I converted an HPI RS4 touring car into an off-road capable rally car (build here) which I am quite happy with overall. I upgraded from the stock 50mm dampers to Yeah Racing 65mm big bore dampers, and I'm using the softest of the three springs they come with-- which are simply labeled soft, medium, and hard. They get the job done, but given they are designed for a touring car, even the softest springs are still quite stiff. Since I run on dirt and gravel, I'd love to try springs that are even softer.

I guess my first problem is that it doesn't seem like many manufacturers publish information about spring rates. So I have no clue what my current spring rate is, nor the rate of other "soft" springs that are marketed at fitting on a 65mm shock body. Seems like I would just have to do trial and error online shopping which sounds like lighting money on fire. I also thought maybe I could buy cushy springs that are designed for a longer shock body and cut them down to size, but I'm not sure how I would get the end I cut into a flat circle, as opposed to the spring randomly stopping mid-spiral at the cut.

Should I maybe look into 1/10th scale crawler springs? Does anyone have a suggestion for an aftermarket company that I should look into for new springs? Hardware store?