Need tire suggestions for 2001 TJ

Needing tires on our 01 Sport. Basically stock setup, though I did do the ZJ conversion and it has the 3(?) washers on the steering for turning radius(?).

So currently it has 235/75R15 Michelin Defenders on it, which IMO don't look right on a Jeep, but there has been nothing wrong with so hadn't yet changed. They are getting into the yellow on tread depth gauge, so time to seriously decide what tires to go with. I think I've settled on the Duratrac's. Now onto size....

Tire shop said factory is 215's, but I thought I read on Goodyear there were 3 sizes with 30 x 9.5 15's being one option on stock TJ Sport. Speedometer is currently off, if it says 40, she's going about 38. Again, this has been fine because it's my teen daughter who drives it and I was fine with her being more on slow side while learning to drive. She also is NOT interested in any lifts at this point, but I think it needs a bit beefier looking tire.

If not mistaken the 235/75 is about 28" tall. If I went to about 30" tall tire, what would that do? Through off speedo more? and does bigger equal slower read on speedo? I can't recall. I'm not sure Duratrac's are made in 30x9.5 15's. Again, it has the spacers and I thought I read I could go to 31's.

I thought 31's were possible. Thanks!

I was talking to Discount Tire about the tires as well and told him I was looking at the Duratrac's he suggested taking a strong look at the Wrangler TrailRunner at a price of about $105 each vs near $200 for the duratrac's. I'm not really sure my daughter cares. They look about like the BG KO2's from what I recall and I agree those are great tires as well.

Well, had them order a set of 31x10.50 15 K02s. Going to look killer I think. They get them in tomorrow and tentatively scheduled to install on the 22nd, unless we can find an earlier time that works.