Tyres

[Guest Dave TDI]

Does anyone know what the best tyre pressure should be for a 1.9 Diesel running with Dunlop 215/55R tyres?

 

The tyres seem to wear very quickly.

 

I have contacted Dunlop Technical who quoted that the manufactures (Ford's) pressures should be used!

 

Ford quote:

 

Normal loading with up to 3 persons

41 psi Front 38 psi Rear

 

Full loading with more than 3 persons

44 psi front 50 psi Rear

 

Thanks in advance

Dave

[seatkid]

Does anyone know what the best tyre pressure should be for a 1.9 Diesel running with Dunlop 215/55R tyres?

 

The tyres seem to wear very quickly.

 

I have contacted Dunlop Technical who quoted that the manufactures (Ford's) pressures should be used!

 

Ford quote:

 

Normal loading with up to 3 persons

41 psi Front 38 psi Rear

 

Full loading with more than 3 persons

44 psi front 50 psi Rear

 

Thanks in advance

Dave

??? My 98 Seat Alhambra (215/60 Continental sportcontacts) quotes 33-36 psi front and 30-39 rear. Quite a bit different for a very similar tyre.

 

My Contis last over 30k on front or 40k when all rotated. Highly recommended and they're quiet!

[Ivor_E_Tower]

I'm running mine at the Ford recommended pressures. First owner had one front replaced with the spare at about 17k miles, and I got the selling garage to put an almost new tyre on the other front wheel before I agreed to buy. The original worn front, which is now my spare, has between 2 and 3mm on it. When/if I have the money, I will probably have to have all 5 tyres replaced at around the 40k mark.

[Ivor_E_Tower]

I'm running mine at the Ford recommended pressures. First owner had one front replaced with the spare at about 17k miles, and I got the selling garage to put an almost new tyre on the other front wheel before I agreed to buy. The original worn front, which is now my spare, has between 2 and 3mm on it. When/if I have the money, I will probably have to have all 5 tyres replaced at around the 40k mark.

[Guest Dave TDI]

Thanks for all the replies.

 

I changed all my tyres at the end of December 2003 (Elite Tyres www.elitedirect.com cheapest I could find!) and will monitor what mileage I run before having to change them again.

I had already changed two tyres in the past and found the mileage very poor.

Better luck this time perhaps.

 

Regards

Dave

[Guest wrampo]

i use mine as a taxi and run the fronts at 44 rears at 46. doing really well at the moment. last lt did 10000 running at the low end of recommended pressures. this lot wearing well at top end of recommended pressures

[charles]

if the wear is at both outsides of the tyre than the tyre was underpressured.

I regulary adjust them to the ford values, but they gradually lose some air which stabilises around 35 psi.

[oggie]

Just changed my dunlop 215/55's, national tyres on a price match, less 10% best price was

[Guest Dansik]

I have a 1.9TDI at 70,000 miles.

 

I just put two new Avon's on the front last week, running at 44 psi so we'll see how we get on.

 

These tyres give much less tyre noise than the Dunlops I took off and they were cheaper too!, fitted at my local garage for just under

[NikpV]

are they (avons) reinforced ? ZR's?

[Dave-G]

B) Dansic,we cant really evaluate your reply as you have failed to declare your model (in vehicle type) (why the secrecy?) or tyre size B)

 

has it got steel or alloy wheels?

 

There is a major price difference between popular sizes [over produced/price war etc] and rare sizes............

 

B) I doubt you got new 215/55/16 at those prices B)

[gazza007]

Some tyre places offer 100% nitrogen inflation this will maintain tyre pressures.

This is because over time the oxygen content of air leaks through the porus rubber compound of a tyre. This is why F1 teams & airlines use it.

[NikpV]

I am intrigued and puzzled by this 100% nitrogen inflation, why should oxygen diffuse through a rubber tyre quicker than nitrogen. Given that both are diatomic gases of very similar relative molecular masses, in fact oxygen being 32g per mole is slightly larger/heavier (nitrogen 28g per mole). If the kinetic energy of the molecules are the same (dependent only on absolute temperature) the oxygen molecules move slightly slower! I can only think that there must be a chemical reason to do with the rubber itself and since normal air contains 78% nitrogen and 18% oxygen the oxygen must positively race through the tyre to make the difference quoted above. Can anybody shed any light on this.

 

I would also like to know where to get 215/55x16 reinforced tyres from (as specified on post facelift (2001 on) galaxies) for

[Mussey1]

Try Nokian Tyres!

