***NOTE***

Please obtain your own quote if you go this route.

Great work.

2" wide might be a bit on the stiff side however.

The spring rate can easily be calculated from the material size. I get 390lbs per inch deflection, which is equivalent to 176kg.

Reducing the width to 1" gets that down to 195lb / 88kg which seems a bit better and a heap easier to fit to the chassis rail if you are using the regular 75x25mm RHS for your chassis

Normally with a car you would choose springs based on the corner weights of the car but a guesstimate is probably sufficient with a cyclekart. Think of the weight of the kart + driver and then divide that by four. If you want to be a little more accurate you can calculate the weight bias which is more towards the rear due to driver and engine placement.

I seem to recall a fella on the GB Cyclekart pages who actually measured his corner-weights, so that info is out there somewhere. All you need are some bathroom scales and blocks to keep everything level.

When I get my Cyclekart out from storage I'll measure it for you if you want.

Hi Tom - I tend to agree with Mick that those springs might be a little too stiff. A cyclekart shouldn't weigh much more than 250kg loaded (inc driver) and about two-thirds of that will be on the back end (assuming a rear engine). So probably less than 100kg on the front or < 50kg on each of the front wheel springs (you said "them", so I'm assuming you're not going for a single transverse leaf spring set-up). Using Mick's numbers based on thinning the leaf down to half width or 1 inch wide (which numbers seem right) - that's maybe half an inch of compression for a 1G force. Not a lot of movement!

If I were having custom springs made, I'd definitely think about something softer. Possibly 4 or 5mm thick rather than 8mm, and made only 25mm wide to begin with.

I was wondering whether something like these would be any good if they were cut down to 25mm wide and just the top leaf used: ebay springs

All the best
Simon

Great points Mick & Simon, I haven't had experience with such lightweight vehicles before and kind of went with that they supply! ill have to change up the requirements for these springs. Thin them down and make them not as wide.

Cheers for your inputs


Tom

Some of the golf cart springs might be potentially usable however I'm not 100% sure on details. The only sizes I could find mentioned online were 24" eye to eye and 1 3/4" wide so perhaps a little too big from an aesthetic perspective but definitely usable.

This kind of thing... https://www.ebay.com.au/itm/273612208277

It might be worth talking to a golf cart repair shop and seeing if they have old springs available as heavy duty spring upgrades seem to be a pretty common listing.

After a fruitless search I ended up making my springs myself, from 3mm mild steel flat bar. Whilst it is not spring steel it still has some 'spring' to it.

They are probably more decorative than they are functional, but then I'm not aiming on breaking any records in it so I figure that's all good.

https://cyclekarts.com.au/stream/item/202

You can see the process I used here - https://cyclekarts.com.au/pages/brooklands-bentley/albums/suspension-and-steering