Front tires lose air

[MountyStan]

I have a 2007 Mountaineer 4.6 AWD with 212,000 miles and still runs great. My current issue is that my front 2 tires are losing around 5 to 7lbs of air a week. The rear tires stay steady with no air loss. Both front tires lose aprox the same amount and have checked and there are no punctures in either. Seems to coincidental to have both front tires lose the same amount but have no idea what the cause might be. This is a recent issue from the last month or two and the tires were new over a year ago. It is a daily driver. Did jack it up and check both front wheels. They spin freely, no noise at all, and no play.

Any thoughts or suggestions are appreciated.

 

[Mbrooks420]

The tires are both leaking air. There’s no connection between the two. Find and fix the leaks.

 

[rhamnik]

Original wheels? Might be corrosion at the seal where the rubber meets the wheel.

 

[Mitchs07explorer]

If you didn’t replace your valves on your rims when you changed out the tires it’s possible that’s where the leak is coming from. If you can, just run it down to a tire shop and have them locate the leaks. Most places will fix fixable leaks for free except if it’s the valve they’ll charge you for those plus tire remounting.

 

[Larryjb]

I had a heck of a time with my original 18" rims leaking air. The tires were fine, but sealing the tire to the rim always seemed to be an issue. I have never had such trouble with the older 16" or even 14" rims.

Also, the OEM 18" rims had this plastic onlay which was easily damaged, and if you hit a curb hard with an 18" rim, it is much more easily damaged than the 16" rims. All in all, I got fed up with 18" rims and got a set of 16" rims.

If you want to keep the 18" rims, take them back to the tire shop and have them reseal them.

 

[07EddyB]

I see that this is your first post. The fact that it is only your front wheels is just a coincidence. I has nothing to do with the position of the tires. If you rotate them to the rear they will do the same thing. It can only be the tire itself. Some aluminum rims can develop leaks - that is an option also. Check each front tire for foreign objects - remember that the fronts will pick up debris before the rears.

 

[Larryjb]

One other thing. My tire guy told me once that the lower profile tires are more prone to leaks like this. The shorter sidewall puts more stress on where the tire fits to the wheel. It seems that these 18" rims are more sensitive to being mounted exactly right..

As for your curiosity that both fronts are affected, it could be that the fronts experience more side to side stress when turning. Do you take spirited turns?

I did have a rear one leaking though, so it's probably more coincidence that it's the two fronts that are leaking.

 

[07EddyB]

One other thing. My tire guy told me once that the lower profile tires are more prone to leaks like this. The shorter sidewall puts more stress on where the tire fits to the wheel. It seems that these 18" rims are more sensitive to being mounted exactly right..

As for your curiosity that both fronts are affected, it could be that the fronts experience more side to side stress when turning. Do you take spirited turns?

I did have a rear one leaking though, so it's probably more coincidence that it's the two fronts that are leaking.

That's an excellent point - a stiffer sidewall can put more stress on the bead - and it can be easily determined in the OPs case by rotating the tires from the front to the back and seeing what happens.

 

[imp]

I have a 2007 Mountaineer 4.6 AWD with 212,000 miles and still runs great. My current issue is that my front 2 tires are losing around 5 to 7lbs of air a week. The rear tires stay steady with no air loss. Both front tires lose aprox the same amount and have checked and there are no punctures in either. Seems to coincidental to have both front tires lose the same amount but have no idea what the cause might be. This is a recent issue from the last month or two and the tires were new over a year ago. It is a daily driver. Did jack it up and check both front wheels. They spin freely, no noise at all, and no play.

Any thoughts or suggestions are appreciated.

When punctures are absolutely ruled out, by dunking the tires in soapy baths in semicircular tanks made for the purpose, stem leakage, rim leakage, or wheel cracks are the only other leak places possible, other than porous rubber (very rare).

Stem leakage may be around the stem/wheel interface, or the Schrader valve in the stem. Easily checked with soapy water and fixed.

Rim leaks may be assessed by lying the wheel flat on a level surface and filling the space between the metal rim and rubber with soapy water. Some rim leaks are so small, the bubbles produced may go unnoticed, very tiny, may take a month to register air loss.

