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JustB
11-15-2014, 07:48 AM
I've had my 500L for over a year now and have been loving it, but something odd has been happening in the past 3 months.

In Sept I drove up to PA for a wedding and a cold front came through one night, dropping down below 32. When I started my 500L the next morning I was warned the left front tyre pressure was low. So I went to the local service station, reinflated and it has been fine since.

Now this week things are starting to get cold where I am. I start my 500L up and there was a warning about the right front tyre pressure. I've left it outside in colder temps last winter and never had this problem.

Has anyone else had this happen?

mp4guy
11-15-2014, 09:20 AM
I've had my 500L for over a year now and have been loving it, but something odd has been happening in the past 3 months.

In Sept I drove up to PA for a wedding and a cold front came through one night, dropping down below 32. When I started my 500L the next morning I was warned the left front tyre pressure was low. So I went to the local service station, reinflated and it has been fine since.

Now this week things are starting to get cold where I am. I start my 500L up and there was a warning about the right front tyre pressure. I've left it outside in colder temps last winter and never had this problem.

Has anyone else had this happen?


It's actually common. Warm weather expands air, cold weather contracts it. One of the first signs of winter- aside from getting your sweaters out of the closet- is the tire pressure warning light going on- tricks everyone.

That's why you always check your tire pressure when they're COLD.

JimmyTestarossa
11-15-2014, 10:22 AM
What mp4guy said.

You also need to remember to check them when the temps start going back up to make sure they are not overinflated.

If you removed a schrader valve from the stem you would be kinda shocked that such a small thing could take as much abuse as it does and still function properly.

Tweak
11-15-2014, 11:13 AM
As stated cold temps will cause this and the sensors often go a bit crazy (some more than others). If you switch to Nitrogen filled then it won't be as much of an issue if it bothers you seeing the light trip and needing to adjust pressures. Nitro filled due to the molecular structure when compared to air are far superior in that they do not suffer leakage or changes due to temps the same way as air alone.

ciao500
11-15-2014, 01:51 PM
General rule is 10*f temp drop = 1psi tire pressure drop

bryanintowson
11-16-2014, 12:24 PM
This. It happened to me constantly on my previous car (Acura TSX). I'm convinced it's thanks to alloy rims and modern lower profile style tires. I bought a $20 electric pump at home depot so I don't have to stop at a gas station when it happens.

piney500
11-16-2014, 12:41 PM
Happened to me a few days ago when this big cold front hit here. Got a warning on all four tires. I just pulled the inflation device from under the seat, topped them off and went about my business. I did, however, notice something that concerned me a little. When I inflated the tires to exactly the pressure prescribed on the sticker inside the door I still got a TPMS warning. Had to go 4-5 lbs over to make it happy. Doesn't take it anywhere near max pressure, but thought it was a bit weird.

Vaejovis carolinanus aka lowconabarth
11-16-2014, 04:54 PM
I have had to go to Costco about once a year to fill or top off with nitrogen since I bought the Abarth it June of 2012. No big deal but it is always the winter cold that triggers the TMPS. Still running factory P7s with about 28k miles on them.

bryanintowson
11-17-2014, 10:06 AM
Happened to me a few days ago when this big cold front hit here. Got a warning on all four tires. I just pulled the inflation device from under the seat, topped them off and went about my business. I did, however, notice something that concerned me a little. When I inflated the tires to exactly the pressure prescribed on the sticker inside the door I still got a TPMS warning. Had to go 4-5 lbs over to make it happy. Doesn't take it anywhere near max pressure, but thought it was a bit weird.

Were you checking the pressure on a separate tire gauge or using the one on the pump? Typically the ones on the pump have a very high +/- error rate, sometimes up to 5psi in either direction. I always tell people to invest in a good quality round-face racing tire gauge rather than the old school pen type or digital ones.

SeaDawg
11-17-2014, 10:22 AM
Were you checking the pressure on a separate tire gauge or using the one on the pump? Typically the ones on the pump have a very high +/- error rate, sometimes up to 5psi in either direction. I always tell people to invest in a good quality round-face racing tire gauge rather than the old school pen type or digital ones.

