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Brompton hub news
Both Sturmey and SRAM three-speeds now fitted
This latest press release from Brompton, below, isn't perhaps the most exciting or earth-shattering news we've ever reported on Velo Vision, but here you go:
Brompton adopts dual supply strategy for internal hubs.
When Sturmey Archer closed in September 2000, Brompton was given no notice, and due to the uniqueness of the hub, was nearly placed in a position of being unable to supply bicycles. Brompton changed the design of its rear frame in order to incorporate the Sram Sachs hub. Sram Sachs implemented a production run of hubs especially for Brompton due to the requirement for a shorter over-locknut dimension.
Since 2000, Brompton has taken steps to ensure this supply situation does not recur in the future by moving to dual supply of certain components. One such step has been to introduce the new Sunrace Sturmey Archer 3 speed hub. This decision follows 18 months of in-house testing to ensure that the new SA 3 speed hub, of which 200,000 units have so far been sold worldwide, is of equal quality to the old one.
From January 1 2005, all Brompton three speed bikes will use the new Sunrace Sturmey Archer 3 speed and Brompton 6 speed bikes will use the Sram Sachs 3 speed hub. The performance of the two hubs is similar. The SRAM 3 speed has a gear range of 1.33:1:0.75. The new Sunrace Sturmey Archer hub has a range of 1.36:1:0.73 and is 50 grams heavier. Both hubs fit a newly designed Universal rear frame: dual applicability being made possible through a combination of washers.
Brompton owners or customers considering a Brompton, will need to keep in mind that upgrading from 3 to 6 speed version will now no longer be possible without the expense of buying a new wheel and hub. This is because the Brompton derailleur system does not work with the Sturmey Archer hub.
Posted on 16 December 2004
Your comments ...
| From: Mary Arneson (gearhappy@eight) on 16 December 2004 | | Why not the 8-speed Nexus? That's what my souped-up Brompton recumbent (the demonstration model for Junik until Brompton changed the frame) came with. It's simple to operate, and the range is nice. |
| From: Ben - Kinetics ([email protected]) on 16 December 2004 | | I presume because of the width - the Brompton hubs are very narrow. |
| From: andy scaife (staring@dropouts) on 16 December 2004 | Yes, I've just tried a few wheels (from Moultons) in a spare rear triangle from a Mk3 Brom. A 7-speed Campag freewheel hub is too wide by a goodly margin. Playing with washers will allow S-A 3,5 or 7 speeds in (of course, the old 5 speed was a S-A sprinter) but not the SRAM or Shimano 7 or 8 speeds. Neither can you squeeze in any hub with coaster or drum brakes, or the old S-A 3-speed dynohubs (the AG model) - pity!
My current Brom resto project may become widened to accomodate a dynohub! Does Ben at Knietics have experience of widening the Brom triangle? |
| From: Ben - Kinetics ([email protected]) on 16 December 2004 | | It's not really do-able - the triangle is very stiff. The usual technique is to chop away at the left side, making effectively a large left dropout which curves around to meet the stays. |
| From: andy scaife ([email protected]) on 17 December 2004 | | OOER! I think I'd better leave it alone. Maybe just slip the 7-speed in and pretend I didn't have wicked thoughts, like eliminating messy bottle dynamos, or being able to stop in the wet (and still having wheel rims in six months time!). |
| From: Nigel Cliffe ([email protected]) on 17 December 2004 | Surely the "hub dynamo" solution is the new narrow-width Bromption specific SON front hub ?
Ben at Kinetics has them on his website, and I'm sure others do as well. |
| From: Simon Parker ([email protected]) on 17 December 2004 | Surely this isn't going to be billed as an upgrade to the Brompton? It's just a supply-chain enhancement for the company which in fact represents a disadvantage for the customer, because the ability to upgrade from three to six speed will be lost.
A real upgrade would be to get rid of that ridiculous dual range transmission altogether and fit a decent seven or eight speed hub. If they've had to modify the rear triangle for this change, why didn't they go all the way?
The optimist in me thinks that this is an interim solution and that someone out there is working on a narrow hub gear for folding bikes, in much the same way that Shimano designed the Capreo derailleur gears specifically for folders.
What chance a proper eight speed Brommie at the 2005 cycle show...?
