The spacers are worn out, this makes for slack between the leaves, and allows them to swing side to side. You need to pull them apart, repack them and pack them back together.

Going down a series in tyres may help. Go from 60series to 55series.

If this doesn't help..simply put, your wheel offsets are wrong.

So look at getting 2mm or 3mm machined off the back of the wheel mounting face. It will need taking the tyres off the wheels.

Cheers,
Chris