Pffffft, I happen to prefer the digital ones. At least the one I have agrees with the professional quality LCD readout one on my LS's pull down hoses.

And YES, I know that probably means both of them just happen to be off the same amount.:nevreness: :Whatever:

afxman
11-17-2014, 10:32 AM
Filling with nitrogen may help with the pressure fluctuations, but if you're running stock Pirellis it could void the tire warranty.

What Is Not Covered By The Warranty?

P-Metric tires used on commercial vehicles or used in commercial applications.
Tires transferred from another vehicle on which they were originally installed.
Tires on any vehicle registered and normally operated outside the United States of America or Canada.
Tires which have been recapped, or retreaded, or regrooved.
Tires used in racing or other competitive events.
Tires improperly repaired or with repairs not conforming to Rubber Manufacturers Association standards, or with section repairs, or with self-vulcanizing plug only.
Tires which have been modified by the addition or removal of material or any tire intentionally altered to change its appearance.
Tires injected with liquid balancer or sealant or in which anything other than air has been used as the support medium.
Tires with weather cracking which were purchased more than four years prior to presentation for adjustment (If no proof of purchase date is available, tires manufactured four or more years prior to presentation for adjustment).
Tire unserviceability caused by tire operation in excess of tire/wheel manufacturers' specifications and recommendations.
Ride related anomalies after the first 2/32" of treadwear.
Tires which are mis-applied due to insufficient speed rating, or undersized, or oversized tires.
Tires which become unserviceable because of a mechanical irregularity in the vehicle such as misalignment, defective brakes, defective shock absorbers, or improper rims.
Tires damaged by fire, chemical corrosion, vandalism, wrecks, chains, theft, run while flat, underinflated, overinflated, or abused during servicing.
Flat Spotting caused by improper transport or storage.
Tires which become unserviceable because of road hazard injuries (e.g., nails, glass, metal objects) or other penetrations or snags, bruises or impact damage.
Tires damaged from improper mounting practices.
Tire dealer/retailer services (e.g., mounting, dismounting, balancing, tire rotation, or wheel alignment).
Mileage warranty is not applicable to tires fitted as Original Equipment.
Tires removed in pairs or sets where no abnormality exists in multiple tires.
Summer tires used at or below 45F (7C) ambient temperature.

Fabio13
11-17-2014, 11:46 AM
I would think nitrogen in this case would be construed as air.

piney500
11-17-2014, 04:00 PM
My question is how would the be able to tell if the tire were flat? If there's a hole in the tire then the nitrogen is all gone anyway. No evidence, no crime.

JimmyTestarossa
11-17-2014, 04:48 PM
Looking at the list of things they won't warranty, the type of gas I use to inflate my tires is of little concern.

Here are two that should concern a few people;


Tires used in racing or other competitive events.

Summer tires used at or below 45F (7C) ambient temperature.

Fabio13
11-17-2014, 06:30 PM
My question is how would the be able to tell if the tire were flat? If there's a hole in the tire then the nitrogen is all gone anyway. No evidence, no crime.

Good point!

Tweak
11-17-2014, 10:50 PM
My question is how would the be able to tell if the tire were flat? If there's a hole in the tire then the nitrogen is all gone anyway. No evidence, no crime.

If you don't remove the "evidence" of the green topped valve stem covers most places use...or if a record has been made (slight possibility of course) then they could see it in their records.

piney500
11-17-2014, 11:21 PM
If you don't remove the "evidence" of the green topped valve stem covers most places use...or if a record has been made (slight possibility of course) then they could see it in their records.

