??? I put my summer tires back on and now its 15 out. Its probably not going to snow so I'm not worried about that, but what about the cold? Aren't summer only tires softer rubber?

I do notice that my Z rubber will let lose very quickly on cold mornings. No traction at all while I'm pulling out, it's easy to spin the wheels with VQ power.

just be careful.

I bought a max used last summer that had some z-rated tires on it. They were all season tires though and I dind't really know much about the effects of speed ratings and the like. The car pulled a 180 on me in on the highway and slammed into a guardrail during thanksgiving break (granted the roads were starting to get a little snowy). Ended up being totaled. Now I've got some tires with a lower speed rating (and better winter handling ratings)..I think it makes a difference.

Z rated tires are useless below 40 degrees, the rubber is designed for warm conditions. Snow traction is none existant with summer tires also, I had to drive in the snow the otehr day and I really had to be carefull.

Today my kumhos were all over the place(25 F outside)!

...What about tires that claim to be max performance 'all-season?' Is that mostly a gimmick? There are yokohama avs Db tires that are ZR rated and high performance but they also list as all-season. I have wondered if they are a great buy, or just as unreliable in cold weather as any other ZR speed rated tire...

Does anyone have any Z rated tires that are supposed to be all-season that they recommend as reliable during cold weather? Here in North Texas we can go from 75 F down to 25 F in the course of one day sometimes in Feb. and March... Its crazy here. Buts its always hot May-Sept....

I have had no problems with my Toyo Proxes FZ4 All Season 225/40 ZR18
holding my 18x7.5 Rotas Rims. I also did drive it in recent New England snow and tested braking in the snow with no problems. I guess sometimes the "You get what you paid for" might apply here, and sometimes you get lucky.

I think for the most part it's a gimmick. If you go to www.tirerack.com you can see ratings for tires submitted by people that have driven on them. If you compare some of the performance lines of all-seasons to touring all-seasons, there's a *big* difference in the average rating for snow handling. I would imaging that the only performance tires that have good snow ratings are the ones with lower speed ratings.

-zach

I'm pretty sure that the speed rating has more to do with the ability to hold sustained speed, which can be independent of traction in cold weather.

According to survey results on tirerack, for snow traction, you should be good with:
Michelin Pilot Sport A/S
BFG G-Force T/A KDWS
Dunlop SP Sport 5000 Asym
But any may still give you decent dry traction in cold weather.

A lot of org members like the SP Sport 5000 for an all-season tire.
I personally had no problem with SP5Ks in the winter with no snow on the ground. They still gripped pretty well.

OTOH, there's a real problem with soft tire compounds that turn hard in cold weather. Without direct advice from the manufacturer or the seller (ie tirerack), I'd look at the treadwear rating, where the lower the rating, it may indicate a "soft" tire that would be problematic in cold weather.