tyre pressure Which tyre pressure should I use in my GSV40R?

[nushydude]

Hi,

I have a 2007 Aurion AT-X GSV40R and as per the manual, the car should use 215/60R16 95V or 215/55R17 93V tyres. The recommended pressure chart is as follows.

I've been using 30 psi (215/60R16 95V, less than 140km/h, up to 4 passengers) on my tyres, but the tyres I have in there are not the exact match as this is a second hand car and the last owner put the Yokohama A-Drive 215/60R16 99H tyres in it. So, it's 95V vs 99H. 

So is it OK to use 30psi, or should I use a different pressure? 

Also, I had been using the compressors at the fuel stations, which as I heard are pretty inaccurate and cannot do it at cool state. Can someone recommend me a reasonably priced unit for doing it (check pressure and inflate) at home? (either 12V car battery or even 240V is OK)

Cheers
 

Edited December 29, 2016 by nushydude

[campbeam]

I have used 36 psi front and rear on my various vehicles over many years.

At last wheel alignment for my Aurion, Bob Jane TMart used 38 psi so I have changed over to now using that tyre pressure.

It makes sense as the Aurion is heavier than most 4cylinder vehicles.

I have bought a 12Volt compressor on eBay but it mainly stays in storage for emergency use or when I want to pump up tyres on an unregistered vehicle.

So, I check tyre pressures at the garage about monthly. I pump up each tyre twice; pump, remove air hose, re-pump or set pressure to 39 psi. Not fussy enough these days to use a personal tyre guage to check the accuracy of the tyre pressure.

[mg85]

I would pump them up about 5-7 psi over your desired pressure at the servo on your way home, using a gauge like this http://www.ebay.com.au/itm/Dr-Air-Tyre-Gauge-Dial-Type-10-50Psi-/321866507074?hash=item4af0bd2342:g:eOQAAOSwyvBV-H8R

Then when they are cold let them down to (36 psi I use) or whatever you decide on.

All the best

 

Edited December 30, 2016 by mg85

[nushydude]

Like I said, I was using 30psi before and today I filled 35psi just to check. I filled each tyre twice just to confirm. The service station was about a mile away from my place, so it would still probably count at cold air...I don't know. 

It sure did affect the comfort level a bit though. But I'm sure it would help with fuel efficiency.

[mg85]

If the servo is only a mile away the tyre pressure would not increase that much unless it was a hot day. Higher tyre pressure should help a bit with fuel economy you could try them at 36 psi and let us know any difference in fuel economy.

[nushydude]

3 hours ago, mg85 said:

If the servo is only a mile away the tyre pressure would not increase that much unless it was a hot day. Higher tyre pressure should help a bit with fuel economy you could try them at 36 psi and let us know any difference in fuel economy.

Don't you feel the ride is not comfortable at that tyre pressure. I felt a noticeable difference at 30psi vs 35psi. (tbh my 30psi had actually dropped to 29psi before I filled at 35psi).

[Buff Hamster]

I had 38psi front and 36psi back. The extra at the front to counter the engine weight.

[mg85]

20 hours ago, nushydude said:

Don't you feel the ride is not comfortable at that tyre pressure. I felt a noticeable difference at 30psi vs 35psi. (tbh my 30psi had actually dropped to 29psi before I filled at 35psi).

Sure the ride is not quite as good but tyre life & fuel economy is better, personal choice really I guess it all depends on what is more important to you.

[nushydude]

39 minutes ago, mg85 said:

Sure the ride is not quite as good but tyre life & fuel economy is better, personal choice really I guess it all depends on what is more important to you.

Wouldn't the increased vibrations be mechanically harmful for the vehicle over a long period of time?

[CONROD]

38 psi F & R

[mg85]

20 hours ago, nushydude said:

Wouldn't the increased vibrations be mechanically harmful for the vehicle over a long period of time?

No mate, the tyre pressure we are talking would not do that. 

[nushydude]

6 hours ago, mg85 said:

No mate, the tyre pressure we are talking would not do that. 

Alright then. 

[ianjoseph]

I use 225/45R18 and it's 40 psi all round. There was a marked difference when i drove in to the shop on 17" and drove out on 18". The drive has become so much firmer. So, if you plan an upgrade sometime, that's my 2 cents worth. 

[trentmeyer23]

1 hour ago, ianjoseph said:

I use 225/45R18 and it's 40 psi all round. There was a marked difference when i drove in to the shop on 17" and drove out on 18". The drive has become so much firmer. So, if you plan an upgrade sometime, that's my 2 cents worth. 

This is not really a reflection of pressures, rather the reduction of sidewall height increasing tyre rigidity.

The same could be said for upgrading to a 19 or 20 inch rim and choosing a tyre to suit the original rolling circumference.

