Cold summer tires in the FL mornings.

[twistedwankel]

It occurred to me the last two mornings here in Hernando where the mercury has dipped into the 30's that both sets of my 200 tires came with warnings about being exposed to under 40F temps. One recommended storing in winters up North inside a heated area. Also Carl told me his daughter took her car with Summer Pilot SS tires 340 rated into the mountains of CA and it ruined them in short order after that one trip.

So the last two mornings I have avoided driving my cars with 200 RE71's and Rivals. I had a set of Toyo's R1R 140 that warned to not mount under 70F or it could destroy the bead/sidewall and invalidate the warrantee.

So off we go in our 93 Crown Vic with AS Firestone tires for a couple days to avoid issues with the "good" tires.

Doug

[CaptainSquirts]

Here's a good read from tirerack.

http://www.tirerack.com/tires/tiretech/ ... techid=220

[CaptainSquirts]

I would think it would be bad design if driving Summer/Extreme Summer tires at 30f destroyed them, not saying they won't. Seems like the 30's for us is only in the early mornings and should be above 40 by 7/8ish so I think you should be fine if you drove them tires as long as you're not doing some autocrossing exercises to wherever you're going.

Everything I've said above should be taken in with as much confidence as a Jiffy Lube employee working on your vehicle.

[Loren]

Summer tires tend to do two things when they are cold:

1. They'll "take a set". The part of the tire that is touching the ground when the temperature drops will stay flat! It will feel like you've got horribly flat-spotted tires (because you do) until they warm up and regain their normal flexibility.

2. They won't grip worth a damn! You'll actually start feeling this at around 60-70 degrees. Summer tires are happy when ambient temps are 70-100 and they can get up to their typically 130ish degree operating temperatures. When it's below 60, they will take a lot longer to get up to temp... so, for 40-second autocross runs, they might NOT get up to operating temperature.

Rapid heat-cycling a tire is never good for it. Avoid doing burn-outs on your icy cold tires.

And remember that cold air condenses, so if your tire pressures were perfect when it was warm, they will read lower when it's cold. Relevant tire temps for autocrossing are what the tires are at their peak when you're autocrossing. This is why I've gotten away for YEARS with setting my pressures hot at an event, and just leaving them alone for months. Sure, the pressures will be all over the map on a cold morning, and maybe marginally high for street use (rougher ride, sharper response), but when they get up to operating temp at an autocross, they're where they should be. Or, at least close enough for my meager skills.

You can get nit-picky and think deeper than that, and a lot of people do. But, y'all know that I don't.

[twistedwankel]

Everything I've said above should be taken in with as much confidence as a Jiffy Lube employee working on your vehicle.

Dan that was a good article from Tire Rack about cracking and storage. Food for thought.

With tires costing about a grand a set mounted I'll err on the conservative side and wait 24 hours as I have another car to drive. Ever try to ride a motorcycle in 40F weather? Damned scary. I only tried it once out of necessity. Never again. Yeah I know they ice race with spikes in Scandinavia:)

I find it interesting they recommend 24 hours wait AFTER 20F cold which is the same amount of time recommended to let them set for the initial "heat cycle" after racing cool down. Something about the molecular links re-attaching to improve wear.

We get so many runs at FAST tire pressure isn't initially a big deal. I take my first run as a tire warm up just like Loren does. Just driving 20 minutes to the event raises the psi 3lbs. Sitting in the sun raises one side 2psi over the shaded side. It all evens out after one medium quick airport run.

[blacksheep-1]

FWIW both Pirelli and Michelin have these "warnings " on them, basically you can't "bounce" the tires under 45 degrees, by that I mean like rolling them out of a truck, or dropping them because it supposedly will mess up the composition, in the case of the Michelins, our Porsche flew over on a cargo plane, sub freezing, and the tires had to be scrapped as per Michelin.
To get by the cold weather, you can try a trick we do in qualifying, jack the pressure up 3-5 pounds to heat the tire up faster, this works exceptionally well on sticker tires where the first 3 lap are the best those tires will ever have, and you can't waste virgin rubber on warming them up. It does mean the driver has to find a hole and get a lap in because they drop off in 3 laps, but that's why they get the big money..or spend it anyway.
This post by Loren is golden, it's HOT pressure, not cold that counts..take a before and after check so you can determine the amount of rise for future events on a similar course.
"And remember that cold air condenses, so if your tire pressures were perfect when it was warm, they will read lower when it's cold. Relevant tire temps for autocrossing are what the tires are at their peak when you're autocrossing. This is why I've gotten away for YEARS with setting my pressures hot at an event, and just leaving them alone for months. Sure, the pressures will be all over the map on a cold morning, and maybe marginally high for street use (rougher ride, sharper response), but when they get up to operating temp at an autocross, they're where they should be. Or, at least close enough for my meager skills."