speedyralph

I just replaced my rear cup tires with the new Super Sport's.

I feel the rear end flexing way too much. My current psi is 37/43.

The car feels like if it had a flat tire and it wobbles enough for you to wait for the *** to settle in order to accelerate out of a turn.

Even in a straight line above 60 the *** wobbles if your changing lanes or dodgin pot holes the *** move enough for you to wait for it.

The tires are brand new. They were road forced balance by the latest Hunter balancing machine.

At this point im pullin my hairs and hating life. I want my cup tires back!

Any of you exprnce this?

tcsracing1

what size tires do you have?

i never had this problem switching from SC to SS tires on my RS

speedyralph

305-30-19

CRex

No problem here either. I suspect you've been over-inflating. I run 30F/32R hot and our cars are about the same weight.

Despite running 305s in the rear (vs. OEM Cups being 325) I had no problem with the flex you mentioned. In fact the MPSS handled so well on highways that I was confident enough to push up to 310km/h (indicated) on a couple occasions.

mdrums

WAY...to much air pressure!

Also new tires have to wear off the mold release so they can be a little squirrely and the tread blocks are deeper that MPSC so those can be moving around some maybe.

Drive it 500 miles and I bet it gets a lot better.

speedyralph

Thanks guys, I always thought that was too much air.

Every technician at "The Collection" in Miami say that they put on ALL GT's that amount of pressure every time they come in for alignment or service. They advised me to ignore what the decal on the driver column states.

Tmro before I had out I'll drop the air to 29/31.

Is this a good base line to start out with?

CRex

Respectfully, your shop doesn't know jack on this subject. I'd take my dollars and go somewhere else.

I think 29/30-ish is the right ballpark to start with. I do prefer my tires on the soft side given the crappy roads here so YMMV.

BBMGT3

I run my PSS 33/35. I struggled with them when I first got them but they improved a lot after the first 1,000km.

TRAKCAR

Put them on 29f and 31r cold. Any lower and you get low pressure warning :-)

M3EvoBR

I'm yet to see something decent coming from THE COLLECTION

speedyralph

I really appreciate all this info guys.

I was itching to do a track day this Sunday @ Homestead, FL with my .1 GT3 that I restored in Thanksgiving, but my rear cups wouldn't last past a session.

After I put the PSS's yesterday, my confidence went out the window. Before I take I will readjust the psi to 29/31 and take it from there.

If it improves, but still wobbles a lil'bit, then I'll just do a session and leave early tomorrow.

I haven't started a thread on my other gt3 build, but here's a pic.

Thanks again for all your input and advice.

TRAKCAR

Those mpsc looked fine to me.

You have some pics of the build in progress? Or some links?

speedyralph

mpsc's were below 1/32 on the inside. I know they were good for a session or almost two, but the car is for sale and I didn't want to take my chances at the track. I kept the tires anyways..

Here's the album of the build in no particular order...

taffin

are you running Supersports now? Tracked them yet?

speedyralph

Thanks guys, the new psi improved the rear end 90%.

It still dances lil bit.

New cluster warnings I gotta get used to.