Adjusting belt tension?

I can see how to tighten or loosen the belt tension from the manual (Strida 5.0). But when I tried it, it didn’t work.

I loosened the adjustment screw, and then tried moving the screw forward and back in the slot. But the screw didn’t budge. Is it normal for this to be very hard to move? Should I try putting some WD-40 in the slot, perhaps?

Can anyone who has experience with this provide any suggestions?

Before you can adjust the eccentric, (and hence belt tension) you also have to slacken off the big ring on the LH side. This ideally needs a ‘c’ spanner, but it can also be loosened by a carefully placed square ended metal rod in one of the slots and a hammer. With this ring slacked, the 8mm screw underneath can be used for adjustment.

I tend to keep belt tension (along with adjustment of snubber) in a sweet spot - minimum tension on belt and tiny gap(0.25mm) between snubber and belt that avoids jumping with a minimum belt tension for max efficiency. Higher belt tensions and tight fitting snubber both cause small amounts of extra bearing drag.

Re-tighten in opposite sequence.

I hope this helps … I also unscrewed my eccentric BB and remounted it with the crank axle at the bottom instead of the top, this gives about 1" more knee room !

Thanks for the clear, helpful answer. Hopefully I can find the tool you mentioned. I wonder why this information wasn’t in the manual?

As an aside, I think my belt loosened up a tiny bit because I had ice build up on it when I was riding in slushy conditions. Before then, my belt didn’t slip, even when it was wet. Now it does occasionally slip when it’s wet, but when it’s dry it’s fine, even on hills.

On my fake strida 5, I thought the drive belt was too tight and I loosened the screw on the bottom of the BB and nothing moved in terms of belt tension. I used a small ,metal rod against the indentations on the outer end of the BB bearing unit, and lightly tapped it with a hammer to push the eccentric housing around a little. This worked very well, and then I re-tightened the screw under the BB. I felt a noticeable easing in pedalling effort with the tension set like this and even up steep hills where I am REALLY pushing hard, the belt does not skip at all.

Dear all

I seem to have the opposite problem to EvilV: I’ve got a Strida 3 and I’m having trouble getting sufficient belt tension - rather than 6.5-8.5kg as specified, I’m doing well if I can get 2kg. I spent a fair bit of time looking into it; the belt tensioner is loose, and can be easily pulled out between finger and thumb - if I understand the tensioning system correctly, that isn’t right, is it? Certainly, when trying to increase the tension (rotating the nut on the tensioner having slackened off the nuts on the BB moulding) nothing is happening.

I’m going to dismantle the entire BB soon and see if I can sort it out. But any comments (even in the line of ‘you’ve got it completely wrong!’) much appreciated.



Ben -

I am not familiar with the Strida 3, but if it has an eccentric BB which is rotated to tension the belt, have you tried carefully drifting the BB unit around with a steel rod and careful hammer taps? Mine (on my knockoff S5 copy) didn’t move at all when I loosened the screw that secures it in the slot on the bottom of the BB, and fortunately, one end of the BB bearing unit has a sort of castellated construction. This made it very easy to use a rod and hammer to lightly tap it in the required direction to make an adjustment. You could even use an old screwdriver if you don’t have a suitable rod, but use it carefully to avoid damage to the BB.

Also, you didn’t mention I think whether the belt is skipping under power. If it isn’t skipping, then it isn’t too loose. As I understand it, the most efficient tension is the lowest that will allow hill climbing without the belt jumping. That’s how I set mine. I have no way of measuring the belt deflection pressure in KG. I remember from my young days with small motor cycles how much power can be wasted by over tight drive chains. Belts will be pretty much the same in that regard, so don’t make it too tight. As mine is now set, I can climb a hill that takes every bit pf power I can produce and there is no sign of belt problems.


Ah - the Strida 3 has a different system to the 5 and its copies. The manual is online here and P 28 tells you how to do it.

It seems that you loosen the bolts that hold the BB unit onto the frame and then turn an adjuster on the backside of it. I expect you know this and have done it already. If the adjuster bolt pulls the BB forward by being threaded into the frame tube, you WON’T get anywhere by tapping it forward or backward either, because the bolt will be holding it in a fixed position.

Hi Ben,

The nut of the belt tensioner of Strida 3 is supposed to be tight in any situation.

If you want to tighten the belt, you have to rotate the nut clockwise after removing the belt from the front pulley and lossen the 4 bolts on the BB moulding. After you have adjusted the nut, you have to retighten the 4 bolts and put the belt back onto the front pulley.



