I've been trying to find a local source of springs for the club. Unfortunately the biggest barrier seems to be obtaining the correct size material. Most (all local) spring manufacturers use 6 x 40mm minimum size which is larger than the 6 x 30mm that is generally prescribed.

I even spent some time talking to tuk-tuk & rickshaw manufacturers in China and India but they too use larger material which is generally 50mm wide by 6mm.

I did some calculations on the locally available material size, using the renegade Cyclekarts springs as a baseline. These are 24" eye-to-eye, 1 1/4" wide and 1/4" thick, which equates to 630mm eye-to-eye and 31mm x 6mm.

Using a spring calculator this gives a baseline spring rate of 103.57 lb/inch

To achieve the same spring rate using the locally available 40mm wide stock we can increase the eye-to-eye distance to 660mm to get a spring rate of 102.31 lb/inch, which is only a marginal increase in length. The increase in length would effectively shift the front axle back by 15mm, which is more or less negligible.

So I think that for a small compromise in length we can get a comparable spring manufactured.

Here's the comparison