Schlumpf Speed Drive

General cycling advice ( NOT technical ! )
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simonineaston
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Schlumpf Speed Drive

Post by simonineaston »

Anyone any experience of buying, fitting and using one of these?
S
(on the look out for Armageddon, on board a Brompton nano & ever-changing Moultons)
Jdsk
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Re: Schlumpf Speed Drive

Post by Jdsk »

Previous discussions, with a fair amount on fitting:
search.php?keywords=schlumpf&terms=all& ... mit=Search

Jonathan
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simonineaston
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Re: Schlumpf Speed Drive

Post by simonineaston »

I've always liked the idea but not enough to take the plunge - the version that adds 65% is ideal for small-wheeled cycles, although there would be much weeping and wailing and gnashing of teeth on removing the luxurious Royce titanium bb...
S
(on the look out for Armageddon, on board a Brompton nano & ever-changing Moultons)
leftpoole
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Re: Schlumpf Speed Drive

Post by leftpoole »

I am no longer able, but when I cycled I had a number of Bromptons. I had one of these fitted with a Schlumpf drive.
The version fitted, lowered the gearing. I rode up a hill in Cornwall. The locals were all watching from their front gardens, in amazement! They had apparently never seen anyone ride a cycle up the hill.
The cost of the thing is unfortunately quite high and not in my opinion worthwhile overall. The advantage gained is not enough. A massive hill indeed was climbed but in daily use the fitment is pretty heavy addition to the cycle. How often it could be used to fully benefit is pretty low in my opinion.
rogerzilla
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Re: Schlumpf Speed Drive

Post by rogerzilla »

I rode with someone who had a Schlumpf Mountain Drive on a fixie. He had to stop to select low gear but then rode up an awful hill out of Bath (Steway Lane, potholed and slimy as well as steep).

Assuming he was running a 70" gear, the Mountain Drive would have got it down to 28".

Really, really low gears on a bike are ok for lugging camping gear over moderately evil hills like a 1 in 5 but, when the gradient gets to 1 in 3, preventing wheelies is more of a challenge than turning the pedals.
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Tigerbiten
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Re: Schlumpf Speed Drive

Post by Tigerbiten »

It all depends on what you're after if a Schlumpf drive works for you.
A pure derailleur setup max's out at around a x6 range.
This can be extended to around a x10 range with a SA hub.
To go wider takes a Schumpf drive.
Also I think the best use for one is to extend the range of a hub gear while keeping the correct chain line.
That the route I went with a Schlumpf HSD and a Rohloff.
Now a Rohloff is really a 7 speed hub with an internal x2.45 step down for 14 unique gears.
So match it up with the x2.5 step up of the HSD give you 7 more unique gears plus 7 overlapped gear and around a x13 range.
I've gone even further with twin chainring for close to a x19 range on my bent trike.
It's an expensive setup but it works for me as it gives me both silly ultra low and silly ultra high gears at the same time.

So what where you thinking of doing with the Speed Drive ??

Luck ........... :D
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simonineaston
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Re: Schlumpf Speed Drive

Post by simonineaston »

So, the Moulton AM uses a range of rear gear clusters, the exact choice depending on the nature of the rear hub. Models made in the '80s are likely to use English thread freewheels. Moulton made available a number of special freewheels where the smallest cog was replaced with a custom-made cluster, typically giving a 7 speed freewheel, ranging from 9t up to 28t. As these are increasingly hard to find, another possibility is to use an easliy found standard freewheel, say 13t to 28t. This wouldn't affect any given transmission at the lower end, but limits the choice of higher gears.
It occured to me that one way round this would be the adoption of Schlumpf's Speed drive - this could give the choices shown below.
example based on a 34t chainring
example based on a 34t chainring
S
(on the look out for Armageddon, on board a Brompton nano & ever-changing Moultons)
leftpoole
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Re: Schlumpf Speed Drive

Post by leftpoole »

The only downside when fitted to a Brompton or I guess a Moulton, is the additional weight. Plus of course the not too low cost.
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Mick F
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Re: Schlumpf Speed Drive

Post by Mick F »

Fit a 3sp SA that'll take a 9sp or a 10sp cassette.
https://www.sturmey-archer.com/en/produ ... rf3-silver
Screen Shot 2022-05-23 at 10.00.48.png
Mick F. Cornwall
Stradageek
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Re: Schlumpf Speed Drive

Post by Stradageek »

I think I'm with Mick F.

I have a Schlumpf speed drive on my Kettwiesel and whilst it does give a large gear range I do notice the 'drag' of the epicyclic gear when it is in 'over-drive'.

In comparison I barely notice the drag on either the SRAM 3x7 DualDrive on my BikeE or the SA AW3's on my town bikes.

Hope this helps :D
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simonineaston
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Re: Schlumpf Speed Drive

Post by simonineaston »

It does indeed, sg - and Mick too. I've been trying to square a circle with respect to my ancient and lumpy & bumpy AM. I only need a limited range - ideally 28 to 78 inches, which is entirely achievable with one or other of the specialist rear gear clusters, however I thought I ought to explore other possibilites. If only pesky Shimano hadn't pulled the Capreo groupset...
I'm on the verge of rejecting all solutions other than the single chainring / special rear cluster approach. :-)
S
(on the look out for Armageddon, on board a Brompton nano & ever-changing Moultons)
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speedsixdave
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Re: Schlumpf Speed Drive

Post by speedsixdave »

https://www.microshift.com/news/introdu ... er-short/
This won't do anything for the aesthetics of your AM7, Simon, but a 9-speed 11-38 cassette could give you around 21-72in on a 48 chainring, which would fit your bill. But, as ever, I suspect it's aimed at 135mm hub spacing and I bet your AM is 130 or even 126mm. Same with the Sturmey though.
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Winders
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Re: Schlumpf Speed Drive

Post by Winders »

The Microshift Advent 9 speed blocks fit on a standard cassette hub. I’ve used their medium length derailleur and their larger 11-42t or 11-46t blocks on two 20” wheeled Tern Links which use 130mm width hubs, because I now live in a city on top of several dormant volcanoes. This works fine. With 17” wheels the super short option should be fine if the range of the 11-38t block suits you. Although it’s marketed at kids MTBs it has the same pull ratio as the rest of the Advent range, so the brifters and bar end shifters will be compatible.
pwa
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Re: Schlumpf Speed Drive

Post by pwa »

leftpoole wrote: 23 May 2022, 9:51am The only downside when fitted to a Brompton or I guess a Moulton, is the additional weight. Plus of course the not too low cost.
My thought too. I used a Brompton for a year or so, and one of its virtues was that for a mainly steel construction it was not very heavy. Which accords with the Brompton design brief of being easily lifted onto trains. As soon as you start adding significant weight to a Brompton you undermine one of its main virtues.
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simonineaston
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Re: Schlumpf Speed Drive

Post by simonineaston »

I didn't know about the Microshift stuff - a small sprocket of 11t, compared with 9t of the Moulton specials is significant, but not in my case, a deal breaker as I don't push stuff at the best of times. I'll have a further look. Thanks.
S
(on the look out for Armageddon, on board a Brompton nano & ever-changing Moultons)
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