Issue with tires

CSA0890

Hey guys I need some help. Im not sure if this is in the right section so move it if its not.
I just got some Nitto Invos in 285/35 19 on the rear with the stock potenzas on front and it has really bad fishtailing going on at 40 and above. It gets way worse the faster I go and is so bad by 80 that its pretty dangerous feeling.
I took it to the dealership and they put on some front wheels off another Z with S.P. and it cleared it up 99%.
They also suggested the rears were wrong for the car not being the right size and also the Invos were meant for the Z
Any suggestions as to what the issue is? I really dont want to keep the Invos on if they are also to blame but dont want to replace the fronts unnecessarily because they still have 50-60% of the tread left.
Sorry for the novel.

Waiz

Hmm what size are your fronts, 40 or 45 series?

Are you seeing the VDC indicator when the wheels are slipping? Are you at full throttle or does it just come on under normal driving?

vdc off and slippery light is always on, HELP

fuzzywuzzy

There are a lot of threads on this, you can't mismatch tires like you did. Nittos are also

threeseventy

You added a taller, wider, softer sidewall tire. With a higher-than stock aspect ratio (normally 30 in the rear), you'll probably need more air pressure than usual. Right now if you had a gopro on them you'd see the tire rolling over and mushrooming as you turn. You have a higher moment of inertia than before, that's the milliseconds between when you turn and when the sidewall loads and the tire grips. What is the air pressure in the tires?

CSA0890

I tried adding air pressure to the rears they were 35 when I put them on. I bumped it up to 46 and drove it and then gradually decreased pressure trying to get it to go away but it didnt. I ordered two more invos for the front so hopefully that will fix it.

kenchan

285/35/19 on the rear is fine, that's the stock size for nismo.

the correct answer is, you have to break them in. tires come out of the mold with release oil. you need to burn through that layer which requires either a quick burn out or driving on them for a good 50-100miles. just use 35-36psi and drive around normally (or do a quick launch with VDC off). even though they are nitto's, they should start gripping more.

fuzzywuzzy

Is it too late to cancel the order for the front nittos? You should really go for a better tire that is properly suited for a car that corners like ours do. Nittos have a soft sidewall and when you take a corner hard your car is going to lean like a Cadillac with nittos.

CSA0890

I did do a quick donut after I noticed the problem but it didnt really help. Ive put about 3-400 miles on them so far and the problem has gone away a good amount. With the treadwear reviews I have been seeing it doesnt seem like I will have them for long at least.
This car is my daily and Im not real hard on it in the corners. I hope the problem will go away or at least close to it so that it wont be so scary to pass multiple cars.

kenchan

sounds good, should get better as they wear to your camber settings too.

CSA0890

Yeah I sure hope so. Thanks for the advice

edub370

let them break in. had the same problem with my nitto neo gens last month when i got them. it feels like u are driving on ice. almost like the cars front and rear end are on different schedules. i even took mine back to the dealer to get it looked at

the remedy: just lets them break in. right now with the break free oil on the tires and the deeper tread valleys make the tire feel unstable. give them a couple hundred miles and they will feel alright. nittos are fine tires

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CSA0890

Ha thats the perfect way to describe it. I get the fronts on friday so ill update this thread then if it improves. I can already tell its gotten better though since i first got them on.

edub370

hah yea i posted this exact same thing a couple weeks back. takes a lil bit, but they will come around

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