aggie300zx

I recently purchased new tires for my Z (rears were very warn, and fronts were fine...replaced by Nissan due to feathering). I'm still using the OEM rims (Performance 18") with 245/40/18 in the front and 275/40/18 in the rear (Nitto NT555 Extreme). I know there are better tires out there, but bang for the buck this is what I went with.

The car definetly feels like it grips the road much better, but on longer sweeping turns the car feels like it is floating to point where I don't feel as though I have complete control of the car. I know that is a confusing statment, believe me I've tried to think about how best to describe this but its the best I can think of right now.

...now here is my question. Will an aftermarket suspension and/or sways resolve this issue (Nismo, HKS, Tein, etc.) or is this just part of having bigger tires no matter what I do to the suspension? The car seems to have a little more body roll then before as well, which might be causing me to think the "floating" idea. I've been thinking about the next mod being suspension, but if its not going to help this issue, then I need to rethink my next steps.

Any thoughts, experience, help on this would great. Especially if you have gone to these size tires with or without suspension upgrades.

Thanks!

KarmaMag

From my experience, 275 is too wide for the stock 8" wheel. The tire side wall will not flex the way it was design to be and that might be the reason why you're feeling like the car is floating.
I don't think installing the aftermarket suspension will fix the problem you're having. You might want to look for a wider wheels. 275 works best on 9"-10" wide wheel.
I'm running 295/30-19 on a 10.5" wide wheels. Even with the stock suspension, I feel the improvement over stock tire size without the floating feeling like you said.

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iTrader: (5)

i know what you mean aggie. i just completed a driving clinic at buttonwillow this weekend and the car definitely rolls a little too much. i have a track with toyo proxes t1s 245 front/255 rears and stock suspension.

i dont think just switching out tires will solve your problem, but a suspension upgrade is in order. i am planning on the nismo s-tune and swaybars for its good reviews on a track and streetability .....gotta keep the gf in mind

aggie300zx

So far, it sounds like two conflicting thoughts....one need larger width rims and the other upgrade suspension.

Still confused???

Todd@ProDyno

of course suspension will help...but the concern you are speaking of is because of the 275s you have out back.

Yes, the Nittos run a tad small...but a 275 is too big for an 8" wheel. Nitto designed it for 9"+
P275/40ZR17 98W 9.0-(9.5)-11.0

This change will give you the feeling of looseness, or floating when pushing the tire.

aggie300zx

Thanks for the info. I thought the rear wheels had an 8.5" width. Ironically enough, I went with this partly based on the advice of the guy at Discount Tire.

Hmmm, so what to do....buy rims o new smaller rear tires, and/or suspension.

While I have your attention DiscountTireDirect, what kind of pricing can I get on the Privat Fahren rim? Any thoughts on quality as well? This is really the only wheel in a reasonable price range that I have found. I'd rather spend $3000 on rims and suspension, rather just rims (I really want the SSR GT3, but thats alot of $$$).

Thanks!

aggie300zx

Also, whats the danger if I push this setup until I can get this resolved?

Todd@ProDyno

The recommendation of a 275 on a 8.5" rim is not necessarily a bad one. However it sounds as if there was not enough communication. Although Nitto recommends a 9", for an average every day drive a 8.5" would suffice. However, I believe you to be someone similar to me, an enthusiast. I think being an internet forum member, and using construction zones as auto-x practice goes hand in hand. Driving hard is in our blood. Now, if I gave your car to my brother he would never have noticed the before and after you and I would have.

Anyway...there is no danger in this size combination. However, it obviously makes you slightly more uneasy when pushing it so take that for what its worth.

If you want the stock feeling back...back to the 245s. Or...get some wider wheels to accomodate the wider rubber.

Suspension will help lots of different attributes of your car, but I think you'll still notice what you call floating.

There are a couple of guys on the site that chose to go 18x8 & 18x9 Privats with the 245-40 and 275-40- combo who are VERY happy. As a member of this site I am offering everyone 5% off the purchase price of a wheel & tire combo if that helps sway you at all.

aggie300zx

Thanks for all the advice. I think most of it made sense and you really hit it on nail that I do feel a little uneasy pushing the car right now.

Sorry for probably restating what you said, but would an 18x9 rim in the back eliminate or dramitically reduce this float feeling using the 275/40/18 tire setup? Does the .5" make that big of difference?

Thats what I needed to know abou the suspenion changing aspects of the ride, but probably not what I'm experience (although I'm weak, so suspension mod is probably not too far away anyway).

Since I have new tires already, would the 5% discount apply if I just got rims?

Thanks again for the advice!
Scott G

Todd@ProDyno

C'mon Scott....you know size matters. That 1/2" will make a difference. Would it get a bit better with a 9.5"..sure.

Ive yet to be inspired by the ride qualities of a stock 350Z. They are certainly a fun car to drive, but Nissan left plenty for us to tinker with. Simply doing springs has made many of the users on this forum think they were driving a whole new, and better car.

Yes..I will most certainly extend that discount to you on wheels alone.

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iTrader: (5)

only track rays are 8.5" in the rears. you have 8" all around.