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Discussion Starter · #1 ·
Recently purchased a set of Falken 245/45R18XL 100W Ziex ZE-612 Plus tires as my OEM's had developed sidewall cracks after 8 Arizona summers and ~37k miles.

I always kept the OEM's at 29psi per Pontiac specs but Discount said to run these at 35. Ride is a lot more harsh & bumpy now, and I'm wondering if these can be dropped to 29 without overheating issues, if anyone knows.

TIA!
 

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I run Vogue tyre at 29psi.
The R/L is 29psi spes.
Tyre states 35psi max.
4 years later they run great @29psi.
LLLFLY
 

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when they put the new tires on the 06, it was rough as hell. I could run over a penny and tell you if it was heads or tails. then I checked the pressure and they had 40psi in them. I brought them down to 32 and it's perfect. sure, by all means, you can run 29. the rating of 35 is probably the max.
 

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No. You can't (necessarily) run them at 29psi. Well you can, but you risk bad wear across the width of the treads. Running lower pressures than optimum causes the outside edges to have more pressure on the road than the middle of the tread, causing excessive edge wear and reduced life. Inversely, too high a pressure wears the middle more than the edges.

Now whether 35 psi is correct or too high, I don't know for your new tires. But don't go by the factory recommendation for the factory tires.

The best way is to use a tire thermometer and test the temps across the tire after spirited driving at a range of different pressures. When the temps at the outside edges match that at the middle, you're good.

Other than that, a good estimate can be found using the formula here: At what pressure do I run my replacement tires at - A formula
 

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Bring it down to about 30 and you'll be fine

Discount said to run these at 35. Ride is a lot more harsh & bumpy now, and I'm wondering if these can be dropped to 29 without overheating issues, if anyone knows.
Do you think the tire dealer knows more about these cars than the manufacturer?

For everyday driving go with what's on the doorjamb specs.

For spirited driving go up to 32 max.
 

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Do you think the tire dealer knows more about these cars than the manufacturer?
Yes. The (car) manufacturer knows only about the tires put on at the factory.

For everyday driving go with what's on the doorjamb specs.

For spirited driving go up to 32 max.
Again, the doorjamb specs are for the factory OEM tires. Different tire brands and models (even in the same sizes) are constructed differently. Different load ratings, sidewall stiffness, tread, bead and belt construction etc,etc. All of which can correspond to different optimum pressures. See my post above yours.
 

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29psi and they run like new 4years later.
The Vogue tyre is a high end tyre also.
Luxury from the ground up.
LLLFLY
 

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Discussion Starter · #8 ·
Thanks for the replies, folks.

Replacement OEM Goodyears weren't available at the time (went in for 'free' rotate & balance, came out with 4 new tires - that'll be $700 please ;-) ); the Falkens were less expensive in any event.

I'll take a look at the shocks/suspension, then - sure is bouncing more and I can feel every pebble. Taking freeway onramp at 45-50mph it gets squirrely going over diagonal junctions with rear wanting to jump to outside. Much more pronounced than with the OEM tires.
 

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Discussion Starter · #9 ·
As it happens, need to replace all 4 struts, gonna happen next week. Going with the stock/OEM struts. Then I'll see how much difference the pressure makes. My mechanic says to go with the door post rec regardless of tire manufacturer as long as it's same size. We'll see.

Thanks again for replies.
Daiwa
 

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Discussion Starter · #10 ·
New struts made a big difference, as expected. No longer feeling every pebble or doing the crunchy hippety-hoppety over speed bumps.

Will run @ 29psi for a while, then try them back @ 35.

Thanks again.
 
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