Check pressures after mounting/balancing

paradocs98 · 03-29-2019, 10:47 AM

This was a new one for me. As I typically do with my cars, I had winter tires mounted on my Audi S3's stock wheels when I started the lease three years ago. I don't love the stock PZero summer tires, so I put them in storage and purchased a nice set of OZ Leggera wheels with Michelin PS4S tires for regular, non-winter use. Now that the lease is almost done, I took the stock wheels/winter tires to a local tire shop (national chain) to have the stock PZeros remounted on the stock wheels. When I got home I checked the pressures to make sure they were roughly where they need to be before sticking them back in the garage for a couple of months. Three of the tires were in the 40psi range, where they need to be, but one was inflated to 75psi.

Thought I was seeing things. Rechecked. Yep, 75psi. Took a lot of bleeding down to get to 40psi. I understand that occasionally lower-profile tires with stiff sidewalls can require high pressures to seat the bead, but even if 75psi were required, they should have lowered the pressure to something reasonable once it was seated. I'm glad I checked and it didn't sit like that in the garage for three months. Or worse, put them back on the car and hit a pothole with that grossly overinflated tire.

So check your tire pressures, folks. Don't assume that the guys at the shop did. I'll add this to my list of things to confirm, along with lug nut/bolt torque settings. I've had dealership service done on various cars before and ended up with four lug bolts impact-wrenched down to 150+ lb-ft and one lug bolt barely finger tight. Can't make this stuff up.

detroitm2 · 03-29-2019, 10:59 AM

Does the M2 tell you if you have an overinflated tires? Never noticed it on mine, it certainly lets you know about underinflation.

mr_lab_rat · 03-29-2019, 11:02 AM

Holy crap, that's insane.

I always check the pressure and wheel bolt torque after anyone touches the car.
Also recently I found out my pressure gauge was not working right. At 41PSI it only read 35 so about 15% off. That was enough to throw TCS off and it was acting up at high speeds (it was limiting power when accelerating in 6th gear, I'm pretty sure I wasn't spinning tires at those speeds

)

ZM2 · 03-29-2019, 01:09 PM

It is crazy that I check PSI on every drive?

I keep the tire temps & pressures idrive screen programmed to one of my radio preset buttons and check my hot pressures quite often, especially as outside temperatures change.

I also bought three tire gauges, checked pressures with all three and returned the one that was the most inconsistent. Both of my good gauges read 1psi higher than my idrive tpms.

If you're really keen, you'll note to get even hot pressures your front left cold psi will be lower than front right b/c the aux radiator puts more heat into the tire once the car is warmed up.

Lastly, the valve caps with the O-rings help a lot with air seepage/loss.

I think all this just comes from running the car at the track a lot.

03-29-2019, 10:47 AM	#1
paradocs98 Lieutenant Colonel 394 Rep 1,519 Posts Drives: M2C Join Date: May 2009 Location: NY iTrader: (0)	Check pressures after mounting/balancing This was a new one for me. As I typically do with my cars, I had winter tires mounted on my Audi S3's stock wheels when I started the lease three years ago. I don't love the stock PZero summer tires, so I put them in storage and purchased a nice set of OZ Leggera wheels with Michelin PS4S tires for regular, non-winter use. Now that the lease is almost done, I took the stock wheels/winter tires to a local tire shop (national chain) to have the stock PZeros remounted on the stock wheels. When I got home I checked the pressures to make sure they were roughly where they need to be before sticking them back in the garage for a couple of months. Three of the tires were in the 40psi range, where they need to be, but one was inflated to 75psi. Thought I was seeing things. Rechecked. Yep, 75psi. Took a lot of bleeding down to get to 40psi. I understand that occasionally lower-profile tires with stiff sidewalls can require high pressures to seat the bead, but even if 75psi were required, they should have lowered the pressure to something reasonable once it was seated. I'm glad I checked and it didn't sit like that in the garage for three months. Or worse, put them back on the car and hit a pothole with that grossly overinflated tire. So check your tire pressures, folks. Don't assume that the guys at the shop did. I'll add this to my list of things to confirm, along with lug nut/bolt torque settings. I've had dealership service done on various cars before and ended up with four lug bolts impact-wrenched down to 150+ lb-ft and one lug bolt barely finger tight. Can't make this stuff up. __________________ Past: E46 330Ci, E60 545i, E60 M5, E90 M3 Present: 2020 M2 Competition, 2022 GT3
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03-29-2019, 10:59 AM	#2
detroitm2 Colonel 2429 Rep 2,526 Posts Drives: 2018 M2 Join Date: Aug 2018 Location: Michigan iTrader: (2) Garage List 2018 BMW M2 [0.00]	Does the M2 tell you if you have an overinflated tires? Never noticed it on mine, it certainly lets you know about underinflation.
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03-29-2019, 11:02 AM	#3
mr_lab_rat Major 566 Rep 1,092 Posts Drives: 2017 M2, 2018 X1 Join Date: Jul 2017 Location: Vancouver iTrader: (0)	Holy crap, that's insane. I always check the pressure and wheel bolt torque after anyone touches the car. Also recently I found out my pressure gauge was not working right. At 41PSI it only read 35 so about 15% off. That was enough to throw TCS off and it was acting up at high speeds (it was limiting power when accelerating in 6th gear, I'm pretty sure I wasn't spinning tires at those speeds )
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03-29-2019, 01:09 PM	#4
ZM2 Brigadier General 2814 Rep 3,696 Posts Drives: 2017 LBB M2 Join Date: Mar 2017 Location: Baltimore iTrader: (1)	It is crazy that I check PSI on every drive? I keep the tire temps & pressures idrive screen programmed to one of my radio preset buttons and check my hot pressures quite often, especially as outside temperatures change. I also bought three tire gauges, checked pressures with all three and returned the one that was the most inconsistent. Both of my good gauges read 1psi higher than my idrive tpms. If you're really keen, you'll note to get even hot pressures your front left cold psi will be lower than front right b/c the aux radiator puts more heat into the tire once the car is warmed up. Lastly, the valve caps with the O-rings help a lot with air seepage/loss. I think all this just comes from running the car at the track a lot.
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