[i30Dave]

I checked my tyres today to see what pressure was in them.
I was surprised to see they were at 37psi. The sticker in the
door trim says 32 for 17" wheels. I know some people on here
are using 34 - 36psi. What pressures are people using and what
psi would be the maximum you would put in safely.

[Dazzler]

Hi Dave... I wouldn't run any more than 36PSI (That's what I run in my 16" ) anything more would be too harsh and wouldn't give a lot of extra benefit handling or economy wise (I.M.O.)

I checked my "Alloy" spare when cleaning out my baby yesterday and they had around 46PSI in it (dropped it back to 38PSI) I can understand allowing a bit for deflation over time but thought that was bit excessive.

Cheers,

Dazz

[TheBunyip]

Hi All,

In these days of ever increasing fuel costs most drivers sooner or later encounter the advice that under inflated tyres can cost significant fuel consumption. Research in the EU has shown it to be quite a problem. http://www.greencarcongress.com/2007/03/study_underinfl.html

The subject of "Tyre Pressures" seems to be one that most ignore and a few get very very excited about. For most of my driving career I was one of the former. In my search for Automotive Engineering Wisdom (which I have but in very small measure  

After reading some heated exchanges about Tyre Pressures on other Car Forums I decided to see what Car Bibles had to say. There is a very long article (and I do mean long) on Tyres on Car Bibles so I decided to work through it. http://www.carbibles.com/tire_bible.html

Wait for it... I am nearly there!!

Anyone else think he is on to something and fancy experimenting with raised Tyre pressures on their i30

[Shambles]

With a reply somewhat shorter than Bun's, I can say I run my 17" at 34psi (they came delivered at 32psi)

Hey Bun, thanks for the Bible bashing links  

[Dazzler]

I thought bunyips were legendary.. Our bunyip is proving to be just as unique in his own way. He hereby receives the official title of "The Researcher"...  

amd others I'm still thinking up....

[Chemist]

Hi,

I have 205/55 R16 (KUMHO SOLUS KH15) tires on my i30.

When I first checked the pressure, it was over maximum of
44 Psi in all 4 tires (46-47 Psi)!  :?:  :roll:

And I did like he said, but then front tires looked a bit deformed, like there
is not enough pressure (probably because of heavy diesel engine)...

So, what to do? Recommended tire pressure is obviously to low, especially when talking about front tires.

What do you think?   Maximum -10% theory or what?

[Dazzler]

Hi Chemist,

I have Hankook 16" tyres which I believe to be the equivalent of yours... as I've said I find 36 PSI about right.. fills out the tyres nicely (firm but acceptable ride and handling)

My tyres were over inflated when I got my car in March (also over 40PSI from memory) and I found that too firm...

Rgds,

Dazz

[eye30]

Just a thought provoker.

Can't under or over tyre pressue sometimes be a contributory factor in causing accidents.

If the Police when examining the vehicle found that this may have contributed towards the accident, even if it wasn't your fault, then may be yours and the other parties car insurance company could refuse to deal with the claim and void the policy.

If no insurance then the only recourse would be to sue them/you.

Does anyone have any views?

[i30manUK]

I'm currently running my tyres (18" wheels) at 35psi/2.4bar - This is a bit of a guess, because the handbook and door labels only give pressures for the smaller wheels. What pressure are you using, Hemmi?

[Hemmi]

I'm currently running my tyres (18" wheels) at 35psi/2.4bar - This is a bit of a guess, because the handbook and door labels only give pressures for the smaller wheels. What pressure are you using, Hemmi?

I'm not sure, I'll check when I can.
Do you have a tyre pressure monitoring system TPMS on your Hyundai i30. I'm always getting the TPMS light and the dealer says that they've been having trouble with all the cars with it, it's to sensitive they say. I took my i30 to them last week and they calibrated it again but now the lights up again.

[i30manUK]

Do you have a tyre pressure monitoring system TPMS on your Hyundai i30.

Yes, I have TPMS - no problems with it so far. Start a new topic on the subject, so you can see if anyone else is having problems with it.

[Thumper]

My 16's I run 42psi in the front, 40psi in the back.

A bit harsh, but I go for outright economy, not comfort!  

(I have to write up the sub install, HiD 3000k Golden yellow fog light install, LED light install, USB HD testing.)  

