Sumitomo HTR Z III spent after 7k miles
 

I'm at the wear bars in the rear with 6,640 miles in a season and a half.
Anyone else cook them this quickly with just street driving?

I guess I should get my alignment checked before replacing them.

I got tons of miles on mine and the previous owner I think got 30,000+ miles on his fronts anyway, backs maybe 15,000-20,000.

Are your tires wearing evenly and down to the wear bars or just on one side or the other?

Are you on 17's?

I'm at rear replacement time, 22000 miles.
The negative camber in the rear causes them to wear at the insides earlier than outside but evenly.
I do have something going on one side that chewed the inside a bit more than the other side. I suspect there is a rear suspension overhaul for my Boxster in the near future

Last set I took 25k+ miles (A bit to far)

How are they wearing, where are they wearing, one tire to the other? Do they look like they are NOT going straight down the road?

Yes, 17's. Just the rears (the fronts look good), and both rears are wearing the same, but it is more toward the inside.

A person who really really knows Porsches and how to set them up for the track also knows what effect each portion of the alignment has on wear and handling. Made all the difference in the world for my Boxster when he set mine up for max tire longevity still within the Porsche defined specs. I only replaced the tires because of age, not wear and the wear was dead even across the tread.

Thanks for the post, I was looking at these tires on tire rack. They got good reviews. For the price you can't beat them but if they only last 7000 miles I'll have to rethink purchasing these tires.

The OP definitely has something else going on. They should last 2-3 times that long.

Great Mileage
 

I'm on my third set of HTRZ III's. Always get great mileage out of them.

Those are UTQG 300 tires which means they should last about 20K miles. See https://www.tirerack.com/tires/tiretech/techpage.jsp?techid=48&

As noted you got something going on with alignment. If you have more ware on the inside then you have too much negative camber for your regular driving. You probably also have toe a bit off. Sloppy parts can be a culprit but when was the last 4 wheel alignment by someone other than Happy Boys or Fire Rock?

Couldn't tell you! It was before I owned it. Its top of my list now.

I ran some Sumis on the track when I was in green and they handled pretty well with reasonable wear (I was in green!). More recently my friend, in a more advanced group chunked them after 2 days! An excellent street tire at a reasonable price.

I ran mine for my first two events, and at my most recent event I ran a session in them after changing to them for the drive home. They were a little slidy, in sweepers in 3rd I could break the rears loose, I also had them aired too low, I had forgotten they have a softer sidewall compared to more dedicated track tires.

Got my alignment checked tonight... dead on.

So the increased wear is being caused by something else. I was planning on doing a suspension refresh in the spring, so maybe I'll just park her for the winter a couple weeks early and not worry about it.

Bonus pic on the rack:
https://i.imgur.com/iA4CzdZ.jpg

Agreed.
I've got 22k on mine and, while I wouldn't push them real hard into turns on smooth, wet asphalt, the tread's otherwise still good for a few more miles. They've been to the track once during that time also.

I was running 35psi all around. Was this too low for the rears?

Just checked the fuel door, factory says 36psi...

The fuel door settings will cause the rears to wear more quickly in the center. To get even wear you have to lower the rear pressures much closer to the front ones, 32 PSI is a good place to start.

The lower rear pressures will give the car more neutral steering. The factory recommendation causes understeer, which is safer for incompetent drivers than neutral steering.

There are two ways to figure ideal tire pressures, One is to monitor wear, which is slow and cumbersome. The other is to measure tire temperatures at the edges and center of the tires immediately after driving enough to bring the tires up to temperature. They should be as even as possible across the tire. If they are hotter in the center you need to lower pressure, if they are cooler in the center you need to raise them.

As anyone who tracks or autocrosses cars will know, the best tire pressure varies between tire brands and models. The numbers on the fuel door are "best" recommendations from the manufacturer, intended to minimize lawsuits from idiots.

All of the above assumes that you have the right alignment!

Whats the best way to get that temp value ?. Can I use one of those no contact IR temp meters or is there a better way . I have just put on a set of Michelin PS4 tires and I want them to last . By the way when I looked at the date stamp on the front tires it was 03 , nearly 15 years old !!

I use an IR thermometer. A more accurate way is to use a thermometer with a needle probe that you stick into the tread. Search for tire pyrometer on eBay.

Froggo - How did the PS4's work out for you? I have a 2004 Boxster S with Yokohama's that are in need of replacement and looking to put on a set of PS4's -- Thanks - Rick

Rick , the PS4s are good ,I can't see any real wear yet but I've only done a few thousand kms so far the Boxster is not my daily driver . Down here they are not the cheapest of tyres ( approx $NZ1800 set ) but they enjoy good reviews . The tyres that these replaced were Hankook Evo II which are now discontinued .
I think the PS4s were a good choice .
Peter