Member Since: 11 May 2006
Location: Off again! :-)
Posts: 73080
Hi Gurvan, long time no see!!!
If it was me I'd obvoiulsly get a new to replace the slashed tyre, put it on with the full sized spare and stick the wheel with the 20k tyre as the spare. Job done!
Then go and find who did it and drive over him in your work car!!!
14th Jun 2008 2:12 pm
Gurvan
Member Since: 02 Jan 2005
Location: Germany... Not far from both the US and Hard German rock...
Posts: 1089
Hi DSL, that's right, I've not been here for awhile...
And, unfortunately, that is my work car no longer...
Thank you for the advice !Georgia On My Mind...
14th Jun 2008 4:16 pm
philthejono
Member Since: 01 Aug 2007
Location: Rugby
Posts: 85
I got as slow puncture after not being able to avoid a piece of wood with a nail sticking out of it on the M6. Had 4 tyres at around 4mm, now have 3 at 4mm or less and the offset front as new. Not noticed any difference in the way the car drives or performes in the 1,000 odd miles I have done since the new tyre.
Can't work out whether I am breaking the car though11 HSE Santorini Black
14th Jun 2008 5:28 pm
MJC73
Member Since: 10 Jan 2006
Location: Gold Coast
Posts: 100
Had my front tyres moved to the back at my 12 month service - dealers suggested and performed the swap and alignment after 17,000kms on the OEM Goodyears - it is incredible the difference that fresh rubber makes to the steering, it almost feels a bit too light now, its taken some getting used to.
16th Jun 2008 3:49 am
Bushwanderer
Member Since: 27 Nov 2007
Location: Northern Rivers, NSW, Australia
Posts: 2050
Hi MJC73,
It might be that the alignment had a big impact. Do you know the before & after settings?
Best Wishes,
Peter
17th Jun 2008 4:24 am
MJC73
Member Since: 10 Jan 2006
Location: Gold Coast
Posts: 100
Hi Bushwanderer
Dont think the alignment was a problem - the wear was even and the issues with alignment seem to be about uneven tyre wear but I didnt get the settings so I guess I'll never know.
I did question the service guy and he said 'well its a big heavy car and they do use a lot of rubber' - suppose he has a point.
20th Jun 2008 3:56 am
AJS4X4
Member Since: 30 Mar 2008
Location: Surrey
Posts: 3224
We will change what the customer wants, one or five the customer is always right.
I would like to add that we will point out and show the customer the condition of the tyres we are not replacing.
All customers differ, we have a long time regular that if he gets a puncture will not have it repaired, no matter what.
Safety is paramount as the person driving around on illegal tyres could be the one that hurts or even kills someone.
It's amazing the condition of some of the tyres we change, the other day we had a chap drive in with a flat on a D3, I would like to add was NOT a D3 member, he had driven untill the rear tyre burst, we said did you not know they were getting low and he said " they told me the tyres needed changing a couple of months ago, but I thought I would get my moneys worth", how he got away with it I just don't know.
Some customers with the D3 just don't know how bad there tyres are on the inside edge, it costs nothing to have them checked.
We have only had one problem fitting just two tyres on a Jeep, customer said he was happy and ONLY wanted two tyres fitted, so two new tyres fitted with about 10-12 mm tread on one end and 2-3 mm on the other end, we told him we were not happy with this but as I said he insisted he only wanted two tyres fitted, got him to sign a disclaimer, funny thing was he was back in next day for the other two tyres to be fitted.
I think a lot of all this is about the manufacturers covering there rear ends.
I would be very happy for ALL customers having all four tyres fitted and the min legal tread depth set at 8mm.
I must add 1.6mm is a bit of a joke as tyres will not work in the wet at all, I think 2.5mm would be a lot safer.
Member Since: 20 Jun 2008
Location: Lancs
Posts: 766
While Costco bang the H & S drum I have never had a decent answer as to why when you have one tyre changed there they fill it with nitrogen as the other tyres had air in I didn't see the point as I have yet to find anywhere that I can top them up with nitrogen
Had an arguement with the fitter when getting one tyre fitted to the wifes Zafira after she decided to remove the side wall. He wanted to complicate the job by changing the worn rear tyres to the front and put the never used spare and a new tyre on the rear and the part worn front tyre as the spare. I pointed out to him that it would then have the rear tyres with different gases in them which when they warmed would obviously have different operating pressures this seemed to go over his head and he started going on about F1 cars and their tyres and how tests had been done to prove the benefit of nitrogen, I then had to point out a Zafira had a lot less downforce and he needed to remove his head from the dark side
20th Jun 2008 12:41 pm
Popelka
Member Since: 31 May 2008
Location: Praha (Prague)
Posts: 2430
surely if anybody has a single tyre worn worse or differently to the rest it would SHOUT problem somewhere (pressure, tracking, caster etc) and needs a quick check of the vehicle (regardless of make/model).
I would agree across axles to keep same on a standard FWD/RWD but on a 4WD I would question the manual/manufacturer as to recommendation.
besides don't all 4 tyres keep in ground contact and thus wear the rubber at a similar rate (not counting articulation or jumping vehicles over obstacles etc) if my car has 120,000km then the wheels/tyres have done the same distance, it's not like I can leave 1 at home
shouldn't the weekly vehicle check we all do spot possible issues before it get too far Experience is a difficult teacher, because she gives the test first and then the lesson afterwards!!!!
