[agentr31]

ive always said the nitrogen thing is a sales pitch to lure n00b's into spending money on something that is completely unnecacary!!

a bit like the time a bloke gave me a "4 wheel, wheel alighment" problem that he had was the car had a "solid" rear axle LOL i quickly corrected him and paid him for a standard wheel alighment...

[Surferdude]

ive always said the nitrogen thing is a sales pitch to lure n00b's into spending money on something that is completely unnecacary!!

a bit like the time a bloke gave me a "4 wheel, wheel alighment" problem that he had was the car had a "solid" rear axle LOL i quickly corrected him and paid him for a standard wheel alighment...

Well, perhaps you've put it more bluntly than I. Refer my earlier comments about NRMA testing.
I actually know very well the guy who was the National Marketing Manager at Bob Jane T Marts who was responsible for introducing the idea into the passenger tyre market in Australia. I hasten to add it was some years later when i first met him.
In fact, I don't question nitrogen's benefits. i do question the need for it in a well maintained car.

[2i30s]

i bought a wheel and tyre package when i first bought my hatch [sr rims are twice as much] at bob janes and the nitrogen was in the price.ive found even if i check the preasures on a stinken hot day they arnt much higher than normal and the same on a freezing cold day.its the first time ive used it in tyres and im converted.i check the wifes tyres that arnt filled with nitrogen once every 3 or 4 weeks and hers allways need 4-6psi.

[Surferdude]

i bought a wheel and tyre package when i first bought my hatch [sr rims are twice as much] at bob janes and the nitrogen was in the price.ive found even if i check the preasures on a stinken hot day they arnt much higher than normal and the same on a freezing cold day.its the first time ive used it in tyres and im converted.i check the wifes tyres that arnt filled with nitrogen once every 3 or 4 weeks and hers allways need 4-6psi.

Mate, I'm a little concerned about 4-6psi drop every month. I would expect less than half that but I guess there's not a lot you can do about it.

Here's a link to a pdf file that I found at a motorcycle Web site. It's very technical (and lots of math), but it fleshes out the issue properly:

http://www.narleychoppers.com/Nitrogen.pdf

Basically, oxygen diffuses faster through rubber than nitrogen because the size of oxygen molecules (2 atoms of oxygen bound together) is smaller than that of nitrogen molecules (also 2 atoms of nitrogen bound together).

Simplified once more, if you use plain air (20% oxygen, 80% notrogen roughly) the tires will deflate somewhat faster than if they were filled with nitrogen only, but only by a very small amount, as the oxygen molecules can diffuse faster through the tire than nitrogen. You might notice a difference over a period of maybe a year or two, not days as some sellers would have you believe.

It comes down to this: if you filled your tires with plain air, you'll have to top up the pressure maybe once more per year than if you filled them with pure nitrogen.

Now, fill the tires with helium, and they won't stay inflated for more than a day or two, because the atomic radius of the helium atom is very small compared to the size of the nitrogen and oxygen molecules.

Gee, I've found a use for my B.Sc. (honours chemistry) after twenty years... Finally!

Cheers!

[Surferdude]

Thanks Doc.

[Mutley]

I put mine at 40 front 38 rear last night. Will see how that goes. So far it hasn't seemed too hard.
At that psi my fronts still look like they need air! Must just be the design of the tyres.

[Surferdude]

I put mine at 40 front 38 rear last night. Will see how that goes. So far it hasn't seemed too hard.
At that psi my fronts still look like they need air! Must just be the design of the tyres.

All radial ply tyres look like that Mutley. You're right. It's the design of the tyres. The "bulge" is part of the tyre's footprint on the road and if you put too much pressure in you distort the footprint so that the loads across it are uneven and that generates unhealthy heat build up in parts of the tread.
Look back here later and I'll post some pics.

[Mutley]

I thought the "bulge" was to make the tyres a bit more "cushiony", to make the ride more confortable. I've been reading about the psi's people use and have decided to try this out for a while. Hopefully it improves my economy without ruining tread wear as it has done for others.

