Potentially Dangerous Failure

[cj10jeeper]

New OEM sport spring and a pair of run flat Conti tyres so they are equal tread and all sorted....

CJ, I know you're a mechanically minded person as I've read a few posts of yours with interest, (I'm particularly thinking of your Jeep rebuild) but I cant help but wonder why you wouldn't change the other side's spring too?, my logic is that if one has gone the other is likely too as well at some point, only doing one side would worry me given the consequences already seen with one letting go.

I don't think coil spring failure is that uncommon these days, my DD Polo snapped one as I was turning in a car park, my work colleagues Corsa broke a spring in much the same way as your daughters with the spring going into the tyre.

Good question.
I base it on 2 considerations. BMW springs don't sag or in any way wear out. They can break after a week or a decade. Even BMW don't replace in pairs.
My Indy who does a dozen springs a week on various cars also confirmed it not to be necessary.

Spending the money on 2 new tyres for balance rather than a 9mm vs 4mm was more important to me.