ObpKB1

Does anyone know the proper tire pressure for the A-Spec 18 inch wheels and 245/45/r18 tires? I recently installed aftermarket 18's in place of my stock 17's and I figure the tire pressure recommended for A-Spec cars is a good starting point.

Thanks!

Nomgle

Yep, here's the driver's door information plate - pressure is the same for 17" and 18" wheels :

HEAVY_RL

iTrader: (1)

In scenarios like this you should use the information on the side wall of the tire, take the weight of the car and do the math.

justnspace

iTrader: (1)

or just keep it inflated at 32-35psi depending on your preferences

as you can manipulate what the car does with tire pressure...

pewpew

I keep my tire at 32 PSI during winter. It usually warms up and ends up at ~35PSI after a little bit of driving.

horseshoez

iTrader: (2)

Ummm, no; the pressure indications on the side wall of the tires has absolutely nothing to do with what is the appropriate pressure for any given car; that is just the maximum pressure which should be used in the tire.

HEAVY_RL

iTrader: (1)

Ok, I'll bite. You realized what you just said right?

Allow me to walk you through OPs post:

Does anyone know the proper tire pressure for the A-Spec 18 inch wheels and 245/45/r18 tires?
Sure we do, because as stated above the FACTORY specs for the factory tires are in the door on the sticker. Which is 100% accurate if you are running the OEM spec tire.

I recently installed aftermarket 18's in place of my stock 17's and I figure the tire pressure recommended for A-Spec cars is a good starting point.
Here we realize OP not on factory wheels, and they are also NOT on factory spec tires AND they are looking for a "STARTING POINT"

Now, hopefully you are comprehending the situation at hand, I will walk you through the proper way to address tire pressure.
Leading off with a Google reference, since you seem like an all knowing and not searching type of member: https://mechanics.stackexchange.com/...on-stock-tires

Similar answer with more ad/spam: https://axleaddict.com/auto-repair/C...rmarket-Wheels

After reading that link, and now that we are all a little educated, lets rethink your approach and apply a little humility in the future.

horseshoez

iTrader: (2)

Not sure what you're trying to say, I stand by my statement, the pressure indicated on the side wall of the tire has absolutely nothing to do with what is the correct pressure for any given car; simple as that.

HEAVY_RL

iTrader: (1)

Ok, I'll try again in less words.

The sticker in the car is ONLY for OEM spec tires on OEM spec wheels on a NON modified car.
Since there are varying load/size/performance aspects of aftermarket tires, they all have different pressure needs.

The numbers on the tire are max for the weight rating of the tire
if you take the weight of the car and do the math you can get a starting point of the correct air pressure for that tires specification.

All that said, if you read the links (which you clearly still haven't) there are numerous methods to achieving the correct air pressure for non OEM spec scenarios which is what the OP is asking about.

horseshoez

iTrader: (2)

Sorry, nothing in the links you provided is even remotely authoritative; once again, the MAX PRESSURE indication on the sidewall of a tire has nothing to do with what is the appropriate pressure for any given tire on any given car. Why is this so hard for you to understand?

HEAVY_RL

iTrader: (1)

Interesting perspective, do you often find yourself wondering why everyone around you never understands?

Ok, this statement, the MAX PRESSURE indication on the sidewall of a tire has nothing to do with what is the appropriate pressure for any given tire on any given car.

Lets start with the basics, although exact in their size, you do realize that not all tires are the same right?

Each tire has a different load rating, traction spec, wear/mileage spec, and possibly rubber compound.
Although you are correct in that the numbers on those tires have nothing to do with the car, they have 100% everything to do with the tire and the application in which its applied.

Using those max numbers as a reference point, then applying the weight of the car you own will allow you to calculate the right air pressure.

For example, if you have a truck that weighs 8000lbs but you have a load rated tire that can work under a load 3 times that weight.
You take the max air pressure which is likely 90psi and reduce it to 30/35psi for daily travel.

horseshoez

iTrader: (2)

It seems you're the one often out in the woods wondering why you aren't understood. The fact is, even for any given tire size, tires from different manufacturers and even different models from a single manufacturer have different max references on the side wall. Dude, you've gone down a rabbit hole you are unable to get out of and you are still arguing. Just stop.

thoiboi

y'all are both right, but also both wrong.



Horsie is right in that for a laymen, looking simply at the sidewall to determine the proper tire pressure is not good enough (for OP)

Heavy is right in that TECHNICALLY his approach of taking into max weight rating and weight of car to calculate the pressure is an approach OP can take.

Heavy is wrong in that Horsie never mentioned the sticker so attacking him regarding that is not called for.


ALL IN ALL, both very smart people that are are getting at one another for no reason.

HEAVY_RL

iTrader: (1)

Attacking? Interesting.

Always good convos with people who perceive debate and education as arguing and attacking.

fabioel99

My sticker is SJA-T0 and does not list the 245/45R18 96Y. Not sure why that tire is shown. Your wheels are either 17 or 18 haha.

Question for the forum. 235/50R17 100W are not available in my country. Only 235/50R17 96W. I'd guess they are fine? Since the other spec tire load is the same right?