[Surferdude]

I can't find the pics I want.
But there are photos taken from under a glass plate with a heat camera which shows the tread pattern in varying colours depending on the heat of that part of the tyre. They are quite dramatic, especially when you see sequence shots comparing the same tyre at different pressures.
They clearly show how underinflation causes excessive heat build up (and thus, wear) on the shoulders and overinflation, the same but only on the centre ribs of the tyre.
I'll keep looking but hopefully the above gives you some idea.

[agentr31]

Gee, I've found a use for my B.Sc. (honours chemistry) after twenty years... Finally!

champion!!!

hrmm *fills tyres with concrete* now they will never go flat

[Mutley]

I can't find the pics I want.
But there are photos taken from under a glass plate with a heat camera which shows the tread pattern in varying colours depending on the heat of that part of the tyre. They are quite dramatic, especially when you see sequence shots comparing the same tyre at different pressures.
They clearly show how underinflation causes excessive heat build up (and thus, wear) on the shoulders and overinflation, the same but only on the centre ribs of the tyre.
I'll keep looking but hopefully the above gives you some idea.

Yes I had read that. I just don't know what pressure to put mine to so that I don't get excessive heat build at any part.

[Dazzler]

Hey Trev, Here's one you might not be able to answer...

Where are these long roads made of glass with very fast moving cameras under them 

I Guess what I'm trying to say is did they ever explain how they do those photos...

[Surferdude]

Hey Trev, Here's one you might not be able to answer...

Where are these long roads made of glass with very fast moving cameras under them 

I Guess what I'm trying to say is did they ever explain how they do those photos...

Sorry Daz.
That's too easy.
It is literally a glass plate with water across the top at specified depths and a high speed camera mounted underneath.
Simple when you know how.

[Dazzler]

   Fair call...

I'm usually good at lateral thinking..

[Surferdude]

  Fair call...

I'm usually good at lateral thinking..

I wasn't sure whether you were having a go at me, so I decided to play a straight (?) bat.

[Dazzler]

Would need to be very high speed cameras 

[Lakes]

I'm a little confused by the replies here. I'd have thought that a tyre inflated to 'normal' pressure would have the maximum road contact area in emergency braking. Maybe widthways the over-inflated one would have the edge, but the length of tread would be greater for normal, surely ?

I'm also a little puzzled by the fact that the recommended tyre pressures are the same for diesels as for for my light petrol engine. The extra weight of the diesel engine is 220 pounds - all over the front wheels - like a fairly porky bloke sat on the bonnet.   

Then again, why wouldn't Hyundai recommend higher pressures if it gave them better MPG figures and was safe?


I'm thinking maybe 34 rear and 33 front at the moment.

hi Diablo, i felt the same as you thinking the heavy diesel motor would not handle as well as the lighter petrol motor. then i drove a petrol i30, but it did not feel as stable at speed as the diesel.
i owned a 6 cyclinder ford SUV owned it for three years and 250,000k, sold if bought another ford SUV with a 5.4Litre V8 at high speed in corners the V8 felt a lot more planted on the road and it had a limited slip diff, i could use throtle control to steer. it was also a one ton load rateing, i asked a tyre guy to put 55psi in the tyres ( GoodYear Cargo 205 60 16" ) he almost died, repeating 55psi. but i was about to put a one ton load on , and he did not know that . but i can tell you if you under inflate tyres you are going to carry a load on they don't last as long. i got 110,000k from the four tyres on that SUV and never needed a wheel alinement.
what you need to know is Hyundai got the suspention worked on for Australia as our roads and driving conditions are a lot different to what you have in europe. different road surface different temperatures and could find ourself a long way from help if we get a flat tyre so we have full size spare. so what we recomend is for Australians only. Hyundai took the time to set up the i30 that we get here in Australia for Aussie conditions. so i thank them for that. the diesel can take the high flow diesel pumps that the big rigs we drive here use, as well as the normal size filler, also i have to drive over the blue mountains and there are some big hill's to go up, the petrol labours up these hills, but that heavy diesel exicutes them mate! cheers come over anytime, it's always good seeing how it's done in other parts of the world.

