Fitting a 205/60 tyre instead of 205/55 - yay or nay? + thoughts on Firestone tyres

[Outrun944]

Need a new set of 4 tyres, still loads of tread on them but they're all mismatched - signs of crack on one and a puncture this morning in the other (thankfully repaired though) has jolted me into life on the elusive tyre hunt.

Front : 205/55 R15 (88V)
Rear : 215/60 R15 (94H)

Still can't find a complete set of 4 from *any* make in those sizes (same model) apart from Continental, but we're looking at £480 before fitting, alignment and VAT - ouch. And..... Firestone....

I've been offered a set of 4 FIRESTONE Firehawks at a massively discounted price - from a very well placed friend of mine -
But they don't do a 205/55 for the fronts, *but instead* have a 205/60

Yay? Or bad idea? The rears will be as before.

I believe it will affect the speedo as it's cabled to the front wheels correct? If so will the difference be that great? Will that show a greater (false) speed on the speedo or less?
Is there anything else to consider - such as handling, balance, fuel consumption, loss of speed?


Also any thoughts and opinions on Firestone (Firehawks) tyres? Bridgestone are a quality make, and I know these are a step down but I've heard good things. I really want a good grippy tyre for in the wet and winter conditions - from what I've read this won't be the best but is still very good and should last a long time. I've researched on here and people seem to like Kuhmo and TR1's ... but I can only seem to either get them for the rears only or front only in my size.

 

[stevie d]

Provided you are running standard 15" 7J wheels then the correct tyre size is either 195/65/15 all round or 215/60/15 all round . To the best of my knowledge Porsche didn't fit staggered tyre widths as standard on 15" rims .

 

[Cater_Racer]

Wouldn't go there myself, it's the first thing the insurance company will look at in the event of..................

Non standard tyre sizes or ratings would certainly be frowned upon.

 

[simdel1]

Unless they're declared []

 

[Pastry]

i'd use standard sizes. you sure you're on 15" and 7J all round? the ones you listed seem an odd set.

manual page;

mines on 195/65 r15.

 

[tref]

That chart is for late offset wheels - I seem to recall the sizes posted by the OP sound about right for an early offset car - mine were different front to rear when on 15" rims, both American spec and UK.

 

[944 man]

As others have stated, the sizes posted by the OP are incorrect and the cars shouldnt have staggered tyre sizes. Theyll certainly affect handling/roadholding (principally by making the car more understeery) and theyll look silly too. 911s warranted differing tyre sizes, but 944s didnt - it was only marketing.

Practically the 205/60/15s might match the size of some 215/60/15s; and they may be wider than others - although this works in both directions of course. Fitting four of the same size probably wont be the end of the world and I dont believe for a minute that it could cause any real insurance problems.

 

[Mike_Pollock]

Unless the car is lowered I found the 205/55x15 looked too small in the arch - I would (did) go for 215/60x15 on my '83 and the manual specifies the same size front and back

 

[Jonny944CS]

911s warranted differing tyre sizes, but 944s didnt - it was only marketing.

On a related subject, I've always thought it a little odd that Porsche specify a 20% lower front tyre pressure for the early 8v models:

924s + 944: 29psi Front / 36psi Rear
944s + S2: 36psi Front / 36psi Rear
968: 36psi Front / 36psi Rear

I'm sure they had their reasons, it just seems a little counter-intuitive.

Thoughts anyone?

 

[simdel1]

Yeah, I've always wondered about that too!

 

[Outrun944]

ORIGINAL: Pastry

i'd use standard sizes. you sure you're on 15" and 7J all round? the ones you listed seem an odd set.

mines on 195/65 r15.

Ummm I believe so! They're the Fuchs ... so I assume they're the standard 15" 7J? Did they vary??

http://a7.sphotos.ak.fbcdn.net/hphotos-ak-snc4/39108_10150215504155427_749340426_13740621_3758656_n.jpg

 

[944 man]

They arent Fuchs wheels, theyre ATS manufactured 'Cookie Cutters'. 7" x 15" ET 23mm. There were three tyre fitments for 7"x15" wheels, but the most suitable was 215/60/15.


Simon

 

[Outrun944]

ORIGINAL: 944 man
They arent Fuchs wheels, theyre ATS manufactured 'Cookie Cutters'. 7" x 15" ET 23mm. There were three tyre fitments for 7"x15" wheels, but the most suitable was 215/60/15.
Simon

Hi Simon, sorry my bad you're absolutely right my mistake and confusion there ... errm yes cookie cutters then.

I tend to get them mixed up being similarish looking! (http://www.wheelenhancement.com/Images/Fuchsblack_ow.jpg vs http://www.wheelenhancement.com/Images/Cookieblackcenter_ow.jpg)
Silly me.

 

[944 man]

Easily done. []

 

[Outrun944]

OK guys!

If possible, could some of you help me on a definitive answer on the *correct* tyre sizes. The manual for mine states -

Someone mentioned that the manual listings are incorrect :S Why would that be the case?

Anyway, to recap I currently have on -

Front 205/55 R15
Rear 215/60 R15

Sounds like from the manual I should have 215/60 on both front and rear! Which Mike suggests. Does that mean I should also stick to having 29psi in the front and 36psi in the rear?

They are the cookie cutters, and I would guess they're 15" given what's currently on right?

Thanks guys!! Want to make sure I get this right ... tyres and brakes ... the different between life and death on the road

 

[Outrun944]

Additional ... I note that a lot of people have put Toyo TR-1's on theirs from searching the forum. They don't do them in 215/60 at all ... so I'm wondering if a lot of people have deviated from whats in the manual, or it changed for post 85.2 cars

 

[944 man]

Very early cars came with 185/70/15 tyres: theyre rubbish. Later fitments were listed as 195/65/15 and 215/60/15 - cars came from the factory with 215/60/15s.

 

[944Turbo]

ORIGINAL: Jonny944CS

911s warranted differing tyre sizes, but 944s didnt - it was only marketing.

On a related subject, I've always thought it a little odd that Porsche specify a 20% lower front tyre pressure for the early 8v models:

924s + 944: 29psi Front / 36psi Rear
944s + S2: 36psi Front / 36psi Rear
968: 36psi Front / 36psi Rear

I'm sure they had their reasons, it just seems a little counter-intuitive.

Thoughts anyone?

And for a while 36 front 42 rear which - when adjusted during a service made my car very tail happy indeed. I run 33 front/rear any higher the centres wear out first. Maybe they had test/development drivers who were trying to create a 911 feel? certainly with 42PSI in the back I would send end up boot first in a hedge.
Tony

 

[Jonny944CS]

ORIGINAL: 944Turbo


Maybe they had test/development drivers who were trying to create a 911 feel?

I came to a similar conclusion Tony. It surely can't be driven by weight distribution!

On track I have been running 32psi all round (hot), for similar reasons.

 

[simdel1]

I've got 35psi all round I think. When I first got the car the front felt a little vague, which led to me increasing the fronts from the published 29psi. The front is far more communicative and 'pointy' now.