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What causes outer tire wear? Over inflated or under inflated? The outer tire wears is significantly worse than the center.




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it could be several things, like too much toe in on your alignment, too much positive camber, etc.

if this looks the same on the inside of your tire, then it's caused from underinflation.
 

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it could be several things, like too much toe in on your alignment, too much positive camber, etc.

if this looks the same on the inside of your tire, then it's caused from underinflation.
Yes inside and outside look the same. The tire pressure is around 35-36 PSI when they are HOT. Cold pressure is around 31 PSI.


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If you are inflated to normal (which is 220 kPa), it must be the alignment. When was the last time you had one and how were the results?

When I got my 2008 in 2011, I also noticed outer tire side worn noticeably more. When I changed the tires and had alignment done (which was all green at the time), that stopped.

Even now when the alignment is not perfectly green (although very slightly, which is insignificant), there's no abnormal tire wear for me.
 

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incorrect toe (in or out) usually causes feathering on the tires
incorrect camber usually causes excessive wear on either the inside or outside of the tire but not both
incorrect pressure usually causes excessive wear either on the center (over inflation) or edges (under inflation). Once mfg switched from biase ply to radial ply tires inflation caused tire wear went down. Radials are more tolerant of inflation variations. 31psi cold is low IIRC but I wouldn't expect it to cause excessive wear, maybe slightly noticeable wear variation, but not excessive.

looking at the pictures it's hard to tell without seeing more but to me it looks a combination of incorrect toe and low pressure.
 

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Is the wear on all four tires or just one axle set? I did lifetime alignment with Firestone when I purchased my 11 MDX adv used back in 2014 and it has paid for itself since. The alignment usually has 1/4 of the adjustment point in the yellow/red when I take the MDX back 1-2 times a year. I also do re-balance/rotation or X-rotation every oil change (lifetime with Discount Tires). I also keep my PSI around 34-36 range.

If the alignment/suspension checks out and the wear is only on the front left tire, it could be just from normal driving? I've noticed this issue with all my Acura cars and that is why I upped the tire rotations. Most left hand turns are long, slower, and sweeping (like from the left turn lane at a stop light). Right hand turns can be be at a sharper angle or higher speeds (90 degree right turns at stop signs or 90/270 degree curved hwy on/off ramps).
 

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You are underinflated if you are setting the tires at 31 PSI cold. Hot is too variable to tell you much. Always set the pressure cold whenever possible. Personally I run mine at 35 PSI cold. The other question not asked is rotation frequency and driving style. If you are going beyond 5-6K miles, drive lots of city miles with lots of turns, and tend to drive aggressively then shorten the rotations, up the pressure a bit, and try not to drive as aggressively.
 

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Discussion Starter #8
I rotated the tires every 10k miles and do a lot of uber driving. Lots of left/right turns.


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You are underinflated if you are setting the tires at 31 PSI cold. Personally I run mine at 35 PSI cold.
Isn't that overinflated? The owner's manual says 220 kPa cold, which is 32 PSI. Which becomes about 240 kPa (so 35 PSI) when they heat up in warm season. So your 35 cold becomes about 37 PSI, which is definitely overinflated.
 

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Isn't that overinflated? The owner's manual says 220 kPa cold, which is 32 PSI. Which becomes about 240 kPa (so 35 PSI) when they heat up in warm season. So your 35 cold becomes about 37 PSI, which is definitely overinflated.
Nothing matters beyond cold inflation. A warm tire can vary significantly based on air temp, pavement temp, and elevation. If you set your pressure at sea level then climb 5,000 ft you will see a 2-3 PSI increase from the elevation change alone. If you set your pressure at 6 am in the desert at 40 degrees then without driving check it in the afternoon at 90 degrees you will see a 5-10 PSI increase. The max cold pressure on the sidewall takes all of this into account. Not applicable to an MDX per se, but I've dealt with customers who had a 1 ton truck where the rear tire max was 80 PSI and the door sticker for the rear was also 80 PSI. He was watching the TPMS as he was driving (while towing) and freaking out because they were hitting 85+ PSI, so he stopped and adjusted air pressure back to 80 PSI. The load capacity for the tire is calculated at max pressure, so he was effectively reducing the max capacity on the tire when he reduced the pressure. Not good when you are approaching max GCVWR with a huge 5th wheel camper attached.

The number on the door jamb is the "factory recommendation" and is a blend of ride comfort, wear, and fuel economy. 31 PSI is definitely underinflated. Yes, 35 PSI is technically overinflated, but I don't mind the slightly firmer ride, crisper handling, and slightly improved fuel economy. There are calculations out there for figuring out how much the load capacity of the tire is reduced for each PSI a tire is underinflated and there is a reason most TPMS systems are set to trigger at ~10% or 3 PSI. That is to give the driver a chance to address the issue before it becomes dangerous. The US federal mandate on TPMS for every car on the road model year 2008+ is thanks to infamous Ford Explorer/Firestone debacle. People were not monitoring their tire pressures and letting them get too low. Once the tire was too low and running at highway speed the heat build up due to reduced weight capacity caused a blow out, loss of control, and high rate of roll over accidents due to the higher CG of the SUV. Neither Ford nor Firestone were at fault, they just happened to be 2 very large corps with deep pockets and the Explorer was the greatest volume SUV at the time meaning that they had a higher frequency of these incidences vs other makes and models.

Bottom line, pressure, driving style, driving type, cargo load, and alignment all play into tire wear. Set the pressure right, which may be actually over the door jamb (I run 40 PSI if towing) if you are loaded to the gills, make sure the alignment is good, rotate more frequently if lots of city stop/go miles, and try to drive less aggressively if making your tires last is the priority. I drive lots of highway miles, so I frequently get to the rated tread wear with tread to spare, but not everyone can. When I was in the tire biz we serviced a local police dept that went through front tires about every 6-7K miles and rears every 10K. They didn't bother to rotate because that was down time that wasn't going to change the end result enough to be useful. That's an extreme, but everyone else falls somewhere between that and the people that get 100K out of a set of tires. I had a set that would have made 100K if it weren't for a sidewall puncture at 81K.
 

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Is the wear on all four tires or just one axle set? I did lifetime alignment with Firestone when I purchased my 11 MDX adv used back in 2014 and it has paid for itself since. The alignment usually has 1/4 of the adjustment point in the yellow/red when I take the MDX back 1-2 times a year. I also do re-balance/rotation or X-rotation every oil change (lifetime with Discount Tires). I also keep my PSI around 34-36 range.

If the alignment/suspension checks out and the wear is only on the front left tire, it could be just from normal driving? I've noticed this issue with all my Acura cars and that is why I upped the tire rotations. Most left hand turns are long, slower, and sweeping (like from the left turn lane at a stop light). Right hand turns can be be at a sharper angle or higher speeds (90 degree right turns at stop signs or 90/270 degree curved hwy on/off ramps).
My 05' TL ate front tires, no matter what I did. Always wore on outside and inside edge, had it aligned 3-4 times a year. I gave up rotating tires and just let it eat the fronts. My 13' MDX was doing the same, just not as bad. I make sure to rotate often, and have Firestone "lifetime alignment", so hopefully this recent set of tires will last longer than the year old, old set. I swear it's an Acura thing as well, haven't had this issue on any other of the crap load of vehicles I've owned over the decades.
 
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