So, I'm walking by my truck in the driveway the other day and see that my tread's getting a little thin (BFG LT, ~41k miles). Upon closer inspection, I see that on all four wheels, the tread on the outside is much thinner than it is on the inside.

They're inflated properly (from what I can tell, anyway. They're at 31 psi after a 3-mile drive. Not quite cold, not exactly warm.) and I have them rotated when I'm told to.

So, what's with the wear pattern? Is it something I should worry about?

Thanks, guys!

well it could be 1 of 2 things. eather you alignment is out. or your tires have been run under inflated. it is proubly from running the tires under inflated. those tire should probubly be run at 35psi if they are a P rated tire. and around 40psi if it is and LT rated tire with a C load range. the easyest way to know what psi to run, is to read the side wall of the tire and what the max psi is and go from there. if the max psi s 35 then run that. if the max is 44psi or more run it about 40. that should help tires run long and wear more evenly.

But I've seen on here numerous times that you should run your tire at what it says on the sticker in the glove compartment, which is 26 psi. I figured 31 or 32 was a good compromise (the side wall of the tire says max psi is 35).

As for ratings and all that, I have no clue what you're talking about.

So, if the max pressure on a tire is 35, and you fill it to 35psi and live in phoenix.. what happens when you drive around?

i bet truck tires are fun down in Phoenix in the summer. i lived down there for a couple of months back in '01. i was in october and it was still a hot bastard down there.

well babyX next time your at the tire store ask them what they would recomend you to run your tire pressure at. from what you were dicribing is a very common sign of underinflation.

i was just reccomending the tire pressure we put in the tires at work. im not an expert yet so im just goin off what i know.

Generally, its under inflation if BOTH outside edges of a tire are worn more than the middle tread area...

When you say the outside edges are worn on all four tires, do you mean BOTH edges on every tire?

If its just the outside edge (Outboard side of truck) of each tire, then its not under inflation.

The best way to determine correct tire pressure is a chalk test....just picking a number doesn't account for each truck's differences, such as weight....One X may weigh 1,000 lb differently than another (What you carry with you, winches, skids, rails, plates, etc...) and, different tires use different pressures to achieve equivalent carrying capacities.

To do a chalk test, get some chalk...

Wait until the tires are cold (Not driven on for several hours...driving a mile will not heat them up much, if at reasonable speeds)

(Do the test with cold/ambient air temp tires)

Find a clean dry area of a contrasting color to the chalk to drive over....

Chalk the tread area of your tires....

Drive over the contrasting surface...

Look at the tracks...if the chalk is evenly deposited across the treads, its the right pressure...

If the chaulk is heaviest at the edges, and light in the middle, its too little pressure...

If the chaulk is heaviest in the middle, and lighter at the edges, its too much pressure...

Adjust until its right, and that's your magic number, for your truck.

When the temperature drops, the pressure in the tire goes down too...

When it gets hot, the pressure goes up...

You need to adjust the pressure if the temp changes...but adjust it to the magic number.

When you drive, the tires heat up, that's normal, and accounted for in the engineering of the tire, and its max pressure ratings, etc.

(If your magic number is the max pressure, its OK when the tire heats up, and the pressure builds...that's normal)

The magic number is based on your cold tire pressure, and the guage pressure is expected to go up when you drive, and drop back down when cool)

BTW - If the chalk tracks show uneveness left to right (DS-PS), then the alignment is probably off too)

Hope that helps!

TJ, I'll try the chalk test, thanks.

When I say one side is worn down, I mean just that one edge, the outside edge. From the middle of the tire inward, the tread is the same depth, but the outside edge is quite a bit thinner. However, this wear pattern is the same on all four tires. I wish I had a digital camera, I'd take pictures.

I'll do the chalk thing and see what happens.

If its just one edge, your camber is off...and you need an alignment to correct it...

If you drive really aggressively, as in you are always skidding around turns, in a 4 wheel drift through off ramps, etc...you can also wear tires in that pattern.

Hey Baby X, when is the last time you had your tires rotated, and or aligned?

Isn't the camber spec actually negative (ie, the tops of the tires are "tipped-out" a bit even when properly aligned)?

Edit - I'm referring to the front only.

I do drive fairly aggressively, but I'm careful about slowing down for turns. I'm always afraid I'll roll or something.

Uh.... the last time I had an alignment/rotation? Good question. I think it was done in April when I had the 30,000 servicing done. I think. I thought about having it done last week, but it's kinda pricey. Plus, I'm at 41k miles, and they do that as part of the 45k miles anyway, so I was thinking I'd just wait.

