Rear alignment on all wheel drive Subaru


#1

I have Subaru Impreza Outback Sport 2.2l engine. I’m getting new tires for it soon -General Altimax HP 205/60r15-



The tire place is including front alignment with mounting; should I get rear alignment as well? Does is make a diference that it’s all wheel drive? Also how important is speed rating on tires? Thankyou!

Is rear alignment necessary?


#2

The primary, if not the only, purpose for wheel alignment is to ensure uniform tire wear. Mis-alignment can also cause an annoying ‘pull’ in the steering, but that will be accompanied by uneven tire wear. Examine the tires you are removing. If they are uniformly worn, then no alignment is necessary.

I was a service tech and automotive technology instructor 25 years ago. Then I moved to a desk job. My observation is that alignments are sometimes carelessly done by marginally competent technicians. There is a nonzero chance that they will start with a well aligned car and give you back a poorly aligned car.

With regard to the importance of speed rating - speed rating is critically important to the vendor who could be held liable if they install tires with a speed rating too low for your car, and a tire fails for ANY reason.

From the drivers’ perspective, speed rating has little or no importance. You are not going to drive faster than 110 or 128 mph for extended periods on a hot day with a 2.2 liter engine. If you were to do so on a public road in the US, something else would surely kill you before tire failure did.

The argument that higher speed rated tires ‘perform’ better or are ‘designed to work with high performance suspensions’ is not supported by the evidence. Some lower speed rated tires handle beautifully, while some high speed rated tires handle poorly. And, let’s face it, an Outback is not a Porsche. When was the last time you really thought about how your tires were affecting your handling? As a driver, the only difference you are likely to see is that higher speed rated tires cost more, have shallower initial tread depth, and don’t last as long.


#3

Since tires are fairly costly I recommend getting a four wheel alignment. I have seen some folks ruin their tires in a short time without a proper alignment, so I think the money is well spent.

That said, it is important to use a good tech; whether the guy doing your alignment is one remains to be seen. I have my independent mechanic do all my suspension and alignment work, and I have plenty of confidence in their work.


#4

When it comes to wheel alignment, it does not really matter that this car is AWD, but it does matter that it has independent rear suspension, rather than a conventional solid rear axle. Because of the independent rear suspension, when an alignment is done, it needs to be done on all 4 wheels. If you want to get the maximum life out of these tires, you should have a 4 wheel alignment done as soon as possible after mounting the tires.

Where your AWD comes into play is with the necessity to regularly rotate your tires. The AWD system is very sensitive to differences in tire circumference, so failure to rotate your tires on a regular schedule can wind up destroying your expensive center differential.

Subaru specifies every 7,500 miles for tire rotation. If you choose to do it every 5k, that is fine also. Just be sure to use the same mileage interval each time that you rotate your tires