But that would only be if the studio tech did it for you, right? And in that case I'd point at them and say "What do you mean you violated my warranty? You guys should know better!". ;)

piney500
11-17-2014, 11:22 PM
But that would only be if the studio tech did it for you, right? And in that case I'd point at them and say "What do you mean you violated my warranty? You guys should know better!". ;)

And in my case the green topped stem valves would definitely not be there. I've got the custom ones with the FIAT logo on them. :)

Tweak
11-17-2014, 11:25 PM
But that would only be if the studio tech did it for you, right? And in that case I'd point at them and say "What do you mean you violated my warranty? You guys should know better!". ;)


And in my case the green topped stem valves would definitely not be there. I've got the custom ones with the FIAT logo on them. :)

I have custom Abarth caps so wouldn't be an issue for me either...but many places including the dealer do use those green caps. I am assuming people might take their cars to places besides the dealer as well. I have a local dealer and one I bought from around 60 miles away, I visit both. Additionally down the road from the local dealer I know the guys at a local tire shop and I go there as well. Today I went by there to borrow their lift for a few minutes. :)

piney500
11-18-2014, 01:39 AM
Were you checking the pressure on a separate tire gauge or using the one on the pump? Typically the ones on the pump have a very high +/- error rate, sometimes up to 5psi in either direction. I always tell people to invest in a good quality round-face racing tire gauge rather than the old school pen type or digital ones.

Separate pen gauge that I've carried in all my cars for about the last 8 years (I don't trust the one on the pump either). Hasn't been that far off on any of my other vehicles. And the pressure reading in the TPMS system agreed with the measurement on my gauge within a 1 or 2 psi, so I'm assuming it was darn close to being right.

streetsurfer
11-18-2014, 01:53 AM
The red text cited above is most certainly not about nitrogen fills. Air is nearly 80% nitrogen anyway. It would be referring to others things such as calcium chloride.

Running on a flat for very long would in all likelyhood leave signs that a knowledgable person could find.

Doohickie
11-18-2014, 11:00 AM
General rule is 10*f temp drop = 1psi tire pressure drop

Not quite that much, but close. If you're at 70 degrees you're at ~500 degrees above absolute zero. Drop that by 50 degrees to 20, and you've lost about 10% of your pressure, since pressure is proportional to temperature (degrees above absolute zero). So a swing of 50 degrees drops your pressure about 3.5 psi (assuming you started from 35) which equals about .7 degree per 10 degrees of temperature drop.


/engineer /nerd /pedantic

Doohickie
11-18-2014, 11:03 AM
My question is how would the be able to tell if the tire were flat? If there's a hole in the tire then the nitrogen is all gone anyway. No evidence, no crime.

They could tell by the little green valve cap places put on your valve stem when you fill up with nitrogen. :P

B3NN3TT
11-18-2014, 03:29 PM
I think that portion of the warranty is referencing things like Fix-A-Flat, where the tire is partially filled with a chemical compound, i.e. "not air".

Nitrogen is air.

streetsurfer
11-18-2014, 03:56 PM
Liquid Tire Sealant is already adressed in the same sentence. Calcium chloride is something other than air that is used as support medium. There may be others. Fix-A-Flat is not meant to be used as support medium.

"Tires injected with liquid balancer or sealant or in which anything other than air has been used as the support medium."

piney500
11-18-2014, 04:37 PM
They could tell by the little green valve cap places put on your valve stem when you fill up with nitrogen. :P

As I responded to Tweak regarding this topic on the previous page, I don't have those as I have the custom valve caps with the Fiat logo on them. I don't imagine that any other prudent person who thinks it would violate their warranty would leave them on when making a claim either any more than they would leave their aftermarket CAI or ECU in place were they bringing it in for a warranty claim on the engine if their studio was the type to try and call them on it.

streetsurfer
11-18-2014, 04:56 PM
You guys are going back and forth over a moot point. It makes no sense. Nitrogen fills and flats are not going to void the tire warranty. Driving on a flat and filling with another medium than air (air including nitrogen fills) which are meant to support the tire ( i.e. Calcium chloride or foam fillers) are what affects warranty. The green caps do not need to be removed when visiting a dealer. All major tire companies support the use of nitrogen fills and that alone will not void a tire warranty.