My 4G has no suspension mods (and I am on the factory rims) so I knew it would be a bit of a risk putting these size tires on, but with the kind of wheeling around where I live (mud and snow) I was willing to take the chance and see what would happen as the extra ground clearance and contact patch of basically a 35" tire would really help.
My fuel economy did drop by about 1 mpg and I did feel a slight loss in power. I bought a Bullydog programmer shortly afterwards and while it did make the power feel back to what it was with the stock tires the fuel economy continues to stay 1 mpg worse. I was able to use the Bullydog to correct my speedo (verified using my Garmin GPS) and also turn off the tire pressure warming/monitor.
Now for the big questions, control arm and inner fender well rubbing. The tires do rub on the control arms a lot when turning tight corners. Eventually I hope to install some offset control arms. I have done one off roading trip where I was on some more technical terrain (a dry riverbed) and with the sway bar disconnected I only noticed some very slight rubbing on the fender wells at high articulation corners where my wheels were turned. When my wheels are straight and I am at full articulation there is no rubbing. However, I have heard of other 4G owners who had pretty significant fender well rubbing when they installed 35" tires with no suspension mods. It may have to do with the slight variation in actual tire size.
Would I take the chance on rubbing if I had to do it all over again? Yes!!!!! I swear a 35" tire is really what these trucks should have come from the factory with. The extra 2" makes such a huge difference off road. For right now I am more than willing to live with control arm rubbing for the vastly improved off road performance.
Some ask why I don't do a mild suspension lift and easily have no rubbing problems at all with the 35" tires and there a 2 main reasons for me. I live where we have 6 months of cold, snowy winter (Edmonton, Alberta) and I REALLY like parking my truck in my garage. I also tow a travel trailer that weighs 7500lbs wet, and often do that with 900-1000lbs of ATVs and gear in the bed. Getting a truck with a raised suspension that can also tow and haul well can get quite costly and that is not in the budget (I did add a set of Hellwig add on leaves).
For reference, the tires are Kelly Safari TSR.
Here are 2 pictures I took today on the snow pile in front of my house. This is at full articulation (one rear tire was off the ground). I will dig up some more pictures and post them soon.
