Is it normal for the outside edges of the front tires to be stairstepping
on the outer inch or two only?
By stairstepping, I mean that you can't see the wear all that much but if
you rub your hand over the tread in one direction, you can feel a lip on
each side swipe tread.
If you run your hand over in the other direction, you don't feel it. You
only feel it if you run your hand from back to front on the outside tread
of the two front tires.
If you do the same with the rear tires or on the inner edge of the front
tires, you don't feel any 'stairstepping".
The tires are about a year old and are wearing the front outside edges
What you feel is known as feathering, one side of the tread block wears
more than the other. If you looked at the end of the block it would
appear as a wedge.
It is commonly caused by improper toe settings and if on one edge only
by improper camber angle as well. BUT it can also be caused by using a
common tire on a vehicle that is driven aggressively. IE high speed
cornering. That places a lot of weight on the outer edge of the tire and
tries to force it to roll under. That will wear the outer edges rapidly.
Now if you had one spot that was "normal" then a wear spot then "normal"
going all the way around the tire that would be cupping. That is
normally a suspension wear problem.
That was a far better answer than I had expected so I appreciate your
expertise. The vehicle was aligned but probably about 2 years ago (while
the tires are about a year old).
The car is driven on a five mile hill every day with scores of hairpins but
it's NEVER driven fast. Those turns are made probably at 20 to 25 MPH (you
can't take the turns any faster and stay on your side of the road).
Could that steep (10% or so) continuously twisting 5-miles each way every
day have caused the "feathering" you explained my "stairstepping" to be?
If it is the alignment, do you concur that it's a combination of the front
camber (tilted out too high at the top) and toe (turned inward too much at
The tires are "feathered" only on the outside edge of the tread (last inch
or two) evenly on both tires, but only on the front.
Camber does not cause feathering. It does cause wear on one side.
The greatest cause of outside edge tyre wear is overenthusiastic cornering.
One point I should note. By all means have your alignment checked. One
thing that can cause feathering is a bent steering arm. Typically, a
bent steering arm will cause a change in toe. If the technician just
corrected the toe, he will have missed the real issue and the car will
now have incorrect *toe out on turns*. A *toe out on turns check* should
always be done at a wheel alignment as it will show up issues like bent
I think the advice so far is good in that it's either of these two:
1. Too much camber (top spread out) + too much toe (front spread in)
2. Hills with curves
If it's the alignment (camber plus toe) it can only be fixed with an
alignment. If it's the hills with curves, there's nothing to fix.
The fact that the rear tires have no obvious strange wear might be a clue
to help. Would the hills with curves also affect the rear?
Or do hills with curves only affect the front feathering?
I don't enthusiastically corner. Period. I drive slowly.
But I can't change the five miles each way that are hills with sharp curves
where most are hairpins and there is no stripe in the road since it's too
narrow for a center stripe.
I'm guessing the speeds are 20mps or so but the turns are extreme.
Would that only affect the front feathering leaving the rear unfeathered?
It's a rear drive 2WD basic SUV with a solid rear axle I am told.
Anything can happen at a pothole or curb but I seriously doubt anything
major is "bent" since I'm the only driver and it was thoroughly checked two
years ago when I bought it, including a full four wheel alignment.
My main question is how to determine if the front feathering is only due to
the 90 and 180 degree corners on a 10% grade (I'm told) I have to go
through at 20 mph every day (at least twenty of them each way).
Would that type of hilly curve NOT affect the rear tires at all?
Thank you for confirming why the rear tires could wear flat while the front
tires seem to wear, as others said, on the outside edge (feathering) due
perhaps to the excessive camber due to the tires "rolling" on the downhill
20mph steep 10% many curves.
My "problem" with doing another alignment is that one was done two years
ago due to tires being 'wasted' but in this case, I don't want to waste an
entire brand-new tire just to doublecheck that alignment.
I realize this is a philosophical issue but it seems to me to be a crime
that alignment costs are such that they waste one of the four things
they're designed to save. In the case of the 4Runner, they waste one of two
things they're trying to save (the front tires).
It's a philosophical issue though, because it's the same cost:benefit issue
you make when you decide to get a heart transplant or a back operation.
