so finding the right axle may be difficult.
Thanks for you reply. I am not looking into the 3 speed internal gear Sturmey but the external gears like the 2 speed brompton (The two cogs on the outside).

The frame I am going to build is 112mm spacing because there are many available even in the asian markets. I want to build a 451 wheel for the rear if this option is possible with the 2 speed hub and the s2e Brompton I believe is 10mm axle nut.

Thanks for your help and sorry for any confusion.
 

Gunk

Veteran
Location
Oxford
Why not just fit a simple old fashioned 5 speed free hub and use a Shimano rear mech, they are still available and very simple and reliable.
 
OP
X

XE007

Regular
Why not just fit a simple old fashioned 5 speed free hub and use a Shimano rear mech, they are still available and very simple and reliable.
I want to do cassette and get to pick my own gears. thx

Maybe this is the wrong thread section. Back to my original question: Can I use a Brompton 2 speed hub on a 451 if I am planning on going this route thanks.
 
I see no reason why you can't use any Brompton compatible hub on any wheel size you like, as long as they both have the same number of spoke holes.
 

T4tomo

Veteran
Back to my original question: Can I use a Brompton 2 speed hub on a 451 if I am planning on going this route thanks.
Dunno if this helps:
the 2/6 speed needs a specific chain tensioner different from the 3 speed ones to allow for movement tis combine with the chai pusher assembly. All these parts will need mounting points on your frame or axle so need to think of that in advance. you have a more flex in the tensioner than you need for a non folding frame but that's not a issue

1613736917927.png


You can get 1 speed to 2 speed converter kits , so you get all the parts you need to run your envisaged 2 speed set up, so you can run say 12T & 16T sprockets.

info on rims (from Brilliant bikes site)
Brompton Spokes and rims (and their associated hubs)
Choosing the correct Brompton spoke / rim combination for you wheel / hub can be confusing - so we have made this (not so simple) guide - if you think of anything that is missing - please let us know so we can improve it!

Rim types
Firstly - there are two rim types that have been used by Brompton:

Single wall rim - made by Alex rims most recently - up until 2013
Front and rear wheels used the same rim

Double wall rim - from 2013 onwards
Along with the double wall rim came a different rim for the front and back
The angled (the spoke holes are drilled at an angle) rims are used for hub gear rear wheels only
The straight (the spoke holes are drilled straight - 90 degrees to the rim) rims are used for front wheels and single / two speed rear wheels

depending on specific rim the spokes specified are PG or DB 14G. length clearly dependent o what rim you choose but would need to be compatible with 14G spokes.
 

12boy

Veteran
Location
Casper WY USA
Assuming you can find the single/2 speed hub without buying the whole wheel, you will have another problem in so far as the Brompton setup requires a chain tensioner with jockey wheels that move sideways as T4tomo,says above. This is because there is no derailleur to shift the chain from one sprocket to the other, but rather a chain pusher. The chain tensioner is mounted on a special plate so your frame would have to have that same arrangement to allow you to mount the chain tensioner to the dropout. If you are making your own frame that could be possible. If you go that route, there are ways to have 3 sprockets instead of two. Bikegang sent me a prototype sprocket with 11, 14 and 17 tooth sprockets which provides a nice mid gear between low and high.
 

TheDoctor

I've seen things you people wouldn't believe
Moderator
Location
Stevenage
If you're getting a frame built for you, I'd go for a standard 130mm OLD and then you can do what you like with sprockets and use a normal rear mech. I wouldn't tie yourself into Brommie-specific stuff unless there's a good reason too.
 
OP
X

XE007

Regular
Dunno if this helps:
the 2/6 speed needs a specific chain tensioner different from the 3 speed ones to allow for movement tis combine with the chai pusher assembly. All these parts will need mounting points on your frame or axle so need to think of that in advance. you have a more flex in the tensioner than you need for a non folding frame but that's not a issue

View attachment 574632

You can get 1 speed to 2 speed converter kits , so you get all the parts you need to run your envisaged 2 speed set up, so you can run say 12T & 16T sprockets.

info on rims (from Brilliant bikes site)
Brompton Spokes and rims (and their associated hubs)
Choosing the correct Brompton spoke / rim combination for you wheel / hub can be confusing - so we have made this (not so simple) guide - if you think of anything that is missing - please let us know so we can improve it!

