How old are the tyres? If they're relatively new they'll be ok. I'm not sure how the weight is broken down between wheels, but you have 4, and I think the weight is divided up between them. Then it's about inflation. Keep them firm to specifications.
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20ft Roma caravan - Mercedes Benz Sprinter - SA-based at the moment. Transport has no borders.
Management makes the decisions, but is not affected by the decisions it makes.