3 litre TDI tyre pressures

[simfin]

I have a 3litre Diesel Avant and have just changed the tyres. The problem I now seem to have is that the ride is "bumpy" compared to the old set of tyres.

I have gone from Michelin PS3 Sport 245/40 18 97YXL to Michelin PS3 Sport 245/40 18 93Y (AO) -audi fitment.

It now seem that the car is very very sensitive to road conditions, but also an increased response to turn in on corners. It makes for quite tedious drive now :( . I have checked the tyre pressures on the door sticker and it suggests 41 PSI front and 36 PSI rear.

These pressures seem a little high? I am thinking that these new tyres are not handling the high pressure as well as the originals which were the XL type. Ofcourse the tyre fitters dont see a problem as they dont have a comparison as to what it was like previously.

I would be interested to see what other 3 litre diesel drivers are running pressure wise.

To be precise, mine is a 3litre TDI Se with dynamic suspension.

[Sam]

I suspect it's something to do with putting 19" tyres on 18" wheels unless you've changed the wheels too.

[Guest 2]

Tyre size for 19" tyres should be 255/35 .. Both a4 courtesy cars both had 255/35 tyres. Your speedo probably is out of sync too as you've changed the rolling radius.

I have 255/35/19 XL on my a6. I'm running 44 on the front and 38 on the rear as per the sticker in the fuel flap.



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[simfin]

Oh Cr*p,, really sorry my mistake. I should have said the new ones were 18's as well. now edited :(

[Sam]

I had secretly hoped that even a tyre fitter wasn't that foolish but you never know :)

How bad were the tyres you took off the car?

[simfin]

I had secretly hoped that even a tyre fitter wasn't that foolish but you never know :)

How bad were the tyres you took off the car?


The tyres I took off were pretty worn, about a 1mm off the wear markers. Its just that the car was super smooth in the way it drove, whereas these new ones have made the ride very sensitive and "jiggly" on poor surfaces. I am pretty sure it is that the new ones arent XL tyres, which is not what the door sticker says I should have anyway. Perhaps the ride now is how it always should have been and the original tyres masked it somewhat ??

I may reduce the pressures a bit and see how it goes.

[zollaf]

just to clarify, your old tyres were extra load and the new ones arn't ?

[simfin]

just to clarify, your old tyres were extra load and the new ones arn't ?


Yep, the old ones were XL and these are not, although the new ones are an AO fitment which I cant find out what it really means.

The label on the door Jam just stipulates the tyres should be 93Y , with no mention of XL


so i went from

245/40 ZR18 97Y XL (extra load)

to

245/40 ZR18 93Y AO (audi fitment)


Both tyres are Michelin Pilot Sport 3's


I dont understand why, but the new ones are definitely more "crashy" through road imperfections. I reckon it has something to do with a lower load rating of 93 and not being XL.
I will see if the tyre fitters can do anything about getting me the same type of tyres as I had previously.

[Sam]

In all the excitement about putting the wrong tyres on the wrong sized wheels I overlooked the XL bit completely!

XL tyres have reinforced sidewalls to carry extra weight and extra pressure.

Putting the same pressure designed for an XL tyre into a "normal" tyre will no doubt mean it was overinflated and thus your ride would be buggered.

[Eshrules]

Have the tyre pressures actually been checked, to see what they actually are?

[simfin]

Have the tyre pressures actually been checked, to see what they actually are?


Yep, all checked and as per the door sticker 41 upfront, 36 at the rear.

I guess if I reduce them, then I would get the opposite problem of the tyres "rolling" under themselves. Spoke to Audi - may as well have saved my breath,, LOL.

I reckon it is a good call on the XL - allows higher pressure without giving the bumpy ride.


The tyre fitters are going to see if they can do anything for me about swapping them over to what I had originally, at a cost no doubt. But, I can stand the car riding like this anymore :(

[markp306]

Just recently put XL tyres on the front axle, but I am running the old tyre's full load pressure of 2.2 bar as the new tyre's specific size (225/50ZR17-98Y) isn't listed on the door sticker.
All the XL tyres listed on it are 2.5 bar regardless of size though. Maybe I will increase the pressure then!

