Tires for 6's and 7's on 16" wheels

[travels68]

Hello all,

I'm running a set of new Conti Extreme Contact DW's on my 1987 911 Targa with factory Fuchs 6x16 and 7x16's and the car handles like a boat. The sidewalls on these tires seem very soft and cornering (and straight line behavior under heavy acceleration and deceleration) feels very 'floaty'. It's got a Cadillac feel to it.

PO had cheap Primwells (wish I knew the size) which I replaced and the car was way better with the cheapo's.

Anyhow, my local Porsche shop, is telling me to put new tires on the car but not the original factory size - they say go with a narrow tire so the sidewalls are not as high.

Here's the factory specs that I'm running now:

Manual Says:
Front: 205/55/16
Rear: 225/50/16

Shop guy says:
Front: 195/55/16
Rear: 205/50/16

Does this make sense? I'm not seeing much selection in the non-standard shop-recommendation sizes - best option appears to be Bridgestone Potenza RE-71R's

The original factory sizes include many other options including RE-11's (which seem to be a gold standard for these cars).

Should I just go with the RE-11's in factory spec or try the new rubber the shop recommends and go with the Potenza RE-71R's? The main goal is solid road tracking and cornering stability. Comfort is not the primary concern.

All opinions welcome!

Thanks in advance.

[travels68]

... forgot to add that I have new shocks/struts, Upper strut mounts in front, steering rack re-greased, new turbo tie rods, new ball joints on the car. Tires seem to be the major issue.


Thanks again.

[SoyRacer]

Your local Porsche shop seems to be autocross oriented.

Unless you want to specifically set the car up for autocrossing then go with the stock size RE-11s.

[travels68]

Thanks... they are definitely a performance oriented shop and I struggle with them to keep the car stock as they are very into 'upgrades' - something I'm resisting to keep the car as original as possible.

I appreciate your advice!

-Kale

[$ Short]

You might get more responses moving this to the technical section.

[darrin]

Originally Posted by travels68

... forgot to add that I have new shocks/struts, Upper strut mounts in front, steering rack re-greased, new turbo tie rods, new ball joints on the car. Tires seem to be the major issue.


Thanks again.

Did you do this before or after you changed tires? I'm running continental extreme contact dw tires too and, while they're not the hardest/most responsive tires I've driven, I do not get the "floaty" feeling you're describing at all. If you made all of these changes at once, perhaps there's something else going on. Did you get a realignment too?

[travels68]

My apologies for poor board selection here - I thought I was posting to the technical forum.

Having said that, I appreciate the feedback and it's been good.

Darrin - I ping'd you on my related post and do appreciate your feedback here.

All of the front suspension work was done before the problem started. Everything in the rear was after. You've got me convinced not to worry about the tires at this point and focus on other causes. Best theory at this point is corner balance out of spec.

-Kale

[Cajundaddy]

Something is loose or alignment has drifted out. DWs are not AX championship tires but should never feel "floaty". Once you get your setup sorted, the RE-11 is a really good max performance summer tire.

[KTL]

New tires can often feel floaty until the mold release agent (the stuff that keeps the rubber from sticking to the manufacturing machinery) wears off. They also can feel floaty for awhile until you get some heat into the tires and the rubber does whatever it does "molecularly" to stabilize itself.

I experienced this heat cycle situation with Toyo RA-1 tires on the track. I know we're talking street driving here & not racetrack driving. But the same situation still applies, just on a much less noticeable scale. The RA-1s were quite nervous when used for the first time with their full tread depth. These tires are actually best when shaved for use in dry conditions to have optimal initial performance. But it's still acceptable to use them unshaved in the dry. Anyhow, the first "scary" drive with them has the car feeling floaty on acceleration and REALLY floaty under heavy braking. After they've gone thru their first heat cycle, with a minimal amount of time to fully cool and go thru that molecular bonding or whatever's going on with the rubber, the next session on track is a lot better. By the end of the day the tires feel pretty good. Heat cycling of the Continental tires on the street is going to take a little bit longer but the same improvement should happen.

So my point is, give them some time and I think the tires will improve. That said, I have noticed that some Continental tires have really flexy sidewalls when handling & mounting them. I found it really surprising how much give the sidewalls had compared to the tires that were coming off the wheels. Therefore they may only improve so much with time and may still feel not as planted to the road as you've felt with other tires.

Just my 2 cents.