Hey all,
When I bought my truck from a dealership recently, they had already done me the solid of putting a 6" lift, 20" rims, and 35" M/Ts on it.
Thing is, I don't care much about fancy rims or their size, and I think I'd rather have A/T's on it now that I've had some time to drive it. Considering selling my rims and tires to buy some plain looking 17" rims and some AT's.
So my main question is, for off-road driving (and I DON'T mean rock crawling, or sitting around doing high-rpm circles in a mud puddle), is there any advantages/disadvantages to certain rim sizes (I've been told things like a smaller rim makes for a bigger footprint when aired down, etc)?
I suppose ancillary questions could also be 1) M/T vs A/T, 2) should I go up from 35 to 37 in the process, and 3) if I don't care about looks, is a cheap rim ok?
Aaaaaaaaaaaaaannnnnnnnnnnnnnnnnnd, GO!
It really comes down to use and environment. My rig is my daily, so I need a tire with acceptable street performance and tread wear. I live in the high desert, so I face mostly granite mountains, open deserts, and sandy or rocky soil. Mud doesn't stick around for long, but snow is an issue; so my choice of tire is the BF Goodrich All Terrain KO2. Other guys run the Goodyear DuraTrac.
If you were living in an area with lots of top soil that gets sloppy and muddy for days at a time, perhaps a Mud Terrain would be a better choice.
As for rim size, here is what I would do: Start by figuring out the smallest OEM rim size available for your vehicle and don't go any smaller than that. This will help avoid surprises like, "Oh, this doesn't fit over the caliper." Then take a look at the tires you want to buy and price them out for different rim sizes, sometimes a given rim size will result in a cheaper tire (my wife's car has factory 19" wheels and it feels like we need to take out another mortgage to afford snow tires). I think that for mixed use, a 16" or
maybe a 17" rim will do nicely, depending on the overall tire size.
A tire with a taller sidewall will have a larger footprint when aired down and the rim will be farther from rocks than a lower profile tire. This will also protect the sidewall from a "snakebite" cut; this happens when the rim slams down on a rock and cuts the sidewall bulge. A high profile tire will have more bulge, but also more space between the rock and the rim. There are downsides to a high profile off road tire though, on-road handling is impacted because you have more squishy sidewall, they are also heavier than a low-profile tire so braking, acceleration, and fuel economy are negatively impacted.
Getting back to rims for a second, the material you choose can make a difference. Alloy rims are lighter than steel, but they can also be cracked. The alloy is harder than steel, so it takes more to damage it, but when it does break you will have to change the wheel for your spare. A cracked alloy will not hold air. A steel wheel is cheaper, but heavier and easier to deform. This means it takes less of an impact to bend the rim. A bent steel rim will still hold air, so you can limp home on one. I think of cheap steel rims as a mechanical fuse, they bend and absorb energy before transmitting it into the much more expensive steering and suspension components. You may go through a lot more steel rims (I've bent a few), but if you buy cheap ones they can be replaced for about $60 each.
I run 16" OEM alloy rims on my rig because that is what it came with and I have not had any problems with them.
