Sign In Join 

You are here: [F] Forums / SUVs / Mazda CX-9 / Mazda CX-9 Tires and Wheels



Mazda CX-9 Tires and Wheels

70 messages,  Last post on Mar 11, 2009 at 10:49 AM

You are in the Mazda CX-9 Forum. Your Hosts are steve_ & tidester

What is this discussion about? Mazda CX-9, Mazda, SUV


Messages Page 8 of 8
1
2
3
4
5
6
7
8
Prev
Next
Last
Go To Msg #
Search This Discussion

#65 of 70
Re: It was these rims... [vermonter] by ceric
Mar 06, 2009 (7:11 pm)
Reply

Replying to: vermonter (Mar 06, 2009 1:33 pm)

Interesting to me about the TPMS.
I did an experiment with my daughter on tire pressure vs MPG.
At 60f when we tested it, the TPMS does not light up until somewhere between 20 to 25psi (i.e. OK at 25psi, light up at 20psi). Tires are warm up after low-speed driving.
 
Basically, you were saying that -6f caused one of the tire to go below 25psi. The absolute zero is -273f. Temp fluctuation from -6 to 40f is less than 20% compared to 273f. The PSI change should be less than 6psi is it was 30psi.
In short, I suspect one of your tires has low pressure (i.e. < 30psi). You might want to check for it.
#66 of 70
Re: It was these rims... [ceric] by tidester HOST
Mar 06, 2009 (9:28 pm)
Reply

Replying to: ceric (Mar 06, 2009 7:11 pm)

The absolute zero is -273f.
 
Actually, absolute zero is about -459.7° Fahrenheit which is about -273° Celsius.
 
tidester, host
SUVs and Smart Shopper
#67 of 70
Re: It was these rims... [tidester] by ceric
Mar 06, 2009 (9:51 pm)
Reply

Replying to: tidester (Mar 06, 2009 9:28 pm)

My bad. Been away from chemistry for way too long...
Anyway, in that case, the % is more like 10% instead of 20%. That means a drop from 40f down to -6f will only cause 3psi difference.... If I am correct this time.
#68 of 70
Re: It was these rims... [ceric] by tidester HOST
Mar 07, 2009 (1:31 am)
Reply

Replying to: ceric (Mar 06, 2009 9:51 pm)

A good rule of thumb is that the pressure changes by about 1 psi for every 10° F change in temperature.
 
tidester, host
SUVs and Smart Shopper
#69 of 70
Re: It was these rims... [tidester] by vermonter
Mar 11, 2009 (5:17 am)
Reply

Replying to: tidester (Mar 07, 2009 1:31 am)

Thanks for the calculations, very interesting. We are vigilent about monitoring our tire pressure and rely on a handheld digital gauge. Do you think the impact of the sun on the sidewalls, when parked, could increase the temp enough to account for the TPMS light turning on and off?
 
I'll reiterate that this only seems to happen when we have extreme temp fluctuations and is not an every day occurence. The dealer as well as a local garage said that TPMS often give false alarms in the colder winter climates.
#70 of 70
Re: It was these rims... [vermonter] by tidester HOST
Mar 11, 2009 (10:49 am)
Reply

Replying to: vermonter (Mar 11, 2009 5:17 am)

Sunlight will certainly heat up the tires though the heat transfer would likely be more via the metal wheels/rims as opposed to the sidewalls.
 
I can't say whether that is sufficient to trip the TPMS but those systems are supposed to be designed to deal properly with changes in ambient temperature. It could be that the threshold for triggering the lights is overly sensitive or the TPMS itself is defective. It would be interesting to know whether others have experienced this problem in other geographic locations.
 
tidester, host
SUVs and Smart Shopper

Messages Page 8 of 8
1
2
3
4
5
6
7
8
Prev
Next
Last
Go To Msg #
Search This Discussion
To POST a message, please Sign In.

You are here: [F] Forums / SUVs / Mazda CX-9 / Mazda CX-9 Tires and Wheels

New? Join Now!

Forum Tools

Please sign in.
Email Address:

Password:

Forgot Password?

Search Forums

Enter Keyword(s)

Advanced Search

Browse by Vehicle



View All Vehicles
Advertisement
Learn More

2010 Mazda CX-9

2010 Mazda CX-9 Grand Touring SUV Shown

More Pictures

DoMore

Ask the Community
See What People Are Asking

Browse by Board

Browse by Topic


View All Topics

Today's Chats

Advertisement