Unless they’re drum brakes. You’re really accustomed to Volvos, aren’t you? 
I disagree. Some RWD and AWD models do not have what I would call significant difference in the amount of treadwear between front and back.
It also works to just drive in reverse half the time.
Ah, but which half?
:smack:
Drums do produce dust, they just keep it inside.
Rick said:
That is not a helpful answer. What about a tire makes it best to only rotate it in one direction? The tread pattern? The wheel it is mounted to? The internal structure? How does one know if he has tires that are designed to only be rotated in one direction? Colored stripe? Big letters on the side? Crayon inside the tire so you have to take it off the wheel? Restating the question as the answer does not make things clear.
From the Tirerack site:
On my car, there are large arrows on the sidewall that indicate the direction of rotation.
It’s a fine answer, though brief. It is because of the tread pattern. There’s at least a directional arrow on the side of the tire usually accompanied by words to that effect. Usually it is on expensive, softer compound high performace tires. The folks paying the premium for them are very likely to know they are directional and to rotate accordingly.
ETA::smack: Pork Rind beat me to it.
Tires have several alphanumeric codes imprinted on the sidewalls, and in my experience a given set of four may very well have four different codes.
I was just checking on this last weekend, curiously, on our Honda Odyssey which still has the factory-installed Michelin Energy tires. Among the gobbledygook is an easy-to-find six-digit number (who knows what it means); that number, as it happens, is different on each tire in my van’s set.
I’ve tried this on several sets of tires - just what codes are there seems to vary by manufacturer, and you don’t always get four distinct ones. If you do, though, you can always use that to confirm tire placement.
The owner’s manual of this van, BTW, recommends the following rotation pattern: front wheels directly back; rear wheels diagonally. Over a four-rotation period, each tire will do a stint at each position. It cautions to instead just go straight front-to-back if you have directional tires, which we currently do not.
Directional tyres are more the norm around here becuase of our tropical downpours - the extra water pumping ability is very important. I have directional tyres on my car which is basically the equivalent of a Corolla.
My car is front wheel drive, and the difference in wear front to rear is VERY noticable - even over 25-30k kilometres.
Rear wheel drive it won’t be so noticeable but will still make a difference.
If you are happy to change two tyres at a time - don’t worry so much about rotating, if you want to change a full set of four each time - rotate.
FWIW - I get one fre rotation at 10,000 km, I will often rotate again myself around 30k, and then the tyres are ready to be changed at about 50k (although my current tyres have done 65,000)
Ouch! Tire rotation is recommended every 5-10K miles (8-16K km), and the wear differential is noticeable even at those intervals.
It’s not just about how many are replaced at a time. There’s a safety issue. Steering and suspension systems are designed with the expectation of relatively even treadwear front and back. Forgoing rotation results in significant difference in said treadwear, with a corresponding difference in traction. Under certain conditions, that can lead to tires on one axle losing their grip prematurely with possibly disastrous results.
Are there really that many mechanics who are so crooked or are so lazy-assed that they would not bother to perform a simple tire rotation?
I don’t wish to sound naïve, but you’ve got the car on the lift, you’re using one of them high tech pneumatic tire nut removers (the one that makes the nifty high pitched squeal) and we’re talking a job that shouldn’t’ take but fifteen minutes, eh?
Now unless you’re employing Goober who is doing the tire rotation the old-fashioned way- with a tire jack and some well placed cinder blocks, I can see how the temptation to pull a fast one might be too great to resist.
Funny thing is, you could probably trust Goober to do it moreso then some garage mechanics.
Note the question, What. Not Why, or how come, or what is the advantage, or how do they work, or how are they marked, but a simple what.
Asked and answered.
Sorry but I gave a perfectly cromulant answer to the question your wrote. If you wanted a entire long post about unidirectional tires you could have asked “tell me more about directional tires, I have never heard of them.” Or some such question and you would have got a more complete answer.
If you want to know how a clock works, don’t ask what time it is.
People confuse tread depth and road holding ability. The two are irrelevant. What affects tire grip is the number of heat cycles and the max temperatures they have reached in their lifespan. So although the tread depth on the front tires might be smaller, the grip characteristics will be the same with the rear ones.
I’d say they’re both relevant - I think your point is that they are independent.
Won’t water on the road affect this?
I am absolutely going to need a cite for that. I have been kicking around the car business for many many years and I have never heard this.
Here’s a good article on heat cycles, max temps, etc. I see these considerations as critically important in short stint racing but they’re the product of conditions rarely forced upon your average passenger tire, leaving tread depth as a more common determinant.
While tread depth is not the only factor in traction, it is certainly not irrelevant.
From Consumer Reports: “Our tests show that tread can give up a significant amount of grip when it’s still at the halfway point…Worn tires—especially bald ones—can be deadly on wet roads, where the grooves aren’t deep enough to channel water out from beneath the tread.”
From safetires.org: " Worn tire tread can cause hydroplaning, a problem that can begin at about 5/32” of tread remaining."
From the National Highway Traffic Safety Administration: “The tire tread provides the gripping action and traction that prevent your vehicle from slipping or sliding, especially when the road is wet or icy.”
From tirereview.com, reporting on tests conducted by The Tire Rack comparing tires with 4/32" remaining tread to those with 2/32": “Not only were braking distances significantly reduced, overall grip noticeably improved.”
For more, Google on tire tread depth safety.
Man, how can they screw up something so simple.
I watched a guy rotating my tires and he did one side at a time. Took the front left off and rolled it towards the back of the car. Took the left rear off and rolled it towards the front of the car. Then put them back on and do the other side the same way.