Let's Talk About Lug Nuts

TL;DR removing 540g with shorter wheel nuts 

The nuts provided with the Image wheels are longer than the original ones, and didn't look quite right with that wheel dimensions. They are quite heavier too.

So I got cheap but good-enough-looking ones in black. I went all with with open nuts(*), With a chance that the studs would end up proud of the fasteners.

Specifications are : M12x1.5 nuts with a 60° taper.   OEM ones are 30.5mm long, with only 0.5mm for the thin round cap, that's 30mm thread in there. 

The open nuts I got are 25mm long, they're made of unspecified stell - I've confirmed that they stick to magnets.

Weight-wise, for the bag of 16 nuts, we have :

• OEM Caterham "Juno" ➡️ 800g
• Image Wheels M12x1.5 ➡️ 890g
• "Tracer" M12x1.5 SW19 ➡️ 350g

In my case that's 540 grams saved on unsprung rotating mass. Compared to the original ones you would be at 450g. Totally worth the 13€ I paid for a pack of 20, even even if I had to skip a pair of duds with a thread that didn't feel right.

After a quick check with a spare nut on the original Juno wheels, they would certainly fit but you'd need to be extra cautious not to scrape the wheels with your 19mm socket. Make sure to use a wheel socket with a plastic shroud that comes proud of the metal.

As I was lifting the car, I took the opportunity to fit the Hayashi Racing brake drums at the same time. I've removed 3540 grams from my car today.

(*) looking for wheel nuts that would fit my steel winter wheels better, I discovered that the Caterham 160 and 165 press cars came with open nuts, as shown in this Autocar review and confirmed in "The Magnificient 7" book. - Steel wheels seem to use two piece nuts with a flat mating surface.

Below : copper grease on the studs will lose its shine and blend in with a bit of dust, and look how an ugly frog it is without the black stripes on the nosecone.