Extreme bump steer??

[rambo]

Hey guys, I recently bought my 2014 touring/sport 370z with 10,000 miles.
What I noticed after driving for a few weeks is that this car has an extreme amount bump steer. It's so bad that I'm sure if a cop were behind me he/she would think i was driving under the influence. The car just follows the bumps in the road.

I know wider front tires can cause this but I'm coming from a lowered 350z with 255 front tires and never experienced this.

I bought the car from Carmax and they supposedly aligned it when I brought it back to complain. No difference.

Any ideas? My only thought is that Carmax either gave it a **** alignment or possibly may have not aligned it at all? Or could the tires (OEM Bridgestones) be the problem?

Also something I just remembered is if I'm at a stop, turn the wheel all the way to the left and slowly accelerate, the tires seem as if they're slipping. (imagine making a u-turn in a cul-de-sac)

[OptionZero]

don't trust Carmax's alignment, do your own.

Also get a front suspension inspection to see if anything is obviously damaged

[Jayhovah]

[rambo]

Originally Posted by OptionZero

don't trust Carmax's alignment, do your own.

Also get a front suspension inspection to see if anything is obviously damaged

Yeah that's actually what I was starting to consider. I'm almost certain the toe settings are way out of line.

Not the mention Carmax never gave me the before and after specs of the alignment like every other alignment I've ever gotten at other shops.

[Hotrodz]

What kind of tires do you have on the car and how much wear are on them? This can cuase trammeling on rutted or roads with groves in them.

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[rambo]

Originally Posted by Hotrodz

What kind of tires do you have on the car and how much wear are on them? This can cuase trammeling on rutted or roads with groves in them.

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I have the OEM Bridgestone Potenzas on the car. Decent wear. Seems the front left tire has more wear on the outer edge of the tire.
If I remember correctly I think the outside tread was measuring at 3-4/32nds and the remaining tread about 6-7/32nds.
Toe out of spec?

[Hotrodz]

Originally Posted by rambo

I have the OEM Bridgestone Potenzas on the car. Decent wear. Seems the front left tire has more wear on the outer edge of the tire.
If I remember correctly I think the outside tread was measuring at 3-4/32nds and the remaining tread about 6-7/32nds.
Toe out of spec?

With that kind of uneven ware I would get two new front tires and an alignment.

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[NoHyperbole]

You and I share many similarities. I too have a 2014 Sport/Touring on the OEM Bridgestone RE050 tires (now at 18,500 miles and 90% worn), and you've described exactly what I've been experiencing the entire time I've owned the car. Further, my previous car was a 350Z that never exhibited these traits, so I understand where you're coming from.

Regarding what you've called "bump steer," here is my take. When driving straight on road with a bunch of minor imperfections, if I take my hands off the steering wheel, it will "dance" or shimmy side to side, although the car will generally track straight. When I hit a moderate to major bump with one front wheel, the steering wheel will do a quick left-right-left (or right-left-right) shake. Again, this is something I never experienced in my 2007 350Z. My thought is that the extra caster in stock 350Zs (around +7.0) versus 370Zs (around +5.0) is a contributing factor in reducing this steering trait.

As for the sensation that the (front) tires are slipping during slow-speed turns at full lock, I know this sensation well, although it seems to happen only when the ground (after rain) or tires (after car wash) are wet. Do you experience this in dry conditions?

As for alignment specs, my numbers on the OEM suspension are as follows:

Camber: LF = -0.6 RF = -0.9 (non-adjustable)
Caster: LF = +4.7 RF = +4.4 (non-adjustable)
Toe: LF = +.05 RF = +.05

Camber: LR = -1.6 RR = -1.5
Toe: LR = +.10 RR = +.10

What are your alignment numbers? I'm curious to see if they differ greatly from mine.

I've tried taking the car to the dealership to have them investigate this issue, but they don't seem to think anything is abnormal. You and I both know something is not quite right. I wonder if this is an issue only a certain number of 2014 Sport/Touring Zs have.