[nushydude]

1 hour ago, ianjoseph said:

I use 225/45R18 and it's 40 psi all round. There was a marked difference when i drove in to the shop on 17" and drove out on 18". The drive has become so much firmer. So, if you plan an upgrade sometime, that's my 2 cents worth. 

I have no plans to upgrade to new rims, as the tyres are in a very good shape, although the stock steel wheels have become rusty and don't look pretty. Also one of the hubcaps has some deep scratches and I will probably replace it sometime. They were like this when I bought the car. 

[trentmeyer23]

31 minutes ago, nushydude said:

the stock steel wheels have become rusty and don't look pretty. 

A rattle can will sort that out pretty quickly.

[jadatis]

i replied yesterday , but could not submit the replie for some reason, 

So now this chort post to see if it is working now.

Registed to this forum to give an answer 

In short your 99Loadindex tyres are XL/reinforced /Extraload , and the Li 95 are Standard load tyres.

You would expect because of the higher LI that XL// can do with lower pressure , but would even need slichtly higher pressure for the same load.

Greatings from a Dutch Pigheaded Selfdeclared tyrepressure-specialist.

Peter

[nushydude]

6 hours ago, trentmeyer23 said:

A rattle can will sort that out pretty quickly.

Not very strong with those type of DIY projects sadly.. 

[trentmeyer23]

1 hour ago, nushydude said:

Not very strong with those type of DIY projects sadly.. 

It's incredibly easy to do.

Remove the wheels, one at a time if need be. Scuff up the rim with some scotchbrite and wipe it down with some wax and grease remover/prepsol. Grab some carboard to cover the tyre and paint.

Youtube has videos that can help as well.

[Tony Prodigy]

On 12/30/2016 at 7:37 PM, mg85 said:

I would pump them up about 5-7 psi over your desired pressure at the servo on your way home, using a gauge like this http://www.ebay.com.au/itm/Dr-Air-Tyre-Gauge-Dial-Type-10-50Psi-/321866507074?hash=item4af0bd2342:g:eOQAAOSwyvBV-H8R

Then when they are cold let them down to (36 psi I use) or whatever you decide on.

All the best

 

Good idea.

Over pump them slightly before heading home and do the adjustment next morning.

That is of course if you have a compressor and tyre inflator of your own. (which I don't have here)

Thanks for the link too. 

[Tony Prodigy]

On 1/3/2017 at 1:03 AM, nushydude said:

I have no plans to upgrade to new rims, as the tyres are in a very good shape, although the stock steel wheels have become rusty and don't look pretty. Also one of the hubcaps has some deep scratches and I will probably replace it sometime. They were like this when I bought the car. 

If you aren't the DIY type, that's ok. 

If you want a nice look and can spare a little extra cash, you can have your original steel rims powder coated for cheap. The finish is incredibly strong and will last forever.

Contact some powder coating companies and get a quote.

If you can't take your car off the road for a week or so while doing this, you can purchase a spare set of rims cheap and have these done in the mean time then take them over to your tyre guy and have the tyres swapped, or wait till the tyres are due and put some new boots on then.

[matt36415]

I go 42 front and 38 rear on 235/40/18 tyres. That and fat sway bars keep it very flat on corners.

[Auri 7]

12 hours ago, matt36415 said:

I go 42 front

Do you have very soft tyres?

42 front would see me bubble off sideways on uneven surfaces (in roundabouts or corners), would also slip on acceleration in the wet on T-junctions.

I guess it depends a great deal on the tyres.

I usually go cornering in some rough large roundabouts and adjust my tyre pressure to the point, where I don't skid (bubble) off anymore. I'm very picky on my pressure, 1 PSI makes all the difference for me. Got my own compressor and gear at home etc. Now on Primacy 3ST (4.5 - 4.8 mm thread left ) I use 36 front and 37 rear (not loaded). Previously on Energy XM I used 32 - 33.

[matt36415]

Auri7, Im assuming you have the factory wheel / tyre sizes. Apart from sticking, I want low fuel use so I go a bit higher pressure than most. 

 

Ive heard commentators on V8 supercars discuss tyre pressure and I think they agreed with you, 1 psi is important. My 235/40/18 tyres are also a significantly different shape in cross section to the standard tyres so there is probably difference there too.

[Auri 7]

4 hours ago, matt36415 said:

Auri7, Im assuming you have the factory wheel / tyre sizes.

 

Yep, I'm on 215/55/R17 , which came with the Touring SE model.

 

4 hours ago, matt36415 said:

I want low fuel use so I go a bit higher pressure than most.

 

Yes, most definitely. Plus you have a wider tyre and higher pressure will help to compensate for that and lighten your steering.

I'm always eager to read, what other drivers are using. This forum can be quite helpful.   Cheers.

Edited January 14, 2017 by Auri 7