Bouncy ride in cold weather?

And that raises an interesting question: how much pressure does a CX-5 tire with 35psi @ 50F lose when it's -30??

The general rule of thumb for tire PSI/ temp drop is: For every 10 degrees F ambient, = 1 PSI

For example, if your tire was inflated to 35 PSI at an ambient temp of 50F degrees, then at the new temp of -30F, (80 degrees difference=8 PSI) The tire will be around 27 PSI.
 
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Thanks for those pdfs, Anchorman.

The thing that I learned from them is that TPMS does a check immediately on engine start and has an audible alarm, which in and of itself makes this system superior to anything that requires some period of rotation to function. What sucks is that you need sensors in all wheels, so having dedicated winter wheels becomes a lot bigger pain, and/or more expensive, twice a year, every year.

And if pressure falls 8 psi as Mazdadude suggests, or <6 psi as the pdfs suggest, I don't see how low tire pressure due to the cold [even an 80 degree drop] can be the cause of a "bouncy ride". If you're used to 35 psi, and your tires uniformly fall to 27 or 29, all you'll feel is slightly less road feel in the steering wheel, a slightly softer ride, and slightly sloppier cornering. Same deal if you run at 32 psi.
 
I dont think it reads pressure, it reads pressure difference.

from tpms.pdf: If the system detects a tire with remarkably low pressure, it alerts the driver using the TPMS warning light and alarm.
I guess that's open to interpretation. (scratch)
And I wish they'd define "remarkably low"!
 

Anchorman, your TPMS PDF implies in a number of places that the sensor measures pressure. It transmits the pressure to the instrument cluster which apparently alerts if the value is out of spec, or if the change is too great.

I think it knows the tire pressure, just doesn't share it with us. I was wondering if it might share it with an OBDii reader.
 
Anchorman, your TPMS PDF implies in a number of places that the sensor measures pressure. It transmits the pressure to the instrument cluster which apparently alerts if the value is out of spec, or if the change is too great.

I think it knows the tire pressure, just doesn't share it with us. I was wondering if it might share it with an OBDii reader.
Pressure, temperature and acceleration are transmitted by the valve stem sensor according to the "WHEEL UNIT PDF" from Mazda provided by ANCHORMAN. (thank you Anchorman!) I have a obd2 reader, but have the old indirect TPMS system. So I cannot help you there...
 
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The OBD adapters aren't expensive, even good ones. Get a free Forscan app, and you get a plethora of generic and Mazda - specific PIDs. You can see lots of inteeesting info, like engine oil, transmission fluid and rear diff temperatures, fuel trims, AWD engagement level, and many more.
Can't verify TPMS data either, old system here, but would imagine PIDs for the pressure, temp and acceleration are there.
 
Also do not forget that the cold temps mean the tread compound in the tires is stiffer, the bushings in the suspension are stiffer, the motor mounts are stiffer, the oil in the shocks and struts is thicker, etc..

We've had a couple of weeks of sub-zero weather and I can attest the motor mounts are very much stiffer. Haven't taken it for a longer trip but I get a terrible engine vibration at these temps. If I manually downshift it smooths out when up around 2500 RPM. I have 4500 miles on my '17 GT. I don't remember the '15 GT being this rough.

I had to loan it out to my son in Duluth whose Audi was down. He says the Mazda starts right up at -20F. He liked the heated steering wheel except it goes from full on to full off. An in-between setting would be nice.
 
Anchorman, your TPMS PDF implies in a number of places that the sensor measures pressure. It transmits the pressure to the instrument cluster which apparently alerts if the value is out of spec, or if the change is too great.

I think it knows the tire pressure, just doesn't share it with us. I was wondering if it might share it with an OBDii reader.

Yes, I know what you were getting at but while it needs to make a distinction between pressures, I don’t think that ever manifests itself as four separate read outs, I think it only has the brains to know they exceed a predetermined range. Could be wrong.
 
We've had a couple of weeks of sub-zero weather and I can attest the motor mounts are very much stiffer. Haven't taken it for a longer trip but I get a terrible engine vibration at these temps. If I manually downshift it smooths out when up around 2500 RPM. I have 4500 miles on my '17 GT. I don't remember the '15 GT being this rough.

I had to loan it out to my son in Duluth whose Audi was down. He says the Mazda starts right up at -20F. He liked the heated steering wheel except it goes from full on to full off. An in-between setting would be nice.

