I tried, I couldn't find pics of a jk with 31x10.50x15s on it. I think they would look tiny on a JK. Why don't you go with the GoodYear Duratrac? It's sold as a 33x12.50x15, but it actually measures 32" tall x 11.50" wide when you mount it on a 15x8" wheel. I know this because that's what I have on my TJ. The Duratracs ride very smooth and quiet on road, they are lighter than most 32"s/33"s. they're great in the rain (safer for your wife), very good off-road, and they look good on the JKs too. I wouldn't think you'd have a noticeable power loss with them. I have 3.07 gears, I went from 30x9.50x15s to these Duratracs and didn't notice a powerloss, just alittle less fuel mpg's, went from 19mpgs to 16mpgs.