Arctic circle?? How many people are worried about tire heat up there?
Sorry, I thought we were talking about car tires in the Northeast US. I was interested in the point made that the Northeast has more hours of sunlight than AZ.
No need to be rude, even if Sparky812 may have overestimated the latitudinal distance between Arizona and the Northeast.
Here are a few relevant places and with latitude and the time from sunset till sundown at summer solstice. (From here)
Nogales - lat. N 31 20’ - sunrise 0520 - sunset 1931 - 14 hours 11 minutes
Phoenix - lat. N 33 30’ - sunrise 0519 - sunset 1941 - 14 hours 22 minutes
Philadelphia - lat. N 40 - sunrise 0432 - sunset 1933 - 15 hours 1 minute
Augusta - lat. N 44 - sunrise 0355 - sunset 1927 - 15 hours 22 minutes
Van Buren - lat. N 47 10’ - sunrise 0336 - sunset 1931 - 15 hours 55 minutes
So on the day with the largest difference, and looking at the places the furthest North and South, maximum 1.75 hours (or 12%) more sunlight hours in the “Northeast” than in “Arizona”.
Why, thank you. I didn’t think there was anything remarkable about admitting that I had made an assumption that I had not thought out. Then I remembered some other posters in other threads I’ve read. 
My thought as well. If I had 4/5 tread separations/blowouts within a two year period of time on “new,” properly inflated tires, I’d be looking into the tire manufactur, batch nos, etc and other possible causal mechanisms instead of just assuming it was the tarmac temp.
Definitely true.
But for consideration of pavement temperatures, hours of sunlight are a lot less important than insolation (received solar energy per unit area). And (as depicted in maps on the linked page) Arizona is going to be well ahead of the NE in that category.
Interesting information, thanks! I’m sorry if that sounded rude, I was certainly not intending to sound so. My tone in posting often gets taken for LOUD. I guess that’s my writing style. My apologies, I was just interested.
No problem. 
I may have overestimated the difference in lattitude a bit, but there is more sunlight.
Interesting… I found this illustration quite informative. Also, here is a list of US major cities.
But can it account for 200F asphalt?
The problem with those references is that they’re annual averages and take into account cloud cover and such to be useful in evaluating solar power opportunities. This makes them less than useful for evaluating worst case scenario asphalt heating.
The pressure-versus-temperature behavior of nitrogen is almost identical to that of air. The presence of liquid water can result in unpredictable pressure swings, and that’s something that can happen if one is sloppy with tire lube or uses really humid air to fill the tire. Plots here.
The moisture problem can be circumvented by using compressed air that has been held in a tank to cool back down to ambient temp, thus condensing some of the water out of it before putting it in the tire (this is why you need to drain the water from your compressor’s air tank periodically); more moisture can be removed with an in-line dryer. But since race teams already have dry nitrogen on hand for servicing suspension components, having an air compressor/tank/dryer would be redundant.
First, road temp won’t matter as much as you think it will. Any given portion of the tread is in contact with the road for maybe 10% of the time, and the tread is only a small portion of the tire/wheel assembly’s surface, the rest of which is exposed to a high-speed airstream that drags the tire temp back down toward ambient. Air temperature is likely to be much more important than road temp here.
Second, assuming you use the same inflation pressure regardless of your choice of inflation gas, the use of nitrogen/elimination of water vapor will not change the tire’s operating temperature significantly. The convective/conductive heat transfer properties of nitrogen and air are virtually identical, and any water vapor will be present in such small amounts as to have a negligible affect.
Are there any cites at all that show road temps actually getting that high? I’ve been searching for two days and have found nothing yet.
It’s too bad we can’t transfer my “+1” to a thread or two going on now in GD. A couple of posters there need it more than I do.
But, on to thread relevant issues:
I’ve been looking. I can’t find anything reliable. My experience is still the best I have to go on, and I can only attest to 180+, meaning < 185, but above 180.
