I was very interested in the high speed drive or speed drive with their ratio of 1:1.65 for the speed and 1:2.5 gear ratio for their high speed model. This looks like an awesome upgrade but also very expensive! but if successful our strida can really get up to like 100+ gear inches. which would be downright scary and probably very hard to pedal so maybe the 1.65 ratio would be best for a good 92 gear inches for some good cruising speed (using the 56 gear inches that they post).
Has someone found another company that sells a cheaper version than this since it’s almost the price of the bike! If not I will probably have to wait for Ming Cycles to come up with a retrofit part since their strida 6’s seems to be all two speed. Hopefully it’s cheaper!
Ming seem to be doing this upgrade themselves but it only looks like its come out in places like Korea, so far. The Ming version of the upgrade comes with a smaller front ‘chainwheel’ and a shorter belt, to give a lower ‘low’ gear and a more reasonable ‘high’ gear.
(there again, add 18inch wheels and the ratios can be raised higher)
you are not the only person who wants this …
lets’ hope Ming supply a lowcost upgrade kit (ie ATS version of Schlumpf, belt and chainwheel).
Personally, I like the simplicity of single speed - ( and it seems, from all the track bikes I see, that fashion is catching up with me, rather than the other way round as is normal ).
I received an email from the Florian Schlumpf himself (or more likely his secretary) stating that a Strida kit will be available in about 4 weeks and its price in 2 weeks. A perfect holiday gift for Strida 5 owners? Here are the photos from Schlumpf:
Just got a bit more info from Mr. Schlumpf: The upgrade kit will include the Speed Drive system, Ming Cycle’s front sprocket (90 teeth?) and a belt (1360-8M-13?). He didn’t mention whether an eccentric bottom bracket is part of the kit, but it is in the photos that he sent me. The kit will only be available through Strida dealers.
Nice beefy-looking locking ring for the bottom bracket in those pics!
Of course it needs to be, with the heavy torque loading on the bottom bracket housing when in high gear. Anyone who’s actually bought and used a Strida 6 for some time? - I’m wondering if there are any problems getting a good locking fit in the housing. For conventional bikes converting to Schlumpf, a fairly fancy taper has to be put on the bottom bracket to keep the mechanism from creeping.
I haven’t heard back from Schlumpf Innovations. Don’t know if the kit is delayed again or Ming’s blocking it. You are welcome to contact Schlumpf or your local Strida distributor and let us know what you find.
I found a presumably 3rd party Speed Drive upgrade kit on a Taiwanese auction site. It includes not a genuine Schlumpf but an ATS Speed Drive, a sprocket (which looks like a deadly ninja weapon ), an eccentric bottom bracket, and a belt. The item goes for TW$16500 (about US$516) but sadly the seller does not ship oversea. If this thing actually works well, I hope someone can import it to the US and sell it here.
May be It would be a new chance for everybody that owns a Strida Sport Duo instead of fitting large wheels, because the mudguards dont match, the big tyres are less comfortable, more expensive and less available. As the fitting 18" wheels purposse in the SD is rising the speed, may be, we could get the same speed in our duos with a different alternative.
The alternative would be to fit the original plastic Strida front pulley to the current Speed drive and keep the 16" wheels. Unfortunattely, the original Strida 5 plastic pulley has four inner spokes instead of the five ones the miny pulley has. One solution would be to use the not holed Strida 3 plastic pulley, although I dont know if , after chopping, the structural strengh of this pulley would be enough.
At last, We could use the new alloy strida 5 pulley (optional), chopping it and adapting an intermediate thin alloy plate.
Andy B: Awesome mod! Mini owners are lucky that their crank arms are 5-bolt just like the Schlumpf SD. Us 5.x owners can’t do the same unless we somehow manage to find a 5-bolt front sprocket to replace the existing 4-bolt one.
A quick update regarding the Schlumpf Speed Drive kit for Strida: I heard the first batch of the kit was almost ready. The delay of release was due to a redesign of clutch geometry. The change was deemed necessary to compensate for the higher tension on the belt (vs. a chain).
If the technical issue is indeed true, it helps to explain why Sports Duo has been produced in such a small quantity. But it may also raise a red flag on the durability of existing Sports Duos.
The official price tag is 519 euros! Maybe it’s to justify the cost or to deter people from buying ATS Speed Drive, Schlumpf made this statement:
“Please notice: the internal parts were modified in order to correspond with the higher proload of the belt compared with a chain. Always ask for the original Schlumpf speed-drive made in Switzerland!”
On another Schlumpf webpage, I found the following warning:
“The belt drive speed-drive comes with a special geometry of the internals, which matches the requirements of the higher belt tension, compared with a chain. Never combine a standard speed-drive with a belt drive.”