Tyres

[Timmo]

The tread pattern on snow tyres is a compromise between an on-road and off road tyre. The pattern is designed to move snow/grit/water off the tyre so that the contact patches have the best foot print....

I guess you can look at it on a graph with 'potential grip' on one axis and 'surface type' on the other.

A racing slick has high potential grip but can only be used on a smooth, clean, DRY surface. Because there are no grooves, any dirt/water etc on the surface will come between the rubber and the road and reduce grip considerably (in effect, no rubber will be touching the surface).

A street tyre has medium potential grip and can be used on most surfaces- The grooves will be able to direct rainwater etc to the outside of the tread allowing the rest of the tyre to contact the road. Obviously if you drive through a large puddle of water or mud, the grooves cant shift enough water to the outside of the tread so the water will again start to come between the rubber and the road.

An offroad tyre or snow tyre has large grooves and knobs in order to shift alot of mud/water/snow etc but the result is less rubber on the road (i.e. low potential grip). The usually also have larger sidewalls (higher profile) and so will 'roll' on the rim a lot more.

So basically, if all roads were dry and smooth we could all use slicks. If all roads were muddy we would use offroad tyres. The reality in NZ is a mix of both so our tyres reflect that. Since we dont have seasonal snow in most parts, we dont really need snow tyres (or at least we dont need them in 80% of the country for 80% of the time)

[J_Eden]

Get rid of snow tyres ASAP! They're bad for 99.9% of NZ roads, and very dangerous. They're only on the tyres on imported cars mainly, and only because they're cheap and they meet minimum international standards. They're exactly that, minimum standards, you should always use tyres fit for the conditions. Take the rims into a tyre shop and they'll fit new tyres on them, should be able to get some the same size without any troubles

Snow tyres are the worst of the worst. They offer b**** all grip in the wet. They're basically end up like a racing slick, except they unfortunatly are legal for the roads.

Bingobob, thanks for pointing that out with the colder weather approaching. The same can be said for summer too or long trips. Always check the tyre pressure when they are cold, because as the tyre heats up, the pressure will also increase. For instance, a truck driving from Wellington to Auckland, the tyre pressure will increase from about 85-90psi to around 100-110psi! Thats a lot of pressure in a very small area. One of the reasons why changing truck tyres especially can be a dangerous occupation (if anyones read about the zipper effect...)

The increase in pressure can lead to the premmature wearing of the tyre in the centre as you say. This can be helped though by filling your tyres with nitrogen instead of compressed air, which will not keep the heat in the tyre, so can add to the lifespan of the tyre (as well as a few other benifiets nitrogen offers!). For an extra $30 to fill all of your tyres on your car, it's a small price to pay with $600 worth of tyres

James

[ardypilot]

Aw rubbish! I was out driving this evening and was meant to go down to the gas station to put some more air in my tyres- must do it sometime soon. Seeing this thread should keep reminding me..

[Bingobob]

Snow Tyres, You got them on a car in Auckland your a idiot waiting to die. Snow tyres only work efficiantly in those conditions and when the mean temperature stays near freezing or below.
Like Timmo said that does not apply to New Zealand, you go into the snow a good set of chains is all you need. Otherwise dont drive!
I have driven on snow tyres before but never in New Zealand, In Europe the Gas Stations have people lining up in October putting Snow Tyres on and in April taking them off. They would never dream of driving on them during the hotter summer months.

Worst place to check your tyre pressures is actually after driving to the service station. Two reasons! First the tyres would have heated up giving a false reading (see james note) secondly the service station pump may not be calibrated properly. The reason being it gets bashed about a bit.

For a couple of bucks you can get a tyre pressure gauge to double check the pump guage.

[HardCorePawn]

snow tyres are fun... NOT

my wifes imported prius came with these rock hard snow tyres on it... omg, even low speed corning I felt like an extra from Fast and The Furious: Tokyo Drift!

nevermind when we'd just had a light shower and the road was nice and greasy!

the nice guy at beaurepaires managed to lever some 195/55 directionals onto the rims (stupid, non-standard japanese tyres!) to get the rolling circumference the same...

now it corners like its on rails

[ardypilot]

Thanks for the further info guys-

Worst place to check your tyre pressures is actually after driving to the service station.

Thats a bit ironical seeing that most gas stations have air pumps then... I think I will fill up at the gas station, as it is convinient for me and I need some gas anyway... dont have enough $$ to go down to beaurepaires or wherever. I guess I'm still going to be safter with more air in my tyres that what I currently have, reguardless if it is from a gas station or workshop.

[Brennanx]

At my house we just use the air compressor it also works for riviting which helps the making of the rv-7 my dad is making might take 6 years for it to be made

[victor_alpha_charlie]

15 points to Bingobob!

Thats exactly what I wanted to hear from someone. The reason I asked the question is because a lady who came into work this morning abused the heck out of me. So much so, I ended up calling the police.

The story goes like this:
The vehicle in question had been brought in because she had a bad vibration thoughout the car. Upon looking at the car, I could see why...
All 4 tyres would've had about 5-10psi in them. Not to mention, the steel was hanging out of them. When telling her that the tyres were extremly unsafe and offering to put some secondhand tyres on for free (not perfect, but a good sight better than what was on!), she started to rant and rave that she had "only just brought the tyres from you guys" and should get a free set. I explained to her that there was no way that they could be brand new. But I was wrong apparantly.
I looked through our records, and yes she had brought a set of tyres from us. 3 years ago.
So yet again, she wanted to know why her tyres went flat...apparantly the principle of air leaking through small holes was not logical enough.
After 15 minutes of her yelling at me, I decided enough was enough. Police arrived and escorted her away.

Happy days!



Remember, 35 psi (the average) and when shopping for tyres, they may seem freaking expensive, but can you put a price on your safety (especially with wetter weather arriving). Always better to get the $20 pricier tyre than the cheap budget tyre.

Drive safely
James

Which tyre shop do you work at?

[J_Eden]

Which tyre shop do you work at?

Heya, Firestone

James

[victor_alpha_charlie]

Which tyre shop do you work at?

Heya, Firestone

James

ohk which one? i'll come see you

[Bingobob]

Thanks for the further info guys-

Worst place to check your tyre pressures is actually after driving to the service station.

Thats a bit ironical seeing that most gas stations have air pumps then... I think I will fill up at the gas station, as it is convinient for me and I need some gas anyway... dont have enough $$ to go down to beaurepaires or wherever. I guess I'm still going to be safter with more air in my tyres that what I currently have, reguardless if it is from a gas station or workshop.

Quick question why do you have to nit pick what people say Trolly? Not surprising that the only sensible advice given out on this subject has been from older and more experianced people.
Guess your going to get those wings sooner rather than later

[Timmo]

I didnt see it as nit picking??? Just an observation....

[ardypilot]

@ Bingo- what Timmo said