I didn't know that. I just looked up the spec on the terra grapplers and it seems that the larger tires have considerably more tread than the smaller factory size tires. However, in the the larger 285-305 Load D/E had almost the same tread depth; 16.4/32 vs 16.5/32. It is definitely a good idea to do some research before buying anything for your car but tires are important.