I have an old Mercedes-Benz ML 270 with alloy wheels taking tyres size 255/60 R17. I use it in the winter to pull a little trailer with the horse manure from a very muddy park. Last winter, I planted it a bit too often. I do not do very many long journeys these days at nearly 70 years of age, so that is not a problem. Can I put on bigger tyres, and what do you recommend?