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I'm sure there's a lot of other OCD people out there that like to check tire pressure from the dash.
There was one past thread on tire pressure - Tire Pressure
It seems like a magic trick on my W204 C63 to finally get pressures "even".
Ex. maybe you set all 4 x tires to 42 PSI cold, and then when they warm up, they turn out to be 45 PSI front, and 47 PSI rear.
Ex. maybe your left front tire is 42 PSI cold, and the right is 43 PSI cold, but when warm, they both end up at 45 PSI. (I think my BMW E93 M3 had tire pressures to 0.5 PSI...)
To me, it would seem that your Front/Rear pressures might vary (in fact, the recommendations for 5 passengers is 41/45), but that Left/Right pressures should be the same.
So now I FINALLY got it so my warm pressures are 45 PSI all around, starting with cold pressures 42 PSI front and 43 PSI rear, but now my car complains sometimes after I get home from work and shut it off that I should "Correct Tire Pressure"... see pic below.
Unless it is CONGRATULATING ME for finally achieving CORRECT TIRE PRESSURE! =X-D
I don't know if any of this is complicated by my updated tire sizes - 245/18 and 275/18 - and/or that they are run flats. (Ready for the RFT haters...)
Anyone else have challenges with the dash TPM numbers?
I dont have a MB but if rear rises more in psi, the rear inside tire temp becomes higher so more weight on rear then front, in normal use of only driver.
I asume your motor to be in front, so this is not expected. But correct me if wrong.
So it can be that the sensors front and rear are misplaced.
can also be more complicated and that you have a temperature compensation build in.
then system compensates psi reading for temp in tire. 42 psi is pretty high so ,I expect the tire inside , not to become the 40/45 degrC 110/115degrF, normal inside temp when driving about 55mh/90km, at outside temp of 18C/65F.
In short, I have my daubt about the acuracy of the TMPS system.
I only look at those numbers as a generalization of what pressure the tires are. if one is WAY different than the rest, it will cause me concern. A lot affects the hot pressure when you are cruising around. For example, if you are on a road trip in the daytime going west, after a while, your left tires will be higher psi than the right due to the sun heating them. How the car is loaded, how you have been driving, and what direction you have been turning a lot all factor in, plus many other things I didn’t list. My OCD comes from checking my cold pressures manually with my Longacre gauge and making sure they are all exactly the same psi to the tenth. I will ALWAYS trust a good manual gauge over a TPMS.
Last edited by chrisridebike8; 11-22-2018 at 01:35 PM.
11-21-2018, 08:40 PM
Tire Pressure OCD
