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Discussion Starter · #1 ·
I try to keep my tires inflated to the recommended 41psi. The rear-left tire sensor keeps telling me that the tire has low pressure and, what do you know, it's doing its job correctly as every time I refill it I get the same warning a couple of days later.

Can I take this anywhere to get the tire repaired or, due to the sensors, should I take it to my dealer? I'd rather have the dealer do it if there's any chance whatsoever of someone at a tire store screwing up the sensor functionality.

I need to get it fixed before a 7 hour drive to Destin next month.
 

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Most good tire stores can deal with the sensors. The federal government is going to require all new cars to have them very soon, anyway. But, since you live in Atlanta, may I recommend you visit Gran Turismo East in Chamblee (770) 455-0347. Ask for Harris. They specialize in performance European cars.:D

I run a body shop and we've been knowing them quite a while... we sub out some the higher-line cars we get to them for alignment work (Like the 2003 E-class we repaired a couple of months ago!).
 

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johnc_22 said:
I try to keep my tires inflated to the recommended 41psi.

I need to get it fixed before a 7 hour drive to Destin next month.
Is it more than 700 miles from Atlanta to Destin?

I only ask because the 41 psi inflation pressure is for average speeds in the range 100 mph to maximum speed. If your vehicle speed typically falls between 0 and 100 mph, the recommended pressure is 35 psi.
 

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Discussion Starter · #4 ·
Most good tire stores can deal with the sensors. The federal government is going to require all new cars to have them very soon, anyway. But, since you live in Atlanta, may I recommend you visit Gran Turismo East in Chamblee (770) 455-0347. Ask for Harris. They specialize in performance European cars.:D
I know about Gran Turismo - I used to live about 2 minutes from there and (thankfully) live in town now. While I would definitely use them to get 4 tires from TireRack mounted and balanced, I'm thinking I can get it done a bit more cost effectively at just about anywhere else since we're just talking about a simple patch (AFAIK). If this tire is toast for some reason I may seriously consider ditching the Pirellis as I refuse to buy another. I probably have some good life left on them so I hope that's not the case.

I only ask because the 41 psi inflation pressure is for average speeds in the range 100 mph to maximum speed. If your vehicle speed typically falls between 0 and 100 mph, the recommended pressure is 35 psi.
It seems that at 35psi all 4 of my sensors would probably be going off - no sh*t! It certainly does make the ride a bit harsher, but when I complained that was the dealer's solution - inflate to 41psi. Can the dealer adjust the sensitivity, or the PSI at which the sensors activate - they sure didn't suggest that they could when I complained about it.

Once I get the leak fixed I may slowly ratchet down the psi and see where the spot is at which the sensors go off and then shoot for just above that.

No matter how far I have to drive I won't do more than about 80 for a stretch, and I'll have my bike on the roof so will likely keep it about 75.
 

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Saabseeker said:
Most good tire stores can deal with the sensors. The federal government is going to require all new cars to have them very soon, anyway. But, since you live in Atlanta, may I recommend you visit Gran Turismo East in Chamblee (770) 455-0347. Ask for Harris. They specialize in performance European cars.:D

I run a body shop and we've been knowing them quite a while... we sub out some the higher-line cars we get to them for alignment work (Like the 2003 E-class we repaired a couple of months ago!).
I've never played with a wheel that had a presure sensor installed, so this makes me curious. What would stop you from finding the source of the leak (most likely a nail or screw), pulling the object out then plugging the tire like you would with a car not equipped with a pressure sensor?
 

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Nothing would keep you from plugging the tire, it's just that if you dismount the tire (for instance, to replace or boot/patch it) you'll probably have to deal with the pressure sensors since they are often fitted to the inside of the valve stems.
 

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johnc_22 said:
It seems that at 35psi all 4 of my sensors would probably be going off - no sh*t! It certainly does make the ride a bit harsher, but when I complained that was the dealer's solution - inflate to 41psi. Can the dealer adjust the sensitivity, or the PSI at which the sensors activate - they sure didn't suggest that they could when I complained about it.
OK, this is insane:evil: Most of the systems I've read about give a fault signal in the 20-25 psi range. If Saab really has it set higher, then either they have changed the recommendations or they better revise their manual. My Vector has the recommended pressures printed on a sticker attached to the glovebox lid. It's basically 35 psi unless your speed exceeds 100 mph.