If all above fail to reveal the leak, remove tire, and remount on another rim. Use "bead sealer" or rubber cement on beads, always, before mounting a tubeless tire. Tire shops all have a can of sealer sitting near their tire machine.

 

[Blackhawkxx]

Good information above. Air up the tire first, using a spray bottle, if you see bubbles at the bead, NAPA and others have bead sealer but it can be messy. I had to do that on my Ranger because the aluminum bead area gets that white powdery corrosion that lets the air leak and it is rust on steel wheels if you have them. So be sure to get the corrosion off before sealing.
BTW-most tires seem to lose more air in the winter IMO.

 

[imp]

Good information above. Air up the tire first, using a spray bottle, if you see bubbles at the bead, NAPA and others have bead sealer but it can be messy. I had to do that on my Ranger because the aluminum bead area gets that white powdery corrosion that lets the air leak and it is rust on steel wheels if you have them. So be sure to get the corrosion off before sealing.
BTW-most tires seem to lose more air in the winter IMO.

Tire pressure varies with temperature. With good, well-sealed tires, the pressure on cold mornings will be lower than normal, higher with rising outside temperature, and may amount to 3-6 psi back and forth.

This principle is commonly called Gay Lussac's Law.

See: Gay-Lussac's law - Wikipedia

 

[RichC_111]

I have a 2007 Mountaineer 4.6 AWD with 212,000 miles and still runs great. My current issue is that my front 2 tires are losing around 5 to 7lbs of air a week. The rear tires stay steady with no air loss. Both front tires lose aprox the same amount and have checked and there are no punctures in either. Seems to coincidental to have both front tires lose the same amount but have no idea what the cause might be. This is a recent issue from the last month or two and the tires were new over a year ago. It is a daily driver. Did jack it up and check both front wheels. They spin freely, no noise at all, and no play.

Any thoughts or suggestions are appreciated.

I have a 2004 Explorer (Eddie Bauer edition) and had similar problems with all of my tires after replacing them. Apparently, it's fairly common with aluminum wheels as they age and develop pitting, etc, especially if your tire place doesn't clean and condition the wheels sufficiently when replacing. Also had one that needed a valve stem replacement. After several trips back to my "new" tire guy, no more leaks. Best of luck, and welcome to the forums!

-Rich

 

[Trainmaster]

I have a 2007 Mountaineer 4.6 AWD with 212,000 miles and still runs great. My current issue is that my front 2 tires are losing around 5 to 7lbs of air a week. The rear tires stay steady with no air loss. Both front tires lose aprox the same amount and have checked and there are no punctures in either. Seems to coincidental to have both front tires lose the same amount but have no idea what the cause might be. This is a recent issue from the last month or two and the tires were new over a year ago. It is a daily driver. Did jack it up and check both front wheels. They spin freely, no noise at all, and no play.

Any thoughts or suggestions are appreciated.

Aluminum rims can corrode and the beads allow air to seep out. A good tire shop can wire brush them and remount the tires with a gel that seals the bead and stops the corrosion. I had to do this with my 2010 stock 20" Explorer wheels.

 

[Blackhawkxx]

Tire pressure varies with temperature. With good, well-sealed tires, the pressure on cold mornings will be lower than normal, higher with rising outside temperature, and may amount to 3-6 psi back and forth.

This principle is commonly called Gay Lussac's Law.

See: Gay-Lussac's law - Wikipedia

I understand the temperature variance but in cases where there is some corrosion, the firmer rubber at cold temps seem to leak more air in my experience. My garage air compressor does the same thing but for different reasons (I'm guessing), it won't lose a pound in the summer but loses air all winter.

 

[imp]

I understand the temperature variance but in cases where there is some corrosion, the firmer rubber at cold temps seem to leak more air in my experience. My garage air compressor does the same thing but for different reasons (I'm guessing), it won't lose a pound in the summer but loses air all winter.

We used to call that "F.M.". Anything unexplainable to do with rubber, which is magic stuff!