Strida C1 and Speeddrive ?

Hi dudes,

did they anybody tried the C1 carbon with a speeddrive ?


Hi Patrick,

you - respectively one of your mechanics - should be able to verify whether the C1 excenter and the common excenter, for example of a Strida SX (parts assembly 130-00), are equal or not.

If both excenters are identical it should be possible to mount speeddrives, though it may happen that the belt starts touching the surface of the bottom tubes upside.
(Because the Carbon tube shape is different, and I believe a bit bigger than Aluminium tubes.)

Just one thing finally, for the case that it is actually possible to use speed drives:
Why would somebody want to use a two speed drive if one could have three speeds, too?
efneo GTRO three speed gearbox

Naturally you could send one of your C1 also to Vienna and I’ll gladly check that for you :sunglasses:

Kind regards,


Hello all.
Blackstridaaustria, would you be able to mount Efneo on strida C1?

best regards

Hello Gregr,

nobody would be able to use the efneo on a C1.

It’s exactly the same situation than that of ATS/Schlumpf drives - beltwheel with 80 teeth and freewheel with 30 teeth will lead implicitly to collision of belt and bottom tube - no way.

boxbike got meanwhile reply from MIng cycle - they tried to mount an ATS in the factory and stated: “…2 speed drive can not be used on the STRIDA C1…”

Kind regards,


It is a real real pity. :frowning:

I’m using 18’ Evo fot about 1,5 month. It’s my first Strida and it is great (besides the tyres, they suck). I’ve put on rinsten spring , saddle shocking absorber, and it becomes more great. 20-30 km is the standard i ride daily. 50 happen too.
But the Evo’s weight is a little bit too high for me while i go for shopping with the bike. And suddenly the opportunity has occured to buy second-handed C1 for a good price. Mudguards are possible to mount, rear carrier rather not, but gears i’ve hoped are the real option here.
It is a real pity that C1 is not liable to modding.
It is a real pity that C1 has no gears :confused: Whyyyyy…

Thanks for your response.

You’re right with the tyres, the “choice” between two racing slicks and the Innova isn’t a choice, that’s just a pita. All I can do is to recommend switching to another rim size - to 349 mm.
If I, as a laymen, am able to lace my own 349er wheels I’d think that this can’t be a big problem for a professional wheelbuilder…but perhaps I’m wrong…
…Strida wheels are different from conventional wheels…omg… :open_mouth:

Well, I think there is still a small chance left over for the installing of gear drives,
BUT there are some major disadvantages and many details of course still unknown.

First; the installing would require a complete change of the drive train from belt to chain.

Next step would be to figure out how many teeth maximally are possible at the rear.
I know that 18 teeth fit, but I’d suspect - and wish - one could go higher, maybe up to 20T.

So - now one could start playing around at the front - possibly we could use here 56 or 58 teeth.

By using a chain there is also a certain chance of adjusting the chain line a bit left or right,
this may also help to get around the bottom tube.

Below a quick shot to illustrate on which base I drew my conclusions above; the parts to the right are a standard BCD 130 50 T chainwheel, laying on the original Strida 80 T beltwheel.
Left a standard pulley with 18 teeth, laying on a genuine 30 T belt pulley.

Interestingly, while writing this I contacted Wiktor from efneo, initially just for some drive details, got already several replies and therefore I’m sure they will help us - if possible.

Another interesting point is for my meaning the C1 bottom bracket:
Is it made completely out of carbon or is there an addidional metal tube inside?
If there is no metal I’d think once again about the project.

Finally a personal question:
The whole thing may end up with an overall gear ratio which is (let’s say) ten percent higher than normal - would you appreciate that or regret?

Thank you very much for such a comprehensive answer I haven’t even expected.

As it seems the ground is totally unknown .
From personal experience a lower gear is more useful than the highest and that is the clue of this modification. Well the highest gear is still really welcome. :smiley:
Modding Strida C1 in the way you have described is similar to building a new prototype, a lot of changes, a lot of “unknowns” and a chance of success uncertain. Putting a chain on Strida looks weird also. Hmm. Lot of work, lot of money , not easy. I think I give up the idea for now.

The weight and design of C1 is still worth consideration as I was given the opportunity to buy one. Hmm…

Thank you once again for answer.
Best regards

Oh I see we crossed each other.

No problem, the whole thing seems highly interesting :laughing:

As mentioned earlier at the efneo thread - the cooperation with the efneo team works simply excellent :smiley:
Wiktor just sent me an interesting proposal and recommended also to involve the Gates Drive support which is a very good idea for my meaning!
I’m going to do that tomorrow - please stay tuned. :unamused:

Forgot to mention the important thing: Wiktor meant it might work with - belt.

I’ll stay tuned.
The topic is getting interesting more and more. :slight_smile:

Today morning arrived the receiving confirmation from Gates support of yesterdays request, but no answers so far.
(Perhaps we’ve caused some headache there.)

However - here’s an image for you to explain the principle of a possible solution.
Imagine the green circle as an additional, small idle roller to guide the belt “around the corner”.
Logically there would be a longer belt required (red line).

Of course you’re right; that is still like prototyping - or one could say that is customization on a fairly high level.

Solving all problems in theory only seems impossible, many details must be checked “live”, on a real bike.


Something like the roller you’ve proposed is the first thing that came to my mind. But it must prevent the belt from sliping off, it can not interfere with the way Strida folds and the longer belt (another not typical part in already not typical bike) will be propably have to be custom-made (or maybe not).
I think the only thing I can do for now is to take the bike for test ride as it is and compare it to 3 speeded EVO. But I think that I like the lowest gear too much to give it up in a daily use.

