Snow Chains

The stock tires have poor traction in snow/ice (are you in the mountains of California?). Either winter tires or "all weather" tires (eg Nokian WR series), not all season tires, will give good traction in bad weather. Chains do give traction, but are a pain to install.

JeffD

 

Cables or tire socks are a better choice. There is very little clearance between the inner tire sidewall and the lower spring perch. Traditional chains can snag there and wreck the whole works.

They're a pain to put on, and when they are on you need to plan for very, very low speed travel. Exceeding 25mph is a serious risk.

The CHPs have a lot of experience with this. Since most people are very bad at driving with chains, they tend to close the roads 5 minutes after giving the order to chain up because it saves them the hassle of pulling everyone out of the ditch later.

So you've got the chains halfway on and suddenly they tell you the road's closed altogether. Might as well save the money for another day on the mountain.

 

If you will be using I-5, that would seem to mean Siskiyou Pass in southern Oregon. Isn't the main issue there within Oregon, not California? That might give you more flexibility if Oregon is less strict than CA and you have decent winter driving skills. Which, if you are asking, you may not.

If you don't like the available low profile cable chains, Washington has some web pages showing approved alternative traction devices, I haven't yet seen an equivalent Oregon list:
https://www.wsp.wa.gov/wp-content/uploads/2020/04/Alternative-Traction-devices-April-1024x626.png
Vehicle & Equipment Requirements - WSP
https://wsdot.com/travel/real-time/mountainpasses/tiresandchains

California also approves some chain alternatives such as AutoSock, but I don't see their full approved list.

Additionally, with an AWD car, you won't be required to put on chains as early as cars lacking AWD, though every state along this route also has a higher chain requirement level that applies to AWDs too. Though it seems this level is rarely used here, it is far more common to just close the road entirely. And when 2WDs must wear chains, your AWD must still carry chains in the car.

And even with AWD, it is still very highly advisable to have real winter tires that are not seriously worn. Half-worn factory All-Season tires are often inadequate.

 

Let’s be clear; the “AWD” prius does not actually have AWD. It has a very low powered electric assist motor in the rear that provides power to the wheels from a dead stop up to like 3 MPH.

“All wheel drive” means that all wheels are driven, all the time… that us not the case here. Toyota should have called it a ‘low speed traction assist’ because that’s all it really is.

Cops are unlikely to know the difference. Get some cheap cables. I wouldn’t worry about ever actually putting them on. Even in snow these cars do fine.

 

... up to 43 mph. More than fast enough in "chains required" conditions when 2WDs are actually using chains.

 

Still not AWD.

 

My '06 Highlander Hybrid AWD rarely slips a tire on snow covered roads. If try to punch the gas and crank the steering wheel, the traction control kicks in preventing the wheels from slipping. It's really no fun to drive at all in the snow.

 

Maybe not by your personal definition. But I'm not seeing it missing out on any legal definition.

On plowed highways and in ski area parking lots, most of the problems I've seen with unchained 2WDs are in trying to get moving again uphill after having to stop for other vehicles ahead. By always using AWD from standing starts up to 10 kph, the Prius system addresses this problem, where a traditional open-differential 2WD gets stuck by any single drive wheel spinning on a slippery patch, or even from being on uneven ground that un- or under-weights any drive wheel.

Prius may not put much power into the rear wheels for this function, but it doesn't need to. And in slippery conditions, there just isn't enough grip available to put a lot of power into the wheels anyway. This isn't meant to be a pickup truck throwing snow everywhere as it tears through a deep-powder TV advertisement with all four wheels overspinning.

This AWD works up to 70 kph, which is faster than any sane 2WD driver will be running on chains.

Deep unplowed roads may be a different matter, but the ones I frequent need more ground clearance than the Prius has anyway.

 

I would NEVER put real chains on my Prius. That is a very fast way to damage the wheel well materials, as well as beating up the fender well sheet metal. Use cable chains, and first PRACTICE installing one in your garage or driveway. Learn how to get it to fit tightly with no flapping or looseness. Then if you ever need to use them, drive slowly....

 

New rubber compounds for bad weather have gritty substances incorporated right into the mix. Not everyone can afford a 2nd set of strict winter treads/wheels nor do all folks have storage capacity for extra tire wheels. But there are also all weather tires containing compounds integrated into all-season tires. sure beats having to install / remove cables with every snowy or curvy icy hill you may need drive on.
.

 

Excuse my ignorance, never venture far from the lower mainland: are chains sometimes mandated, you’ve gotta have them?

I do use snow tires, never had chains.

 

Mendel,

The usual rule in harsh weather is either chains or tires with the snowflake logo (real winter tires or All Weather tires).

JeffD

 

Ah, ok. I'm good. Thanks.

 

In my area, primarily on Snoqualmie Pass (I-90) and Stevens Pass (US-2), we experience several stages, listed in order of the amount of time they are posted (for light vehicles only, rigs over 10,000 GVW must chain up earlier):

(*) (Winter) Traction tires advised -- very common;
(*) Traction Tires (or chains) required -- very common;
(*) Chains required except on AWD -- somewhat common;
(*) Chains required even on AWD -- rare, road usually entirely closed instead.

These postings often last just a few hours at a time, before being changed for rapidly changing weather and road grooming conditions. So if a driver is blocked by a chain requirement, it is often reasonable to wait a little while until conditions improve. Though deterioration is also a possibility. I-90 has numerous settlements with restaurants or other practical short-term hangouts, US-2 less so.

Snoqualmie Pass used to have many closures for controlling and clearing avalanches. Now that the highway has been rebuilt for the worst avalanche chutes to run beneath the road, most closures now are for "spinouts and collisions", so road crews can safely tow away those who were improperly equipped, ill skilled at winter driving, or just simply screwed up. Then they must plow away the new snow accumulations before reopening.

Oregon and California have the same stages, though with differing labels. I don't remember British Columbia's regulations for changing conditions, but they do require winter traction tires or chains on certain mountain routes all winter (7 months there), with a specified minimum tread depth greater than any U.S. tread depth requirement.

All these jurisdictions have major highways crossing coastal or near-coastal mountain ranges, which have quite different weather challenges than regions farther inland.

 

Right now (as I post) is an example of Snoqualmie Pass (I-90) requiring chains on all 2WD vehicles, even if wearing the best grades of winter traction tires:



It was closed for a while yesterday afternoon for multiple spinouts and blocking collisions, one fatal. TV interviews with drivers stranded in backups revealed numerous comments about ill-equipped drivers not slowing down for conditions. Fortunately, my brother-in-law made it through several hours earlier, before the worst accumulations. I crossed the evening before, in monsoon conditions but no snow accumulation.

At the same moment, Stevens and White Passes are posted one level lower, winter traction tires alone are sufficient: