Hello. I recently went from Bridgestone 245/45/18 tires to staggered Falken 452s with 275/30/20 in the rear and 245/30/20 in the front.

I have been getting conflicting information from the vendor who sold me the tires and the installer on what tire pressure I should be using.

Discount Tire who I bought the tires from told me I should fill them to 2 psi higher than the specs on the stock tire located on the door sim. My installer of the tires, told me that I would wear out these tires if I did that and instead I should fill them to around 40 psi or 45 psi, this doesnt sound right to me but that is what the tires came filled from discount.

Will someone who knows this stuff please confirm, I dont want to overinflate.

Second question, my wheels came with new tpms sensors but when I installed them the tire sensor light went off after 30 miles of driving. Do I have to go to a nissan or tire center that has the right equipment to reinitialize the tpms or will this light go away when the tire pressure starts communicating with the car?

 

Papa bear says 35 PSI is too high.
Momma bear says 35 PSI is too low.
Baby bear says 35 PSI just right.

 

and dada bear says david comes to the rescue again, 35 psi it is

 

https://my350z.com/forum/showthread....9&postcount=44

 

You are the master of mixing humor with information (and your posts are always interesting and accurate). I always enjoy reading your messages, and this is one of your better efforts.

Just so it’s clear, 34-36 psi is where you want to set your tire pressure on the Z.

--Spike

 

thanks got it so i have to reprogram and am going to use around 35-36 psi

 

Your installer told you 45? Isnt that the max tire pressure?

 

no max pressure is 50 on the falkens

 

So I called Falken Tire and they said that 35 psi is the WRONG tire pressure to put on the car. According to them, because my original tires had a load rating of 91 (front) and 96 (rear) and my new tires have a load rating of 90 (front) and 97 (rear) I should be putting 40 psi in the front and 41 psi in the rear, they said 41 all around is ok too.

 

^^ That information is totally bogus. If you follow that advise, you will have a car that handles very poorly. 40 psi is very high for the Z. The car will ride awfully, and the tires will wear poorly.

Are you sure that you provided Falken with correct information?

--Spike

 

Yes in fact they repeated it on my telephone voicemail, she even recited my stock tire size and car information.

I have been driving on 40 psi because the installer didnt change the tire pressure and hte car has been handling quite well, should I just put the tire pressure down to 37 or so (for the plus sizing) and confirm with another vendor?

See this, I dont know how to read it properly:

http://www.toyo.com/docs/tires/loadinflationtables.asp

http://www.eng-tips.com/faqs.cfm?fid=1148

http://www.vanagonauts.com/Tire-Pressure4.htm

 

Latest, Im so confused now, called Discount Tire, where I bought the tires and wheels, guys says I should put 38 psi all around, if I notice wear in the center of the tire, move down to 35, if I notice wear on the outside move up, bottom line doesnt look like anybody know the real answer here

 

That's why I stay bone stock, bumper to bumper.

 

With conflicting reports, I'd go with davidv & Spike.

 

leave it at 40psi and you can tell falken they F'ed up and get yourself new tires. =]

 

Oy, we all actually might be wrong, 40+ psi might be the right tire pressure, I spoke to a tire engineer, the falken are XL reinforced, they can handle a lot more pressure than the stock tires, see here:

http://answers.yahoo.com/question/in...4151450AAeO2yQ

Falken wrote back to me, a specialist confirmed 42 psi all around

 

So… you have received a lot of different opinions on what is the best psi for your tires:

That would be 37 to 38 psi.


That would be very odd. A 5 psi difference is huge and ludicrous (your quote from your installer: “fill them to around 40 psi or 45 psi”).


So now we are at 40 or 41 psi (a difference or 1 psi, especially when you are way over the recommended psi for a Z, isn’t significant). Notice that the load ratings are nearly identical, so why is this a factor?


So now we’re back to 38 psi, or even 35 psi depending upon wear? How would you see wear that quickly? And, it you see it that quickly, wouldn’t it be a little late to start adjusting tire pressures?


Jeez, now we are back to 42 psi!?

Well… I guess why not! Those 20’s will ride like wagon wheels anyway, so why not pump-up the tire pressures to a ridiculous level.

Since you have a response from a Falken specialist, would you kindly post the specialist’s message here? I’m interested in what he says about psi and the Z.

--Spike

 

Thanks Spike, here you go, btw they dont drive like wagon wheels THe car handles so well, aggressive cornering and very good control:

------------------
We recommend 42 PSI front & rear.

Make sure any servicing mechanic does not just read the door sticker and put in the old 35 PSI shown for the original tires.

Regards,

[Name of Director]
Director, Quality Assurance
Falken Tire Corporation
[email ide]
[tel no]

-------------------------

As an aside, I also wrote back to him with this message, will post the reply once I get it:

Thanks XXXX, Im so confused.

1. Discount tire, where I bought your tires from, tell me 38 psi is the right pressure.

2. Online, at the tech center for 350z, see this link, Im being told to fill 35:

https://my350z.com/forum/wheels-and-...ket-tires.html

3. I called your office and spoke to XXXXX? She told me the front should be 40 and the rear 41 psi.

So as you can see, im so confused, just to reiterate, I have a 2008 Nissan 350z touring, and went from 225/45/18 front and 245/45/18 Bridgestone to 245/30/20 Falken 452 front and 275/30/20 falken 452 rear. Im looking for the best handling and control, please confirm 42psi is the right pressure all around.

THANKS.

 

I got a reply:

We recommend 42 PSI on our website Application Guide, primarily due to the replacement tires being a Reinforced spec, which requires higher pressures for the load to be matched. It may be that other sites or companies are not considering the Reinforced issue, which we have noticed on several competitors' instructions.

Regards,

 

I use 39 psi on mine.. and I'm fine