My first 911! Need some tire advice

mbintx · 08-20-2016, 01:59 PM

Hello all,
My Cayman needed a friend, so last night I added a 1974 911 to the garage. Couldn't be more excited to join the air cooled gang!

Tires on the car need to be replaced. Wheels are 15x6 and 15x7 Fuchs. Car is currently sitting on ancient 205/60-15s all around, which seems odd. Looking around online, there are not too many tire choice for 15s that would work for the 911. So I'm looking for help with:
* proper stagger for my wheels
* largest tire size (width) that will fit my wheels without rubbing
* best tire to purchase for best summer performance.

This is a nice weather, weekend fun car that will see limited miles and no foul weather. I assuming a stagger is preferred; just not sure of which combinations work best.

Thanks in advance for your suggestions!

Pro198 · Pro198's Garage

I put Toyo R1R's on mine (16") and they softned the ride up a bit, gave grip but not a thunk thunk over bumps now.

Bob Kontak · Bob Kontak's Garage

I have used Michelin Pilot Mud and Snow tires since I bought it in 1996. Mainly because I bought them before I got into this board.

Don't do this. Get a nice quality summer tire.

Folks speak (spoke?) highly of the Bridgestone R11's but I have been out of the tire loop for several years.

HarryD · 08-20-2016, 05:10 PM

15 inch tires performance tires are getting harder to find. My car (same body style and flare as yours) came from the factory with 185/70-15 all around on 15x6 wheels.

Current recommended sizes for my car are 195/65-15 or 205/60-15 which will not casue much speedo error. You need to compare tire diameters to get you profiles. I do not think anything wider than a 205 tire would fit without some serious suspension changes or going to a lower profile which will make your speedo error large.

Check Tirerack.com for recommendations.

manbridge 74 · 05:46 PM

I'm going the other way. While the above is only 195, the tread is 7.7 inches. Some 205s are a lot less. It is a little short at 23.4 diameter.

manbridge 74 · 05:54 PM

I'd try this for street use. About 24in but a little less tread width. Reviews place it a little outside of a true summer tire.

mbintx · 08-20-2016, 06:37 PM

Manbridge--what tire is that? ( the second one)

So, no one seems to think a square setup is a concern on a 911?

manbridge 74 · 08-20-2016, 06:59 PM

My screen shot was a little off.

Kumho ecsta PS31. A lot newer tire design than Michelin sport comp above.

mbintx · 08-20-2016, 07:04 PM

So none is concerned with a square set-up? Even if I have 15x6s up front and 15x7s in the rear?

manbridge 74 · 08-20-2016, 07:48 PM

I'm gonna do the same thing as I just bought a pair of 15x7 wheels. I believe guys in other makes do something similar. Example some AWD cars can benefit from the rounded tire edge brought about by the inch smaller rim. The wider rim will push out the tire edge a little further.

The thing about 911s is you want a fairly firm sidewall so it doesn't have a wallowing, delayed reaction type of feel.

HarryD · 08-20-2016, 09:58 PM

Quote:

Originally Posted by manbridge 74

I'm going the other way. While the above is only 195, the tread is 7.7 inches. Some 205s are a lot less. It is a little short at 23.4 diameter.

great tire but in 55 profile, the speedo is way off. Speedo reads high and odo reads low.

manbridge 74 · 08-20-2016, 10:41 PM

Yeah, and probably looks like an o-ring over a plate but for DE it's this or Trofeos in 205/50.

HarryD · 08-21-2016, 04:06 PM

Quote:

Originally Posted by manbridge 74

Yeah, and probably looks like an o-ring over a plate but for DE it's this or Trofeos in 205/50.

For a competition tire, 205/50-15 is about the only size available. I use this size for my AX tires. I like the better gearing from the shortened ratios.

mbintx · 08-21-2016, 05:20 PM

I had no idea this would be so difficult. Still no closer to an answer.

HarryD · 08-21-2016, 09:55 PM

Quote:

Originally Posted by mbintx

I had no idea this would be so difficult. Still no closer to an answer.

OK, lets start at the beginning.

When the car was first delivered, from some research I did, the factory owner's manual from 1974 recommends 165HR15, 185/70VR15 or 215/60VR15. A 205/60-15 would work as well.

If you are out to win concurs, you can go to the Coker tire web site and find period correct looking tires in the correct sizes (bring your wallet).

If you are looking for modern tires, and since you are not looking for the ultimate in performance, something like a BFG Radial TA in a 205/60-15 or 215/60-15 would not be a bad choice.

Quicksilver · 08-22-2016, 11:47 AM

Quote:

Originally Posted by mbintx

I had no idea this would be so difficult. Still no closer to an answer.

A big part of the difficulty is that 15" tires are getting far and few between. 16" wheels have more options and 17" have even more.

What you need to look for is something close to 25" in diameter (You can't go much larger unless you go with a real skinny tire). A good tool for this is on Tire Rack's site. If you bring up a tire, look down the page for a tab labeled "Specs". That will show you the complete specs of every size of that model of tire. That helps you pick and choose tires that are in range and with the widths you want. You can shorten the tire but it will effect the speedo, the ride height, the rake (if not matched front to rear). I wouldn't consider less then 24". Some people go that way for track cars but they know what they are trying to achieve and it doesn't include driving around town.

Yes, staggered sizes would be nice but it is going to be REALLY hard to find in a 15.

What kind of tire is even a harder question because it depends on what you are going to use the car for and what you want out of a tire. A lot of people want a decent wearing tire that is good for road trips and has reasonable grip. Some of us bought a fun corner burner car and we want the maximum cornering grip at all costs. Some live in rainy areas and wet grip is important. It makes a big difference.

Play with the Tire Rack specs pages and see if it helps you.
(But don't be surprised if you start eyeing a set of 16" rims just out of frustration!)

Charles Freeborn · Charles Freeborn's Garage

205/60/15 all seasons for everyday and 205/50/16 extreme summer for track days.
The 7's aren't original to your car. If the rear fenders are still original width, a 205 is about the limit.
205/50/15's will not be a good street choice. While good for low speed AX sillies, at speed they'll make you constantly run in high rpm ranges. More torque but less top end. If the car still has it's original CIS intake system it does not favor those higher rpm ranges.
The choices in 15's are very limited for extreme summer tires, which is why I got the set of 6x16's (front wheels from an SC).

bbturbo · 08-22-2016, 01:15 PM

+1 on the G Sport 2s. I've bought two sets and they are great for the buck. I'm actually getting ready to buy a third set for my 964.

garment · garment's Garage

I've got Continental DWs on my '83SC and I've been happy.

mbintx · 08-22-2016, 04:28 PM

Thanks for all of the feedback. I ended up ordered Dunlop Direzzas in a 205/55-15. A little shorter than the BFG TAs, but I just couldn't pull the trigger on those all season touring tires. Since all 4 cost approx what one rear Michelin costs for my Cayman, it's not a huge gamble if they turn out not to look good or ride well.