The situation:
Recently (ever since I put new tires on the back) the front end of my 2007 350z feels "loose". Driving around the city is cool, I can throw it around every corner and it handles great! On the freeway is another story, mainly if I'm traveling about 65mph. So when I'm on the freeway going about 70-75mph it's like I can feel the front end walking around, pulls left and right, feels like it's not part of the car. For example, I was about 73mph and there was a bend in the freeway, now usually I can even speed up and fly through it. Well luckily this time I didn't, I entered the turn and it was like I lost control mid turn, it felt like the back-end wanted to swing out and the front end stability was gone! It's really hard to describe the feeling besides it's loose and feels dangerous.

Possible causes:
1. About a month before new rear tires I raised my coilovers up so I need an alignment but did new rear tires make it worse?
2. I found a very small bulge in my drivers front tire that I'm relating to the fact that I'm pretty sure I was driving around on too low of air pressure since my temps dropped to winter seasons up by me. So new tires?
3. Something in the suspension is broken... I've taken it apart a few times, check sway bar, sway bar end links, and control arms and it all checked out okay!


Any help is appreciated guys!!!
Thanks

 

Sounds like there is a suspension problem and you need to carefully go through your Z. Unless your front tires are underinflated or badly worn, this sounds more like a suspension component like a swaybar is not working.

 

You said you need an alignment, did you go get one?!

 

What are your tire sizes? You said you replaced the back tires but not the front. Are both ends high performance summer tires or have you mixed summer and all season tires? I suspect your problem has something to do with the new tires.

 

to me it sounds like an alignment or bushing issue....i would start with alignment before tearing the car apart to replace bushings.

good luck sir

 

I haven't got the alignment yet because I wait for this certain tech to be working at my local Honda dealership. The guys is crazy good at alignments and they have an in-ground rack, but I will have an alignment by Saturday so hopefully that's the problem.

The rear tires are Michilen X-Ice tires 245/45/18 and the fronts are Goodyear all seasons 225/45/18, and to be honest they do need changed but they aren't that bad to me, I've gone far longer before.

I really don't think its a suspension component because over bumps and turns at low speeds theres no noises or anything weird.

I always thought that if problems occur at certain speeds that indicated an alignment or tire wear issue.

So maybe I'll get the alignment, if that doesn't help I'll throw on new tires (probably winter ones even though it sits for 80% of winter).

 

I suspect your problem has to do with the Michelin winter tires on the back. You need winter tires on the front as well. Mixing winter and all season tires is a no-no.

 

Check your lower control arms bushings my car felt like that

 

I kinda thought it was the new winter tires too since it just started happening when they were put on! But I couldn't justify that major dangerous feeling to new tires...but maybe that is it.

I did check the LCA but I also am not very aware on how to tell if a bushing is bad, not to mention I did go to my local Nissan dealership and asked how much the part was...$300 for one side. I walked out hoping it's something else.

That's why I'll get the alignment first (since I get a discount on $$$) and I'll go from there; but any other suggestions or options I'm open to hearing!

 

Quick added update, I'm pretty sure my LCA bushing is fine because with the wheels in the air I pull hard on the wheels left and right and the wheel doesn't budge. So I think that's a sign that they're okay

 

Take a pic of the bushing , or search a hair for pics of good vs blown

 

mine is blown, it will drip snot all on the inside of the wheel and you can clearly see a crack in it

 

The bushing drips grease? I thought bushings were solid rubber mounts...?

I'm at work now, then I have my alignment right after work. If things aren't better I'll check out the bushings and post a picture up on here!

If all checks out then what...tires?

Thanks guys, it all helps a lot!!!

 

crap, i am thinking lower ball joint... my bad

 

Blown LCA bushing, if it's good it will be centered

 

I would check your ball joints and Lower control arm bushings. Also a huge factor in the steering can be a shot compression rod bushing. My car also dances to the left and right at 70mph+. I changed my lower knuckle ball joints and LCA bushing since they were shot. It helped a lot but I will just be changing all the bushings in the front even upgrading the sway bar. Their are many factors that can cause the car to drive loose. Best bet is to change everything. Most of are bushings are either liquid filled or rubber that doesn't last.

 

bushings.....like terrasmak mentioned.......check them all....

-J

 

Getting an alignment with blown bushings won't do you any good at all. skip the alignment if bushings are blown. Fix the bushings, then get an alignment.

 

Update:

After the alignment it was VERY MUCH improved! There's a little bit of play left but I'm relating that to the fact that I do need new front tires as well. It's for sure more confidence inspiring when taking corners again

 

good to hear