Hi my side sticker reads that the stock setup was p215/75r/15 at 33psi...I just purchased k03s and they are lt215/75r/15...when using the tire pressure calculator on tire size.com its saying 43psi? I was running 28 the first week I've had them lol was I way under inflated? I don't plan on carrying anything, or towing. Just plain highway and city driving..43...can't be right...is it? I need some help. Lol thank you.
I don't think I realized they came stock with 28" tires. I would set the pressure at whatever gives a good ride & check it with a chalk test. Most everybody here runs well under the "recommended" pressure.
Mopar’s “recommended” pressures for non LT rated OEM tires are way over inflated. The best basis is to use the recommendation for factory 30x9.50R15LT @ 29 psi and adjust from there.
As such, I run 37 psi in my LT215/75R15 KO3s and it runs great.
37 psi on this size maintains 1,400 lbs of capacity per tire which total for a TJ is spot on. If you followed 43 psi, you’d have an additional 155 lbs of capacity per tire, leading to 620 lbs of extra capacity. Nobody needs that on a TJ.
As such, I run 37 psi in my LT215/75R15 KO3s and it runs great.
37 psi on this size maintains 1,400 lbs of capacity per tire which total for a TJ is spot on. If you followed 43 psi, you’d have an additional 155 lbs of capacity per tire, leading to 620 lbs of extra capacity. Nobody needs that on a TJ.
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I am sure an expert will give you some calculated answer and probably tell me I am wrong as this is solely my opinion.
The side of the tire will have a max PSI rating obviously you do not want to be higher than that. The sticker on the car are for the stock tires that it came with. So maybe use that as a guide.
Higher PSI will give a firmer ride and slightly better MPG.
Lower will give you smoother ride. I would say start around 36-38 and see how it feels. Then adjust as needed.
Maybe you will get someone that has those exact tires and can tell you there feedback.
The side of the tire will have a max PSI rating obviously you do not want to be higher than that. The sticker on the car are for the stock tires that it came with. So maybe use that as a guide.
Higher PSI will give a firmer ride and slightly better MPG.
Lower will give you smoother ride. I would say start around 36-38 and see how it feels. Then adjust as needed.
Maybe you will get someone that has those exact tires and can tell you there feedback.
speeding_infraction
TJ Enthusiast
That's only saying that you would get a load capacity of 1553 lbs per tire if you ran them at 43 psi. Obviously you don't need that much load capacity, so lower it until it rides good and you have a good chalk test.
For whatever it’s worth, if you ran them at 33 psi, total capacity would be ~5,100 lbs. 30 psi would be ~4,800 lbs. You need more capacity than the weight of the Jeep to make them maintain shape when hitting dynamic loads such as potholes and other bumps at speed. Also with the KO3 being an LT, they need more air pressure than the equivalent size non-LT tire to properly air up the thicker carcass. Think about how you’d need more pressure to blow up a thicker balloon.
You could probably get by with either of those but I’ve found extrapolating from the factory 30” rec and adjusting accordingly based on that has worked well for me.
highway and city driving? was I at risk of damaging the tire at 28psi when I drove on the highway?
Nah, I’m sure it’s probably fine. Maybe would have worn the center a bit over time but they’re probably fine.
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