Hey guys- so I'm running 33x12.5R18s on my stock 7.5" FX4 rims the Toyo M/T's are rated to a 8.5" rim. the recommended cold PSI is 65. now obviously that is for a properly fitted tire. I am running my tires at 50 PSI cold...is that still too much? what is a good convention to keep in mind with my tires? apprectiate all the help

Justin

 

That is way too much for daily driving. The max psi listed on the sidewall is for towing/hauling heavy loads. I would try around 40psi for daily driving. I wouldn't go any lower than 35psi.

 

Thanks Wandell- what are the consequences of running at 50? I would assume that they wouldnt wear faster at center since i'm not over-inflating? I'm headed down to Cheyenne, Wy for a wedding- drive's about 1k each direction. for all intensive purposes of maximizing my fuel economy, would you still drop the psi?

 

I think the combonation of 50 psi and 7.5 inch wide wheels will make the center portion of the tread wear quickly. I would drop it to at least 40psi.

 

hey wandell- and for anyone reading... when I originally posted this, I also had just emailed TOYO asking them about my situation specifically- posted here because i assumed i wouldnt get a response from toyo for a couple days... well, just got a call from toyo's chief engineer with custom calculations for a 2005 F150 Supercab 6.5' bed running this setup. based on the M/T load ratings/tire specs, and ford spec 18"x7.5" rims/specific truck specs, the optimal psi that all four tires should be run at to avoid poor ride, balance, and abnormal tire wear due to the difference in rim width/approved width is 55 psi. i was quite taken aback speaking with chief engineer concerning the tires, and didn't half expect them to go to the trouble they did to answer my question - very helpful folks down there. well, thanks for your help!

Justin

 

Wow, that seems really high. But, they made the tires.