Will going 19inch make the ride harsher?

essldn · October 8, 2021

Currently have 235/45/18 on my 17 gs luxury.

For 19 is the correct tyre size 245/40/19?

Also will this affect ride comfort? I see the tyre width increase but tyre height decrease.

Las Palmas · October 8, 2021

Absolutely. It will be firmer / harsher. Depending on how you look at it.

You will also go 1.48% longer each turn of the wheel.

essldn · October 8, 2021

13 minutes ago, Las Palmas said:

Absolutely. It will be firmer / harsher. Depending on how you look at it.

You will also go 1.48% longer each turn of the wheel.

Thanks, I think I will go for aftermarket 18s as I don't like the stock ones. Too much tyre height and gap on the GS but I guess that comes with the comfort. I had 20s on mercedes e class lower ride and very little gap. But that was a bit harsh as expected.

JDM-Fiend · October 9, 2021

10 hours ago, essldn said:

Thanks, I think I will go for aftermarket 18s as I don't like the stock ones. Too much tyre height and gap on the GS but I guess that comes with the comfort. I had 20s on mercedes e class lower ride and very little gap. But that was a bit harsh as expected.

My advice would be, if you go aftermarket - buy a good brand of alloys.

Cheaper aftermarket alloys are cheap for a reason.

Best of luck and show us pics before and after.

essldn · October 9, 2021

39 minutes ago, JDM-Fiend said:

My advice would be, if you go aftermarket - buy a good brand of alloys.

Cheaper aftermarket alloys are cheap for a reason.

Best of luck and show us pics before and after.

These are the options I've narrowed it down do. I have always preferred black wheels. But I think diamond/polish face will give the car a more modern look. Also as its only 18 inch I think the spokes will need to touch right to the top of the rim or the wheels will look small.

Chris111 · October 9, 2021

FYI Shane the GS F Sport is fitted with 19" wheels as standard. 8"x19" front and 9"x19" rear. Tyre size is 235/40/19 front and 265/35/19 rear. If you were to fit 8"x19" all round with the 235/40/19 tyre size, the difference in overall diameter from 18"to 19" is only +0.28% (or 2mm), not the +1.48% (or 10mm) if you fitted 245/40/19. I personally also don't think that a reduction in the tyre profile height from 45 to 40 would make a huge reduction in ride comfort.

Las Palmas · October 9, 2021

Want to buy aftermarket wheels?

Have a look at BBS. Used to be among the very best.

Have won a lot of 24-hour races.

I am happy with what Lexus has put on the car but should I get tempted BBS would be my choice.

essldn · October 10, 2021

On 10/9/2021 at 6:54 PM, Chris111 said:

FYI Shane the GS F Sport is fitted with 19" wheels as standard. 8"x19" front and 9"x19" rear. Tyre size is 235/40/19 front and 265/35/19 rear. If you were to fit 8"x19" all round with the 235/40/19 tyre size, the difference in overall diameter from 18"to 19" is only +0.28% (or 2mm), not the +1.48% (or 10mm) if you fitted 245/40/19. I personally also don't think that a reduction in the tyre profile height from 45 to 40 would make a huge reduction in ride comfort.

Thanks for that info. If the difference is only 2mm I don't think ride comfort will change much ?

ColinBarber · October 10, 2021

24 minutes ago, essldn said:

Thanks for that info. If the difference is only 2mm I don't think ride comfort will change much ?

2mm is the increase in tyre diameter. But the sidewall height of the tyre is greatly reduced as the alloy wheel is larger.

235/45 means a sidewall height of 105.75 mm (235 x 0.45)

235/40 has a sidewall height of 94 mm

So you are giving up nearly 12 mm of sidewall height which will make the ride harder.

Initial P · October 10, 2021

I can't tell the difference on ride quality on my 19" wheels on my GS4 vs my old 18" on my old GS3.

ColinBarber · October 10, 2021

13 hours ago, Initial P said:

I can't tell the difference on ride quality on my 19" wheels on my GS4 vs my old 18" on my old GS3.

I'd say that is mainly due to the series IV having a better suspension design and a more compliant ride.

essldn · October 11, 2021

17 hours ago, Initial P said:

I can't tell the difference on ride quality on my 19" wheels on my GS4 vs my old 18" on my old GS3.

What tyre size do you have, also what is it like over small bumps and imperfect Roads?

essldn · October 11, 2021

17 hours ago, ColinBarber said:

2mm is the increase in tyre diameter. But the sidewall height of the tyre is greatly reduced as the alloy wheel is larger.

235/45 means a sidewall height of 105.75 mm (235 x 0.45)

235/40 has a sidewall height of 94 mm

So you are giving up nearly 12 mm of sidewall height which will make the ride harder.

What about 240/40 instead of 235/40?

ColinBarber · October 11, 2021

3 hours ago, essldn said:

What about 240/40 instead of 235/40?

240 mm x 0.4 = 96 mm so not a great difference.

The fact is that making the wheel an inch larger means you need to reduce the tyre side wall 1/2 inch to keep the total wheel/tyre radius roughly the same which will impact ride comfort. How much that impacts you is personal - some people don't mind, others will feel it is too harsh.