Ride quality - specific observation

XML · September 21

UX 300h F Sport Design with Bridgestone Alenza RFTs, tire pressure lowered based on advise from this forum. Also was told that F Sport Design has a normal suspension, Sport is just a name.

Let me explain what I am trying to achieve. I think in general ride quality can be described by these two components:

1. High frequency, low amplitude vibration when driving on a flat surface that does not have potholes or bumps. In a car with a stiff suspension or low profile tires you get that a lot.

2. Jumping over bumps. This is when you drive over a pothole or a bump.

My observation:

First component - no issues, the ride is smooth, no vibration.

Second component - the UX jumps too hard, especially when both rear wheels go over the bump at the same time.

I noticed that many cars do the same, for example, MB GLA, B-class. On a flat surface the ride is smooth, feels heavy and expensive but once you hit a bump or a pothole it just jumps too hard.

Hoping that the run flats are the reason.

PCM · September 21

2 hours ago, XML said:

Let me explain what I am trying to achieve. I think in general ride quality can be described by these two components:

Q. Are you after a particular ride quality?

geoffl · September 21

I have just changed my Bridgestone RFs for Goodyear EfficientGrip Performance2 225/50R18 (not run flat) chiefly for ride quality and I find a significant improvement. The Goodyear tyres are rated as B(Fuel efficiency), A (Wet braking) and 69db (noise). At £640 for 4 tyres, it's not an easy decision, but noise and quality of ride were paramount.

Don C · September 21

I’ve changed to Good Year all seasons and I get that resonating. I was convinced it was the tyres but I’m not so sure.

XML · September 22

I am thinking about Michelin Premacy 4.

Pauly C · September 22

Interesting….I still have ride quality questions on my UX. ….but I’m starting to think it’s not the tyres. My ‘resonating’/‘shivering’/‘shuddering’ or whatever words you want to use, come and go….most notably in the power band, going up hills. Never had any issue whatsoever like this with my last car…my UX just does not feel ‘tight’ in such situations….like a 22K mile Lexus should🤔

Don C · September 22

20 hours ago, XML said:

I am thinking about Michelin Premacy 4.

Good tyres but hopeless if you get the slightest bit of snow.

XML · September 24

On 9/21/2024 at 9:58 AM, PCM said:

Q. Are you after a particular ride quality?

Yes. I want driving over bumps to be not a sharp sudden punch but a softer, longer movement. Plan is the following:

Check if transportation spacers have been removed

Replace Bridgestone Runflats with Michelin Premacy 4

Potentially fit smaller rims

Report back to this forum

GMB · September 24

Both our cars have Michelin pilot sports tyres, low profile. The 200t is hard as a rock and the ISF is like it has no suspension at all - hard as a very hard rock. If you push down on the rear quarter it does not budge, and yes the suspension is correct and not faulty, it's just the way it is. Crash bang wallop. But the handling at speed ( on a dry road ) is spot on. I have not dared push it anywhere near its limits and capability.

Don C · September 24

Mine is quieter and softer with Good Year all seasons on.

XML · September 25

What does it take to fit smaller rims? I assume that the rolling circumference will be different so some software adjustments will have to be made?

ColinBarber · September 25

2 hours ago, XML said:

What does it take to fit smaller rims? I assume that the rolling circumference will be different so some software adjustments will have to be made?

No, you need higher profile tyres so the circumference remains the same (within a percentage or two). What size are your current rims?

XML · September 29

On 9/25/2024 at 10:26 PM, ColinBarber said:

No, you need higher profile tyres so the circumference remains the same (within a percentage or two). What size are your current rims?

It is 225/50 RF18 95V

Pauly C · September 29

On 9/24/2024 at 6:08 AM, XML said:

Yes. I want driving over bumps to be not a sharp sudden punch but a softer, longer movement. Plan is the following:

Check if transportation spacers have been removed

Replace Bridgestone Runflats with Michelin Premacy 4

Potentially fit smaller rims

Report back to this forum

Just out of interest - why are you going to all this trouble and cost? If you don't like the way your car rides, get a different model...or a different marque altogether😉

ColinBarber · September 29

3 hours ago, XML said:

It is 225/50 RF18 95V

If you want smaller rims then you would be best to stick with the standard sizes so you could drop to 17" rims with 215/60R17 tyres, and if you got some original Lexus UX rims then you wouldn't need to inform your insurance company.