19s to 18s for ride comfort - worth the effort?

[DibblyDobbler]

Hi All.

Currently running a G20 330i M-Sport with 19s + RFTs and adaptive (gratuitous pic below ). Generally very happy with the car - very well built, pulls nicely and amazing economy.

I am in my mid 50s now () and comfort is a priority - the ride is not terrible in comfort mode but any improvement would be welcome. So my options are:

1. Switch to non-RFTs and leave it on 19s
2. Switch to non-RFTs on 18s

Option 2 is a fair bit more effort (eg informing insurance, selling on the old wheels etc) and it may be that I get 80% of the benefit with option 1 - anybody done similar or got any views?

Thanks for any replies (except 'you bought the wrong car Grandpa' etc)


Untitled by Mike Smith, on Flickr

[Panamax]

I had a similar "problem" and was contemplating selling the car (not a BMW). Concrete suspension is no fun on British roads - I will never again buy a saloon/estate with any form of Sport package.

Yes, I bought a set of used wheels 1" smaller diameter and with taller tyres so the rolling radius remained almost identical. Problem solved.

Sure, if you press the car into a corner you can feel greater deflection in the tyre walls and the car is less keen to turn but I found it a price worth paying and have been able to live with a car that was otherwise unacceptable. It's a bit of a bodge but it worked.

You may also get a nicer ride by abandoning runflats although the difference isn't anything like as pronounced as it was 10 years ago.

If you stick with OEM wheels and tyres in a spec recommended for the car you shouldn't trip over any "boy racer" issues with your insurers. I declared my changed wheels and the insurers made a note but weren't bothered.

[d_a_n1979]

I dropped to 19s for summers and 18s for winters, from 20s on my previous F01

All non RFTs and they made enough of a difference to know I'd done the right thing...

I think a simple change to non RFTs will do a good enough job for you; and 18s if you want to run winters etc

19s:



18s:

[Darren-7ypkg]

F31 335d on 19" wheels & AC Schnitzer springs here. I recently changed from Bridgestone RFT to Michelin PS5 non-RFT and the noise level & ride quality have noticeably improved. I'd start there if it was my money.

[BenS94]

I changed mothers' Mini JCW from Pirelli Cinturato P7 RFTs to non RFT Dunlop SportMaxx RT2s - a HUGE difference all round. Did buy a genuine puncture repair kit etc to keep it legal, still saved quite a chunk all in over RFTs too.

[DibblyDobbler]

Panamax said:

I had a similar "problem" and was contemplating selling the car (not a BMW). Concrete suspension is no fun on British roads - I will never again buy a saloon/estate with any form of Sport package.

Yes, I bought a set of used wheels 1" smaller diameter and with taller tyres so the rolling radius remained almost identical. Problem solved.

Sure, if you press the car into a corner you can feel greater deflection in the tyre walls and the car is less keen to turn but I found it a price worth paying and have been able to live with a car that was otherwise unacceptable. It's a bit of a bodge but it worked.

You may also get a nicer ride by abandoning runflats although the difference isn't anything like as pronounced as it was 10 years ago.

If you stick with OEM wheels and tyres in a spec recommended for the car you shouldn't trip over any "boy racer" issues with your insurers. I declared my changed wheels and the insurers made a note but weren't bothered.

Thanks for the reply - the section I've put in bold is interesting, I was wondering if RFTs have improved over the years so maybe aren't as brick hard as they were in the past? I'm currently on Goodyear Eagle AS3 ROF but I can't find much information about them.

[DibblyDobbler]

d_a_n1979 said:

I dropped to 19s for summers and 18s for winters, from 20s on my previous F01

All non RFTs and they made enough of a difference to know I'd done the right thing...

I think a simple change to non RFTs will do a good enough job for you; and 18s if you want to run winters etc

19s:



18s:

Thanks Dan - I hope you are right as this would be easier but I just don't want to feel like I've done half the job...

[DibblyDobbler]

Darren-7ypkg said:

F31 335d on 19" wheels & AC Schnitzer springs here. I recently changed from Bridgestone RFT to Michelin PS5 non-RFT and the noise level & ride quality have noticeably improved. I'd start there if it was my money.

Thanks Darren - that is good to hear! And welcome

[DibblyDobbler]

BenS94 said:

I changed mothers' Mini JCW from Pirelli Cinturato P7 RFTs to non RFT Dunlop SportMaxx RT2s - a HUGE difference all round. Did buy a genuine puncture repair kit etc to keep it legal, still saved quite a chunk all in over RFTs too.

Thanks Ben - again, good to hear

[Mr Tidy]

I think you bought the right colour.

Anyway I think switching to non run-flats might be your best option.

I switched from 19" to 18" wheels on my Z4M (both were non run-flats) and didn't notice an improvement in ride comfort.

My E91 came with 16" run-flat Bridgestone Blizzak winters fitted so I bought a set of 17s with run-flat Pirelli P Zero summer tyres and didn't notice any deterioration in ride, although both were slightly better than the 17" Bridgestone Potenza run-flats on my current E90.

[Billy_Rosewood]

Went from 19" summer rfts to 18" non-rft all-seasons.. This is in the f30 with m sport suspension.

There's a marked increase in comfort/reduction in noise. But if the Mrs didn't drive the car I'd be happy to stay in the 19" with the eagle f1 rfts..