1st Jul 2008 7:39 am
cmyers_uk
Member Since: 10 Apr 2005
Location: Near Bristol, UK
Posts: 433
Quote:
He wanted to complicate the job by changing the worn rear tyres to the front and put the never used spare and a new tyre on the rear and the part worn front tyre as the spare.
I think we do need to appreciate that they are not doing this for fun. It is the advice from their tyre supplier that recommends the newer tyres are always fitted to the rear. The following link explains why they do this.
I pointed out to him that it would then have the rear tyres with different gases in them which when they warmed would obviously have different operating pressures this seemed to go over his head
Oxygen and Nitrogen and Air all respond in the same way to temperature changes as the tyre heats up and cools down: they all have the same rate of pressure change for an equal amount of temperature change.
So the tyre fitter may not be able to articulate why he was doing what he was doing but he was following the recommendation of the manufacturer of the tyre he was fitting so I say hats off to him for doing the right thing.
In all honesty if you had an accident because he had not swapped the tyres and as you now know this goes against manufacture recommendations would you not consider him negligent?
To be pedantic, Nitrogen expands ever-so-slightly-less than does air as it is heated (about 3/10,000 difference in expansion coefficient), but this is not a real reason for not using air. A clue to why Nitrogen may be specified is the aircraft industry. High pressure aircraft tyres require Nitrogen, not air. This has to do with oxidation (ie, burning rubber) than with expansion. A hot tyre (eg, after braking hard) with high pressure air (being about 20% oxygen) can start oxidizing on the inside. This is not so much of an issue in lower pressure D3 tyres, but it would be interesting if someone were to volunteer and put pure Oxygen in a tyre, then get it really hot while driving around. It might catch fire from the inside. Any offerers?
Also bottled nitrogen is completely free of moisture, but air compressed at a tyre shop has moisture in it. The moisture can condense in cold conditions (not a problem in Oz, admittedly) and form a lump of ice on a low spot. Makes for interesting effects in aircraft cruising at -55C.Jim Dowell - D4 HSE TDi, 12,000 hydraulic winch & hidden winch mount, MTRs, TyreDog, Traxide 2 x aux battery system, fixed air compressor, Dolium roof rack, MitchHitch.
RIP 2005 D3 HSE V8 5 seater gold (stolen and torched)
3rd Jul 2008 6:35 am
Bushwanderer
Member Since: 27 Nov 2007
Location: Northern Rivers, NSW, Australia
Posts: 2050
And the last time I looked, air is approx. 79.1% nitrogen & 20.9% oxygen.
I think that most (industrial) air compressors also have a filter, which should remove most moisture. (Do you like all the qualifiers?
Okay Peter. you're more precise for sea level air (but N2 does increase ever so slightly with altitude - not an issue for Perth!) and there's CO2, Argon, and some other bits floating about in our breathing fluid. The 21% Oxygen (approx ) can cause a propensity to oxidation (combustion), which was my primary point.
On the moisture issue, filters don't remove water vapour, just liquid water in air systems (unless they contain dessicant which needs to be changed out very often). The compressed air in the compressor's storage tank is warm, and holds some water vapour. When cooled (like an Alaskan night or at 12,000m cruise height for aircraft) this bit of moisture condenses out of the air and freezes forming a bit of ice. I learned about this the hard way whilst working in a hospital in Leadville, Colorado (at 9,997 ft elevation). The medical oxygen used to freeze up regularly (higher altitude = lower air pressure = more pressure drop from the tank = colder Oxygen out of tank = freeze-up). Problem was solved using aviation grade Oxygen, which is much drier than is medical grade Oxygen and hence less likely to freeze up. You've no idea how hard it was to get US gov't approval for using non-medical grade Oxygen in a hospital. The fact that at this altitude water boiled at 82 deg C meant that the autoclaves had to be designed to run at 5psi higher pressure than normal sea level to kill the bugs (I recall we never could get this approved so just had to ignore it, then run to Australia when found out )Jim Dowell - D4 HSE TDi, 12,000 hydraulic winch & hidden winch mount, MTRs, TyreDog, Traxide 2 x aux battery system, fixed air compressor, Dolium roof rack, MitchHitch.
RIP 2005 D3 HSE V8 5 seater gold (stolen and torched)
3rd Jul 2008 7:43 am
cmyers_uk
Member Since: 10 Apr 2005
Location: Near Bristol, UK
Posts: 433
Quote:
To be pedantic, Nitrogen expands ever-so-slightly-less than does air as it is heated (about 3/10,000 difference in expansion coefficient), but this is not a real reason for not using air.
So being pedantic, are we saying that in the volumes put into a car tyre there will be no noticeable difference in tyre pressure between nitrogen fill tyre and air filled tyre? Because thats my take on it.
Last time I looked I was driving a car not an aircraft as such fire from my speeding tyres does not worry me, indeed nor does the watervapour freezing at 32000 ft but your points are both true and well made
Cheers
3rd Jul 2008 3:25 pm
Bushwanderer
Member Since: 27 Nov 2007
Location: Northern Rivers, NSW, Australia
Posts: 2050
Accepting DingMark's figure of the difference in expansion coefficient between air & nitrogen, the difference is a whopping 0.03%.
The pressure gauges aren't sufficiently accurate for setting the pressures on car tyres within, I estimate, 2%.
Therefore to answer your answer directly - It makes NO difference.
I think that DingMark is just playing with figures.
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spot possible issues before it get too far 
(Do you like all the qualifiers? 
) can cause a propensity to oxidation (combustion), which was my primary point.
