Hi,
You wish to have a 60mm hook spanner. Please refer to @Blackstridaaustria’s topic: Strida workshop tool guide.
Loosen the nut screw that should fix the bottom bracket in position and loosen the bolt of Your kick stand.
With a kick stand mounted, like You have it, my experiene is that the forces You can apply to Your kick stand are good enough to tighten the belt with the aluminum bottom bracket. It’s more difficult with the old plastic bottom bracket.
There is a way more than sufficient solution for aluminum and plastic bottom brackets, that i described in: Upgrade Your Strida: Bring down the bottom bracket.
However, with the aluminum bottom bracket and a kick stand, i don’t consider such a modification necessary.
The optimum belt tension:
You need more belt tension in the rain as the friction is not the same where belt and freewheel are wet. Tension Your belt so that it is sufficient for Your needs in dry weather and You’ll need more belt tension in the rain.
I ride my Stridas with a “just enough” approach to the belt tension as this has the least possible amount of wear and losses in the drive train. This is where the individual rider will have to find their way to go.
Optimum belt tension according to the strida manual is when You need some 3,25 to 4,25 kg of weight to press the belt down to the bottom tube where the belt crosses that tube (Strida manual_2018, p 24/30). This test is to be done wit the Strida in riding configuration and not while it’s folded.
For me, i like the thought that the belt feels like the E-string (the low pitch one) of a base guitar when i ipick it. My belt feels tight but not overtensioned like the high pitch strings of a guitar would feel.
My experience is that the aluminum freewheel does not need as much tension as the plastic freewheel of older Stridas.
You have found Your belt tension so You hold it while You tighten the nut screw (part No. 130-05) arresting the bottom bracket. Tighten the screw that holds the kick stand and You are ready to go.
regards: Klaus