I rotate my tires every 10k, and at 30k discovered the right rear tire tread looked like it was sliced and was worn down to Exposing the steel reinforcing threads. I assumed that I had driven over something. But I just looked and the right rear is starting the same dangerous cut. I will take it in ASAP, but does anyone have any thoughts on what is causing this.

 

Just 30,000 miles of wear.

 

In my experience, with the exception of some ultra-high performance machinery. OEM tire choice is a compromise with the accountants having the largest vote.

 

what you need to look for is any uneven treadwear. You didn't mention what year and if you have AWD etc and how often you have done an alignment. Most cars should get an alignment once a year or every 10K miles (I own a VW CC which are notorious for eating tires so that car gets aligned with each summer/winter tire changeover). Depending on the brand of tire, its not uncommon for replacing after 25-30K miles. Check the sidewall for the tire's wear rating number. Anything under 400 is a soft, fast wearing tire. Over 600 and its a rock hard hyper-miler...

 

Hunter Engineering (the alignment and wheel balancer equipment people) send me (my shop) sales brochures every couple of years touting their newest equipment - Their latest one had the headline on it in bold and italics -

Alignment has the highest profit margin of any auto service - How many are you doing today!

Imho people have been convinced they need alignments - And for shops, because it's very profitable, and a low skilled job (well not really if you want it correct) - so shops can put their cheapest employee on alignments - we call that gravy - easy work, you don't have to think, you bill your flat rate, you're not going to break anything or if you do it's expected - hey it was rusted! Cha-ching, more labor! For the shop it's the most profitable service and everybody thinks they need one! An easy sell!

For a cars alignment to be off - something has to wear or get bent and that is usually not going to happen exactly evenly on both sides. That means if there is something worn/bent the steering wheel will not be straight or pull, etc. - Now sure you can easily bend a rear stay on a 01-07 xvs60/70 and have it not change the steering much - but you will have extreme rear tie wear, worse on one side. (and hopefully someone notices, but maybe not if it's the oil change guy doing the alignment!)

 

funny thing about alignments - you may not realize you need one until you get one :-) I typically get a 4 point done at a local tire shop chain as part of a seasonal tire change over deal and always remind them I want the print out when they are done. The bigger shops all run modern computer based equiment same as a dealer so I trust they'll do it right - but you never know. That's a lot better than waiting for your tires to cup and get noisy. That said, not all makes and models are equally sensitive to alignment, particularly tall tire SUVs.

 

Yes, I bought 2 Hunter machines for my shop over the years - the latest was very modern, it had cute color pictures and everything - so simple the shop boy could do "alignments" (I didn't let him, other than his own car)

Tire cupping I always blamed on slightly imperfect wheel balance and/or small undampened movement in shocks (worn or air bubble)

And alignments still have the highest profit of any service (and are oversold)