PS.Will you recommend any Strida seller in Austria? I’ve shown Strida to my friends last week and they looked pretty interested. They both live in Austria, Salzburg.

Best regards.

Hi Gregr,

yesterday I’ve got reply from Gates.
Unfortunately it turned out that I sent the request to the wrong department - to that of Gates Carbon Drive (these belts are dedicated for bicycles only).
Just the HTD belt type used on Strida is actually an industrial belt.

It seems that neither Gates nor Continental ever accepted that their industrial belts are in use for at least one folding bike, too. :neutral_face:

The request will be sent again asap, but this time to Gates industrial support.

I do not think so because the snubber does that already and there is no reason not to keep that part.

Agree fully.

  1. There are two belts available for Strida; the shorter one shown above is 1360 mm long.
    The longer one, used for single speed Strida and EVO has 1440 mm - perhaps that’s long enough to allow the additional roller.

  2. There is no chance to get custom made belts; belts are generally made in certain length steps and certain widths. All one can do is to cut their width accordingly.

Strida dealer in Austria:
As far as I know there are just two - and they are in Vienna.

This is actually a good friend of mine; therefore I can tell that Mike does not at all like to sell bikes via internet. He’s an old-school type of local dealer; he wants the customer to try the desired bike before buying and he also wants to explain and adjust each bike together with the customer.

The other one is Tom; of course I know him also personally but I could not tell if he sells online.
Please tell your friends to ask him by themselves.

Generally I can not recommend to buy a Strida bike without having ridden one before.

Kind regards,


Thak you for all the answers.
I recommended my friends to check the Strida onplace in the shop as I did myself. I told them that the bike is so specific that it requires to test before buying.

Best regards

I’ve got a question.
Why do designers of EFNEO for Strida don’t just propose in sale the orignal speed-up-wheel size of EVO and C1 (1440 mm belt drive) instead of making it 1360 mm ? Such a designing move should have made a problem solved.

best regards

Hi Gregr,

before I start to explain I’d like to point out that the efneo wasn’t designed just for Strida - the Polish guys created a drive which should be suitable for ALL bikes.

You overlooked that here are two things to consider; one is the design and the other are the technical specifications of the installed drive.

To comprehend, we need to take a look at the inner gear ratios of the mentioned drives, these are like this:

1st EVO gear: 0,787
2nd EVO gear: 1,0
3rd EVO gear: 1,257

1st efneo gear: 1,0
2nd efneo gear: 1,43
3rd efneo gear: 1,79

(Note that the direct gear, represented by the factor 1,0, is on the EVO drive the middle gear while it is the lowest gear on the efneo.)

So, if we mount a 100 teeth beltwheel, we could achieve these teeth counts:

1st EVO gear: 78,7 (virtual) teeth → lower than single speed ratio
2nd EVO gear: 100 (real) teeth → same ratio than single speed
3rd EVO gear: 125,7 (virtual) teeth → higher than single speed

1st efneo gear: 100 (real) teeth → lowest ratio equal to single speed (too high for a low gear)
2nd efneo gear: 143 (virtual) teeth → a bit higher than 3rd gear on EVO (should be manageable)
3rd efneo gear: 179 (virtual) teeth - > much higher than 3rd gear EVO (too high to pedal)

The inside gear ratios of the efneo drive (just like on Schlumpf/ATS drives) require explicitly the use of a smaller beltwheel, with 80 teeth are the efneo tooth numbers:

1st efneo gear: 1,0 x 80 = 80 (real) teeth → lower than single speed ratio
2nd efneo gear: 1,43 x 80 = 114,4 (virtual) teeth → a bit higher than single speed but doable
3rd efneo gear: 1,79 x 80 = 143,2 (virtual) teeth → a bit higher than 3rd gear EVO

Regarding Gates:
(It’s so boring…what a pity that some companies, like Gates or Ming cycle, obviously really do not like to talk with simple customers…)
The last request, kept very plain, was sent to Gates Aachen already at 14. 05.
They were so far not able to reply… :unamused:

Best regards,


Hi Blackstridaaustria

Thank you for the explanation.
It was not as simple and obvious as somebody would expect.
Now I understand what the problem is.

PS. Didnt’t know EFNEO inventors are from Poland. Zdolne chłopaki. :sunglasses:

Best regards

Hi gregory,

gladly, and yes, the issues are partially not that obvious.

Still nothing from Gates, maybe you want to try yourself?
The question is; what has to be watched when adding an additional, very small beltwheel, similar to a tensioner.
(That should be the correct department:

Gates GmbH
Eisenbahnweg 50
52068 Aachen

Got that from the bicycle belt support, but without an email address, so I tried that one:

  • no reply so far.)

That’s great if you can talk with the efneo guys in their mother’s tongue :smiley:
(But their English is also very good.)




it took a while, but it’s finished.
Strida C1 with ATS speed drive!
Extra feature: Schwalbe big apple (my pressure at the rear 3 bar!)
Thanks to Mark for the great support!


Hey Ingo,

welcome at Stridaforum! :smiley:

Please do let me know how you solved the issues :laughing:



Many thanks for the image :smiley:

There are two things which I can’t understand, would you please enlighten me:

  • That seems to be a 100 teeth beltwheel, is that correct?

  • If these are the original wheels (which I do believe) then it should be 18" (ETRTO 355) - just the Schwalbe Big Apple doesn’t exist in that size (I thought)?