31″ Check Up 1

Thick all-terrain tires give courage to try interesting things with wheel placement at speed. I’m not enthusiastic or proud enough though to go through the trouble of supplying you with action shots. So here is a boring picture-less post.

When I installed my 31×10.5″ BFG A/T’s I expected the consequences to be decreased fuel economy and occasional rubbing. Pssht. I don’t entirely get it, but after having the tires on for a month now, I’ve actually observed BETTER fuel economy than I did with the 235/75 15 winters. Not significantly better mind you… but better. Over the past month I have observed an amazing… 16.2L/100km That’s a little better than 14mpg fwiw. In the six months prior to that, we averaged 16.9L/100km which is about 13.9mpg. Not great fuel economy either way, but interesting that it actually has improved mildly. This might also be due to our better weather as of late, but it is certainly not due to the type of driving we’ve been doing. I’ve been volunteering with a company in town and have actually been stuck in some pretty nasty bumper to bumper traffic with good frequency. Usually we are just highway cruising to and from our somewhat rural home.

Why would this be? The 10.5″ width of the new rubber is about 3 cm wider than the old winters, which cannot help things in anyway. Neither can big All Terrain blocks, even if the BFG A/T is one of the more streetable of All Terrain radials. The extra inch in diameter should bog things down on acceleration as well… but maybe that is offset well enough by allowing us to cruise at lower revs. It’s the only thing I can think of besides the warmer temperatures.

Rubbing also… has not been a problem. At least not on bodywork… not even once. You might recall that after install I was having problems with the wider tires rubbing on the lower control arms at lock. This was tremendously easy to fix, as Jeep actually uses a bolt on the hub assembly as a steering stop. Two washers behind that bolt eliminated all rubbing.

Actually… my only regret about my 31’s are that I installed them on the stock wheels. They are nice looking wheels, and they go along with the stock appearance I want to maintain. However… they’re sunken… and offset is everything. I knew this going in, but all the forum nancies actually had me so worried about rubbing that I didn’t want to increase scrub radius with my lower offset YJ wheels and then increase the amount of supposed bumper and fender trimming I would have to do.

Since rubbing now seems like an impossibility unless I disconnect my front sway bar, I’d prefer a little more street credit and “STANCE”.

Truth be told, the most difficult aspect of installing 31’s was installing… a 31″ spare in the stock location. It fits… now… but it didn’t. I had to raise and extend the OEM fastener… which was a new experience with the welder. But still only a 15 minute job. I might get Yoshiko to “let out” the OEM leather cover as well… as it fit quite snug to begin with, and doesn’t have a hope of fitting the upsized tire.

Cake.