[CnSky]

Can anyone tell me their before and after opinion on changing specifically from 20 RFT to non RFT.

Even better if your in a pre LCI 530e and have VDC.

Im chasing the cause of a crashy rear end but staring to think it may just be me that's not used to the RFTs in such a large diameter.

I know BMW USA even warned people taking that option about a harsh ride on 20 inch.

I find the car crashy and rear end shaky around town on surfaces that are anything but perfect when below 80kms . On the motorway it's all but gone.

Could it just be those harsh large RFTs and may lack of previous experience as the largest RFT I used before was 18" on our X1 and my previous E92.

Would be about same price to have BMW keep chasing deeper into rear subframe etc vs just changing the tyres to Michelin pilot sport 4s.

[raduron10]

For such large wheels I personally wouldn't consider non-RFT's unless you have perfect roads.
I had 19" non-RFT on an older E93 and on bad roads I've managed to destroy at least 10 tyres in 2.5 years. The moment I've changed to RFT's I've lost 15% comfort but never had a flat tyre.

[Nadz]

My experience of 19" wheels was the opposite. On the bad roads here i had all 4 RFT's bubble and need replaced. My My21 came with non-RFT's and have had no issues with them at all.

[CnSky]

Thank guys I'm mainly interested in those that have 20s and did the ride get less crashy in town with non run flats.

[crypto]

I'm not sure what you mean by crashy but I hope I never describe anything that happens with my car using that adjective. With that said ... there ride with 20" wheels certainly is not harsh at all. I only had my RFTs on for about 80 miles, but the main difference I noticed were my non-RFTs are quieter. The ride is probably smoother but I was new to the car and didn't have it long enough to really compare otherwise.

[CnSky]

I guess it would be good to describe what I mean by crashy, some people use the word jittery what I mean is an unstable/shaky feeling at low speed as you drive over manholes small ridges and minor pot holes.

Rear in particular is moving side to side on any type of uneven surface that doesn't stretch right across the wheels or wheel base.

For example it's fine over a speed bump or remains of a hole cut uniformly across the road for drainage works but hit a small indentation (not even a pot hole) or edge of man hole cover, shore cover on one wheel only and the car doesn't like it. Moves/shakes right to left in rear before taking longer than usual to settle.

Doesn't happen at speed only around town.

[hlothery]

I have a 2019 M550 with 20 inch 668Ms. I didn't change to non-RFTs. I changed RFTs, and it made a world of difference. The Goodyear RFTs that came on the car were horrible. I changed to Michelin PS3ZP RFTs, and the ride, grip (both wet and dry) and general performance were night and day improved. You might consider them. Had two blowouts with the Goodyears, none since in over 25K miles (knock on wood).

[Joe-BMW33]

Originally Posted by raduron10

For such large wheels I personally wouldn't consider non-RFT's unless you have perfect roads.
I had 19" non-RFT on an older E93 and on bad roads I've managed to destroy at least 10 tyres in 2.5 years. The moment I've changed to RFT's I've lost 15% comfort but never had a flat tyre.

Hmmm....my thinking is the complete opposite and I have experience. My Summer Michelin Super Sports handle my New England pothole ridden roads quite well. Very smooth relatively speaking. I had 19" Run-flats on my F10 and went through 9 of them in two years. See pothole, hit pothole (too late to react), flat tire light on.

I believe the steel sidewalls of the run-flats creates a lack of compression in the rubber and therefore, the hardness is transferred to the driving experience. If you are old enough, think about your first tricycle with the solid rubber tires. Similar phenomena with RFT's.

IDK, maybe it's a combination of Summer softies and non-run flats that has me pleased with my 20" ride.

[Joe-BMW33]

Originally Posted by hlothery

I have a 2019 M550 with 20 inch 668Ms. I didn't change to non-RFTs. I changed RFTs, and it made a world of difference. The Goodyear RFTs that came on the car were horrible. I changed to Michelin PS3ZP RFTs, and the ride, grip (both wet and dry) and general performance were night and day improved. You might consider them. Had two blowouts with the Goodyears, none since in over 25K miles (knock on wood).

All Seasons or Max Summer Performance? I know in my parts, when you selected the 20" run flat option, they only came in All Season. Given you are in TX, Summer rubber would be ideal and they ride SO much softer than All Seasons.

[pickigar]

I did the same as hlothery, went from Goodyear’s to Michelin Pilot Sport 3s recently, the difference is night and day, noise, comfort, handling… all massively improved. Had bubbles on the sidewalks with all 4 Goodyear’s, and the final straw was a split when in for some recent work. Would highly recommend it! I nearly changed cars over it, and am now happy I didn’t!

[CnSky]

Thank hlothery but I'm already running MP3ZP brand new on new oem alloys.


QUOTE=hlothery;27697186]I have a 2019 M550 with 20 inch 668Ms. I didn't change to non-RFTs. I changed RFTs, and it made a world of difference. The Goodyear RFTs that came on the car were horrible. I changed to Michelin PS3ZP RFTs, and the ride, grip (both wet and dry) and general performance were night and day improved. You might consider them. Had two blowouts with the Goodyears, none since in over 25K miles (knock on wood).[/QUOTE]

[CnSky]

Any chance all of you running PS3ZP live in warm climates?

I noticed with the temp high 23c - 75f last few days in ireland (rare) that the car handles much better but at night back to being crashy/jittery in town and early mornings.

Hence why I'm starting to lean towards the rubber compound being softer in non RFTs would make a huge difference.

[Joe-BMW33]

Originally Posted by CnSky

Any chance all of you running PS3ZP live in warm climates?