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| From: Ben - Kinetics ([email protected]) on 17 December 2004 | Note to self: read and understand message before replying!
Modifying the rear triangle is very hard. Spreading the forks is relatively easy - but with the new SON XS, you don't need to - and it's lighter as well... |
| From: Tom ([email protected]) on 17 December 2004 | | Seem to remeber that the current VV mentions a narrow 8-spd. Peter? |
| From: Ralf Grosser ([email protected]) on 17 December 2004 | The dual supply strategy is a good idea.
Some markets for example in Germany, getting parts like tugglechains, and shiftlevers, is quite easy with Sram, but often it�s next to impossible, to get Sunrace Sturmy spares.
On Shimano Nexus hubs, well Andrew Richie is rumored, for some reason to be a Shimano hater.
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| From: andy scaife (flinching@price) on 18 December 2004 | The Narrow SON idea is a good one for more affluent owners! (Struggling single-parent alert!).
Too many bikes, too little money, and much joy derived from finding low, and no-cost alternatives and improvements. This IS the Brompton that came from the tip after all! |
| From: Andrew Sutcliffe (brompton.beef.com) on 18 December 2004 | If only they would extend the rear triangle to allow whatever type of gears you wanted?
PPLLLLEEEEEEEEEAAASSEEE! |
| From: Ben - Kinetics ([email protected]) on 18 December 2004 | For the majority of Brompton owners, the 3 or 6 gears is enough, and the narrow rear triangle does quite a bit to reduce the size of the folded package.
You can always add a Speed Drive or Mountain Drive to get more gears ;-) |
| From: Andrew Sutcliffe (brompton.beef.com) on 19 December 2004 | Am I right in thinking the Brompton uses a 114mm OLN rear triangle, as apposed to 130mm for road hubs?
That's an 8mm increase each side. It doesn't seem much to me. Though I do know the derailleur would cause problems, as it reduces the space between it and the front wheel, but the tensioner is fairly large anyway.
Any thoughts? |
| From: andy scaife ([email protected]) on 19 December 2004 | You see, there we go again. With no offence meant to Ben, as I do admire his bikes and his business, but we're not talking dream-bikes here. We're talking ordinary people improving their old Brommies at as little cost as possible, for the joy of it. I'd pop in a Schlumpf on most of my bikes if I could afford the �6,000 that would cost! In fact I'd shell out �18 grand on Rohloffs for everything if money was no object! So that's the price of a new Mercedes on bicycle gears! Then there would be the Padersen, the Windcheetah, Carbon Hurricane, Moulton double-pylon,.... aahhhhh!
I love your ad in the new VV though, Ben. It gives us all a little fantasy-trip to while away the dark nights! |
| From: Ben - Kinetics ([email protected]) on 20 December 2004 | Nothing wrong with bodging Brommies - it's fun ;-)
As I've stopped making derailleur kits for the Brompton, I'm happy to tell others how to do it. Basically, you get a 9-speed Shimano road hub, swap the freehub body to a 7/8-speed one, remove all the spacers and washers, and cut down the axle and file flats on it. It'll now slide straight into a Brompton rear frame without modification. Then use a bolt-on derailleur hanger.
The flaw is that you have to use a short-cage mech, which isn't enough to take up all the chain slack when you fold - but it's no worse than a Birdy in that respect.
Front derailleurs are also bodgable, but I could never get them to work perfectly, which is why I like the Speed Drive ;-) |
| From: Robin (MrPedantic@Bristol) on 21 December 2004 | Ben wrote:
> swap the [9 speed] freehub body to a 7/8-speed
Isn't an 8 speed Shimano freehub the same as a 9 speed?
Robin
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| From: Ben - Kinetics ([email protected]) on 22 December 2004 | | Ahem ;-) Yes - make it a 7-speed... |
| From: Mike Smithson ([email protected]) on 02 January 2005 | Interesting how all the promotional material for Jon Whyte's new Mezzo folder makes great play of having "standard size parts" and "Designed around standards size parts for easy maintenance or upgrading".
http://www.chwhite.btinternet.co.uk/html/mezzo_d_9.html
Having played about with one at Condor Cycles this is going to be the first serious competition the Brommie has had to face. Same price as an T6 - but with 9 gears and 3Lb lighter - and much faster unfolding.
Not ridden it yet though. |
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