Quick question, related to the above post.

How is the steering configured differently in Australia from the other European/American configurations? Is it tire-related?

[Lakes]

Quick question, related to the above post.

How is the steering configured differently in Australia from the other European/American configurations? Is it tire-related?

hi Dr pepper, not the steering mate, its the spring or damping rate they worked on for Australia. they talked about it back in late 07 when they first released the i30. they got someone to look at spring & damping rate for Australian conditions or so they said.
about the Nitrogen, BMW use it in new cars here. a friend got a new 5 series, he told me tyre pressure does not need checking for one year and they do it with service, as nitrogen filled. guys at the track ( race track ) use it in there motorcycles they just keep a cylinder of it to adjust tyre pressure. sorry i know you all spell tires not yres like us, i don't know why we use the y does not stand to reason but we do.
cheers

[Surferdude]

Steering as well, guys.......
from.........NEWS RELEASE

News media release Monday, 1 October 2007
NEW i30: INNOVATION, INSPIRATION AND INTELLIGENCE FROM HYUNDAI

Advanced suspension - further refined for Australia
i30 suspension and steering have been specially calibrated for Australian driving conditions. This involved refining i30's European settings to accommodate our multi-patched, lumpier, bumpier local roads.

Testing was undertaken, both in Korea and in Australia, to specify the optimum combination of front and rear springs, shock absorbers and anti-roll bars, together with revised mapping of the control unit on the electric power steering system. The components chosen for Australian i30s debut a combination that is unique in the world (although NZ cars will also share them).

The result is a considerably sportier driving experience but with enough built-in compliance to smooth out our rougher roads. i30 has more neutral handling characteristics with no unexpected vices, with steering that benefits from increased weight and more feel. It is a dynamic package fully in tune with i30's youthful target market in Australia.

i30's suspension uses coil springs and gas shock absorbers in MacPherson struts at the front and a newly developed Independent 'Torsion Blade' multi-link rear suspension, configured to fit under i30's short rear end.

i30's independent Torsion Blade rear suspension incorporates upper arms and a fourth link each side and blade-type longitudinal links whose twist actions supplement the springs. The springs are separated from the shock absorbers, increasing boot room by allowing smaller wheelhouses. Optimised geometry incorporates an element of passive rear steer to balance the car's natural understeer handling characteristics.

i30's MDPS (Motor Driven Power Steering) saves fuel by minimising energy loss compared to conventional hydraulic power steering. It is engine and road speed-sensitive and reads the driver's steering wheel inputs and turning angle to optimise the level of assistance needed.

Front and rear disc brakes are large at 280mm and 262mm respectively. The long wheelbase reduces pitch while the wide wheel tracks translate into overall ride stability and enhanced balance.

NVH (noise, vibration and harshness) analysis has been a crucial aspect of i30's development to ensure the ideal choice of absorption materials for each body part and to strengthen and reinforce the sub-frame and body panels. Then strategic padding was used to seal and isolate wind and vibration hotspots. Combined with the body's extra strength and rigidity, the interior air management system adds to the distinctly quieter interior.

[Dazzler]

Nice find Trev... I had read something about it some time ago but had forgotten the detail..

[Surferdude]

Nice find Trev... I had read something about it some time ago but had forgotten the detail..

I particularly like this bit, don't you Daz?

It is a dynamic package fully in tune with i30's youthful target market in Australia.

That's us. Youthful.

[Lorian]

On the maintenance menu for the EPS motor profile there are options for various tyres sizes and fuel types, and one that just says "Australia". This tells the system how much assitance to apply at what speeds. They haven't published torque graphs though.

[Dazzler]

That's us. Youthful.

Some days I feel more"youthful" than others...

[diablo]

That's us. Youthful.

Youthful am I.

Knackered old git more like.

[Lorian]

Youthful am I.

Yoda more like