The ride was far far superior to the crashy nature of the old e60 on 18" rfts.

[McGee_22]

We were looking for a F33 435d cab about 6 years ago - almost every car we looked at and test drove had 19” RFTs and the ride in the front was harsh but in the back bone shattering. Managed to find an example with 18” RFTs and the ride was leagues better, so we bought it.

[Caddyshack]

Yes, it will ride better.

Modern cars are often sprung too hard and under damped as that is a much cheaper setup but it gets expensive to start replacing that lot - especially on adaptive cars.


Someone in EVO once wrote that the best riding car is probably a 528i E39 in comfort spec…they said that sadly those cars stopped production long, long ago. (They also wrote it long ago but I think it is even truer now.)

I was very disappointed with the ride in a Bentley Speed (continental - can’t remember the full model name) when I went out in it.

[Panamax]

DibblyDobbler said:

Panamax said:

You may also get a nicer ride by abandoning runflats although the difference isn't anything like as pronounced as it was 10 years ago.

Thanks for the reply - the section I've put in bold is interesting, I was wondering if RFTs have improved over the years so maybe aren't as brick hard as they were in the past? I'm currently on Goodyear Eagle AS3 ROF but I can't find much information about them.

My experience has been that modern runflats are more compliant than the early versions.

Equally my experience has been that conventional tyres can in some case be pretty darned stiff - which could possibly be because the sizes I'm using are only available in "XL" specification. I don't know what the letters XL (or "reinforced") actually add to the more familiar "load rating" figures.

[DibblyDobbler]

Mr Tidy said:

I think you bought the right colour.

Anyway I think switching to non run-flats might be your best option.

I switched from 19" to 18" wheels on my Z4M (both were non run-flats) and didn't notice an improvement in ride comfort.

My E91 came with 16" run-flat Bridgestone Blizzak winters fitted so I bought a set of 17s with run-flat Pirelli P Zero summer tyres and didn't notice any deterioration in ride, although both were slightly better than the 17" Bridgestone Potenza run-flats on my current E90.

Thanks! It wasn't what I set out to but at all but when I saw it in the flesh I loved it

I agree - I think a 1 inch change in wheel size is probably only going to make a small difference (all other things being equal)

[DibblyDobbler]

Billy_Rosewood said:

Went from 19" summer rfts to 18" non-rft all-seasons.. This is in the f30 with m sport suspension.

There's a marked increase in comfort/reduction in noise. But if the Mrs didn't drive the car I'd be happy to stay in the 19" with the eagle f1 rfts..

The ride was far far superior to the crashy nature of the old e60 on 18" rfts.

Thanks Billy - appreciate the input This is what I am after but it's whether I'd get most of the way there just with new tyres...

[DibblyDobbler]

McGee_22 said:

We were looking for a F33 435d cab about 6 years ago - almost every car we looked at and test drove had 19” RFTs and the ride in the front was harsh but in the back bone shattering. Managed to find an example with 18” RFTs and the ride was leagues better, so we bought it.

Thanks - that is interesting

[DibblyDobbler]

Caddyshack said:

Yes, it will ride better.

Modern cars are often sprung too hard and under damped as that is a much cheaper setup but it gets expensive to start replacing that lot - especially on adaptive cars.


Someone in EVO once wrote that the best riding car is probably a 528i E39 in comfort spec…they said that sadly those cars stopped production long, long ago. (They also wrote it long ago but I think it is even truer now.)

I was very disappointed with the ride in a Bentley Speed (continental - can’t remember the full model name) when I went out in it.

Thanks - the ride is not terrible at present but I'm hoping to keep the car for some time so I want to get it right

[DibblyDobbler]

Panamax said:

DibblyDobbler said:

Panamax said:

You may also get a nicer ride by abandoning runflats although the difference isn't anything like as pronounced as it was 10 years ago.

Thanks for the reply - the section I've put in bold is interesting, I was wondering if RFTs have improved over the years so maybe aren't as brick hard as they were in the past? I'm currently on Goodyear Eagle AS3 ROF but I can't find much information about them.

My experience has been that modern runflats are more compliant than the early versions.

Equally my experience has been that conventional tyres can in some case be pretty darned stiff - which could possibly be because the sizes I'm using are only available in "XL" specification. I don't know what the letters XL (or "reinforced") actually add to the more familiar "load rating" figures.

Thanks again, that is interesting

[BenS94]

DibblyDobbler said:

Panamax said:

DibblyDobbler said:

Panamax said:

You may also get a nicer ride by abandoning runflats although the difference isn't anything like as pronounced as it was 10 years ago.

Thanks for the reply - the section I've put in bold is interesting, I was wondering if RFTs have improved over the years so maybe aren't as brick hard as they were in the past? I'm currently on Goodyear Eagle AS3 ROF but I can't find much information about them.

My experience has been that modern runflats are more compliant than the early versions.

Equally my experience has been that conventional tyres can in some case be pretty darned stiff - which could possibly be because the sizes I'm using are only available in "XL" specification. I don't know what the letters XL (or "reinforced") actually add to the more familiar "load rating" figures.

Thanks again, that is interesting

XL is for Extra Load - much thicker sidewall. Chose these for mothers' JCW as she's had one too many mishaps with kerbs - causing this: