How important is it to have directional tires going the right direction?

[94touring]

Opinions? 

[MPlayle]

The tread patterns on directional tires are set up to provide their grip and water dispersion when traveling in the proper direction.  The water dispersion will be especially bad (potentially far more prone to hydroplaning) when used in the wrong direction.  The tread wear duration may also be compromised, but I doubt that it would be significant.  There might be slightly more wear on the tread block edges and more road/tire noise.

The biggest concern is the decrease in wet road handling.  If intended for only short emergency purposes, it should not be a problem. 

[94touring]

Thats kinda what I was thinking too.  I replaced and rotated some tires on the bini and now I have one rotating the wrong way.  However living in Arizona doesn't provide much worry for hydroplaning.  It has rained twice in the past three months, and both times for about ten minutes. 

[MPlayle]

What rotation procedure did you use?  With modern radial tires, you should be only doing a "front-to-rear" rotation, not the old "cross-over" rotation.

[94touring]

Originally I had replaced a right rear last summer with a different tire, cause I'm not a fan of run flats.  Then a couple weeks ago I had a front left sidewall start to bulge on one of the original run flats.  So not putting much thought into it I took the newest right rear and moved it to the front left, mainly because the negative camber in the rear makes them wear poorly.  I then put the new tire on the front right to match those brands and took a good run flat from the front right and moved it back to the right rear.  Musical tires.  The fronts are the new tires, the rears are the old tires.  Had I been thinking I would have moved the right rear to the front right and told the guy the new tire was going on the front left.  The existing run flats will be due for replacement by the end of the year if I had to guess, so I can resolved the one tire rotating the wrong direction then. 

[MPlayle]

Makes sense now.  Just continue to watch them for abnormal wear.

[azbornmini]

Here's a good article on this subject.

http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=188

[94touring]

Dang so not that big of a deal at all.  Only 1/100th difference in time mounted wrong in wet conditions.