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Discussion Starter #1
Hey guys I need some advice here, couple days ago I installed two brand new nitto nt555 g2 on the rear of my 13 5.0 , they are 275/40/19 mounted on 19x9.5 sve drift wheels, my car is lowered on HR ss springs and has aftermarket control arms with poly bushings, also rear relocation brackets and the alignment is in spec. Well I installed the tires and set the pressure first at 36psi and went out for a test, initial impressions is that they hooked pretty good rolling from a 35-40 roll. Now it gets weird when I get up to highway speeds, when going straight at around 60+ mph if I start jerking the steering wheel left and right slightly the rear end feels really loose almost like if its hydroplaning. Feels like if the panhar bar was not in the car and the rearend was moving side to side while driving. What could be causing this on the tires? It has to be the tires, this happens now after they were put in. Does the pressure need to be higher to stiffen up the sidewalls? Do they need a brake in period or maybe doing a good burnout and heating them up can change how the act. ?
 

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Were the tires balanced correctly? I would take it back to the shop that installed the tires and have them check that they are balanced. Improperly balanced tires will cause vibrations at high speeds, and is probably what is causing your issues.

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Is it the first time you've had the aftermarket wheels on the car? Take them off and make sure you took off the clips that are on two of the rear wheel studs from the factory.

What tires are on the front? Could be that the 555's are harder and lose grip while the fronts hold on
 

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May sound dumb but check your lug nut torque make sure they are tight! It is easy to overlook. The odds of it being the tires is slim it's definitely possible but slim. Have the wheel balance checked on the wheels in question.
 

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Discussion Starter #5
I work at a dealer as a tech so I mounted my own tires and balanced them, I torqued all the lugnuts to 95lbs, my problem is not vibration, my car is very smooth at highway speeds as far as tire vibrations. And I have had my wheels for 1.5 years now and this is the 3 set of tires I have on the rear, all previous tires including Pirellis Corsas that were similar to these nittos as far as grip did not have this problem. The last set was a pair of Michelin Pilot Sports, they did not grip for crap but they handled directional input better than these nittos. Im going to try and bump up the tire pressure 42 psi tomorrow to stiffen the tire up and see if that fixes the issue. Today while driving I aimed my mirror down to take a look at my sidewall and while moving the steering wheel left and right I could see the sidewall flex and that is with 32 psi. Nitto told me from their calculation that the equivalent air pressure or this tire on my car was 25.5 psi when converted from the stock pressure and stock wheel and tire size, but 25 psi is way to low to be driving everyday , it probably works at the drag strip but not the street. Anyways lets see if increasing the tire pressure will stiffen the sidewalls to not flex so much and cause the rear to wobble so much. And I have already looked everywhere and visited other forums of people having the same issue when putting new tires in their car and its always a high performance tire with soft compound. Other people are saying to break them in but comeone does a tire really needs to be broken in, a nice hot burnout should do it.
 

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You might have a defective tire,I have seen brand new tires where the tread is loose from the carcus of the tire, and it squirms around,take it back and have the tires checked.
 

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Are you mixing brands compared to what's up front, since you say you bought two new? The two sets might not be liking working together.
 

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I'm really interested in whats causing this problem. I have been considering the 555 g2's. 275 40 19 on Brembo 9 inch wide wheel might exhibit the same problem. Maybe the sidwalls are not stiff enough.
 

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What tires do you have on the front?

A mismatch front to rear with tires that are either stiffer or softer can cause issues like you describe
 

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Maybe I am wrong. But I don't think adding air in the tire will stiffen your sidewall. And I don't know if going over the recommended tire pressure indicated in the owners manual is good either.

And I believe the proper torque on the lug nuts is supposed to be 100 ft-lbs dry threads. No lubricant.
 

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Bump it down to 30psi. Had the same thing happen years ago and it was too much pressure. Too much will ballon the center and make it loose feeling.
 

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Brand new tires are likely to still have some of the mold release agent in/on the tread rubber. Don't expect them to perform as intended until you've scrubbed it off. This should occur within a couple hundred miles of normal driving, and that's arguably the better way to get this done. Get this done and see if the problem goes away.


There isn't enough information for me to suggest a different rear tire pressure.


Norm
 

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Brand new tires are likely to still have some of the mold release agent in/on the tread rubber. Don't expect them to perform as intended until you've scrubbed it off. This should occur within a couple hundred miles of normal driving, and that's arguably the better way to get this done. Get this done and see if the problem goes away.


There isn't enough information for me to suggest a different rear tire pressure.


Norm
This. I just put 4 new tires on my car and noticed the exact same sensation when driving it home. After a few days of driving to and from work (and some spirited cornering for good measure), the car drives just like it did before replacing the tires. Give it a few days and see if it's still a problem.
 

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Discussion Starter #15
Ok guys sorry I have been away for some days, well I lowered the tire pressure to 30 psi and the car feels way better, like the nitto rep said lowering the pressure helped. Its funny because my front tires are some use takeoffs from a Mercedes benz s class and they are Michelin runflats 275/40/19 just like the rears, im pretty sure these tires are playing a role on how the rears behave because of how hard those tires are and runflats I guess act different. Well as far as for the person that was wondering on the nt555 g2, get them, I love the tires, they got decent thread wear at 320 and they hook really good, not like drag radials but man once heated up they stick to the ground. I think having it at 36 psi was too high and caused the tire to ballon a bit and that's why I was getting that looseness sensation on the rear.
 

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bump it down to 30psi. Had the same thing happen years ago and it was too much pressure. Too much will ballon the center and make it loose feeling.
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