Concave flywheels designed for noobs
I had my clutch replaced a little over a year ago on my 2005 Rubicon unlimited. Used a Luk Gold series, and tossed the cheesy plastic throwout bearing, I think for a SKF branded one. Had the flywheel taken down a one thousandths of an inch. The machine shop that performed it said they've done dozens of them, and showed me their shop manual pertaining to that model of Mopar flywheel and that the limit is three thousandths of an inch. They also explained the reason behind the "factory concave finish" is for persons unfamiliar with clutching, providing a 'smooth engagement' for the uninitiated. It's mostly for the sales people to show how it easy it was, 15 years ago to drive a standard transmission. I asked the machinist why the Jeep service manual 'recommends not surfacing and buying a new flywheel', and he stated "because they want you to buy expensive parts that are not needed." and he further stated "your flywheel is fine, no scoring or burn marks, what is it about five years old?" and he was surprised when I told him 13 years old. And I wasn't gentle with it either. Was almost certain I'd burned on at least two occasions. But after I had the flywheel and clutch installed, I noticed no difference on engagement whatsoever, and that was over 10,000 miles ago. So, in finality, don't believe that crap about it being concave permanently, it wears flat anyways. But above all, stay away from the Centerforce brand. I'm sure for the rice burners, and boulevard blasters that produce their torque and horsepower curves above 7K RPM, it does no real benefit for a trail haulin Jeep.