225 vs 245 tyre width

[Msaville]

Hi There,

Has someone tried 225 width tyres. I have read somewhere they give more predictable handling. I need to replace my 245's soon and feel that they sit too "square" on the road - especially on 7J rims!. I know "Porsche knows better than I", but after owning some more modern high performance wagons my thoughts are that a 225 or 235 would sit better on the rim and give a nore progressive "edge" (as well as being cheaper!).

Help!

Macca the Kiwi

[jeremyc]

Macca,

Good to hear from you! The RS2 tyre issue is a complex one; there has been much discussion on the Yahoo! Groups RS2list on this in the past, but hopefully I can summarise here.

The OFFICIAL word from Dunlop (the company that was contracted to make the bespoke 245/40/17 SP Sport 8000 tyres specifically for this model) is NOT to fit 245/40/17 tyres from any other manufacturer. Most 245 tyres are actually wider than the SP Sport 8000 tyres and are TOO WIDE for a 7 inch rim. The problem comes in the manufacturing process where most 245 tyres are heated and stretched to 8.5 or even 9.5 inches wide. This means that in normal operation, when the tyres heat up they can and will expand beyond your wheels capability and will come off
which is clearly a significant safety risk.

Either fit:
245/40/17 Dunlop SP Sport 8000 tyres OR
225/45/17 tyres that can safely be put on 7 inch wide rims NOTE: not all 225/45/17 tyres are safe for this size wheel either).

Dunlop stopped the manufacture of the SP8000 some time ago, although some RS2 owners here in the UK have been lobbying for a further production run.

So, 225 section tyres are your best bet.

Regards,

Jeremy

[Msaville]

Jeremy,

You are a star! Pretty hard to find info in NZ. Infact with 8 cars in a country almost as large as the UK (size not pop) - its pretty hard to find another RS2 owner!

I have two further questions for you:

A). How do I access the discussion board on Yahoo?

B). Do you for example know of any 225 section tyres that will work on 7J rims (i.e. Bridgestone S03/2/2a or P zereo asymetricos etc)

Cheers

Macca the Kiwi [img]images/graemlins/1syellow1.gif[/img]

[Jani]

We actually had a kiwi RS2 owner on yahoo list, just upgraded to S8.

S02 225/45-17 has been fitted, and is OK. 245/40-17 S02 actually broke on listers wheel -so wheel issues are nothing new in RS-range [img]images/graemlins/smirk.gif[/img]

Number of listers have been fitting new Goodyear Eagle F1 (GS-D3), and have been happy. Especially wet grip is astonishing they say.

I have S03 (although 235/40-18 on 8.5x18"), they are a little noisy. Otherwise a good tyre, stands up to track punishment as well, stiff sidewall gives good turn in and keen steering feel (compared to PZero). Wet grip is not very good. Next I'm planning to go GS-D3.

The mentioned yahoo group is at:
http://autos.groups.yahoo.com/group/RS2list/

Web interface a lot worse than this, works ok as email list though.

[johneroberts]

Number of listers have been fitting new Goodyear Eagle F1 (GS-D3), and have been happy. Especially wet grip is astonishing they say.

This tyre is unsuitable for heavy cars like the RS4/RS2 and i would stongly advise you not to use it, we have had reports of Goodyear giving full refunds to users recently, i peronslly would plum for the SO3s .
Cheers
jr

[Jani]

Interesting John,

my Dad has them in S3 (not that light, nearly 1500 kg), works well. I would have thought that the extra load Goodyear would work well, I'll have to look into it more.

What is the specific problem with GS-D3? Is it sure that it is a design flaw, not some manufacturing fault affecting a batch?

[johneroberts]

Taring down the centre seem , due to the side wall under heavy cornering colaspes and distorts the tyre causing it to [img]images/graemlins/frown.gif[/img] split

[MPSeed]

P-Zero tread width too large, tried SO2, fine, but some white lining, advice from Silverline (Warwick)is 4wd behave better if tyres are NOT directional.. I recall my original Goodyear did not white line when new, and SO2's did.

[Bushy]

Taring down the centre seem , due to the side wall under heavy cornering colaspes and distorts the tyre causing it to [img]images/graemlins/frown.gif[/img] split

No strictly true

My understanding is that the centre of the tyre has a silica bead below the surface which is designed to absorb heat until it is dispersed from the tyres surface

The large ribs of rubber tread channel the heat to the centre bead to keep heat away from the shoulders, giving better cornering grip

The silica bead is covered with a harder compound rubber, which appears to not be able to cope with the heat.

So our heavy cars under hard driving/cornering genereate a large amount of heat which causes the hard rubber bead to expand and become unglued, this then can cause problems as the whole surface of the tyre is not bonded together correctly

Although not strictly a safety issue as the steel beads will hold the tyre together it could shred with continued high speed driving/cornering IMHO

[Riz_RS4]

Although not strictly a safety issue as the steel beads will hold the tyre together

yikes..... what would happen if you went over a pot hole and the standard alloy bent and you carried on driving with these tyres on........ [img]images/graemlins/1syellow1.gif[/img]

[Bushy]

they are ok, trust me

but i had them sent back anyway

just awaiting a report on how much of a refund i am likely to get

[Riz_RS4]

Mmmmmm since i have no RS4 [img]images/graemlins/frown.gif[/img] and dont run those tyre`s i`ll be ok [img]images/graemlins/smile.gif[/img] hee hee [img]images/graemlins/s3addict.gif[/img] [img]images/graemlins/jump.gif[/img]

[kiwi_mtm]

RE: your rotor request. Try "trade parts" in Auckland.

[Greg_S]

i thought the RS2 had 7.5J rims like the S2? I have 8Jx17 rims fitted and the recommended tyre for the 7.5J x 17 is 225/45 R17 by audi and would have thought the RS2 would be the same.

[Cobstar]

Hi Greg

The original Audi RS2 Promotional Brochure says the wheels are "exclusive Porsche alloys - 7J x 17 in". With "special wide wheels: 245/40 ZR17 Dunlop SP8000".