Any vehicle in minus 15 to minus 20 degree temps will have stiffer shocks/suspension and engine mounts due to the extreme temps...I noticed this in all my previous and current vehicles as I live in an extreme cold climate area (here in Cda) and it is just a fact of life. Even my previous Toyota minivan than had smooth buttery suspension from yrs ago would stiffen at that temp...I also owned a Volvo SUV that had suspension control and that too would stiffen in minus 20 to minus 30 deg C
 
I had to loan it out to my son in Duluth whose Audi was down. He says the Mazda starts right up at -20F. He liked the heated steering wheel except it goes from full on to full off. An in-between setting would be nice.

Is the heated steering wheel needed once the car interior has warmed up, or is just that it gets too hot when it's on?
 
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Is the heated steering wheel needed once the car interior has warmed up, or is just that it gets too hot when it's on?

It shuts itself off after some time but I usually never wait that long. I shut off both the seat heater and the steering heater as soon as the cabin gets warm.
 
Exactly

If by bounce you mean vibrations at the speed you mentioned, the cause might be packed snow or ice stuck to the rims. That will throw the wheel balance off.

I just went trough that this weekend. Heavy snow in NY, went out east. Somehow my wheels were packed with snow. On the 70 mile ride home, nothing by a bouncing ride. Terrible. Went to car wash the following day, all snow, ice is gone and ride is normal. Never had this happen to me before.
 
Thanks for those pdfs, Anchorman.

The thing that I learned from them is that TPMS does a check immediately on engine start and has an audible alarm, which in and of itself makes this system superior to anything that requires some period of rotation to function. What sucks is that you need sensors in all wheels, so having dedicated winter wheels becomes a lot bigger pain, and/or more expensive, twice a year, every year.

And if pressure falls 8 psi as Mazdadude suggests, or <6 psi as the pdfs suggest, I don't see how low tire pressure due to the cold [even an 80 degree drop] can be the cause of a "bouncy ride". If you're used to 35 psi, and your tires uniformly fall to 27 or 29, all you'll feel is slightly less road feel in the steering wheel, a slightly softer ride, and slightly sloppier cornering. Same deal if you run at 32 psi.

Hi everyone. This is the newest thread I could find for the TPMS system, so I decided to post my query here.

The TPMS alarm activated in my car yesterday after work, right after I started the car. Temps were in the single digits and the car sat in the parking garage all day. I checked the tire pressure and fronts were at 28.5 and rears at 27.5, so I'm guessing the 'greater than 6 PSI' rule was the reason for the alert. I drove home and added air to all four tires (to approx. 32 in each tire) before I left for work this morning. The TPMS light has not gone out on the car after driving several miles. Any ideas why? I didn't want to overfill the tires as it is single digits again today and then supposed to be in the fifties by Thursday! I'm thinking I may stop by the dealership after work today if the light is still on when I leave from work.
 
Hi everyone. This is the newest thread I could find for the TPMS system, so I decided to post my query here.

The TPMS alarm activated in my car yesterday after work, right after I started the car. Temps were in the single digits and the car sat in the parking garage all day. I checked the tire pressure and fronts were at 28.5 and rears at 27.5, so I'm guessing the 'greater than 6 PSI' rule was the reason for the alert. I drove home and added air to all four tires (to approx. 32 in each tire) before I left for work this morning. The TPMS light has not gone out on the car after driving several miles. Any ideas why? I didn't want to overfill the tires as it is single digits again today and then supposed to be in the fifties by Thursday! I'm thinking I may stop by the dealership after work today if the light is still on when I leave from work.
Did you try resetting it?
 
I thought that was what driving around was supposed to do? Is there an actual process to resetting the light to go off? I thought the 17's had no reset button.
 
Hi everyone. This is the newest thread I could find for the TPMS system, so I decided to post my query here.

The TPMS alarm activated in my car yesterday after work, right after I started the car. Temps were in the single digits and the car sat in the parking garage all day. I checked the tire pressure and fronts were at 28.5 and rears at 27.5, so I'm guessing the 'greater than 6 PSI' rule was the reason for the alert. I drove home and added air to all four tires (to approx. 32 in each tire) before I left for work this morning. The TPMS light has not gone out on the car after driving several miles. Any ideas why? I didn't want to overfill the tires as it is single digits again today and then supposed to be in the fifties by Thursday! I'm thinking I may stop by the dealership after work today if the light is still on when I leave from work.

Not sure why the TPMS didn't turn the warning light off but FYI your tire pressure will increase again with the temperature so make sure you aren't over-inflated when the temp goes back up. Generally if you know the warning is just because it's cold, it's better to just leave it.
 
Not sure why the TPMS didn't turn the warning light off but FYI your tire pressure will increase again with the temperature so make sure you aren't over-inflated when the temp goes back up. Generally if you know the warning is just because it's cold, it's better to just leave it.

He's aware of that. He said "I didn't want to overfill the tires as it is single digits again today and then supposed to be in the fifties by Thursday!"
 
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