I asked this question for a mate on another forum. This what they said:
Suzuki put 215/75-15's on their test fleet fot off road test drive days so they should work OK, also I know a lot of people who run 195-15's on std suspension set up. I run 215-15's with a 2" lift, which you can run without the lift but you will get some rubbing on the arches and inner wing. This is about as big as you can go without realy [!Expletive Deleted!] up the gearing. Colway do cheap tyres in both sizes in A/T or M/T patterns