Assuming costs in my area are about $100 (on sale) for an alignment and
about $100 per tire (includes mounting), the philosophical issue is that
the alignment costs 1/2 of what you're trying to save.
Philosophically, is it a smart decision to definitely kill half of what
you're trying to save, just to measure to see if it needs to be saved?
I must not have made the philosophical argument clear if you say that, so
let me just outline a WORST CASE scenario (philosophically speaking).
1. Assume alignment is fine (for the worst-case scenario philosophically)
2. Assume front tires only are wearing on the outside edges (feathering)
How much does a brand new tire cost, mounted?
How much does an alignment check cost, on sale, where I live?
That's a philosophical tradeoff of 1 mounted tire to 1 alignment check.
The logic is thus:
A. If the alignment is obviously bad, then it will cause excess wear to
EVERY tire ever put on the front axle, so, of course, you have the
alignment fixed because of the obvious cost:benefit ratio.
B. However, if the alignment is actually ok, then it's not cost effective
to have the alignment checked since the best you will do is save partial
wear to the tires but at worst, you just threw away an entire brand new
tire ($100) just to have the alignment checked.
My point is that checking the alignment costs as much money as does a brand
new tire, so, where would you rather put your money IF the alignment is
On Sat, 8 Jul 2017 16:32:25 +0000 (UTC), Chaya Eve
The way you're looking at this, there's no point in doing anything.
Once the tires are feathered, there is nothing you can do - they are
essentially ruined. If they are not dangerously worn, and not noisy
enough yet to drive you nuts, then just forget about it. You can do an
alignment when you finally replace the tires.
At the same time, it would be nice to know that your front suspension
and steering parts are not dangerously worn, and that should be
checked in an alignment. But it's your car, your life, and your money,
so do whatever you want. You've gotten solid advice here, you just
have to make a decision.
I agree with you that the advice is "solid" here.
* It could be normal given the steep slow many curves, or,
* It could be both the camber and toe is too positive.
The only way to tell whether that's the case is to sink $100 into an
I don't think it's at the level of "dangerously worn" though but you seem
to think so (but on what evidence?).
On Sun, 9 Jul 2017 05:51:14 +0000 (UTC), Chaya Eve
No, I have no reason to think that. What I did say is that they are
ruined, and nothing can change that, even if they are still usable and
safe. If you rotate the tires, you'll just ruin the back tires, too.
The feathering itself does not make them dangerous, but they will
become noisy, if they aren't already.
On Sat, 8 Jul 2017 16:32:25 +0000 (UTC), Chaya Eve
You can have an alignment CHECKED - if no adjustment is required,
for a whole lot less than $100 if you get it to the right shop.
Also, you do not need a "4 wheel" alighnment. The toe in can be easily
checked, even without a fancy alignment machine, by anyone worthy to
call himself a mechanic. Less than half an hour's work either way if
no adjustment is required.
Either way, I'd pay to MAKE SURE rather than take a chance on having
to keep throwing tires at it.
That said - in YOUR SITUATION, the first thing I would do is check and
verify tire pressures, and AIR UP 5 PSI.
That's the HOLY GRAIL of services if it exists.
What would be perfect is a "free alignment check" and no charge if the
alignment doesn't need adjusting - but that may never happen for two
* Alignment is a range (it's not just a single number), and,
* Nobody offers that anyway (that I can find).
Second-best (and perfectly acceptable) is a $25 alignment check-only, just
like I go to diagnostic-only smog stations, where all they do is MEASURE
the front toe and front camber (which is all that I need).
I've been reading up on alignment where the Toyota only has front
camber/caster (which is one setting) and toe, so that's all I need are
those two things.
If I can find a shop who will do those two CHECKS for around $25 that would
make logical sense.
But to pay for an entire mounted tire just to save on a mounted tire seems
like throwing good money away logically as it was aligned two years ago
(and at that time, it needed it because the front left was wearing really
Now they're wearing evenly.
I googled how to check toe and LOTS of people seem to be using string.
All I need is to tie a string to the center point and then cut the ends off
on each side at the center of the tire tread in front and in back at the
midpoint of the wheel axle.