[ozsnowman]

I checked mine the other week, they were mostly sitting on 31, but I have raised that to 34, and havent noticed any detrimental efects yet

[davet]

I've always added around 4 psi to the manufacturers specification to improve handling fuel economy and tyre wear.

[eye30]

Question.

Reading the postings of putting additional psi in tyres I can see the benefits, better ride, better mpg etc but I've always err'd on the side of caution.

Tyre manufacturers give psi when cold and this must be for a good reason - safe use of the tyre.

But question I have always wondered is why does the same tyre have different psi on different cars?

As the car travels the tyres warm up and therefore the psi increases.
If you are running at + psi when cold, then when warm you are increasing the psi signicicantly running the risk of tyre failure, or are you.

It may be worth members posting cold and hot psi's to see the increase and then compare to the tyre manufactures safe working limits.

Any views by others?

[Lakes]

A good friend of mine that was a tyre expert b4 he died of cancer ( RIP m8) always told me Car manufacturers always say lower pressure than tyre manufacturers recommend. i think they want you comfortable. i have been running 38 psi, i feel the tyres after a long drive to check they are running cool, under inflation and they run hot and wear faster. i got 110.000k out of the four original Good years that came with my ute, i ran 50 psi in that and every 10,000k i rotated them keeping them all turning same direction just put front tyres on the rear and rear tyres on the front. i think we will need to do it about every 5 or 6,000 k as the i30 is front wheel drive also the drive wheels do the steering, plus they have good Torque at low rev's the rear tyres will last a lot longer so rotate them and have the four tyres last the same distance, run more air to help them run cooler and last longer. this is if you want cheaper running costs.
cheers

Eye 30, just read the last part of your post, they say always set your tyre pressure cold m8, low inflated tyres will increase the tyre pressure more to high inflated tyres as they will increase there temperature by a lot more. also with our strict speed limits and those limits being relatively slow, we don't have to worry too much here m8.but 40 psi is safe and less chance of tyre failure than low inflation

Also forgot to mention, have your tyre pressure test equipment checked regularly as the one's at service stations are not very accurate , i found the digital type to mostly be closest. i take my gauge to be tested every month. so i know what i really have in my tyres. ever tried helium gas?


.

[130MAN]

When we bought our car it had 40 psi.  I thought it was too high, now I run 36psi.

One question, Does the Hyundai i30's have a monitor sensor to tell you the tyres are low?

[eye30]

I don't have the model with Tyre Pressure Monitoring System (TPMS)

I check manually with a type pressure gauge every couple of weeks and run at 32 as stated on the sticker on the body you see when you open the drivers door.

[Dazzler]

I don't have the model with Tyre Pressure Monitoring System (TPMS)
I check manually with a type pressure gauge every couple of weeks and run at 32 as stated on the sticker on the body you see when you open the drivers door.

 

Hi Eye,  have you considered trying 34 or 36 psi... it doesn't seem to effect the ride but should improve your economy a little bit...

38 front, 34 rear.

[Goldfish_8]

I have the 2.0 CRDi with the 18 inch wheels. I run 34 in the fronts, 32 in the rears, now , though when I had Khumos all round was running 34 all round. Now just have the Khumos on the front, and Toyo Proxies T-1r's on the rear. The Toyos have a higher load rating and a stiffer sidewall, so don't need the extra air the Khumo's do.

Have to say that some of the pressures mentioned do seem to be rather high, I would have thought verging on over inflation, cause excess wear to the centre of the tyre, yes improving economy, as less tyre in contact with the road, but reducing the tread patch in contact with the road thus reducing grip and safe handling.

With the TPMS, it seems to warn when the pressure drops to about 25PSI.

Mark

With most emergency stops being in a straight line, it might be very surprising how much extra "weight" is on the front tyres during such an incident.  What may seem to be over-inflated tyres in normal running can be just what's needed to present the full tread to the road when the weight transfers forward in a hard stop.

Personally, I don't think it is possible to over-inflate the (front) tyres in any sensible way. 

[Si]

On my i30 the sticker in the door say 32psi all round for both normal and fully loaded. The handbook give higher settings for fully loaded - which sounds right.

Any ideas what is correct - the handbook or the sticker??!!

Thanks

Si

[eye30]

Any ideas what is correct - the handbook or the sticker??!!

I follow the sticker. Like you 32 no matter the loading.

I run at 32 (cold as don't forget the PSI will increases with heat from movement) because that's what is says on the sticker.

