Rear tires getting real hot

hello everyone, My rear tires are getting very hot under easy cruising. I have noticed this many times in the past month (which has probably been hapening since i got the car) My exhaust is stock except for fister modded mufflers. My tires are at the correct pressure (40 psi, i know 2 psi lower than factory rec.) and the mufflers are about 4-5" from the tires. when i park in the driveway after coming home, i felt the tire all over the tread about half way around, and it was very hot like i just got done autocrossing in 100 degree heat. this cant be good for the tires. anyone else notice this? anyone attached a heat shield to the mufflers on the back side?

Camber

the car is new to you right? ask the PO if he has the alignment numbers and post them if you can... In your pics the camber looks like a street/performance setting, but could be higher - Like Cory, I think its alignment more then the exhaust (or rubbing / brake dragging type thing) OR take a picture right in line of the tire and we should see it if the camber is too aggressive (I think) - In your very last pic on the other thread is the only one where the camber looks aggressive to me.... better angle will help

Well before you do anything, take a real temperature reading, post here, and compare with another car. Post the ambient temperature, make model size of tire, and the tire temperature. 911s do tend to cook their rear tires, what with camber, exhaust, weight, etc., and the smell of all that baking rubber can be disconcerting for some initially. I don't want that to keep you from diagnosing a problem, it's just that qualitative measures (hot) are difficult to troubleshoot with! Good luck!

good point first time mine got "hot" I thought the car was going up in flames... now I cant wait to smell that - must be like the air cooled guys....they have a smell that says "Porsche" to them, the water cooled have it, but its differant.

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The P-car is new to me, and that smell scared me the first time I smelled it! Lol! I got down on my hands and knees in my garage smelling everything under and around the car like a freaking bloodhound. I must have looked ridiculous! But now I'm used to it. Almost.

OH - By all means... dont stop getting down on all four and smelling the car - thats a sign of old age !!

Cosmoline?

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Or a sign of borderline P-car perversion! LOL!

HAHAHAH Yea that too !! the neighbors will stop looking - - - after about a year (then they stop talking to you as well)

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Depending upon ambient temperature even moderate driving can heat tires quite a bit. They can take it but over time will get a bit harder. However tire life usually brought up by wear and not by heat cycles, although I note with my Boxster by the time I've gone through a 2nd pair of rear tires while the front tires still have good depth of tread the rubber is quite a bit harder and the tires noisy so I replace all 4 tires. I expect the same with my 996 Turbo. And I expect you'll experience the same thing as well. Running the tires under inflated even by two psi doesn't help. Under inflation results in more side wall flex and this creates additional heat. Buy a good quality tire air pressure gage and be sure tire cold inflation pressures correct. I assume alignment ok? If not not only will tires wear out faster but they'll run hotter as well while they're wearing out. Lastly the 996 has alot of hardware in a confined space and this space enclosed on two sides by rear tires. Engine and exhaust system and drive train heat are all concentrated in a small area. Mid and rear engined cars tend to result in a hotter engine compartment cause compartment cooling not as good as with front engined cars. And since when you exit the car you're pretty close to the engine and engine compartment if there's anything to smell, and there will be, you're going to smell it. Sincerely, Macster.

The guys are right. Find a pyrometer and get an actual temp reading. "Regular" hot vs. "too" hot can be perceptiion sometimes and we need to make sure you are safe.

Forgot, you have ~66% of the cars total weight on the rear tires too. Add camber to this and you have a recipe for accelerated tire wear.

Has anyone tracked their car, or done a "spirited" drive around town, and taken the rear tread tire temps directly after using an infrared temp gun? I'll try to take a measurement tonight or tomorrow and post it. The data point will only be for a 6 mile drive on city streets (i.e. lights) with only occasional hard accelerations, no vigorous turning or cornering. But, it'll be a data point all the same.

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+1 But Toe really needs to be considered in the equation as well. Camber itself won't increase wear THAT much and really shouldn't cause temps to be too warm either. However most performance alignments for 911's will have a good bit of toe-in at the rear to combat bump steer issues even for cars at stock height. Toe + camber creates alot of wear and heat. Bit of a necessary evil to keep the rear planted and under control. Andy

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+1. The OP mentioned that the OUTSIDE of the tire felt hot to the touch, while increased negative camber + toe in would heat up the INSIDE of the tire. My guess is really that running the tires a few psi below spec is causing the issue (assuming there is one, which needs to be confirmed with a probe type pyrometer, not an infrared meter as there is too much radiant heat around the tires in the back).

the hot temp is across the tread section. i agree i need to check the actual temp, but im telling you guys, they are hot! i have had 10 cars in my life and i know how hot normal tires get, and these are the highest by far for just a lightfooted cruise in the evening. but yes i will look around for a temp gauge. and look at the camber/toe tomorrow