Driving to altitude - temperature impact

[944boy]

Dot-R's are even worse in cold weather. If your in cold weather for long periods you really should have a second set of cold weather tires if you want to keep the sticky summer tires. Thats what I do.

[edevlin]

Good info, I have never pushed my PS2 in the cold,

Ed

I have done a lot of this kind of driving on my PS (first set) and PS2's (current tires), since I try to get the car out early in April, and keep it out into late October. The first couple hours in the early morning (low-low 40's) can be a little tricky! This is when the air temperatures are at their lowest point, for the day.

When the sun comes out and starts warming the road up, it is a very big difference. Or until you can get some heat built-up into the tires.

Another thing to consider is that for every 10 degree temp change, there is a 1 PSI impact on the actual cold-tire pressures. I find that our car/tire combo (especially in 19" wheels) is very sensitive to having a proper cold-tire pressure. So, a 1/2 or 1 PSI change makes a difference in the car's handeling.

In Hops example, the temp he departed at was 49 and when he got to the highest elevation the air temp was 32. If the tires had an opportunity to cool down, I would suspect that you lost at least 1-1.5 PSI. IMHO, this had a major impact on the car's shift in handeling too.

[rick3000]

I've driven up to the mountains with my summer tires, during this time of year. I start at 5,000 feet (50°) and drive up to 10,000 feet (30°).
There is a significant difference in handling, from the rubber hardening. But most high performance summer tires, perform very badly (and unsafely) below 40°. It has more to do with the temperature than the altitude.

I have driven in light snow with my summer tires, and my thought was that as long as there isn't snow on the road, the friction from the tires will keep them heated enough to provide sufficient traction, but I wouldn't risk it very long. I only did this until my winter tires arrived. In freezing weather, driving on my summer tires was very scary because there was almost no traction.

I've also found that my car doesn't run as well (overheating to the 200+ mark) at 10,00 feet, and I am guessing it's because the air is so much thinner.

[mikefocke]

around 9AM after driving 3-4 miles at 40 MPH, I totaled a '99 Boxster on very good tread Pirelli summer UHP tires when I tried to brake hard in a straight line and had no traction at around 30MPH.

You can't tell me those tires had warmed up enough to grip the surface of the road (asphalt) effectively.

So be especially cautious if the temperature is rising, the road surface may be cooling those tires, not warming them.

[Lil bastard]

Altitude has nothing to do with it. You can experience the same temperatures at Sea Level. It takes about 10 miles @45 degrees or below to fully warm the tires.

[blue2000s]

Originally Posted by Lil bastard

Altitude has nothing to do with it. You can experience the same temperatures at Sea Level. It takes about 10 miles @45 degrees or below to fully warm the tires.

When you go up in altitude, the ambient pressure decreases, increasing the effective tire pressure.