We have 20" front segment monoleafs on our Challenger (using the old S/S spring mounts) and as stated, it does hit the tyre hard. We had our rear D/A Afco's re-valved by Menscer to control it. Without looking at our settings book, I'm pretty sure we are close, 6 or so clicks from full tightness on extension but it works well. We have Santhuffs on the front. We are running a radial slick 29.5 x 10.5 between 19 / 21 psi. car weighs over 4000lb and we regularly 60ft with the backs around 1.38 with a 1.36 best. A couple of years we were putting them down before the 60 beam with a best of 1.34. 4.10 rear (though we are changing to 3.73) 5500 stall, 51.5% over the rear.