Another tyre size question

[chrisg]

Hey Peanut, Apologies if you're aware of this already but, the profile number 45, 50, etc is a percentage of the width. So for your tyres: 225/ 45 = 45% of 225 = 101.25 255/40 = 40% of 255 = 102 So, although these are an exact match you end up with tyres that give or take a couple of mm (subject obviously to wear) are the same diameter and don't affect the gearing of the car. Having said that though, my 951 runs as standard on 16" with: 225/50 = 50% of 225 = 112.5 245/45 = 45% of = 110.25 So in effect by my reckoning the total diameter of your wheel/tyre combination is larger than the standard turbo/ s2 which has an effect on both top speed and acceleration - I can't remember which way round this is though, I'm sure someone will correct me !

 

[peanut]

thank you Chris for your prompt response. yes i am aware of the 'aspect ratio' of tyres but because these 17" 911 wheels are not standard equipment on a S2 I am not sure that the correct tyres were fitted by the previous owner. before i order up £500 worth of tyres to be fitted I want to make sure I am specifying the correct tyres for these wheels. They are Cup 2 wheels which I believe are off a 911 ? or boxter ? i really don't know [link=http://www.porsche968uk.co.uk/images/cup-2-alloy-wheel.jpg]http://www.porsche968uk.co.uk/images/cup-2-alloy-wheel.jpg[/link]

 

[peanut]

I need 4x tyres for my S2 to pass the test.

I have just noticed that the two rear tyres are a different profile to the front. Can anyone tell me the correct tyre size for 17" cup2 wheels please?
This is what is on there at present
Front 8.5" 225x45x17
Rear 10" ? 255x40x17

 

[Pastry]

sound like 993 wheels. maybe ask on that forum? I know a 993 owner with 17" cup2s but they're 7.5J front and 9J rear (nearly bought them but he put them back on). I know the rears were 255 wide but cant remember the profile.

 

[Diver944]

Peanut, You have the exact 100% correct size tyres for 17" wheels on a 944. It's what the 968 was supplied with on 17" wheels, and when you take into account the wheel itself has a larger diameter and add it to the profile height that Chris provided above, it all matches The wheels themselves are slightly wider than the 968 version (7.5" and 9") but that will not make much difference

 

[peanut]

thanks guys you are ace.! I measured overall width because the tyres were fitted. Just realised the wheel width is taken between the rims doh...... I'll go quietly.[] So sizes are ok but tyre prices sure have gone up. Budget tyres are going to cost £350 crikey I can buy a taxed and MOT'd Mondeo for that [&o] I may have to SORN the pig unless I can find some used tyres

 

[peanut]

ORIGINAL: Pastry sound like 993 wheels. maybe ask on that forum? I know a 993 owner with 17" cup2s but they're 7.5J front and 9J rear (nearly bought them but he put them back on). I know the rears were 255 wide but cant remember the profile.

I have to say compared to the previous S2 i had with 16" standard wheels the Cup2's really fill the arches and transform the looks of the car . Its a great upgrade imo

 

[david924s]

My S2 has Cup1s in the same size as you quote and I agree they fill the arches and look great, I got four Toyo T1Rs fitted (2yr ago) for £330 and they are still going strong with around 6-7K miles on them, great in the dry and good enough in the wet. See below the wheel specs for a 968 Cup1's to 93 cup2's 94- MY [link=http://www.porsche968uk.co.uk/images/cup-alloy-wheel.jpg]

[/link] [link=http://www.porsche968uk.co.uk/images/cup-2-alloy-wheel.jpg]

[/link] All coupes and cabs had 16" cup 1's as std. pre '94 coupe's could have 17" cup 1's as option, and would have if upgraded to sports suspension (M030). 17" cup 1's on pre-94 CS's Post 93/94my sport and cs's all had cup 2's.

 

[peanut]

yeah the Toyo's look great don't they ! I just wish i could afford them. My Father got Dementia last year and I had to close both my companies and quit work to be his full time carer. We get no income support or carer's allowance and last month the benefits dept suspended our rent and council tax payments so now we have no money . My Bank have just this week charged me £ 150 penalties for all the direct debits that hit my bank 1st of the month and now we have no car ,no money and I'm heading for a nervous breakdown . Still must look on the bright side at least it isn't raining!........ ...................oh it is raining lol[] good luck to ya matey Nick