If I was involved in an accident the boys in blue may check settings etc as part of the road accident report and I may then be charged if they deem the car is unroad worthy due to psi above manufacturers stated psi.

[Lakes]

the Tyre manufacturer is the one to ask, not the car manufacturer. all car manufacturers seem to recomend low inflation settings, were tyre manufacturers recomend higher settings. the tyre manufacturers do a lot more testing with the tyres than the car manufacturers do.
i like 38 front 36 rear. my tyres are lasting too. you also need to have the gauge you use to test pressure checked for accuracy, a lot are in acurate. i just ask the tyre guy to check mine against what he is useing. check tyres every week .
how offten do you check yours Eye? and do you know if your gauge is accurate?
i've never seen a Cop here with a tyre pressure gauge yet just a breath test gauge.

[freakzoide]

I check my tires every two weeks.
I use 2.5bar (~36PSi) on the front and 2.2bar (~32Psi) in the rear.

[Phil №❶]

surferdude

Have just read this discussion and was looking for advice on pressured for our diesels. It seems everyone is doing / advising their own theories and I'm more confused than b4.

btw, if a tyre is 38 psi cold, how much would the pressure increase in highway cruising (summer) temps

There would have to be an argument for not over inflating if the car was in an accident & the cops took it to their  yard for investigation. Where would we stand criminally & insurance wise. 

[beerman]

Interesting more than 1 I30 came with the tyre pressure at 40....

I run mine at 38 front and back, my reasons are;
1) Both my cars spend most of their time on the highway hence do not see the rougher side roads.
2) I did a care course where we absolutely drove the cars hard, multiple emergency stops, emergency lane changes, skid pan and the like. They ran their tyres at 42.
3) I do not notice much drop in ride quality.
4) If I (or more likely I don't get into the wives car for a while) am slack and don't check the tyres for a while, there is a good chance that the pressure will be ok.
5) I have run this pressure for a long time, and the tyres all wear flat, hence there is no hint of over inflation wear. In fact my tyres seem to last a long time (though again, this would no doubt be contributed to by highway milage, the last set on my EL lasted 80,000k).


I suspect the topic of tyre pressure is much like the topic of what tyre to use, many opinions abound, for every person who offers an opinion, there are two waiting to shout them down.

[Surferdude]

surferdude

Have just read this discussion and was looking for advice on pressured for our diesels. It seems everyone is doing / advising their own theories and I'm more confused than b4.

btw, if a tyre is 38 psi cold, how much would the pressure increase in highway cruising (summer) temps

There would have to be an argument for not over inflating if the car was in an accident & the cops took it to their  yard for investigation. Where would we stand criminally & insurance wise. 

We pretty much covered all this here... https://www.i30ownersclub.com/forum/index.php?topic=11288.0

Nothing's changed but the topic we are in now started back in 2008 I think. Even back then, lakes was advocating what Beerman and I are saying.
However, I can't tell you what pressure a tyre increases to when it warms up. I can tell you it varies in relation to the pressure at which it starts cold. It's irrelevant as long as it starts its day within range.
There are some "givens".
1/ Vehicle manufacturers are only concerned with ride quality. They don't want a new car owner thinking their car rides harshly, so they'll recommend the lower end of the acceptable range for any given tyre/rim/vehicle combination. If tcnhe tyre wears out rapidly or unevenly, they'll simply refer you to the tyre manufacturer.

2/ Tyre manufacturers are in an extremely competitive market. The only chance they have to impress you is with the tyre which come on your car. And they recognise that you'll base your replacement decisions on how you feel about their tyres at the end of their life. In other words, you won't necessarily remember that you thought they were a bit harsh when you drove out of the showroom 40 or so thousand klms ago.You will notice if they're worn down evenly, and they gave you good mileage. And how they handled in difficult or emergency situations. Pressures at the higher end of the scale will provide a better overall experience for you than those at the lower end of the scale.

3/ Every tyre has a "maximum allowable pressure" As long as you aren't exceeding that there can be no issue with your insurance or legalities. Just went through something similar with Qld Transport today. So it's a topical question.
I think you'll find it's around the low 40's (psi) for most car tyres. But it should be on it somewhere. I have never heard of a situation where "excess" tyre pressure became an issue in an accident or a vehicle inspection. Which is not to say someone, somewhere hasn't.

I run my 1.4 petrol 16 in alloys at 34 psi all round seems ok for me