Checking tire temps while driving

[BlackandBlue]

Checking tire temps while driving

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[Elp_jc]

It's more like 10-deg F per psi I think, but close . I drove to the mountains today. It got to 105 below, and 82 above. Started at 32, and it fluctuated from 35 to 37 (the latter at 105 deg and 90-100). Didn't push the car hard in the twisties since my wife had a headache, but was running 36 psi all around up there at 82 deg. Really wish the TPMS menu was with the gauges and G-meter. It's a PITA to see it, then go back to the gauges. By the way, my diff was at 220; the Torsen is awesome.

 

[BimmerDriver]

Newer BMWs (with coding to turn on the option) will show tire temperatures (well, the air inside the tire, for the pedantic) along with pressures. Pretty cool.

 

[Bikeman315]

I understand how outside temperature effects tire pressure. I also understand how tire pressure effects the way a car drives and handles. What additional knowledge does knowing the internal tire temperature bring? Also, wouldn’t the internal temperature vary based on tire size?

 

[BimmerDriver]

I understand how outside temperature effects tire pressure. I also understand how tire pressure effects the way a car drives and handles. What additional knowledge does knowing the internal tire temperature bring? Also, wouldn’t the internal temperature vary based on tire size?

High performance (race) and summer (summer) tires perform better when they are warm. So that's the big thing. Sure, a bigger tire would take longer to heat up too.

 

[Vlad Soare]

The internal temperature, or rather its variance rate, can indicate if your tire pressure is correct for the current driving conditions. The temperature of an underinflated tire will increase more and faster than that of a properly inflated one.
Also, knowing how hot or cold your tires are can be useful on the track.
The TPMS sensors know the temperature and communicate it to the car, so I don't see why the information couldn't be displayed somewhere.

 

[Bikeman315]

High performance (race) and summer (summer) tires perform better when they are warm. So that's the big thing. Sure, a bigger tire would take longer to heat up too.

The internal temperature, or rather its variance rate, can indicate if your tire pressure is correct for the current driving conditions. The temperature of an underinflated tire will increase more and faster than that of a properly inflated one.
Also, knowing how hot or cold your tires are can be useful on the track.
The TPMS sensors know the temperature and communicate it to the car, so I don't see why the information couldn't be displayed somewhere.

Thank you for your responses. This makes total sense. More so for the track, than for street driving, but I get it.

 

[kiksbutt]

What are disadvantages of running higher PSI in tires? I had some wheel vibration when I swapped new tires and dealer upped the PSI to reduce it (I think from 32 or 34 whatever is the standard to 39). Vibration is gone but they do get around 41-42 PSI when warm.

 

[Bikeman315]

What are disadvantages of running higher PSI in tires? I had some wheel vibration when I swapped new tires and dealer upped the PSI to reduce it (I think from 32 or 34 whatever is the standard to 39). Vibration is gone but they do get around 41-42 PSI when warm.

Sorry, but get a new dealer. They didn't fix it, they covered it up. That is not the way to handle a vibration issue. Overinflation can be equally as bad as under inflation. A pound or two over for street driving is fine but 39 to start, NFW.

 

[Norm Peterson]

It's more like 10-deg F per psi I think, but close

It depends on your initial temperature, and also on your initial inflation pressure.

Starting at 32 psi @ 0°F, a 10° temperature rise gives very close to a 1 psi increase. If you start at 100 psi (18-wheeler tire), a 10° temperature rise will get you to about 102.5 psi.

At 100°F, getting a 1 psi increase from 32 psi takes a 12°F temperature rise. That 18 wheeler tire only needs about a 5° temperature rise to gain that 1 psi.

The above is for dry air or nitrogen.


Norm

 

[kiksbutt]

Sorry, but get a new dealer. They didn't fix it, they covered it up. That is not the way to handle a vibration issue. Overinflation can be equally as bad as under inflation. A pound or two over for street driving is fine but 39 to start, NFW.

I agree - their response was that new tires on these cars cause wheel vibration. What is "too" much as far as PSI?

 

[Vlad Soare]

That's correct. But on the other hand the 'optimum pressure' is rather an optimum range of pressures, and manufacturers tend to recommend the lower end of that range, because it makes the car feel more comfortable. 5 to 10 psi over Ford's recommendation is not only perfectly safe, but even beneficial with a heavy car wearing wide, low-profile tires.

 

[Bikeman315]

Your vibration should be fixed by balancing, not by overinflating the tire. 34-35 warm is recommended for most OEM size tires.

Yes.

5 to 10 psi over Ford's recommendation is not only perfectly safe, but even beneficial with a heavy car wearing wide, low-profile tires.

No, sorry. Possible loss of grip due to overinflation is not safe. The only advantage is slight higher gas mileage but it's not worth the tradeoff.

Personally, for day to day driving I keep it a 33/34 which becomes 35/37 when hot.

 

[Vlad Soare]

I agree. Overinflation is bad. But it takes more than just a few psi to get overinflation. If anything, the tires may even be a bit underinflated at the recommended pressures. The recommended pressure is the bare minimum that the manufacturer deems safe; not necessarily the best.

 

[Bikeman315]

I agree. Overinflation is bad. But it takes more than just a few psi to get overinflation. If anything, the tires are a bit underinflated at the recommended pressures. The recommended pressure is the bare minimum that the manufacturer deems safe; not necessarily the best.

Vlad, you recommended 5-10 over. That could be as high as 45 hot. That is way too much.
Also I do not know what the regulations are in your country but in the United States we have agencies like the DOT that oversees tire safety. I do not believe that there is a bare minimum when it comes to safety (except maybe the Firestone tire fiasco back in the 90's). The recommended number takes into account all parameters and it is the best overall number for performance, economy and safety.

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