I’ve just tried to fit an Optimal anti roll bar link (supplied by Advanced Factors).
There’s either something wrong with the torque I’m using, or the nyloc nut supplied with the link, or something else I’ve done!
I’ve just destroyed the thread on the link and the nut.
Torque I’m using is 100Nm/74lbft (seems high to me), per the workshop manual.
Wish I had used the original LR flanged nut as that might have been stronger.

Any advice would be welcome!

I’ve checked and 100Nm is appropriate for an M12 thread.

Did you lever the anti-roll bar with a crowbar to take the strain off the linkage ball joint thread whilst tightening the nut? 2015 Range Rover Autobiography 4.4 SDV8

No, but it looked like it was sitting straight to me.
Will take the pressure off next time. Thanks GaryRR.

This is probably the reason then. The nut will tighten no problem and without stripping the threads once the pressure from the anti-roll bar is released, and once tightened, the load is then distributed across the nut face and the mating surface on the ball joint. 2015 Range Rover Autobiography 4.4 SDV8

I've often experienced different thread pitches on aftermarket ARB links.
Is it possible the nut didn't match the ARB stud ? Paul,
2001 Discovery 2 TD5, 211,000 miles & climbing
2006 FFRR TDV8 Vogue 145,000 miles & climbing
Member of Midland (Land) Rover Owners Club, www.mroc.co.uk

Good call, but this was the nuts that came on the new link.