Hi, I recently purchased a Brompton on Ebay, 3 gear, roughly 2003 model. The gears kept playing up so I took it to my local Brompton cycle shop. 3 staff members were scratching their heads then they discovered the issue. My Brompton has a button at the end of the crank arm which when pressed changes the gears to a lower set. None of the experienced staff had seen this before, they said it is effectively a 6 gear bike and that its unique. Has anyone heard of this before?
Brompton Unique Gear System
- Thread starter Nel66
- Start date
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Specialeyes
Guru
- Location
- Essex
A button at the end of the crank arm? Can you upload some photos, as that sounds frankly very odd?!
404 Not Found Anywhere
Über Member
Not unique, I’m afraid! It sounds like a Schlumpf Drive, depending upon whether direct drive is in the high or low range it’s either a Mountain Drive or a Speed Drive (there’s also an even more highly geared High Speed Drive). Treasure it, they cost a fortune!
Schlumpf
(I‘m not surprised your bike shop didn’t know what it was, it’s at the more esoteric end of the spectrum occupied by recumbents, unicycles and eccentric cyclists. I had one once…)
Schlumpf
(I‘m not surprised your bike shop didn’t know what it was, it’s at the more esoteric end of the spectrum occupied by recumbents, unicycles and eccentric cyclists. I had one once…)
404 Not Found Anywhere
Über Member
Look up the Schlumpf maintenance details… it might be starved of a bit of lube which might cause it to run erratically. Like other hub gears, it has some specific lubricant needs.
berlinonaut
Veteran
- Location
- Berlin Germany
When Sturmey Archer went bust in Summer 2000 Brompton only had 3 speed bikes for a while, first remaining S/A hubs, later Sachs(Sram hubs until the 6-speed with derailleur was invented in 2002. At that time it became kind of common to fit a Schlumpf drive in addition to the hub gears to overcome the limitations. Don't know about the situation in the UK but in Germany it was possible to order it directly with your Brompton for a relatively low price until 2009, when the BWR was invented. As the Schlumpf-drive added weight (and to the price as well) it was not as common as the 6-speed but still far from being unique. It is pretty bullet proof and adds massive spread to the gearing system.
So the staff in your workshop seem possibly to be of a bit of a younger generation. ;-)
So the staff in your workshop seem possibly to be of a bit of a younger generation. ;-)
Kell
Veteran
- Location
- High Wycombe/London
I’ve been tempted by the idea of a Schlumpf Mountain drive in the past.
Not necessary just yet, but as I get older even first on my six speed is getting harder and harder to make it up the ‘big hill’ on my commute.
Not necessary just yet, but as I get older even first on my six speed is getting harder and harder to make it up the ‘big hill’ on my commute.
404 Not Found Anywhere
Über Member
Yes, that’s a Schlumpf Mountain Drive. You can (or could) buy plates that would activate the gear change by tapping anywhere along the crank if the button is too hard to hit.
BrooklynEdie
New Member
I have a Schlumpf Mountain Drive. As mentioned above for Germany, I had mine installed at purchase time but in Belgium... in 2006. It's a terrific system essentially doubling your gears - in my case from 3 to 6 - with just a few drawbacks.
First is that you may occasionally kick it by accident causing an upshift, or worse... downshift! as you're speeding at a certain pace.
Second, if the button is not tightened properly it will fall off as you ride. This started happening to me until I lost the button and had to go through hoops trying to replace it. I finally did (shipped from Wisconsin, $12 for the part, $15 for shipping and $130 for other stuff I decided to splurge on, which is the danger of looking at Sale items on bike websites), but not knowing that I needed to properly tighten the set screw to a certain tension level, I lost it again, found it, lost it, then found it and stopped riding because of new issues... keep reading.
Another is that it's difficult and expensive to repair if you ever have to. Here in the Eastern US we only have one shop listed, in North Carolina I think. I am in New York so for me it's closer to go to either the option in Quebec or Ontario if I wanted to service the part in person (a road trip to beautiful Canada is very tempting I have to say). Then there's a shop in biking crazy Wisconsin, Colorado, then the West Coast of the US. So it's a whole thing getting this done as right now I am going through a whole process trying to service the drive which finally started to snap out of gear regularly. A Seattle bike shop, about 3000 miles away from me, was willing to order me a special tool to remove the part ($50+~) and at least a few weeks of waiting, get the part by mail ($25?), service it for $100 and return it to me ($25). Of course I would still have to reinstall it. I got lucky and went to a friend with a small shop in NYC who took the part off for me ($50), and though he wasn't able to service it he said he can reinstall it upon its return ($???).
So that's the difficulty of having a very unusual but really high quality piece of technology installed on a Brompton. However, my case is pretty rare. Most of the time these things work the way intended for decades (mine did for 12 years or so). It's worth getting a Schlumpf Drive, certainly if you live in a place that required gears. Combining that with a wonderful bike like a Brompton is a smart, lifelong investment. I hope you're enjoying yours right now Nel66
First is that you may occasionally kick it by accident causing an upshift, or worse... downshift! as you're speeding at a certain pace.
