For those of us in Chicagoland...

I found a section of I-294, south from I-290 and north of 95th ST where my 350Z Performance will get this weird repeating bouncing/porposing motion, which actually made me feel ill going northbound. I tried to vary speed between 60-80, doesn't seem to help. The only good thing about going southbound is the concrete alternates with sections of asphalt.

Happen to anyone else?

I saw in one of the other forums someone said the ride got much better with 150lbs of pamphlets in the hatch. I haven't had a chance to drive this route again with more weight in the car.

 

I KNOW JUST WHERE YOUR TALKING ABOUT..IT'S AWFUL.
i'VE LOWERED MY PSI TO 33 COLD AND IT HAS HELPED A TINY TINY BIT.

My wfe and I thought that the suspension was going to fall apart but then we realized were in a sports car..hmmph!~

 

It happens northbound on 94 after 294 ends up north too. I think it's the damn road! I had this happen on the same section in my last two cars. It sucks!

 

it happens to me on 88 between. I actually get a headache afterwords.

dan

 

Yeah. I got a section like that on the way home from work.

Just that special combination uneven road, short wheel base and stiff ride, feels like I'm in a moon bounce.

If the seat was stiffer it wouldn't be so bad, just a pain in the a$$.

Every time I drive it I hope no one is looking.

 

Happened to me right after I picked up my Z from Countryside Nissan, I was going North on I-294 from I-55...it was pretty bad, didn't feel sick that time, but I regularly travel up and down I-355 and it does it on there too, almost felt sick one or two times. I had an "interview" with a Nissan engineering manager and told him about it, along with other things that I like and dislike about the car, he said that the engineers in Japan will hear my exact conversation (translated of course) because he tape recorded the whole thing. Hope they redo the spring rate or dampining on the rear suspension.

 

I TRAVEL THIS ROUTE VERY FREQUENTLY AND EXPERIENCE THE SAME PROBLEM. OTHER THAN REDUCING TIRE PRESURE, WHAT SPECIFICALLY CAN I SUGGEST TO NISSAN TECHS TO ADJUST SUSPENSION/SPRINGS???????

 

I wouldn't lower the tire air pressure, it makes it worse. I got new Michelin A/Ss and the installer set pressure at 32psi. The bounce was just as bad until I put 35 psi, rec'ed max, in the tires. 95% of the bounce went away. If you keep the OE tires, watch your pressure very closely when its cold. They lose pressure very easily.

 

Boomer has 17" rims. I have the 18" rims and haven't seen a good solution posted yet for us 18" rim owners. The tires Boomer recommends aren't available in both stock tire sizes for 18"

I'm not going to shell out extra cash for tires that may not fix the problem or make it any better. I'd rather let someone else be the guinea pig

One of the other posters put 150 lbs of weight in the back, that seemed to help. I'm waiting for winter to be over before I drive my Z again, so someone else will have to try this.

 

guys...it's a suspension problem....NOT a tire problem...

 

Max, I think its both a tire and supension problem, IMHO.

 

ok...I'll bite...


I have a Touring 6MT (18s) and it bounces on some highways

I also have a set of 17s with Michelin Pilot Alpin Tires (snows), and it ALSO bounces just the same on those highways.

I respect peoples' opinions, but the fact is that tires ARE NOT causing the problem. The problem is a mis-match of the rear spring rate and rear shock dampening along with our short wheel base.

 

Have you tried the "weight in the hatch" solution to see if it reduces the bouncing?

 

Ive got a base model and my bounce reduces greatly when my bowling equipment is in the trunk...four ***** two bags aprox. 70 lbs. it helps a lot so i'd say is a shock vs. suspension issue.

 

I have the Touring 5AT w/17s and the bounce was lessened, not cured, by changing to Michelin A/Ss at 1600 miles. Even w/35 psi cold, it still bounces slightly on certain roads, so the tire change helped, but did not fix the problem.

There is a mismatch between the shocks and springs, w/o a doubt, and I will be addressing the remaining bounce in the coming months with some sort of suspenson change, probably w/adjustable shocks. Do you still have the 040s on your 18s?

Michelin Alpines are not the same as A/Ss and you certainly can have different behavior from different tires from the same brand. Some may bounce more than others, it is not a direct comparison. If you have 18" summer tires and 17" winter tires, their behavior can be different over the road than all season 17s, like the A/Ss, which have a special tread construction unlike other Ultra High Performance all season tires like the A/Ss. Look their construction up at Tire Rack for their analysis, its an interesting read.

Boomer--my opinion, use it or lose it, I don't care.

 

Yes I still have the 040s on my 18s, and they have approx. 200miles on them.

I think what you're dealing with is that your "tire purchase" gave you a little placebo effect. Basically you "thought" that the tires should reduce the bouncing...so in your mind they did. If anything, my snow tires should bounce LESS than the A/Ss...since they have a weaker sidewall..they absorb the bumps better. The tread pattern has absoutely NOTHING to do with your suspension bouncing and occilating over uneven road surfaces.

By your logic, the ONLY tires that will reduce this "bouncing" are the Michelin Pilot A/S tires....come on....

 

I can't believe that my opinion counts for much at all. All I said was they reduced my bounce over the roads I travel, not all roads, that is absurd. I live in the 18 Wheeler capital of the USA, Several carriers have their headquarters here at the junction of I35 and I40 in Central Okla.

All I, not someone else, said was my bouncing was much improved where I drive and I stand by my statement. I invite you or your representative to come to my area and find out for yourself. Placebos are for those who are easily led by statements taken out of contex, read my posts if you wish to judge my opinions and see if I need a placebo.

You assume too much if you think you can analyze a stranger you haven't met. I spent 23 yrs planning services for the Mentally Ill, Substance Abusers and Survivors of Domestic Violence here in the State Department. If you are half as intelligent as you think you are, you owe me an apology for your ignorant and insulting remarks. You opinions have no standing with me, Ace.

 

I have only two questions. How again did I "ignorantly insult" you? What do your career acomplishments have to do with this discussion about CARS?

 

You might reread your post where you said I "thought" and "placebo" in reference to bounce, and I took exception to your amateurish analysis when we were talking about "CARS". When you've been in the business, any attempt to analyze a person from his posts on a 350Z website, is an ignorant and insulting thing to do. Even if I hadn't been in the business before, it is still insulting on a CAR site, and my opinion is just as good as yours, amounting to not much in cyberspace.

Oh, don't post me again on this or any other subject, or I will report your attitude to the Moderator. You need to read the "Rules", they are quite serious about them. I just hit my ignore button.

Boomer--hoisted on your own petard.

 

Maybe you need to someone to analyze YOU. What are you so upset about? I see nothing wrong with BriGuy's post, he was just stating his opinion, just like yourself. Quit being so sensitive...

Now....to the problem. IMO the springs/shocks are not working in harmony. I have a feeling that the dampening of the shocks wasnt tuned properly. Tires ARE NOT the problem. You can put Michelin Energy's(Luxury car tires) on the car and it will still bounch.