I’ve a slightly off-topic safety warning, in case people haven’t heard of it.
US Capt Jenna Wilcox was killed in Scotland last year, when she swapped a bulging tyre on her hire car, and sat it on her lap just before it exploded.
It’s possible that the tires were inflated to the maximum allowable pressure rather than the recommended pressure. It’s a great way to have a blow out, or to wear out the centre of the tread.
Does nothing to improve gas mileage, of course. :smack:
I don’t live in Arizona, but I’ll do an estimate.
At the Indy 500 last weekend, the air temp above the track was 96 degrees, while the pavement was at 131 degrees. Cite. This is consistent with a Minnesota DOT report (see last section “Heat Wave 1997”), indicating an air/pavement delta of roughly 40 degrees.
The pavement is warmed via solar heating, and cooled via radiation and convection. Using a pavement emissivity of 0.89 (from a heat transfer text) and the Indy 500 known temperature values, we can identify a convective coefficient. Assuming we’re at 3000 feet elevation in Arizona (and Indy is at 700 feet), then in Arizona the convection coefficient will be only 92% of the Indy value due to reduced air density.
Using that adjusted convective coefficient and a representative Arizona air temperature of 115F, I came up with a pavement temperature of 148F. This is consistent with Sparky812’s report from the city of Phoenix, claiming 150F.
These guys claim to have observed a temp in Phoenix, on dark-colored pavement, of 172F. Not clear what the ambient air temp was at the time, but clearly this was exceptionally hot.
My results are also consistent with this report; I’m not gonna purchase the whole thing, but the abstract mentions pavement temp measurements in southern US and Arizona, and claims the max observed pavement surface temp was 142F.
Higher elevations (e.g. Grand Canyon Village, at 6700 feet) have a further-reduced convective coefficient, but they also have lower ambient temps, which tend to cancel each other out (probably not exactly, but I’m not going to bother calculating).
Pavement radiative properties may vary widely depending on composition, age, etc. and of course my own calcs relied on a single data point from the Indy 500, but I would be very surprised if pavement temps in Arizona ever reached 200 degrees, even after a protracted heat wave.
Added info from my experience. The only times I ever saw the pavement temp in the 180 area, the air temperature was always about 100, no breeze at all, and most important, it was always humid and hazy. That’s the important part, because if you take an infrared thermometer and point it at the sky on clear days, you are actually measuring the air temperature of the atmosphere quite a ways up, and get in the 30s or lower. Re-radiation to the sky is where most of the heat’s going to go when the ground level air temp is high. Low level haze (caused by humidity) is going to block that. So, my guess now is that unless you get an air temp of 120 or so, no wind at all, and very humid and hazy, my 180+ is probably about the highest you will ever see. Since Arizona people are always going on about “dry heat”, I doubt they ever get that humidity condition, and so 200 is now sounding rather dubious.
In one of the Tintin books (Seven Crystal Balls?) the tires on a car explode sitting in the hot summer sun in (southern?) France. Obviously, in the 1930’s or so with more primitive tire construction this could be a legitimate concern, since the situation appeared to be unusual but not unheard of.
Plus, a lot of people nowadays neglect to check pressure in their tires. Usually this results in underpressure, but if the tire was over-filled in a colder season and then left in the hot sun, sitting in an area of very black pavement, it could get very hot.
A recent news story highlighted the dangers of playground equipment - a green plastic slide in the hot sun gave a child serious burns to her hands and legs. When I was a kid, the typical “how hot is it?” news story showed frying an egg on the sidewalk.
Tintin also has a talking dog and has ridden a private rocket to the moon.
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It was presumably in Belgium, not France, since Tintin and Herge were Belgian.
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IIRC the tyres exploded in the evening, after the sun had set.
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The temperatures were high because of the approach of a a flaming meteor
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It was a kid’s story. It wasn’t real. :smack:
As if Tintin’s adventures were limited to Belgium!
Powers &8^]