Second, if the button is not tightened properly it will fall off as you ride. This started happening to me until I lost the button and had to go through hoops trying to replace it. I finally did (shipped from Wisconsin, $12 for the part, $15 for shipping and $130 for other stuff I decided to splurge on, which is the danger of looking at Sale items on bike websites), but not knowing that I needed to properly tighten the set screw to a certain tension level, I lost it again, found it, lost it, then found it and stopped riding because of new issues... keep reading.
Another is that it's difficult and expensive to repair if you ever have to. Here in the Eastern US we only have one shop listed, in North Carolina I think. I am in New York so for me it's closer to go to either the option in Quebec or Ontario if I wanted to service the part in person (a road trip to beautiful Canada is very tempting I have to say). Then there's a shop in biking crazy Wisconsin, Colorado, then the West Coast of the US. So it's a whole thing getting this done as right now I am going through a whole process trying to service the drive which finally started to snap out of gear regularly. A Seattle bike shop, about 3000 miles away from me, was willing to order me a special tool to remove the part ($50+~) and at least a few weeks of waiting, get the part by mail ($25?), service it for $100 and return it to me ($25). Of course I would still have to reinstall it. I got lucky and went to a friend with a small shop in NYC who took the part off for me ($50), and though he wasn't able to service it he said he can reinstall it upon its return ($???).
So that's the difficulty of having a very unusual but really high quality piece of technology installed on a Brompton. However, my case is pretty rare. Most of the time these things work the way intended for decades (mine did for 12 years or so). It's worth getting a Schlumpf Drive, certainly if you live in a place that required gears. Combining that with a wonderful bike like a Brompton is a smart, lifelong investment. I hope you're enjoying yours right now Nel66
berlinonaut
Veteran
- Location
- Berlin Germany
This sounds a bit weird. Freshly installing a Schlumpf drive is an expert's job and needs special tools as well. The thing is more or less maintenance free, possibly a bit of grease would be nice after many years. The knob that you mentioned costs 9€ list price as a spare part and those are available w/o issues, at least within Europe. Here's the 2022 pricelist: http://www.schlumpfdrive.com/files/Preisliste_Bestellformular/Preisliste Haberstock Mobility 04-2022 Privatkunde.pdf
Florian Schlumpf sold the gearing business to Haberstock in southern Germany back in 2011. They took over everything, including the very extensive online documentation (which, as far as I remember, also mentioned securing the button you lost). However, at the moment their webpage is completely defective - something seems to have gone wrong badly, as there's only the admin panel of the webpage left.
I'd assume in a couple of days everything should be back on track: http://www.haberstock-mobility.com/
In the mean time you can still find the old pages of Schlumpf on archive.org including the section about maintenance as well as the extensive pdf-manual
Edit: However, the webpage "schlumpfdrive.com" that @404 Not Found Anywhere found (despite his name) and menitoned earlier in this thread is still active and on it a list of technical documents http://www.schlumpfdrive.com/index.php/technical-documents-254.html They seem to have some issues with some of the links on there as well, but in general it works.
Florian Schlumpf sold the gearing business to Haberstock in southern Germany back in 2011. They took over everything, including the very extensive online documentation (which, as far as I remember, also mentioned securing the button you lost). However, at the moment their webpage is completely defective - something seems to have gone wrong badly, as there's only the admin panel of the webpage left.
I'd assume in a couple of days everything should be back on track: http://www.haberstock-mobility.com/
In the mean time you can still find the old pages of Schlumpf on archive.org including the section about maintenance as well as the extensive pdf-manual
Edit: However, the webpage "schlumpfdrive.com" that @404 Not Found Anywhere found (despite his name) and menitoned earlier in this thread is still active and on it a list of technical documents http://www.schlumpfdrive.com/index.php/technical-documents-254.html They seem to have some issues with some of the links on there as well, but in general it works.
Last edited:
biggs682
Touch it up and ride it
- Location
- Northamptonshire
Every day is a learning day
ExBrit
Über Member
- Location
- Southern California
@berlinonaut - you are a fount of knowledge and one of the reasons I keep coming back to this forum. Thanks
berlinonaut
Veteran
- Location
- Berlin Germany
@berlinonaut - you are a fount of knowledge and one of the reasons I keep coming back to this forum. Thanks
In this case you'll probably love the information that the name of the inventor "Schlumpf" is also the German word for smurf. And what would a tiny-wheeled bike fit better than a smurf-drive?
rogerzilla
Legendary Member
I know someone who uses a Mountain Drive on a fixie, which has to be quite rare. He stops to change gear - not sure exactly why, but maybe the device isn't supposed to be shifted when the cranks are moving.