I know that Americas Tire has a policy that they rotate and ballance tires at no charge. Their part of the Discount Tire Direct chain and they have locations in Texas and probably near you.

Even if it's not free, it probably won't be much. Usual rotation is about 5-7k miles.

For me , it's every other oil change or so.

4WD Models
=NGSU0032S02

Alignment Spec for Camber:

Camber
Degree minute (Decimal degree)
Minimum 0°06′(0.10°)
Nominal 0°36′(0.60°)
Maximum 1°06′(1.10°)
Left and right difference 45′(0.75°) or less



The tires should wear evenly across the tread.



If you rotate every 7-8K miles, it helps.

Good Luck!

Awesome, thanks Patrick! I'll have a look at that.

I know the dealer charges something like $70 or $80 for an alignment. I've actually never taken the X anywhere for servicing other than the dealer. I guess it's about time.

Could be camber or alignment.

An alignment won't correct camber, though.

"Play" in steering components can also give the appearance of wear on both sides of each tire.

Baby X:

Get alignment, suspension and steering checked out. Since you said "outside" (was worn), I bet you just need an alignment, though.

How often do you rotate your tires??? You aren't mistaking the normal tire wear from turning as a bigger problem. Also Inflate your stock tires to the Manufactures recomended tire preasure. there is a sticker in your glove box telling you what that is. I'll bet its 30psi at all 4 corners. dont try and be creative and use a different tire preasure. there are engineers that get paid a lot of money to figure these things out.

Alignment specs can include caster, camber, and king pin inclination, toe in/out, etc....its called alignment, which is short for proper alignment of all of the suspension/steering geometry components.

If you pay for an alignment, and they just do toe, you've been ripped off. (And good luck adjusting the rear live axle stuff)



Blue - Nissan's engineers only know about a stock X on Crappers/OEM rubber...if you get new tires, with different carrying capacities/load ratings...and you add stuff/weight when modding, etc...all bets are off...and you need to compensate for the changes...30 psi in one tire will not support the same weight as 30 psi in another....and if the weights change, even the same tire won't work the same if the air pressure is not proportionally adjusted.

Nissan's engineers also need to go as soft as possible on the ride, as most mall cruisers want a cushy ride in their new truck...and to have an understeer condition, so the soccer mom hauling little asses to practice going into the off ramp too hot won't spin/roll, but will instead push wide on the turn (easier to control for an unskilled driver)...front to rear tire pressure balance influences over/understeer...an aggressive/skilled driver will want neutral steering most of the time for better responsiveness, etc.

So - Thinking is better than trusting.

Not true.

Toe angle is all they're going to adjust for you on a standard alignment.

Caster/camber angles (on an X) are consequences of suspension height in conjunction with front end component sizes. That's why the lifted guys have new UCAs; to correct camber (and get some extra travel). Alignment shops aren't going to adjust t-bars to fix camber (and I don't want them to).

If the king pin angle has changed, It's time to trade in the X, because there is no adjustment to fix that!!

If the stock t-bars have sagged at all over time then a re-indexing and the follow up allignment would get the truck back into spec. If in fact that has occured.

Also, on an allignment there is adjustment with the eccentrics as well as the toe adjustment. That's why those bolts are there.

Why would you say that a tech would not make any adjustments necessary to get the truck into spec?

Oh god, I knew this was going to be complicated.

Yes I will agree with the arguement that once you modify the size tire you use, you will indead need to use a different tire preasure. But its my understanding that he has a BFG long trail. Although available in a larger size not the first choice for most off roaders with a lift added weight etc... SO common sense says stock tire, stock truck. Or close too it. But thats just an assumption.

Actually Jeff, that's not true.

As part of an alignment for the Xterra, as well as any other 4 wheel drive that has camber/caster/toe/ride height adjustments, we always align it using everything. What's the use of aligning the vehicle with toe if the camber or caster is out? There is none.

Ride height affects camber. Camber affects toe. Incorrect camber adjustment affects caster. Kingpin angle isn't really used any more. It's more of a diagnostic tool, similar to Steering Axis Inclination angles.

Anyone that states that they only do a 'Toe-n-go' type of alignment on a vehicle that has all the adjustments available, is a rip off. They need to adjust the entire vehicle, not just the toe-in.

