# Recommended tire pressure for 235/45/17 tires on Golf R?



## roninsoldier83 (Jun 26, 2009)

Hello wheel & tire gurus! 

I just recently put on a set of 235/45/17 winter tires; mounted to [smaller diameter than stock] 17x8 wheels. Just a quick question: what tire pressure would you guys recommend for these tires on my 2013 Golf R? 

I've found recommendations in other threads that were pretty varied, so I figured I would just ask. 

Thanks in advance!

-Brandon


----------



## afawal2012 (Jan 9, 2013)

I would say 32 - 35 psi. You don't want a winter tire to be too stiff, especially if you're trying to go through the white stuff.


----------



## roninsoldier83 (Jun 26, 2009)

Duly noted, thanks for the reply!


----------



## glifahrenheitcameron (Sep 14, 2011)

Read what the tire says.


----------



## [email protected] (Apr 9, 2008)

glifahrenheitcameron said:


> Read what the tire says.


I hate being a naysayer, but this is not correct. Max PSI is just that, not the proper inflation pressure for the vehicle. 

Here is a link on my website explaning the principle.


----------



## [email protected] (Apr 9, 2008)

roninsoldier83 said:


> Hello wheel & tire gurus!
> 
> I just recently put on a set of 235/45/17 winter tires; mounted to [smaller diameter than stock] 17x8 wheels. Just a quick question: what tire pressure would you guys recommend for these tires on my 2013 Golf R?
> 
> ...





afawal2012 said:


> I would say 32 - 35 psi. You don't want a winter tire to be too stiff, especially if you're trying to go through the white stuff.


What is the load index of the tire that you are using? If it is a 92 load index you'll want to go by the 38psi recommended cold inflation pressure.


----------



## roninsoldier83 (Jun 26, 2009)

[email protected] said:


> What is the load index of the tire that you are using? If it is a 92 load index like the OE 225/40R18, you'll want to go by the 38psi recommended cold inflation pressure.


The load index is 97. What would you recommend? 

Thanks in advance!


----------



## roninsoldier83 (Jun 26, 2009)

[email protected] said:


> What is the load index of the tire that you are using? If it is a 92 load index like the OE 225/40R18, you'll want to go by the 38psi recommended cold inflation pressure.



After doing a bit of research and calculation with the 97 load rating this is what I came up with. Please correct me if I'm wrong. 

Vehicle curb weight: 3325 lbs (I know, arbitrary for this)
Vehicle GVWR: 4542 lbs

OEM tire is 225/40R18 with a *92*H load rating. The 92 load rating means at maximum pressure (which is 50psi), the tire can handle 1389 lbs per corner/tire. 

So, not taking into account axle ratings, 1389 x 4= 5556 lbs total rating. Divide that by the maximum pressure of 50psi to get 5556 / 50 = 111.12 . 

I then divided the GVWR of 4542 lbs by 111.12 to get *40.87psi*, which aligns with the recommendation inside the doorjamb of *41psi*. However, I understand that I will likely never come close to loading the car up to the GVWR, and hence why 38psi is the more normal OEM inflation recommendation. Am I correct? 

The new tire has a 97 load rating and as such is marked as being rated to carry 1609 lbs per corner at 50psi. Same formula: 

1609 x 4= 6436 lbs / 50 (psi)= 128.72. 
GVWR 4542 / 128.72 = *35.28psi *

^^^Granted that calculation is based on the GVWR which is considerably more weight than I would likely ever have packed into my vehicle. Based on that rough estimate, I'm assuming somewhere in the 32psi-35psi range would be recommended for my vehicle on these tires? 

Sorry I didn't post up the load rating to begin with.


----------



## [email protected] (Apr 9, 2008)

roninsoldier83 said:


> Hello wheel & tire gurus!
> 
> I just recently put on a set of 235/45/17 winter tires; mounted to [smaller diameter than stock] 17x8 wheels. Just a quick question: what tire pressure would you guys recommend for these tires on my 2013 Golf R?
> 
> ...





afawal2012 said:


> I would say 32 - 35 psi. You don't want a winter tire to be too stiff, especially if you're trying to go through the white stuff.





roninsoldier83 said:


> After doing a bit of research and calculation with the 97 load rating this is what I came up with. Please correct me if I'm wrong.
> 
> Vehicle curb weight: 3325 lbs (I know, arbitrary for this)
> Vehicle GVWR: 4542 lbs
> ...


I wasn't able to find GAWR on the vehicle, so you may have to double check your inflation placard. Also, I show the cold inflation at 38psi for the vehicle, and not 41psi. Is my information not correct? If not, let me know. With that information I had to run the numbers again. 

You and I were figuring this one out in tandem. I did my equation a little different but we came to the same result:

Pressure= MaxPressure x (load/max load)​
Your OE 225/40R18 92H tires that have a 1389 max load at 50 psi:

-if your placard reads 38 psi cold inflation pressure then 38psi= 50psi x (1056lbs/1389 max), or the tires are holding 1056lbs at 38psi cold inflation
-if your placard reads 41 psi cold inflation pressure then 41psi= 50psi x (1140lbs/1389 max), or the tires are holding 1140lbs at 41psi cold inflation

Using the information above: 1056lbs if 38psi and 1140lbs at 41psi, I then tried to figure out what pressure you need to use get the same weight carrying capacity from your 235/45R17 97H tires that have a 1609 max load at 50psi:

-if your placard reads 38 psi cold inflation pressure then 32psi= 50psi x (1056lbs/1609 max), or the tires are holding 1056lbs at 32psi cold inflation
-if your placard reads 41 psi cold inflation pressure then 35psi= 50psi x (1140lbs/1609 max), or the tires are holding 1140lbs at 35psi cold inflation

So, in a nutshell if your placard reads 38psi cold with your stock size, then you will need to inflate the 235/45R17 97 tires to 32psi cold, and if 41psi then 35psi.


----------



## roninsoldier83 (Jun 26, 2009)

[email protected] said:


> I wasn't able to find GAWR on the vehicle, so you may have to double check your inflation placard. Also, I show the cold inflation at 38psi for the vehicle, and not 41psi. Is my information not correct? If not, let me know. With that information I had to run the numbers again.
> 
> You and I were figuring this one out in tandem. I did my equation a little different but we came to the same result:
> 
> ...


Thanks Gavin! 

I pulled the GVWR and recommended tire pressure figures off of the placards in the door sill. It does recommend 41psi for OEM tires. 

I believe the [lighter] VW GTI recommends 38psi, which would make sense, as the GTI is rated at being ~212 lbs lighter than the Golf R (curb weights: 3113 lbs (GTI) vs 3325 lbs (R); GVWR's: 4256 lbs (GTI) vs 4542 lbs (R)), yet they both wear the same rubber.


----------

