How bad is the cold for summer tires?
 

Living in PA we occasionally deal with near-freezing temps long before snow hits the ground. As a general rule I try to switch from my summer tires to my snow tires before December starts. But during November and as early as October, temps in the morning can hover around freezing during rush hour.

Could driving in sub 40 degree temps, even for an hour a day for a couple of months seriously damage summer tires? I mean damage them in such a way to cause noticable performance issues?

Heat, Moisture and UV rays will damage tires. Only extreme cold, like the type not found naturally, will damage the rubber.

Cold won't hurt the tires per se, they just loose grip (they get harder, less compliant) more than all season tires in the cold because of the rubber compounds used to hold up in extreme heat. This is the trade-off any tire design must make between hot and cold performance.

All Season tires are not as good in the summer heat and/or on the track, but will do better in the winter months - you just have to determine your priority and buy tires accordingly - or buy two sets, one for summer, one for winter.

You can drive the summer tires below 40F but the problem is, they dont feel like theyre grippin the road, kind have to drive around for like 10 mins or so until the car feels stable and responsive. Definitely do not drive it in the snow though. Summer tires in snow will own you and the 8.

Cold weather won't damage your tires but your tires may end up damaging your car. My RE040s are off the car at the end of Oct at the latest.

my rt 615s are flat spotted for the first 5 mins of driving in sub freezin temps, i was too excited for summer and put the rt's on like 3 week ago, its been 70, then 40, then 60 for weeks here in philly. it sucks...

Depends on the compound(tires). Some compounds can be damaged by temperatures below freezing, most are not however.

Here's why I ask. At the beginning of December 2005 I took my Kumho SPTs off my 8 and stored them for the winter (on their side, mounted to the stock wheels). Spring 2006 comes around and I take my snows off and put the Kumhos back on. The car drives nothing like it did before winter. It shakes like it's out of alignment (an alignment and balance check says otherwise) and the tires are noisy as hell. My mechanic, the dealership and an independent tire shop all tell me that the tires are cupped and have flat spots.

Again I reiterate that my SPTs felt fine prior to putting them away. Even in cold weather they grip well and I never felt like they were going to break free. I'm fanatical about maintaining pressure and alignment, so I don't see that as being a problem. The only thing I can think of is that because I drove them on a daily basis in the sometimes freezing cold that they were adversly affected.

Then again it could all just be in my head.

In a week or two I have to get new tires to replace the Kumhos which I continued to drive last season because I didn't want to ditch a set of tires that had a ton of tread left on them. I liked the way the Kumhos handled the wet. Hands down they were the best wet tires I've ever driven on. And I know that everyone here raves about how great their SPTs are, but I can't say I've had the same experience.

So I don't know if I should treat it like a fluke and just get another set of Kumhos, go with another highly rated inexpensive tire like the General Exclaim UHP, or bite the bullet and buy an expensive set of high performance tires like the Toyo T1Rs.

I want good handling, long tread life, and a reasonable price. I don't think I've found a tire yet the fits the bill. The SPTs came pretty close, though.

It sounds like you stored them right. The only other thing you could have done is to put each of them in a garbage bag. Standing them on the end would have created a flat spot. Not laying them on their side.
I have no idea why they ended up they way they did. Cupping is caused by suspension problems. Mostly worn out shocks or struts.