I have the "Conti "tires and have had absolutely no problems with any type of shaking or vibration when it's cold. The only thing the cold seems to effect is the shifting (6-speed)for a mile or so then everything is fine. The shifter gets really stiff just for a minute or so, then it returns to normal.

What are you running for pressure in your tires? Will adding a couple of pounds make it a little more unlikely to develop a flat spot?

At first I thought you may have a balance problem but that wouldn't go away after a period of time. Have a friend drive along side of you to observe your tires and see if he can spot the tires vibrating a little instead of running true. It's easy to spot a tire that isn't running true when it is traveling down the highway. You can actually see the vibration on conventional tires. May be it won't be that easy on these low profile tires.

You may want to drag your hand across the tread of each tire and see if it feels even in each direction. If it's smooth one way but drags against your hand the other way, you may have an alignment problem. Yet again, your vibration goes away in time when the tires heat up. Keep in mind I'm just guessing, but you never know.

Bob M.