You can up the tire size if you want, but i wouldn't go much bigger then a inch if you do so. Only reason i say this is because the bigger tire you go with the more power it takes to turn them. So you can up your tires one inch and it shouldn't effect much in the way of your performance. Example: If you have say a 25x10-12 Rear and a 24x8-11 Front tire, then you should always keep the offset tire size. Example: Say you want to go bigger let's say by one inch, well you would then put a 26x10-12 Rear and a 25x8-11 Front tire. You can also change the width of the tire as well, just take into consideration interference in the steering system or rubbing if you do so. And welcome to the forum.