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Tyre Sizes '85 Carrera 3.2 Sport

Philly

Well-known member
Joined
10 Sep 2002
Messages
52
I had a look at the tyres on my 911 and I've got 215/60 VR 15's all round. Good news that they are W rated (168mph).

Not sure what rims these are on - can check if this is important.

I thought that tyre/wheel sizes were usually different front/rear on 911's. However the handbook shows several different combinations and a search on the web hasn't thrown up anything conclusive on this.

Any help in understanding a) whether the set up is OK from a handling perspective and b) regarding speedo accuracy would be really appreciated.

Also, could this have been a standard set-up?

Thanks.


Migration info. Legacy thread was 608
 
Same size all round is not normal on anything other than the early, non-flared cars - that is why you have flares!

I think Carrera 3.2s came with
195/65 15 for the fronts, and 215/60 15 for the rears, although 16" wheels were an option. The "normal" upgrade is
to 205 at the front and 225 at the rear but there are not too many manufactures who produce those for 15" wheels though. You could go to 205/55/15 in from and 225/50/15 but your speedo would be slighty affected (not a mjor issue really).

Rim size is important though, but given that you have 15" rims my guess would be that they are the orginal, standard wheels which I think are 7" front and 8" rear.

I am surprised you can get 215s on the front. Have a look in the wheel arches and make sure there aren't signs of rubbing. Also check to see if the wheel arch lips have been rolled or cut - nothing wrong with that, but it might explain why 215s fit up front.

The tyres are the correct profile though so your speedo ect should be accurate. I would defintely go for 225s on the rear though - it can only help that heavy rear end grip and should look better too.

Cheers, James


Migration info. Legacy thread was 612
 
According to the Porsche Red Book, standard wheels for 1985 were 6x15 front & 7x15 rear, with 185/70 & 215/60 respectively. Around 1987 front tyres were changed to 195/65, retaining the same sized wheel.

Nathan


Migration info. Legacy thread was 615
 
Sounds like I was talking crap then. My info came off the web. I will have a dig through some of my books and see what else I can come up with.

Nonetheless, having the same size tyres front and rear is not right!

Cheers, James


Migration info. Legacy thread was 619
 
Just looked up wheel data in Peter Morgan's "Original Porsche 911" and he agrees with Nathan's info:

From 1984 to 1987 the standard wheel sizes were 15 inch 6 and 7 with 185/70 and 215/60. An option was 16 inch 7 and 8 with 205/55 and 225/50.

Apologies for any confusion from my first post - just goes to show thatyou can't trust what you read on the internet! :wink:

James


Migration info. Legacy thread was 621
 
Thanks for the info.

Looks like the wheels are 6x15 on the front and 7x15 on the back. The rear ones are right then.

I can't see any signs of rubbing in the front wheel arches - maybe it hasn't been driven very hard since the tyres were added?

Arches look normal i.e. not noticably different to others, but I'm no expert.

What I'll do is leave them on for the time being and replace with 195/65's when they're shot.

My guess is that they will affect handling very differently wet vs. dry.

In the dry there will be more grip and thus less understeer - likely to make the back end snap out more drastically when right on the limit.

In the wet they will understeer more easily, but that overall handling will not really change that much.

All a bit academic for the moment - I don't plan to drive anywhere near the limit on the road. Track days, maybe next year - any views/insight on the above?

Phil.


Migration info. Legacy thread was 632
 
I reckon you are about right in your thoughts on handling. It might be worth talking to a specialist about it just to make sure there aren't are othr implications. I wonder if the front suspension/steering rack etc might be over-stressed by the extra grip at the front? Probably not.

James


Migration info. Legacy thread was 633
 
Looking on Rennlist their tech. advisors say 225's on the front is the max. you can go to, so I don't think stress on components will be an issue.

Also, most of the stuff about rolling wheel arch lips is about putting 16" wheels onto lowered suspension.

OK, tyre width will be the same, but with 15" wheels and stock suspension set-up there will be more room in the wheel arches.

I will ask a specialist, but in the meantime I won't worry too much.



Phil.


Migration info. Legacy thread was 636
 
215 wide on front will not rub, but 225 probably will unless you roll in the fender lips.

With 7" and 8" wide wheels, I think you should be using 205 wide on the front and 225 on the back.


Migration info. Legacy thread was 797
 

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