nikneym

Hi,
I am new to the community so I hope you don't mind if I am doing this wrong.

I bought my car (IS300 awd, 2017) just a few weeks ago. I love the car and everything was perfect but something happened.
There is a bumpy feeling, especially going in low speeds (I can still feel it at any speed though). It is not very strong but when I am not pushing the throttle, it is easier to recognize. I can feel it with my whole body, not just from the steering wheel.

1. I went to the service and they checked the alignment etc but did not solve the problem.
2. I think I can feel the road more compared to before. It is kind of a sport car so it might be normal but again, it may have increased. (This arises suspicions on suspension, although the mechanic claimed that they checked. Maybe they missed it because they did not check good enough.)
3. Some mechanics drove it and claimed everything is normal. I drove with one of the agents there and even if he was trying to show everything was normal, he could not deny that there is a bit of a bumpiness.
4. This may not be important but it happened instantly. I felt the change in the car, it was not over time. I was driving on the highway and did not hit any pothole or anything. The car was changing gears, probably in high revs and I felt the difference afterwards. Again, it may not be relevant but I just wanted to say.

I hope you can give me some good ideas so that I can ask the mechanics to check. I just bought it and I don't want to drive the car like this for a long time.

dshu

Maybe the wheels need to be balanced

skiracer

+1 this might be it. Had this problem before...

nikneym

they did this already and I think it did not change anything. It does not feel like a balance problem anyway. My old car had it and I know the feeling. It is more like a shakiness than bumpiness. This is different. As if something is attached to the wheel (not exactly but something like that).

dshu

What tires do you have on it?

skiracer

Could be tire "Cupping" or "Scalloping" Check here:
https://www.utires.com/articles/back-tires-cupping/


It may not be totally visible, but rub your hands along each tire to see if you can feel any noticeable bumps... I had tires previously cup on me...

zhifan1

Let us know the specs of your tires pls.. if they are anything in 19inches, then it is absolutely normal. Next is the PSI.. if you are on 38psi, maybe change to 36psi and see how it goes..

nikneym

it is low profile tires. Before the service, psi was around 32, now it is around 38.

I can understand the difference between low and high profile tires. Of course, you are going to feel the road more. In my case, there was a change. I have been driving the car for 900 miles and something changed suddenly. That is why I am curious.

Also, I haven't checked the cupping yet. I actually assumed that mechanics were supposed to look at them. Anyway, I'll let you know if there is any cupping.

zhifan1

Any chance that the service guys missed out on a leaking hydraulic fluids of the absorbers?

arentz07

Seems like 32 to 38 would be a difference you could feel - but in the warmer months mine are usually at 37, and it wouldn't say the ride feels "bumpy" - if I am on an even surface, the ride is even, as well.

Like others have said though, probably would be good to do your own inspection of the tires.

600rr

Thoroughly check for damages on all of your tires. Cupping, side damage, air bubble, a nail perhaps. Look for anything out of the ordinary.

Miintt

Im running 36 psi in my tires now but my ride was way bumpier before when the psi was 32. Im on 19" wheels though so im not sure if that matters

jkonquer

I had similar problem as well, at first I thought it was blown shocks since that's what it felt like. But it would only do it once in a while. Took it to the dealership and the shocks weren't blown.
It "feel" like AVS dampening on certain shocks are not engaging causing the bumpy ride. lately it has been fine.

nikneym

That is totally possible. I will ask for that next time. Thanks.

nikneym

Yes, I was going to say as well that it does not happen all the time. Although it happens very often in my case. I am not sure if it is related to AVS but I will ask them to check that as well. Thanks.