Rim types
Firstly - there are two rim types that have been used by Brompton:

Single wall rim - made by Alex rims most recently - up until 2013
Front and rear wheels used the same rim

Double wall rim - from 2013 onwards
Along with the double wall rim came a different rim for the front and back
The angled (the spoke holes are drilled at an angle) rims are used for hub gear rear wheels only
The straight (the spoke holes are drilled straight - 90 degrees to the rim) rims are used for front wheels and single / two speed rear wheels

depending on specific rim the spokes specified are PG or DB 14G. length clearly dependent o what rim you choose but would need to be compatible with 14G spokes.
Assuming you can find the single/2 speed hub without buying the whole wheel, you will have another problem in so far as the Brompton setup requires a chain tensioner with jockey wheels that move sideways as T4tomo,says above. This is because there is no derailleur to shift the chain from one sprocket to the other, but rather a chain pusher. The chain tensioner is mounted on a special plate so your frame would have to have that same arrangement to allow you to mount the chain tensioner to the dropout. If you are making your own frame that could be possible. If you go that route, there are ways to have 3 sprockets instead of two. Bikegang sent me a prototype sprocket with 11, 14 and 17 tooth sprockets which provides a nice mid gear between low and high.

Thanks. I see what you mean but a cog is a cog whether its a brommie or not so the whole setup is not necessary as the brompton cog is similiar to the market ones.

I think this will work after thinking this through. The axle is a standard 10mm and the frame spacing is 112mm so no needs for a brommie derailleur.

What I have to know is whether the holes on the hub are standard as all road bikes.

thx
 
OP
X

XE007

Regular
If you're getting a frame built for you, I'd go for a standard 130mm OLD and then you can do what you like with sprockets and use a normal rear mech. I wouldn't tie yourself into Brommie-specific stuff unless there's a good reason too.
Thanks for your reply! Yeah you are correct. The frame I want build will be compact and slim on the rear. Brommie parts are wide spread and I wrote to the other replies I just need to know if brommie hubs are the same 28 hole hubs as other market hubs then I can build the 451 wheel.

I think I will go to brommie enthusiast and ask this question as they would know more about the hibs themselves. Had a brommie one time and sold it without learning about it. ;-(
 

berlinonaut

Senior Member
Location
Berlin Germany
The Brompton hub has 28 holes and - as others have already said - you can use rims of any size with it as long as they are 28 holes. Why should there be a problem?
Regarding the derailleur I'd assume that there's no need for the Brompton specific one - you should be able to use more or less any classic oldschool deraillieur. In the 80ies I had a similar halfstep 2*3 solution on a bigwheeled bike with the hub being a Sachs Torpedo and the halfstep parts being a retrofit kit from them.
You should be aware that the Brompton derailler acts also as a chain tensioner that takes up chain slack in folded sate. So in case that your planned bike will be a folder you may have to have in mind how to deal with that topic, depending if and how your rear frame folds. Not too much rocket science but something to have in mind.

However, as others aletaday said: If you let a frame build for you I as well personally would not go for 112mm OLD unless there's a good reason for that. You limit yourself and your choice of gears and hubs massively.
 
OP
X

XE007

Regular
The Brompton hub has 28 holes and - as others have already said - you can use rims of any size with it as long as they are 28 holes. Why should there be a problem?
Regarding the derailleur I'd assume that there's no need for the Brompton specific one - you should be able to use more or less any classic oldschool deraillieur. In the 80ies I had a similar halfstep 2*3 solution on a bigwheeled bike with the hub being a Sachs Torpedo and the halfstep parts being a retrofit kit from them.
You should be aware that the Brompton derailler acts also as a chain tensioner that takes up chain slack in folded sate. So in case that your planned bike will be a folder you may have to have in mind how to deal with that topic, depending if and how your rear frame folds. Not too much rocket science but something to have in mind.

However, as others aletaday said: If you let a frame build for you I as well personally would not go for 112mm OLD unless there's a good reason for that. You limit yourself and your choice of gears and hubs massively.

Yeah thanks man. Sorry for the late reply. After much thought I went with a 130mm for the design. I did get feedback from Brompton fans and the hub would work well with any wheelset the problem is finding the right Derailleur so I just gave up and decided to get a 7 speed setup.

Thanks again!
 

berlinonaut

Senior Member
Location
Berlin Germany
Yeah thanks man. Sorry for the late reply. After much thought I went with a 130mm for the design. I did get feedback from Brompton fans and the hub would work well with any wheelset the problem is finding the right Derailleur so I just gave up and decided to get a 7 speed setup.
Better choice I'd say. But as said before: Finding a suitable derailleur would have been no problem at all.
 
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