[NoHyperbole]

Originally Posted by rambo

I have the OEM Bridgestone Potenzas on the car. Decent wear. Seems the front left tire has more wear on the outer edge of the tire.
If I remember correctly I think the outside tread was measuring at 3-4/32nds and the remaining tread about 6-7/32nds.
Toe out of spec?

I too thought I had outside tire wear, but upon closer inspection, it's actually the inside that has worn more. The tread near the channel closest to the outer edge of the tire will appear more worn than the tread surrounding the three inner channels; on each of my tires, mine is almost completely worn down in this area, but I have a bit of tread remaining above the wear bars in the three inner channels. This outermost channel does not have a wear bar and should not be used to gauge tread depth.

If you are able to see the very inner edge of your tires, then you may see excessive wear in that area. I didn't realize this until I had the wheels off the car and looked closely at the tires.

[rambo]

Originally Posted by NoHyperbole

You and I share many similarities. I too have a 2014 Sport/Touring on the OEM Bridgestone RE050 tires (now at 18,500 miles and 90% worn), and you've described exactly what I've been experiencing the entire time I've owned the car. Further, my previous car was a 350Z that never exhibited these traits, so I understand where you're coming from.

Regarding what you've called "bump steer," here is my take. When driving straight on road with a bunch of minor imperfections, if I take my hands off the steering wheel, it will "dance" or shimmy side to side, although the car will generally track straight. When I hit a moderate to major bump with one front wheel, the steering wheel will do a quick left-right-left (or right-left-right) shake. Again, this is something I never experienced in my 2007 350Z. My thought is that the extra caster in stock 350Zs (around +7.0) versus 370Zs (around +5.0) is a contributing factor in reducing this steering trait.


As for the sensation that the (front) tires are slipping during slow-speed turns at full lock, I know this sensation well, although it seems to happen only when the ground (after rain) or tires (after car wash) are wet. Do you experience this in dry conditions?

As for alignment specs, my numbers on the OEM suspension are as follows:

Camber: LF = -0.6 RF = -0.9 (non-adjustable)
Caster: LF = +4.7 RF = +4.4 (non-adjustable)
Toe: LF = +.05 RF = +.05

Camber: LR = -1.6 RR = -1.5
Toe: LR = +.10 RR = +.10

What are your alignment numbers? I'm curious to see if they differ greatly from mine.

I've tried taking the car to the dealership to have them investigate this issue, but they don't seem to think anything is abnormal. You and I both know something is not quite right. I wonder if this is an issue only a certain number of 2014 Sport/Touring Zs have.

Wow well I certainly hope it has nothing to do with the 2014s although that wouldn't make any sense.
I don't have my last alignment numbers. I dropped the car off at carmax a few weeks after purchase to have them align it and they never gave me the before/after configurations. I wish I asked for them.
I'll likely look into getting new front tires and another alignment.

Are you still currently on the Bridgestone tires?
I was really hoping that I may have incorrect toe settings but if you're experiencing the same problem with good toe settings....

It just sucks considering these cars typically have outstanding handling/suspension and I don't even feel comfortable driving with one hand on certain roads now.

[rambo]

Oh and for the tires slipping sensation I experience it in both dry and wet although wet is certainly worse.

[Hotrodz]

What kind of tire pressure are you running?

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[rambo]

35 psi

[NoHyperbole]

I'm at 35 psi cold as well, and I do check often with an accurate gauge.

I'm also still on the OEM Bridgestone tires, and they have 18,500 miles on them.

I purchased lifetime alignments at Firestone, so I have had maybe 10 (!) alignments so far, some of which were at different locations to make sure the numbers were the same on different machines. And they were.

I feel like I've tried everything to fix this issue. Perhaps the easiest move--and my next one in a few months--will yield an improvement: getting new tires.

[Hotrodz]

Yup, I think new tires are in order as everything else seems to within standard. I know my car drove a lot better when I put a new set of tires on.

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