Adjusting ride height isn't used to get camber into spec. It's used to get the vehicle level. Adjustments to camber often are performed due to sagging torsion bars. If the bars are properly readjusted back to get the vehicle level (or within specs for stockers) then the camber isn't usually needing to be messed with, as it goes back to where it was previous to sagging. Make sense? So the height adjustment just happens to bring it back in, only because the sagging suspension was the cause of the out-of-spec camber.

So do some research when getting alignments performed. Ask what kind of alignments they do, what adjustments are included with the alignment and what the warranty is for the alignment (will they correct an off center steering wheel within a reasonable amount of time, correct for a drift, etc.).

Not harshin' bro! Just a bit of knowledge for the readers out there. Hope you can come up Saturday (cutting the top off the X!).

****** posted by cyclemut ******

"Actually Jeff, that's not true.

As part of an alignment for the Xterra, as well as any other 4 wheel drive that has camber/caster/toe/ride height adjustments, we always align it using everything. What's the use of aligning the vehicle with toe if the camber or caster is out? There is none."
******

Of course there is. For people who have the T-bar crank (like me), the camber and caster will be out unless they lower my ride height back to stock. So adjusting the toe angle will minimize the effects of my foolishness (t-bar crank).

*****
"Ride height affects camber. Camber affects toe. Incorrect camber adjustment affects caster. Kingpin angle isn't really used any more. It's more of a diagnostic tool, similar to Steering Axis Inclination angles."
*****

How does Camber affect toe?

I can understand how conditions causing camber can also affect caster and toe, but my impression was this:

Toe in/out is primarily caused by the proper adjustment of tie rods. (Which is affected by ride height, but can be adjusted with tie rods)

Caster is the front-to-back angle of steering angles. It can affect wheel camber when turning. (Which is affected by ride height.) CANNOT be corrected with new UCA's.

Camber is whether or not the wheels are "plumb" when pointed forward. Even if camber is "correct" improper caster can affect camber when turning. (Which can be off due to sagging or cranked t-bars, but can be fixed with new UCA's)

*****
"Anyone that states that they only do a 'Toe-n-go' type of alignment on a vehicle that has all the adjustments available, is a rip off. They need to adjust the entire vehicle, not just the toe-in.

Adjusting ride height isn't used to get camber into spec. It's used to get the vehicle level. Adjustments to camber often are performed due to sagging torsion bars. If the bars are properly readjusted back to get the vehicle level (or within specs for stockers) then the camber isn't usually needing to be messed with, as it goes back to where it was previous to sagging. Make sense? So the height adjustment just happens to bring it back in, only because the sagging suspension was the cause of the out-of-spec camber."
*****

If camber can be adjusted (I wasn't aware it could be) then why are the SLR and Calmini UCA's engineered to correct the camber angles caused by a suspension lift?

If you know a way to affect the camber other than adjusting ride height, I'm dying to hear about it.

*****
"So do some research when getting alignments performed. Ask what kind of alignments they do, what adjustments are included with the alignment and what the warranty is for the alignment (will they correct an off center steering wheel within a reasonable amount of time, correct for a drift, etc.)."
*****

So you mean I can get camber an caster adjustments without affecting ride height? News to me. How, exactly do they do that?

I think we are agreeing. I just want to clarify. :biggrin:

*****
"Not harshin' bro! Just a bit of knowledge for the readers out there. Hope you can come up Saturday (cutting the top off the X!). "
*****

Shit!

I have a relative's graduation to go to in People's Republic of Boulder. I'd love to stop by with the sawzall if time permits! I'll go check our forums for times & locations!!!!

Thanks, Cyclemut. I was hoping you'd chime in.

I called Discount Tire who then referred me to Brake Specialists ("tell 'em we sent you, they'll give you a discount"). So Brake Specialists said they check the camber, castor and toe, don't need an appt (yay!), and charge $50. The dealership charges $80 and requires an appt.

I forgot to ask about a warranty on their work, though. Oh well. I'll give 'em a shot tomorrow and see what happens.

Thanks, everyone!

Jeff, Camber and Caster on an Xterra are adjusted by the eccentric washers and bolts on the upper control arm. Totally adjustable!

When you adjust the camber (unless you have absolutely 0º caster) the toe in will change due to the distance of the two steering points of the wheels having not changed at the same time. So when you adjust camber, you'll have to redo the toe.

In theory, you can adjust caster without adjusting toe, but it never works that way. You're always off a fuzz, leaving toe off a fuzz as well.

So, in short, using the exxentric washers and bolts in the upper control arm are useable without affecting ride height, no problem.