I noticed with the temp high 23c - 75f last few days in ireland (rare) that the car handles much better but at night back to being crashy/jittery in town and early mornings.

Hence why I'm starting to lean towards the rubber compound being softer in non RFTs would make a huge difference.

The higher the outside temp, the softer the rubber and the softer the asphalt. 75F is my favorite temp to drive a car. Minimal AC drag and soft and grippy driving. The ultimate tire for handling and ride are max summer performance non run flats. Preferably Michelin's such as super sports. I've heard good things about General and Continental too. But not everyone can pull off summer tires.

[CnSky]

I need to find someone in Ireland who has 20' non RFTs locally to test it out as it's approx $1500 to change and the current RFTs are brand new.

If it fixed it for sure would change no problem but if not it's like throwing cash's away.

Any Irish/Northern Irish on here who have made the change on 20s? would even contemplate a ferry and drive to Wales or Scotland to check would be an interesting trip.




QUOTE=Joe-BMW33;27699456]

Originally Posted by CnSky

Any chance all of you running PS3ZP live in warm climates?

I noticed with the temp high 23c - 75f last few days in ireland (rare) that the car handles much better but at night back to being crashy/jittery in town and early mornings.

Hence why I'm starting to lean towards the rubber compound being softer in non RFTs would make a huge difference.

The higher the outside temp, the softer the rubber and the softer the asphalt. 75F is my favorite temp to drive a car. Minimal AC drag and soft and grippy driving. The ultimate tire for handling and ride are max summer performance non run flats. Preferably Michelin's such as super sports. I've heard good things about General and Continental too. But not everyone can pull off summer tires.[/QUOTE]

[hlothery]

Originally Posted by Joe-BMW33

All Seasons or Max Summer Performance? I know in my parts, when you selected the 20" run flat option, they only came in All Season. Given you are in TX, Summer rubber would be ideal and they ride SO much softer than All Seasons.

They are definitely Summer tires.

[jjscsix]

I went for the 20 runflats to 19 non runflat all seasons. My ride was noticeably better of course. Keeping the 20s will be better, but not as much. There is just not enough sidewall to absorb impacts. Think about this, if the sidewall does it’s job of absorbing impacts you are a lot closer to damaging a wheel with short sidewalls.

The best combination is a non M-Sport with 19” all season tires. I’ve had loaners with that combination and even though they had runflats the car rode worlds betting than my M-Sport with either tires I had on it.

[CnSky]

Thanks for the input I'm wondering if I could go 275/35/20 on rear in non run flat current size is 275/30/20. Extra 5mm makes the difference and softer compound.

Knowing BMW the car wouldn't like it.


QUOTE=jjscsix;27702439]I went for the 20 runflats to 19 non runflat all seasons. My ride was noticeably better of course. Keeping the 20s will be better, but not as much. There is just not enough sidewall to absorb impacts. Think about this, if the sidewall does it's job of absorbing impacts you are a lot closer to damaging a wheel with short sidewalls.

The best combination is a non M-Sport with 19" all season tires. I've had loaners with that combination and even though they had runflats the car rode worlds betting than my M-Sport with either tires I had on it.[/QUOTE]

[Joe-BMW33]

)

Originally Posted by jjscsix

I went for the 20 runflats to 19 non runflat all seasons. My ride was noticeably better of course. Keeping the 20s will be better, but not as much. There is just not enough sidewall to absorb impacts. Think about this, if the sidewall does it’s job of absorbing impacts you are a lot closer to damaging a wheel with short sidewalls.

The best combination is a non M-Sport with 19” all season tires. I’ve had loaners with that combination and even though they had runflats the car rode worlds betting than my M-Sport with either tires I had on it.

But that's no fun.

[CnSky]

Can anyone tell me (or show a picture) of what MPS4S look like at 275/35/20 rear and 275/40/20 front I'm changing to non RFT Michelin's 100%.

Saw a M5 with 275/35 F and 285/35 R and it looked great the MSP4S sidewall is straight, the wheels looked matched and tyre is much softer.

I'm worried 40 at front may be too much?

Want to order Monday so any advice much appreciated.

Also I'm on VDC so 10m higher than M sport shocks so maybe even 40 all round would look better.

Open to ideas.

[GTFISH]

I switched to non RFT Michelin MPS4's from the PS3ZP RFTs and they ride a lot better and the grip is much improved as well.

[CnSky]

Thanks my order is placed will be fitted this week by BMW at 1170 Euro which was only marginally more expensive than my local tyre place and I have peace of mind it will be done correctly with no alloy damage.

I went with larger side walls 40 front 35 rear as advised by a BMW technician similar to the M5 (which is 35 all around from one we looked at on the lot) so hope it sorts out my crashy low speed ride on local uneven road surfaces. Will easily fit as my VDC rides 10 mm higher than M sport shocks and I run 15mm spacers all around.

Fingers crossed as it's the last niggling issue I have on an otherwise perfect car.

[Junebug85]

Originally Posted by CnSky

Thank guys I'm mainly interested in those that have 20s and did the ride get less crashy in town with non run flats.

I have a Pre LCI 540i and I went from 20" Goodyear Eagle F1 AS3 Run Flats to 20" Michelin PS4S non Run Flats.

Standard sizes too 245/35/20 and 275/30/20.

No regrets or complaints - It has improved the ride quality. With 20" it's not the best as it is but moving away from non run flats has improved it some what.

I carry a slime tyre repair kit, few extra cans of tyre gel and a tyre plug repair kit just incase.