[eyyjey]

Hello-

I have a 2016 228xi Coupe M Sport with stock 18" wheels (225/40R18) [Square Set up]

Current Tires : RF P7 Cinturato All Season

I've been running into pothole issues lately due to my tires having very thin sidewalls and I wanted to see if anyone has any NON Run Flat with THICKER Sidewalls tire recommendations for my car? Been wanting to swap for awhile but I don't have any clue to what's best out there. Any feedback/help is appreciated!

Let me know what you're running in your 2 Series and if you ever had issues like me with potholes

Thanks a lot!

[Sportstick]

Originally Posted by eyyjey

Hello-

I have a 2016 228xi Coupe M Sport with stock 18" wheels (225/40R18) [Square Set up]

Current Tires : RF P7 Cinturato All Season

I've been running into pothole issues lately due to my tires having very thin sidewalls and I wanted to see if anyone has any NON Run Flat with THICKER Sidewalls tire recommendations for my car? Been wanting to swap for awhile but I don't have any clue to what's best out there. Any feedback/help is appreciated!

Let me know what you're running in your 2 Series and if you ever had issues like me with potholes Thanks a lot!

You cannot just put a taller sidewall tire (higher aspect ratio, e.g. 50 vs 40) tire on the same 18" wheel without possible issues of fit, turning radius, and speedometer accuracy. In Michigan, where the roads were lunar landscapes, I changed from the original 18s to 17s to install 225/45-17s in a square setup, which provided the taller sidewall, for the same reasons you mention in NJ. Think of a doughnut...more doughnut, smaller hole, same overall circumference. Some here will howl about aesthetics of a 17...so be it...they are not the ones replacing your tires and wheels when damaged. I have no issue with the look. Smaller wheels are usually lighter, as are the tires, and that actually improves performance, braking distance, and ride harshness.

Once you make the move to 17s, there are many tires to choose from. I suggest, being in NJ, you choose from the UHPAS (ultra high performance all season) category for great summertime performance, but can tolerate the temperatures of the transitional early Spring/late Fall when temps are too low for summer tires, but there is no snow yet for you to swap to winter tires which NJ weather indicates. Take a look here for tires in a 17" size.

https://www.tirerack.com/tires/surve...jsp?type=UHPAS

They also sell wheels. It's very subjective, but look to avoid "gravity cast" in the specs. Pressure cast or better are higher quality. I happened to choose from BBS, a high quality wheel producer. Good luck!

[msej449]

The P7 is not a good match for the 2 Series. It's rarely - if at all - fitted in Europe as original equipment and I've no idea why BMW do so in the USA. The Pirelli UK site doesn't even list the P7 in any type or size as a match for any model of F22/23.

Because runflats are fitted as OE in the US, and you seem to suffer from disproportionate poor road surface damage, a lot of owners blame damage on the tires being runflats. But runflats actually have stronger sidewalls than goflats, so in theory, they should be more - not less - resistant to damage.

In the UK, people switch to goflats not because of any tendency to damage from runflats, but because they feel that the thinner sidewalls of the goflats provide better handling in performance models. I don't think I've ever seen a thread on UK forums talking about runflats being more prone to damage. All the discussion is about how much of any improvement in handling is down to a change to a better brand, versus a runflat>goflat swap.

So your road damage is almost certainly arising more from running low-profile 18" wheels/tires and unsuitable P7 tires, than from using runflats. So the idea of switching to 17" is a sound solution: I have 225/45x17 runflats on 7.5J rims on all four wheels as my winter setup and certainly, the ride is smoother than on the summer staggered 18" wheels.

If you look in your Owners Manual, you'll see the various combinations of higher-profile tyres and wheels that are certified to fit, with the winter specs' generally being the highest profile. In my case I can go as far as 205/50x17 on 7J rims and while of course, the handling wouldn't be as good in high summer as with the OE 245/35x18 on 8Jx18" rims, if the road conditions were worse, I might be willing to make that compromise.

If you are unconvinced that staying with runflats is a good idea, or want to cover all the bases, so to speak, then do the move to goflats. It's not going to do any harm, other than remove the potential benefit of runflats in being able to tolerate minor deflation damage. I can appreciate that given the cost of a wheel and tyre change, you may want to take every measure available to you even if it's unclear which measures make what difference. The only comment I'd make is that theoretically, as I said, the thicker-sidewalled runflats should be more, not less, robust over potholes: the counter I've seen posted is that the thinner-sidewalled goflats more readily deform. I don't know enough to comment on which is the truer.

Here is the car with its winter Alutec Drive 17" x 7.7J wheels and 225/45 winter tires (Pirelli Winter Sottozero S3):



And just as background (apologies if you know this already), as you change wheel and tyre sizes, one thing that is meant to stay the same is the 'rolling radius' - that's the distance from the centre of the wheel to the edge of the tire (i.e. the tread surface). The suspension engineers rely on this being the case when they design and tune the suspension. That's why, as you go from 17" to 18" to 19" the tyre wall has to reduce in height. That height is expressed as a % of the tyre width, so as you increase the wheel diameter, the height gets less and less, hence 'low profile'. As you increase the wheel width and decrease the sidewall height, the upside is that it's easier to turn and makes for more manoeuvrability, but the downsides are that (a) over rough surfaces, the ride is harsher, (b) potholes will be more likely to cause damage and (c) the associated wider tyres are more prone to hydroplaning.

Conversely, as you decrease the wheel diameter (19" > 18" > 17" for our vehicles) and increase the aspect ratio/profile (30% > 35% > 45%-50%), the ride becomes smoother, potholes are less likely to cause damage, and the associated narrower tyres are less prone to hydroplaning. But the price you pay is in decreased tyre 'agility'.