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I had a nail puncture on an AWD Subaru I inherited recently (left rear). Being unable to match the OEM Futura tire, I replaced both rear tires (with Dunlops) so they would be a matched set side-to-side. Last weekend, while driving in a light rain, I took an off ramp at normal speed and started hydroplaning, doing a full 360 before coming to a stop. Fortunately traffic was light and there were no resulting damages or injuries involved. The next morning I replaced all four tires with a new set of Michelins.
Did I, as I suspect, create an imbalance in the AWD system by having two different types of tires front and rear on the car?
I only had the Dunlops on a few weeks and the car was lightly used on dry roads during that time. First time I ran into this situation. Lesson learned!
i will never again use Dunlops. I've had three sets over 20 years, including the set on one of my current vehicles (on it when we bought the car). Worse tires I've ever owned. Not much wet weather traction, very noisy at highway speed (which is getting worse with age), wear characteristics appear very sensitive to slight air pressure variations.
Last Subaru I had recommended less than 1/4 inch variation in circumference when installing tires. That was one car that always got 4 new tires, even if it only needed one. Subaru must know what they are doing, it was the best AWD vehicle I've ever owned when we ventured into snow.
I'm going to do a little speculating here because you didn't give a specific model to ID the type of AWD system being used.
Most often, manufacturers spec to replace all 4 tires with the SAME brand and type at a time? Why? Tire diameters.
You can buy a 205/55/16 from two different manufactuers, and find they are slightly different diameters. This is why the same brand/type tire needs to be used. Secondly, some AWD systems do lock the center diff. This becomes an issue when the vehicle enters a turn.
Disregard the text on this photo and focus on the arcs the tire makes during a turn
If you notice, the tires all travel different distances through a turn. This is important to understand now because on an AWD setup, with a center diff that locks, the drivetrain could attempt to slow or speed up one of the wheels due to a difference in tire diameter (due to wear or brand differences) and that tugging/pushing action could cause a wheel to lose traction in a turn. Add in worn tires, and you have a recipe for hydroplaning that could be the cause of what you experienced.
There are always exceptions to the rule though depending on how the particular AWD system works. Most use open differentials, so if you replaced ONE tire, and left the other 3 alone, the open diff could "absorb" the different rotational speeds of two different diameters on the same axle. The big no-no comes when you replace two tires on the same axle that are a different diameter (slightly) from the other two. Enter a turn, center diff is gripping pretty good...and you have a tugging match between the wheels.
Ever toss a truck in 4WD on dry pavement and try to make a tight turn? Tires will squeal in protest as they fight each other due to being restricted by the amount they can spin due to the drivetrain
Yes, you get a bad flat and have to replace all 4 tires. Otherwise your AWD system and transmission are toast. #love
If the other 3 still have good tread far more sensible to just get one new tire but have it shaved down to matching tread depth.
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