For tyre size 235/65 R17 M+S, you can use snow chains designed for 235/70 R17. The difference of 5 mm in the tyre tread is generally acceptable as long as the chains are not too tight and can be fitted without any problems. It is important that the chain is not tightened too tightly to prevent damage to the tyre or chain. Before riding, check that the chain is secure and that no parts are rubbing against the vehicle.