That's a cost of four strings!
I completely understand and agree that if EVERY tire was wearing unusually
fast (which is what happened two years ago to the left front tire), then a
$100 alignment makes perfect logical sense.
But to pay the cost of an entire 40,0000-mile tire just for a remote chance
of getting a thousand or two thousand miles out of the process seems like a
horrid cost:benefit ratio to me.
A $100 alignment is an entire $100 tire completely wasted (in terms of
opportunity cost) if the $100 alignment is not needed.
Here's what I definitely will do given the really sound advice.
* Since I never check PSI, I'll start using 40psi (35 is normal)
* Next time I'll get stiffer sidewalls (105S instead of 102S)
* I will rotate every change of seasons (I cross hatch with no spare)
* I will take the downhills slower (if I can but I'm always the slowest)
* I will look for a $25 toe/camber-caster only check around town
To me, if a $25 toe/camber-caster only check existed, it would be a no
brainer. But to definitely throw away a perfectly good $100 40K-mile tire
in opportunity cost just to possibly save a couple thousand miles of wear
on two tires seems not like an obvious cost:benefit logical decision of a
I would be very, very suspicious of anyone who did this. They likely have
some kid who knows how to put numbers into the machine doing the job, instead
of an alignment expert doing the work.
It's going to take the tech about half an hour to do the suspension check
over....going around pulling on things and hitting things with a mallet and
getting some sense of the general condition of the suspension. Then he is
going to spend ten or fifteen minutes talking with you about how you drive,
THEN he's going to start measuring the suspension. So figure an hour's time
for a full-priced technician just to look everything over.
What you MOST need is the guy pushing and prodding and hitting things with a
hammer to make sure everything on the suspension is stable. The actual
alignment on the machine is the easy part and the less important part.
You take it to the tire store, they put it on the machine, they measure it,
they put shims in so everything looks good on the machine and they declare
it aligned. But if you have anything loose and worn, it will be out of
alignment again by the time you get it out of the shop. Before putting it
on the machine you need to verify this isn't the case.
It's maintenance. Every 3,000 miles you change the oil, and you look over
all the hoses and belts and check the fluid levels just to make sure everything
is okay. You're not wasting time or money doing the check just because it
_is_ okay. You spend the time or money to make sure it stays that way. Every
once in a while you need to check the state of the suspension as well.
And yeah, finding someone who actually knows what they are doing and who
can do a careful alignment is rare, and it's worth supporting that person.
"C'est un Nagra. C'est suisse, et tres, tres precis."
This makes logical sense that the industry might not benefit from having a
$25 alignment check only.
In a way, one could argue that it's like having an appointment to the
doctor where they only checked your eyes for the need for glasses and
Again this is logical. An hour could easily be $100 shop rate.
I never disagreed that it's best to have the alignment checked.
I only pointed out the "opportunity cost" was an entire mounted tire.
Cost of alignment check = cost of 1 mounted tire
The logic is so inescapable that I was surprised people had trouble with
that math, since it's simple logical math that they teach you in school all
the time ("opportunity cost") although the "true cost" is what I need to
calculate, not just the upfront cost.
Yes. I know. I talk to them while they're aligning my vehicle and I ask
what they're doing. Sometimes they kick me out behind the yellow line but
other times they let me walk around with them.
This is a good point in that it's the standard cost of maintaining a car
just like rotating the tires and changing the oil is.
I just wish it didn't cost as much as the thing it's trying to save!
I think the price point is set too high - but you've made a point that it's
an hour and an hour costs what an hour costs. Period.
You don't do maintenance to save your tires. You do maintenance to save your
Maybe you have a tie rod going bad. Maybe you have a steering knuckle wearing
out. Probably not, but unless you check it, you don't know. And if you do
have a front end problem, the only symptom you may have is odd tire wear. So
you check it out.
You check the front end because the consequences of front end failure on a
twisty road are very, very bad and may well involve your head becoming
separated from the rest of your body as your vehicle rolls down the side of
Tire life? Who cares. Tires are cheap, passengers are expensive.
"C'est un Nagra. C'est suisse, et tres, tres precis."
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