fly_s2k

iTrader: (1)

I am trying to get some feedback on tire pressures for those that are running 20" wheels on the LS and the corresponding tire wear patterns they have observed. I've already gone through the tire/wheel thread but those only list their preferred tire pressures and not so much on longevity. I used the feedback in that thread to set my baseline pressures from the beginning (38-40PSI).

My Setup:
Front
20 x 8.5" Wheels
Hankook Ventus V12 Evo2 245/40/20
Hot tire pressure: 38-40 PSI
Tire wear patterns: Excellent/Even across tread width
Mileage: 22K miles - still about 3/32 from wear bars (tires dismounted and flipped at 12K miles)

Rear (Problem child)
20 x 10.5"
Hankook Ventus V12 Evo2 275/35/20
Hot tire pressure: 38 PSI (from 0-12K miles) lowered to 34-33 PSI (from 12K-22K miles) when center wear was noticed and thought to have been over-inflation
Tire wear patterns: Wearing predominantly in the center
Mileage: @12K miles - noticeable center tread wear observed in respect to shoulder, tires dismounted and flipped then lowered hot operating pressure to 33-34PSI; @22K miles - center tread is done, shoulder tread still good.

Alignment was checked annually and has never really been way out of spec to contribute to rear tire wear.

In a nut shell, I am trying to understand if these tires were truly over-inflated from 0-12K miles or under-inflated the whole time (based on what others are running in the tire/wheel thread, 40-42PSI).

Internet wisdom has pointed to the tire being initially over-inflated judging by the predominant center wear, although I've also read that under-inflation of "performance tires" can also show center wear. Based on my personal account, lowering the tire pressure at 12K miles didn't seem to slow down the rate of center wear in relation to the shoulder either so perhaps my understanding is out of sorts. Thus I'm seeking for some feedback from other members here....

1WILLY1

iTrader: (9)

I run my 22's at 50 psi hot, (approx 44-45 cold) The tires are going to wear either way I wouldnt worry too much about it

Chuckinnj

The better handling "soft compound" tires wear quickly..... I have been very unhappy with tire wear on ALL my cars tires despite proper inflation, rotation and alignment BUT happy with the handling characteristics. I would recommend dropping the rear tire pressure 5 psi and keep an eye on the wear with a tire tread gauge every 2000 miles to see how they are wearing THEN adjust the psi accordingly either up or down. You can also dive in a little deeper with a tire pyrometer to scan the tread temps across the tire after driving on different road conditions.
Basically ALL tires wear and you can "go crazy" adjusting tire pressures to compensate for wear and car handling.

When I get a set of new tires I get them filled with nitrogen (flame suit is now on) and get a 4 wheel alignment done at a shop with a "modern" alignment rack (EG: Hunter)
Drive it and check tire pressures every 1000 miles or before/after long trips.
Rotate the tires every 7000 miles and keep an eye on them for wear patterns.
THEN complain about how bad ALL these "pricey high end" tires wear despite proper tire wear maintenance.

sktn77a

iTrader: (2)

If your tires are wearing in the center, then they are over-inflated for your application. Sounds like you need to lower the rear pressure even more. Unfortunately, going to extreme wheel/tire combinations can have unpredictable handling and wear characteristics. With 40psi front and 30psi rear, you may experience some odd handling/feel.

fly_s2k

iTrader: (1)

Thank you for all the feedback. Once I get the new set of rears on, I'll try dropping the pressure even more and monitor at 1-2K intervals to assess. I have access to a pyrometer as well, so perhaps that may provide me with more data.