 

I have had them on my car for a year and they seem fine.

 

Mine cost

[Richmond]

NikpV, I'm not sure that gas diffusion through a barrier is dependent only on molecule size, although I cannot understand why it isn't. I seem to remember seeing an experiment years ago (I have no idea where) which showed that hydrogen (tiny little molecule) diffused out of a balloon more slowly than air! I'm probably misremebering, it's certainly counter intuitive.

 

I doubt that much of the pressure loss in a tyre is due to diffusion through the tyre; they're not exactly designed to be porous and they're pretty thick. I'm sure it is almost entirely due to leakage around the rim and through and around the valve, and I doubt that the size or weight of the gas molecues makes any difference to that.

[Ivor_E_Tower]

Air is 80% nitrogen anyway, so for road use there is almost no benefit in using nitrogen only - and what happens when the tyre loses a bit of pressure and you need to pump it up a couple of psi???

There is a reason that nitrogen is used in racing tyres - cannot remember exactly why, but it may be something to do with expansion and pressure difference when the tyre heats up. Road going tyres don't heat up that much, whereas racing tyres do.

[NikpV]

Molar heat capacity (temp rise for a given number of joules of thermal enregy) of oxygen and nitrogen are the same, being diatomic the thermal energy is distributed between rotational(around common COM), vibrational and translational energy monotomic gases like helium and neon etc have different heat capacities so cant really see much advantage on the heat front. Had a chat with a chemist (not pharmacist) friend today and we can come up with a few possible reasons why it would be advantageous.

1) A pure nitrogen fill would be a much closer approximation to an ideal gas fewer intermolecular forces (van der waals) - probably would bonce back from deformation better (agrees with Ivor I think) :rolleyes:

2) Oxygen may chemically attack the rubber - free oxygen radicals are extremely reactive.

3) In both the aviation industry and F1 tanks of liquified gases containing oxygen would be more hazardous - think about the explosive risks when the uninformed grease the valves on oxygen cylinders ;)

 

Richmond - as far as diffusion goes the rate of diffusion is proportional to the sqaure root of the mass quotient e.g sqrt(32/28) = 1.07 ie nitrogen will diffuse at 1.07 times the rate of oxygen (slightly quicker) although this is simple diffusion the permeability of the membrame (tyre) needs to be accounted for.

There are certainly anomalies found at extreme temperatures and pressures e.g. liquified helium(3 I think) does funny things like flow up surfaces and through very small holes very quickly but if you can remember were you saw the bit about hydrogen diffusing slower than air tell us all - we could all become billionaires. It could be used to purify hydrogen as a fuel gas :D :D .

[Guest Dansik]

sorry to take so long to reply, been busy latley.

 

My car is an 03 1.9TDI with alloy wheels

 

I filled 2 Avon 215-55 -16 reinforced tyres. they have an unusual tread pattern but are definatly quieter.

 

By the way I am told if you try to fit non-reinforced tyres they will come of the rim on cornering.

 

The fitted cost on the vehicle was just under

[Richmond]

NikpV, yes, I know you're right. I've racked my brains and I think that I saw the hydrogen/air/balloon experiment on some kids' science TV programme about a hundred years; the kids had done the experiment and found that hydrogen diffused more slowly than air. I also remember that Prof Heinz Wolff (a mad TV professor with wild hair, of central European extraction (all of him, not just his hair)) was sceptical about it. The dangers of a poor memory!

 

Does anyone think that diffusion of gas through the tyre wall is a significant contribution to deflation (other than when the tyre is punctured!)?

 

Since tyres don't usually fail because the rubber has been attacked by oxygen in the air, I don't see that replacing it with nitrogen will improve tyre life.

 

I suppose that in F1, having a rubber bag containg hot pressurised oxygen at each corner of your car might be regarded as undesirable in the event of a crash.

[Ivor_E_Tower]

Just had to pay

[Dave-G]

:( Well DANSIC, that generated a lot of hot air! :lol:

[DubDriver]

I have a Sharan with Dunlop 2020 215/55 16 tyres.

 

The pressures for 3 persons are the same as you quote for the Galaxy but for fully loaded are 44 front 45 rear.

 

I have just changed one at the front and also changed over the spare. The were still legal but barely and had done 18500 miles mostly motorway driving.

 

The one which I bought cost

[Guest seatalhambra]

Irun at 42 allround which is with myself and a boot load of med weight kit. seems fine