My advice is to investigate the technology. It's probably special valve stems, but it may be decals affixed to the rim. In either case you can probably find replacements that will allow a more reasonable pressure.

41 psi is too high for a passenger car with normal load. Compounding the stupidity is the fact that the Rossos already show preferential wear in the center of the contact area. Over-inflating them will only worsen that tendency.

This system is ripe for "upgrading" by the vehicle owner. I'm glad I don't have the system. When someone finds a reasonable solution it belongs in the FAQ!
 

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I know they are modules, not stickers. And I'm pretty sure they are programmable via the vehicle computer system. I know the modules can change their nominal values based on temperature & wheel size. I have a little bit of info you can find here:
http://www.mrandmrs-g.net/SGFOG/item-c04.htm

I wisht hey were user configurable via the SID. That would be awesome, and not that difficult to do since the whole system is on the Bus. After all, Saab recommends different pressures for different loadings, and the vehicle doesn't know how many passengers there are or how many cinder blocks/wife's luggage/gold ingots you're toting.
 

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As far as repairing your leak any reasonable tire shop should be able to help you. Just tell them you have pressure monitors. They probably just don't bother touching the stems, unless the stem is leaking.

You can easily find the leak yourself unless it is a really slow leak. Just squirt some soapy water on the tire. You can do this while the tire is still on the car. That will allow you to check one bead and the stem. To check the tread and the inner bead you will need to dismount the tire. Use a few drops of liquid dish detergent in about 1 cup of water. I use an old shampoo bottle to squirt it on. If the leak is small you can often find it by temporarily over-inflating the tire to 50 psi.

If you find a nail or screw, don't pull it unless you have a plug ready to go. If the sidewall is damaged you need a new tire.

A plug tool kit with a few plugs will run you about $10. Get a tool kit which has T-type handles. This will save your palms when you are shoving the plug into the tire.
 

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Discussion Starter · #10 ·
OK, as was suggested I lowered the PSI of all tires that weren't leaking to 36psi yesterday. The slow leak one was sitting around 34psi. Now that I've lowered the other 3 I'm not getting a warning about the leaky one! :confused: Not to mention the fact that of course the ride is much nicer. :D I've had the tires at 41 for so long that I'd forgotten how well the car should ride. I will say that the sticker on inner driver door frame says 41psi all the way around. I need to RTFM and see what it says.

I'm wondering if the tire pressure monitors' sensitivity is relative to the average inflation of all the tires? So, when I had the tires at 41psi, 34 looked bad, but when they're at 36, 34 is close enough?

Pure speculation of course.
 

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johnc_22 said:
I will say that the sticker on inner driver door frame says 41psi all the way around. I need to RTFM and see what it says.
I can double check my manual too.

Meanwhile, here's a semi-focused picture of the sticker affixed to my glovebox door. The car is a 2003 Vector with the 17" Rossos. This tire shows horrendous wear in the center tread. So it's probably over-inflated even at 35 psi.

The numbers badly blurred are "0-160 km/h" and "0-100 mph."
 

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Discussion Starter · #12 ·
No sticker in the glovebox in my '04 Aero but the manual confirms exactly what you said. So long as the sensors don't go off I'm leaving it around 35-36.

Thanks for the advice.
 

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johnc_22 said:
Can I take this anywhere to get the tire repaired or, due to the sensors, should I take it to my dealer? I'd rather have the dealer do it if there's any chance whatsoever of someone at a tire store screwing up the sensor functionality.
I had a slow leak too. I had the dealer fix it on one of way too many visits I made there. He charged me $15. I don't know for sure what your dealer will charge you, but if it's only $15, it's a small price for peace of mind. Sensors are expensive if damaged.

That said, a reputable tire shop in your area should also be equipped to handle them.
 

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Do not plug!

This isnt a minivan or some hunk of junk. If you plug, your handling may act funny over duration of tire. Better to patch than to plug. Furthermore, ur better off replace 2 tires as it is. These tires wear fast on this car anyway. just my opinion.
 
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