Cue the angry mobs! Let the forum “experts” converge!!!!
Let’s discuss directional tires…specifically, running them…. backwards.
If you ask this question on a car forum (remember forums?), you may hear from a bunch of “Experts” touting their expert knowledge that if a directional tire is run in reverse… it will surely kill you.
I even read some anecdotes about car crashes that “happened because their mechanic put the tires on backwards!” (not because they were driving poorly, or going too fast in bad conditions)
Like drilled brake rotors, there are a surprising amount of people spewing “facts” and anecdotes with no information to back their claims. It is hard to see anyone has done any actual testing, Tire rack had done some testing and had an article. Unfortunately, they removed it from their site a couple years ago... so my own story here isn’t backed up by facts as much as a lot of experience and murky research… so trust me, or not.
Tire Rack’s testing was done on an autocross size course, with speeds around 40-55mph. To sum it up: in dry conditions, their testing showed running typical directional tires backwards did NOT make a difference. In wet conditions, at those speeds, it still did NOT make a difference. However, they did note that as speeds increased to highway and above they expected (but did not test) a difference on the wet surfaces.
This surprised me! I figured it was fine in the dry, but was very surprised that it was still generally okay to do in the wet. A larger assumption here is that this is tread-pattern dependent, with the functional importance of direction varying on the design.
Beyond a sparse few articles online it is hard to find official testing done on this (Even the tire rack article mentioned earlier was found on google, not from navigating their site). I’m not a lawyer, but my assumption is that if someone had an incident, their first thought would be to blame “that website” for suggesting to run a tire “against manufacturer recommendations”… Whether or not the tire was actually at fault. So, take my advice at your own risk, of course.
Who cares? Why is this relevant?
There’s no performance advantage to running directional tires “The wrong way” but as they wear, you can extend their life quite a bit by rotating them to different corners of the car. While you have the option of swapping tires front to back, often you’ll end up with a particular side that wears more. For example, at NJ Motorsports Park I see much more wear on my left side tires. If I had directional tires, I would blow through left tires much quicker than rights. If I occasionally ran my tires on the opposite sides (with the tread pattern in reverse) on dry days, it could help keep the wear more even.
So, if your directional tires are wearing more on one side of the car than the other, flip them on some dry days to even out the wear. If you’re brave, flip them on a wet day (and email me your results… if you survive)
Need some more tire-saving strategies? Check our this post: 7 Tips for getting the most out of your Trackday tires: Post 35
To sum it up:
Will the tire be damaged running it in the opposite direction? NO. No tread separation, no damage to the inner carcass of the tire, nothing. No problem.
Would I recommend running directional tires in reverse in wet conditions? Not on purpose. I’m sure at track speeds there is some minor but measurable disadvantage. Specific tread patterns may see more or less of a change. On the street it should be fine, but on track when 1/10th of a second can be the difference between 1st and 4th, we try to avoid even the slightest disadvantage.
Would I recommend running directional tires in reverse in DRY conditions to help even out tire wear? YES.
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