Thanks for bringing this to my attention!!

[SunnyBard]

I have a 3litre Diesel Avant and have just changed the tyres. The problem I now seem to have is that the ride is "bumpy" compared to the old set of tyres.

I have gone from Michelin PS3 Sport 245/40 18 97YXL to Michelin PS3 Sport 245/40 18 93Y (AO) -audi fitment.

I have 3.0TDI S line with 20mm sports lowered rather than 30mm S line lowered suspension, no dynamic damping (BOO!! I wish I'd spotted how cheap an extra this would have been, given that I do have the sport diff)

It arrived with Pirelli P7 245/40 R18 97Y XL, which agrees with the sticker on my door, 93Y are not an option according to my sticker, nor are non-XL tyres with 18" or 19" wheels.

Pressures of 41 and 36 are what I use as per the sticker, they have always struck me as pretty harsh, not very forgiving of bad road surfaces or speed humps, I did try it 2-3 psi lower but it wallowed a bit, especially over wet white lines :-(

4.0mm left on rears and 5.5mm left on fronts after 19,500 miles, I 'll be changing from the P7s.

[simfin]

I have 3.0TDI S line with 20mm sports lowered rather than 30mm S line lowered suspension, no dynamic damping (BOO!! I wish I'd spotted how cheap an extra this would have been, given that I do have the sport diff)

It arrived with Pirelli P7 245/40 R18 97Y XL, which agrees with the sticker on my door, 93Y are not an option according to my sticker, nor are non-XL tyres with 18" or 19" wheels.

Pressures of 41 and 36 are what I use as per the sticker, they have always struck me as pretty harsh, not very forgiving of bad road surfaces or speed humps, I did try it 2-3 psi lower but it wallowed a bit, especially over wet white lines :-(

4.0mm left on rears and 5.5mm left on fronts after 19,500 miles, I 'll be changing from the P7s.


Thanks for the reply.

Weird that my door sticker states 93Y and no mention of XL.


Perhaps the wrong sticker was put on the door for my car

[SunnyBard]

The label on the door Jam just stipulates the tyres should be 93Y , with no mention of XL

Your sticker must be different to mine then ... the red highlighting was for my benefit ...

http://adslpipe.co.uk/car/tyre%20pressures.jpg

[simfin]

Your sticker must be different to mine then ... the red highlighting was for my benefit ...

http://adslpipe.co.uk/car/tyre%20pressures.jpg


Excellent, thanks again.

So mine is an SE yours a S line

mine is a Manual yours a Auto.


I cant see those differences making the tyres different. Does make me think they have put the wrong sticker on my car. Any other 3litre TDI owners know what their stickers say ?


Cheers :)

[theskyfox]

Curious. On my 3.0TDi Saloon, I use 42 at the front and 36 at the back. That applies to both the 19" Summer wheels/tyres and the 17" winter wheels/tyres.

-Andrew

[simfin]

Your sticker must be different to mine then ... the red highlighting was for my benefit ...

http://adslpipe.co.uk/car/tyre%20pressures.jpg


and this is my door sticker, so there are differences.

http://img.photobucket.com/albums/v477/simfin/IMAG0150.jpg

[Sam]

Check the part numbers of the stickers, they're the same save for the last two digits. The last two digits usually indicate a revision of an item.

[simfin]

Check the part numbers of the stickers, they're the same save for the last two digits. The last two digits usually indicate a revision of an item.


Yep, checked with Audi. They say my car was built with 93Y tyres so that is what they "would recommend". He did go quiet when I quoted the part number of the sticker, as I reckon they have updated the sticker later in the model run. My car was one of the first models made, a showroom sample apprantly.

So, the tyre company have said they wont swap them over - which is fair enough from their point of view I guess. Which basically leaves me with these tyres, that I am having to live with or change again to the 97Y XL's and sell these on.

[druidt1]

I'm having similar problems and found this thread when doing a search.

I replaced the rears with Pilot Sport 3 and 245/40/18 and the drive is not the same - it's sensitive to the road conditions like OP. I was hoping this was due the tyre needing run-in.

I've just called the garage (kwickfit) to have a look at them and will taking the car in tomorrow.