You might possibly need spacers. I don't know how the RC upper control arms compare to the stock ones, but with a 2.5" level I couldn't go wider than a 295/65R20 tire. About a 12" wide tire. Stock height and stock tire I had about .5" of space between the tire sidewall and UC ball joint. After level and with the wider tires I maintain that .5" gap. This is with 20x9 stock night edition wheels. I know in my case I couldn't fit the 12.5 wides.Put a 3.5 RC lift on my 22 ram need to know if 35 12.50 will clear upper control arm ball joint on stock 20x9 rims