Whenever you own/drive a performance oriented vehicle with staggard wheels/tires, running a lot of negative rear camber and sometimes a lot of front caster (BMW/MB) you can expect about 1/2 the advertised wear on the tires, tire maintenance is the key to tire wear, proper rotations about every 5,000 miles which with your type of vehicle you can not do that and non aggressive camber/caster angles that accelerate tire wear, and again you can not do…
As the old saying goes, If ya want to play, you got to pay…
I’m guessing that the Lexus IS has more than normal negative camber. That is getting to be common in high performance cars. If the camber is not adjustable, you can get a camber kit that makes it adjustable, then dial in less camber. Cornering will be reduced but the tires will last longer.
I see this very complaint regularly on EuroLux and some Asian performance sedans. The suspensions are purposely designed with more positive caster and negative camber to enhance the driving experience by providing better handling and feel during aggressive cornering and high speed maneuvers. This causes more outer edge tire wear when the car is driving in conditions that involve lots of low speed tight turning, like most city driving.
Yes there are kits that can be installed to bring the alignment angles closer to a neutral position. But if you want your Mercedes or Lexus to drive like a Buick, why did you buy it in the first place?
Yes it is. Cars that have a lot of positive caster will exhibit a significant amount of camber roll on tight radius turns, like making a right turn on a city street or pulling into a parking spot. The outer wheel tucks under and really wears the tire shoulder. Not an issue in Autobahn driving but when driven like the majority of cars in an urban setting, it will eat up tires like crazy.
Yes, my '65 Olds 98 and '61 Cadillac had that one-finger steering. Also back in those days there were different alignment specs depending on whether the car had power or manual steering. Negative caster was needed to allow you to park the car without pulling a muscle.
So every mechanic I spoke to, and all the documentation I read online about alignment angles is wrong when they told me that caster was not a wear angle?
I’d rather a car that is a bear in a parking lot but had some feel to the steering.
@asemaster, are you answering this late at night when you are half asleep? Negative camber causes the inner edges of the tire to wear, not the outer edges. Most of the driving is in a straight line, unless you drive the “Tail of the Dragon” everyday. So most of the weight of the vehicles is riding on the inside edges.
Caster only affects the suspension in turns. The only straight line effect is that positive caster make the steering harder so the vehicle tends to be more stable. In a turn, it should theoretically compensate for tire roll under, but watching slow motion videos of vehicles, even high performance vehicles, doing slaloms it doesn’t seem to be working. I suspect that is because with unequal length control arms where the control arm bushings are spaced farther apart vertically than the ball joints is why that doesn’t work as I would expect it to.
Not wrong. Just incomplete. You’re talking about camber and caster when the car is sitting on the alignment rack. What happens when you drive it and make a turn? And remember, we’re not talking about a typical Subaru or Chevy. We’re talking about performance sedans.
Nope, wide awake.
And during turns is when tire wear occurs. Tires don’t wear out driving leisurely on the boulevard at 40mph.
Of course the geometry changes depending on what kind and how many control arms there are. But let’s take a generic Eurolux car, with camber at -1* and caster at +9*. That much caster will drive the outboard wheel towards positive camber at all but the slightest turns. So when making a right turn from one street to another, or coming out of a driveway, that LF wheel is probably at +3-4* camber. Combine that with the weight of the car causing that wheel to tuck under and the acceleration of trying to avoid that oncoming bus, you’re going to wear the outer edges. Then straighten out the wheel and cruise, and the negative camber is back to wearing the inner edges.
The cars we’re talking about were designed to do just that. Not drop the kids off at soccer and stop at the grocery.
Caster will never wear a tire while going in a straight line, only in turns, the greater the +caster, the tighter the turning as well as the amount (more) of turning, the faster the wear… Look at about any sedan (BMW/MB) with staggered tires with the front tires left in the turn position and you will notice the tires are almost laying over, like parking a motor cycle on the kickstand with the wheel turned, the tire is both leaning and turned… it is riding on the edge of the tire… Big trucks, (19.5 and 22.5’s) run a negative caster to help with turning at slow speeds, but you don’t see edge wear very often… Your standard caster on your Accord and my Vibe/Matrix will not show major edge wear on the fronts (both sides) unless you are an Uber/Lift/Taxi driver in the city making tons of sharp turns, then you will see major tire wear, Taxi’s get about 1/2 the advertised tread life out of any tire they run in the Nashville area, even with proper rotations and alignments… just the nature of the beast…
But YES, asemaster is 100% correct about camber/caster wear…
Also a note, a lot of, or most, asymmetrical tires have a harder inner tread to help combat the negative rear camber wear…
Well, in 20 years of researching and learning about the primary alignment angles, he’s the first one I’ve known to state that caster is a (significant) wear angle.
Toe and camber angles are static - that is those angles hold, for the most part, when the car is going straight. The only places where caster may become a significant wear angle is on a road like the Halsema Highway between Baguio and Sagada-Bontoc in the Philippines.
Ask me how I know about that road!
As for wheel alignment on large trucks, here is a link to Mack Trucks alignments, which includes 4 degrees, plus/minus 1 degrees, positive Caster:
Well since you put it that way, the biggest difference between he and I vs you is, you have read about it for 20 years, we have been doing it for over 30 years and have seen it with our on eyes…
And I learned about caster wear 35 years ago when I got my associate degree in Automotive Technology…
And to be blunt, I will trust a Dr that does something every day and has 1st hand experience over a politician that has only read about it… (NOT meant to be a political statement for either side, just an example) and to make a point…
Another words, I don’t care how many years the Napa guy has been mixing paint, that doesn’t mean he knows how to paint a car…
Yeah, I haven’t messed with big trucks since before you started reading about them, and with advancements in the world stuff has changed somewhat, but the older dump trucks, not highway runners like big rigs, ran a neg caster to a zero caster…
Don’t take my word for it, go out and look at the BMW’s and MB’s cars with staggard wheels that have the wheels turned almost to lock, the are leaning over bad, almost like a ball joint broke or something, but it is just the angle… Again, take a motorcycle with some rake to it and lean the bike over on the kickstand and turn the bars, the wheel is leaning , same thing with a BMW/MB, and it is THAT caster angle that wears a tire… AGAIN, you will not see it as much if any on your Accord…
Not picking , just trying to explain the truth a little better so maybe you will understand it better…
You’re oversimplifying the alignment angles. Let me try to clarify. Caster in itself does not cause any kind of tire wear. But, in cars that specify a high amount of caster, the camber angle changes drastically as soon as the steering wheel is moved from the neutral position. So much so that a car that has negative camber straight ahead will exhibit wildly positive caster (and very accelerated tire wear) when turning. A typical family sedan may have a caster angle of +3*. I’m talking about cars with +9* or +10*.
This combination of angles results in very snappy and responsive steering, great road feel, and excellent handling during aggressive maneuvers. The price to pay for these things is that the outer edges of your tires may wear to the cords in 20,000 miles. And the wear is most noticeable on cars that are driven primarily in urban settings, such as turning from one street to another and in and out of parking lots all day.
Now none of this affects the typical Subaru, Honda, or Chevy driver. But to the people out there who say there’s a defect in the car because their sport sedan wears out tires quickly, I say the car is operating as designed. And that’s where the discussion started, I believe.