Sorry to resurrect this thread, just a quick additional question … anyone happen to know exactly what size c-spanner would be required? (FYI, this is called a “Hakenschlüssel” in German. :slight_smile: )

Help!!! The big ring on the LH side is not loosening at all (I am using the metal rod method and I am afraid that I am going to start taking big chunks out of it.) :blush:

Can someone please confirm which direction is loose and which is tight? I assumed counterclockwise to loosen it, but then I wondered if it is threaded in the opposite way, like the left hand pedal normally is??

Yes- its standard Right hand thread.
now I will TRY and attach pictures (the in use picture is tightening the ring)

Oooops … how do you attach a pic ?

Luckily, google pictures shows…
similar application … ighten.jpg
(this is tightening the ring)

and universal c-spanner … (say 1 to 2" in size) … … ber-1.html

Here is a BBcode guide on adding images to a post:

Or you can just use the “upload attachment” function available in this forum to upload and attach image files directly on the post. :wink:

Thanks - it would be nice to be able to upload a pic from a pc to here, rather than uploading somewhere else and linking to it … or have I missed something ? but this is not a big issue.

sorry for interlude - now back to belt tensioning

As a follow-up, I was able to find a mechanic with a c-spanner. Couldn’t find one to buy anywhere – only some of the bike mechanics had even heard of it. Apparently it used to be needed for a lot of bikes, but nowadays the manufacturers have custom wrenches that fit exactly to the specs of their ring. (What exactly is this ring called, anyway?) I ordered the tool for myself, but the mechanic had to look through 4 different catalogs before he found it!

(An interesting aside to this whole saga is that sent me this reply after I’d already managed to loosen the ring:


Anyway, my belt is now tighter and there is less popping, but not no popping. Looking at the freewheel, I fear that this could be due to wear. The teeth are all supposed to be straight across, are they not? On my freewheel, several are concave. It is also interesting that with the belt tighter, there is some “rear-end wobble” that I hadn’t noticed before.

Maybe I should revisit the snubber. That leads me to a new question. On the 5.0, there is a disc (of course, since it has disc brakes) that makes it quite hard to get at the bolt head of the snubber. Should I just try to find a really flat wrench, or do I need to take the wheel apart?!

Those C-Spanners are not necessarily bike tools - I got mine from a general hardware store, I think the ‘ring’ could be called a ‘lock ring’ ?

Snubber gap to back of belt should be as small as possible without being in constant contact with the belt. 0.25mm would be about right 0.75 or 1mm too big. If you belt has been running with loose snubber and tension for some time (ie regularly popping) it may be possible you have damaged a few kevlar cords - reducing the belt’s stiffness and so making it more prone squeezing past snubber, and so jumping more than a new belt would do.

I find a THIN flat spanner is best the get to head of snubber between it and disc – OR a slim socket through the disc. Adjusting the snubber to get the be optimum 0.25mm gap is fiddly … I seem to need 3 hands !! (1/2" / 13mm Spanner for head, 0.25mm feeler gauge / plastic strip to set 0.25mm gap, and another 11mm spanner for the lock nut ).

If all goes well your belt will not ever jump - good luck (this message will self destruct in 3 minutes :smiley: )

Hi Human Amp,

It is possible to attach photos on how to lossen/tighten the snubber head to get the 0.25 mm gap? I have problem finding the right bolt and nut though you have provided a quite detailed explanation.

Thank you very much.

Hey - check out

and if these don’t work … try whole new ‘Strida Tech album’

Dear Human Amp,

Thanks. Will try it out. :smiley:

I have no idea why, but today I started to get the ‘popping’ sound on hills that tells that the drive belt is too slack. I pushed it uphills so as not to wear the pulleys by slippage and rode it on the flat until I got back home. The SLO has been ridden about 250 miles and never a ‘pop’ until now really and when I investigated, the BB was tight and seemed well secured by the adjustment hex screw. I suppose it might be possible that some mighty torque applied by me on a hill made the BB slip around even though the securing / adjustment screw remained seemingly secure, but I don’t feel it is likely. Another possibility is that the rather warmer temperatures of today have made the belt expand (it is 10c here now, and the bike has been ridden in somewhat cooler temperatures of around -3C to about +5C). However, the belts are not supposed to react like that. Kevlar has a strange negative expansion when warmed. The belt is supposed to be kevlar reinforced, so that shouldn’t happen if it’s true.

Anyhow - I adjusted it and all seems well now, but I don’t have a lot of adjustment left if there is any more expansion. Nothing else can move as far as I can see, so either the belt has stretched or expanded, or the BB slippped around.

Perhaps the problem is at the other end … Does the freewheel have any signs of wear on the teeth? And what about the snubber, does it still have a small enough gap?