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[Spin_dry]

Looking for a smoother ride out of my 135. 17" winter wheels are installed. I find the ride to be improved over the OEM 18" with run flats. Can I get a similar ride quality by switching to non run flat 18" tires?

[FredrikM]

I went from 18" Run flats to 19" Non run flats and i have a smoother ride. So yes i definitely would think you will feel an improvement with 18" non run flats.

[BrokenVert]

I had a set of PS2s on my OEM wheels before switching to a 17" summer set. Yes, good regular tires on the OEM wheels improve the ride and handling. However, 17s and a good set of summer rubber make it outstanding

[Freon]

Yes, non RFT 18" will ride better, but sacrifice some steering feel. The factory setup counts on stiff tires and loose bushings.

I actually run RFT 17" winter and non-RFT summer 18" tires.

[Gary@TireRack]

This all depends on what brand/model of run flat vs what brand and model of non run flat. I carry some run flat tires that ride more softly than some non run flat tires... For example, a Bridgstone Driveguard runflat rides more softly than a non run flat Michelin Pilot Super Sport.

[TheSt|G]

Originally Posted by BrokenVert

I had a set of PS2s on my OEM wheels before switching to a 17" summer set. Yes, good regular tires on the OEM wheels improve the ride and handling. However, 17s and a good set of summer rubber make it outstanding

Exactly.

[128Convertibleguy]

Originally Posted by Spin_dry

Looking for a smoother ride out of my 135. 17" winter wheels are installed. I find the ride to be improved over the OEM 18" with run flats. Can I get a similar ride quality by switching to non run flat 18" tires?

Close call, depends on exactly what tires we're talking about.

Given either both run flats or both non runflats, higher profile 17s will ride better than lower profile 18s.

Given both 17s or both 18s, non runflats will ride better than run flats.

If you make one change favorable to ride (non run flats instead of run flats) and one change unfavorable to ride (18s instead of 17s) they'll at least somewhat cancel each other out. Which will win now becomes a closer call that can be changed by exactly what tires are involved. You winter tires probably also had softer sidewalls than summer tires. This is not a simple question with an easy answer.

If ride is your goal, clearly the best option is 17" non run flats. If the low profile look is your goal that changes things. Handling and steering response complicate things farther. There is no universal truth here, it all depends on your tastes and your priorities. Some people prefer 17s, some 18s. Some people even prefer run flats, it's hard to duplicate their steering response.

[MotoWPK]

Originally Posted by 128Convertibleguy

Handling and steering response complicate things farther. There is no universal truth here, it all depends on your tastes and your priorities. Some people prefer 17s, some 18s. Some people even prefer run flats, it's hard to duplicate their steering response.

This is what I'm struggling with. I'm going to replace the OEM Goodyear Eagle LS-2's on my 128i (205/50-17) and, while I've been pleased with them, have considered the cost, ride, noise advantages of non-runflats. I am concerned, however, about losing steering response because of the more flexible sidewalls of non-runflats.

Have thought about Michelin AS3's thinking that, being ultra high performance all seasons vs. grand touring all seasons, as the Goodyear LS2's are, would compensate for this.

Then I became aware of the Bridgestone Driveguard runflats which receive really good reviews by Tire Rack and customers, clearly superior to the Goodyears. I've read how the Driveguards are made with more flexible sidewalls than other runflats to provide a better ride and lower noise - and they cost like non-runflats. Given that both the Driveguards and Goodyear LS2's are runflat, grand touring all season tires, I'm now wondering if perhaps the Driveguards are the way to go with benefits of lower cost, better ride, lower noise and, still being runflats, more likely to provide a steering response similar to that I've enjoyed with the Goodyear LS2 runflats.

I know the Driveguards aren't going to provide the traction levels of the AS3's, but that's not my priority.

[APC7654]

MotoWPK, did you end up getting the Bridgestone Driveguards? And if so, how did they perform when compared to the OEM's?

I'm seriously considering replacing my OEM Goodyear Eagle NCT5's with the Driveguards.