Tires: tires difference between 89h and 91 h -mixing same, alignment problem, cold climate

Question
Hello

I am in a quandary. I was told by my mechanic I needed my front end aligned [he does not do that] and I needed 2 front tires [he does not sell tires].

my tires at present / 2000 accord ex honda spec p195/65R1589h.  They are michelins--what "variety" I do not know. some may be original some are not.

I was thinking about getting two at costco but they said they only have 91h not 89h.  Will it matter mixing them w/ the 89h if they are kept together--ie either front or back?

Should I rotate the tires putting the new ones on the rear? my trunk does have a lot of stuff in it and will likely continue to.

is michelin's harmony a good tire? costco charges $128 + $15 to install.  Are the additional warranties worth getting? they are just under $20--don't know if costco sells them.

do i buy the tires and then align---or align and then buy the tires?

and does one automatically toss the tires out after they reach a certain age?

thank you and with MUCH MUCH MUCH appreciation
msd

Answer
Meryl,

So long as the tire size is the same, you'll be good to go.  The difference in Load Index is caused by differences in the way different countries rate tires and - for practical purposes is not a difference.

New tires should go on the rear.

And if you have an alignment problem, get it done.  It doesn't matter if it is done before or after buying the tires, except to say, don't wait too long - we're talking weeks, not months.

Recent bulletins from the tire industry indicate that tires degrade simply due to time.  The age of a tire is important even if the tire is unused.  There some disagreement over how to best express this age limitation, but my take is:

If you live in a hot climate (AZ, CA, NV, TX, and FL# then the limit is six years.  If you live in a cold climate #MN, ND, WI, MT, etc), then the limit is 10 years.  States in between are  ..... ah ........ in between.

Here's how to tell how old the tires are:

First locate the letters "DOT" on the sidewall of the tire.  Nearby will be the DOT code.  DOT codes are 10 to 12 digits long.  BTW the digits can be numbers or letters.

The first 2 digits are a code for the manufacturing plant.  

The next 2 digits are a code for the tire size.  

The next 3 or 4 digits are a code for the type of tire.  

The last 3 or 4 digits are the date code.  The format is week/week/year/year or week/week/year.  These are always numbers.

Starting in the year 2000, the date coding used was 4 digits.  That means the largest number you should see for the year is 10.  Before 1999 the format was 3 digits.  1999 and 2000 are transition years, so you will find both 3 and 4 digits.

The date code only has to be on one side – and it is permissible for there to be a partial DOT code, so long as one side has the complete code.