Chazbo

In Washington, you are required to carry chains even if you have 4WD, though you are usually not required to use them. From the DOT site:

"Tire chains required - except four-wheel/all-wheel drive.

On a front-wheel drive vehicle, you must install chains on the front two tires. On a rear-wheel drive vehicle, you must install chains on the rear two tires.

If your vehicle can not accommodate chains, the Washington State Patrol has a list of approved alternate traction devices that may be used when ‘Chains Required’ signs are posted on mountain pass highways. The list can be found at www.wsp.wa.gov/traveler/traction.htm.

Under extreme weather conditions, the Washington State Patrol can mandate that all vehicles chain up, including four-wheel/all-wheel drive vehicles. Drivers must then install chains on one set of drive tires."

gwpfan

Ok I am an idiot, my stock 20's are 275/55R20's, which unfortunately are also excluded from chains being acceptable.
So stock 20's are 31.91 diameter, new 18's are 32.07, this makes more sense as a difference of only 0.16, unfortunately not in the favor of chains. I will try to check this weekend.
Quick measurement while parked and 275/65R18's closest point is at rear wheels and rear most fender, approx. 2-1/4". Front is approx. 2-1/2". All stock.

gwpfan

I am going to go with it. I fitted & cut my chains down to make sure I have a tight fit. The clearance is 2" w/chains on on the rear.

Tight spots are at inside of rear shock, but that's just plastic, and it's really tight on the inside of the front tire, so I'll just have to make sure I keep them tight.

*BTW ordered chains from tirechains.com, had them in 3 days.

lariut

which brand/model did you get from the website?

gwpfan

LTS07 5.5mm Square Truck Chain w/Cams
x 2 - got enough to chain up all 4 if needed.

danonbar

Thanks for all of the info.

I saw in the owner's guide where chains were not approved on my Lariat's 275/65R18 tires, but the next the next couple of lines made it a bit ambiguous: "Follow these guidelines when using snow tires and chains: Use only SAE Class S chains." Class S chains are low profile for where clearance is an issue.

I called the service dept. at the local dealer and that was a waste of time. "Just follow what the book says...." Grrrr... Said if I used 4WD drive I wouldn't need chains. Told him the best tires in the world won't help on black ice.

BTW, gwpfan's setup on his post above is the same chain I'm considering and on a Lariat wheel, so I just don't see how it can be a problem for the rim. As for the clearance with the shock v. the inside of the tire, there is about 2 inches of clearance, so I don't see a problem there, either.

Re: studded tires, they would be my preference but the drive from the coast to the mountains is about 3.5 hours. Studded tires aren't permitted where conditions don't warrant them due to the potential damage to the road surface, and I don't want to have to change tires mid-trip. But if I lived in a snow area I'd have a set.

jedimasterbrad

This might be the dumbest thing I've ever heard. What kind of offroad vehicle is not capable of using snow chains? Ford REALLY dropped the ball on this one. I've lived my whole life in Colorado. I've driven many, many roads that were impassible without chains, but easily driven with chains. I own a 4x4 for use on just these type of roads and I've been stuck in situations where chains were the difference between walking for miles through the deep mountain snow for help, and driving leisurely on our way. Getting stuck in remote areas of the Rocky mountains is dangerous. Hell, I think this borders on a liability issue for Ford. OK, rant over.

Now, what if my truck has a leveling kit? The front tires are the only ones that need to be chained up anyway. Two chains will get you where you need to go. Four chains will get you in trouble.

PS Trying really hard to ignore the guys that "have been off-roading their whole life and never needed chains" Pfffft. Flatlanders with limited experience driving in truly adverse conditions.

byte

They say NOT to use the chains on the 20 inch rims...

nanookjr

I use the same set gwpfan uses. I have used them many times without an issue yet. The way I look at it some of the places I have to go for work require me to use the chains to get there, I go slow and pay attention to the chain tension. I'd rather bang up a shock or fender as apposed to getting stuck in 40 below temps.

kevin7898

Has anyone heard of the auto sock? I run a set of the drives on my work truck and tgey work as well as chains, are about 200lbs lighterand you can put one on in about 10 min.