tyre wear

shaunthesheep · Post by **shaunthesheep** » 16 Oct 2002, 03:05

i've got syptoms of under inflated tyres on the front & rear, but they are all set to the correct presare. the wheel aliment is ok, as is the balancing.
has anyone got any ideas as to what could be cauing it??
dom

skiing39 · Post by **skiing39** » 16 Oct 2002, 04:01

Driving to fast!
David M G Jones

shaunthesheep · Post by **shaunthesheep** » 16 Oct 2002, 04:15

haha very funny <img src=icon_smile_big.gif border=0 align=middle>
dom

Chris_L · Post by **Chris_L** » 16 Oct 2002, 18:43

Dom,
I'm confused with this one... How can your tyres be under-inflated if they're at the correct pressures? Are you sure your pressures are correct for your size of tyre (assuming you mean they *feel* under-inflated)?
Chris

shaunthesheep · Post by **shaunthesheep** » 16 Oct 2002, 23:25

chris,
well acording to the sticker on the drivers door piller, and my local tyre dealer, i've got the correct size tyres and inflated to the correct pressare, but why are my tyres wearing on the outside & inside edge, as if they are under inflatted. <img src=icon_smile_sad.gif border=0 align=middle>
how would i check to see if they are 'under inflated'?
dom

alan s · Post by **alan s** » 17 Oct 2002, 03:52

Dom,
Presumably all 4 are doing the same thing. Where do you normally check your pressures or do you use your own gauge? It may be a simple case of dodgy gauges (it may also be that you've been struck by lightning - a few times, about as possible that they're all faulty)
Personally, I never go by the book as far as tyre pressures go as I feel there are a number of variables at work. Load; do you normally drive solo or with a load? How balanced is the load?
Are the tyres always checked when dead cold?
Do the tyres on the car at present have a fairly stiff or soft wall?
What kind of road surfaces do you drive on? How do you drive? and so it goes on.
I personally tend to set my own just by 'feel.' In my case, I drive a lot solo or with one front seat passenger. As a result I run a front tyre pressure of around 35psi with a rear of 28 or if I am going on a trip, 30 with just passengers or 32 with passengers & a load in the boot. I use a digital pocket gauge (deadly accurate) and try to do the tyres at home with the car in the garage. Tyre pressures will change dramatically due to weather (heat & cold) and the ultimate tyre fill is to get the air sucked out & replaced with nitrogen. This is what the interstate trucks do here in Summer to compensate for the high road temps and resultant erratic pressures.
Alan S

shaunthesheep · Post by **shaunthesheep** » 17 Oct 2002, 05:57

alan,
it is all 4 tyres that are showing the same symtoms, i check my pressares when the tyres are cold & and out of sunlight. i often drive solo, drive on tarmac roads mostly, speeds are mostly around 30mph approx 55kph. i check the pressares with a manual pressare gauge (one thats goes in & out), but might invest in a digtal one instead.
will check the tyre walls in the morning.
thanks
dom

NiSk · Post by **NiSk** » 17 Oct 2002, 17:08

Hi Alan;
Quote:
"Tyre pressures will change dramatically due to weather (heat & cold) and the ultimate tyre fill is to get the air sucked out & replaced with nitrogen. This is what the interstate trucks do here in Summer to compensate for the high road temps and resultant erratic pressures.
Alan S"
Take a look at your old physics books, especially Boyle's law! Plus the fact that air contains 70% nitrogen - I don't think you will achieve much by filling your tyres with pure nitrogen - apart from the fact that it's kinder to rubber than air.
//NiSk

alan s · Post by **alan s** » 17 Oct 2002, 18:25

Better tell the truckies that used to leave $1000 tyres shredded all over the highways; t'was there idea not mine. I think the word "stability" comes into the equation. Which is why dragsters and racing touring cars do the same things..well in tropical climates anyway <img src=icon_smile_wink.gif border=0 align=middle>
Also if this is not effective, why do they use nitro in spheres & not compressed air??
Alan S
Edited by - alans on 17 Oct 2002 13:27:25

NiSk · Post by **NiSk** » 17 Oct 2002, 18:58

Like I said, Nitrogen is kinder to rubber! It's a relatively inert (chemically) gas and I guess that tyres last longer with an inert gas at high pressure inside; on the other hand, there's not much you can do about the vast quantities of air attacking the outside of the tyre! And physically there is no measurable difference in the way nitrogen behaves compared with air.
//NiSk

Chris_L · Post by **Chris_L** » 17 Oct 2002, 20:27

Dom,
I would say its one of two things... Either your tyres aren't pumped up enough (maybe due to faulty gauge or different pressures required for the particular make / model of tyre than the 'book' says), or you're cornering like a madman!! <img src=icon_smile_wink.gif border=0 align=middle>
Like Alan, I'd suspect the gauge first. You can usually feel when the tyres are underflated through heavy steering and excessive wallow on hard cornering. What I would suggest is just experiment with adding more air in the tyres until it feels right. If you put too much in, the ride will feel very hard and when cornering, you will feel a tendancy to understeer (as the tyre won't flex enough and not enough of the surface will be in contact with the road). Once you've got the fronts right, then adjust the backs so that they're about 2psi down on the fronts.
Good luck (and try another gauge!).
Chris

shaunthesheep · Post by **shaunthesheep** » 18 Oct 2002, 03:22

thanks for you input fellas,
will look into 'playing with the presares', if i can stop cornering like a madman <img src=icon_smile_tongue.gif border=0 align=middle><img src=icon_smile_wink.gif border=0 align=middle>
dom

FFX-DM · Post by **FFX-DM** » 23 Oct 2002, 19:34

Rather topically, I have just been with sad Corsa driving chum to get a new battery. I noticed with interest that MeriTyre of Thame are offering inflation with Nitrogen for £1.25 per tyre (plus VAT).
They list the benefits as:
less expansion and therefore more consistent pressure readings.
Increased pressure retention.
A study in Rubber and Plastics News (ooh er missus!) found that nitrogen inflation made radial tyres more durable
Eliminate harmful moisture and thus wheel corrosion
Proper inflation reduces rolling resistance and inproves fuel economy (but that it true of air too,of course).
Hmm, well I am not convinced that I am going to rush out and get it done. It is cheap enough, but I would think that regular checking of your tyres pressures would be good enough. Mind you, they do assure us that Nitrogen is not explosive, which as I breathe in is a great relief! <img src=icon_smile_wink.gif border=0 align=middle>

NiSk · Post by **NiSk** » 24 Oct 2002, 13:37

Yea, that's one thing I didn't think about - if the nitrogen is dry, there will be a considerable difference compared with air, which normally comes from a compressor at your local garage and depending on the amount of water vapour in the air (as I imagine there aren't many fitted with dryers) so you could end up with quite a lot of water vapour in your tyre and THAT does make a difference (see Boyles law again!).
//NiSk

shaunthesheep · Post by **shaunthesheep** » 26 Oct 2002, 04:54

ALL,
on much closer inspection eg with the use of a pit, it is just the front which are wearing oddly!!, by oddly i mean not at the same rate, the passangers side seems to be be wearing just the outside edge more faster than the drivers side!, could this have something to do with the steering wheel not being on the correct spline, eg could it be a spline out??, as have noticed that the sealing paint on the steering wheel nut has been chipped off.
have been advised to 'mesaure the exposed threads on the tracking arm' to see if the tracking arms are wrongly adjusted, can i just mesaure them, or could i count them??
dom