[Noggie]

Ever since I took delivery of my i3s in November last year, it has been on winter tires, 19" Mud&Snow 155 tires.

Through my months of ownership, and 3000km, I have enjoyed the car, but there has been a few things that bugged a lot.
1. The steering was very light, way too light for my liking, just resting my hand on it would turn the car.
2. The disappointing understeer.
3. General stability, car always felt wobbly especially at highway speeds, did not like driving close and above 100kph/60mph at all, the light steering did not help.
4. Directional stability and "self correcting" stability (steering returning to center) was really bad, I like it when I need to counter the cars intention to straighten itself.
5. Very sensitive to wind

Always wondered if the summer tires would change any of that.

So a couple of day ago I put on the 20" 175/195 i3s spec summer tires.
WOW! completely different car.
Steering is now a bit heavier and much more to my liking.
Understeer is greatly reduced, got more of a go-kart feel to the car now.
Stability is way better, the car feels so much more stable at high speeds, no longer wobbly, directional stability is good, "self correcting" stability is also better, we had pretty bad side winds yesterday (25+kts) and the car is much less affected by the wind now as well.

It's amazing what a slightly larger contact patch can do to a car.
While the wider rubber will hurt range, I will gladly trade that for the handling improvements to the car.
The smiles and enjoyment of driving this car is currently at a completely different level.

I guess anyone driving the standard tire size will find the s model tire spec a well worth upgrade.

[Coastali8]

I’m not surprised that the summer tires made a huge difference in the way the car drives.

I recently purchased a 2018 “s” after driving both the standard and the S. The i3s is a completely different driving car. It feels much more planted to the road with the suspension improvements, wider track, and tires.
In the used market the difference in price for the S versus the standard is nearly negligible but the difference in the way the car drives is huge.

[garys3]

What about the wheel spacers, do they make a big difference? If so which size?

[Noggie]

Standard summer wheels. (155 tire)
F: 5" et 43mm
R: 5,5" et 53mm

S-model summer wheels
F: 5,5" et 33 (175 tire)
R: 6" et39 (195 tire)

if you want to space out the standard wheel close to S spec, you can use a 10mm spacer front and a 15mm rear.
This will change the offsets on the standard wheels:
F: 43mm to 33mm
R: 53 to 38mm

Should make the car a little more stable.
I guess you could put a 175 on the rear and run a 155/175 setup on the standard wheels.

I know that the S model can be spaced out a further 10mm as well, so if you want to be bold, you can space out the stock setup another 10mm front and rear, but I think that might look a little funny with the narrow tires sitting that far out.

[ovekvam]

If you decide to go with spacers, make sure they are hubcentric. That means the spacer is centered on the hub, and the wheel is centered on the spacer. For 10 mm spacers, I guess that is difficult or impossible. Use thicker spacers or none.

[MightyMike75]

Originally Posted by ovekvam

If you decide to go with spacers, make sure they are hubcentric. That means the spacer is centered on the hub, and the wheel is centered on the spacer. For 10 mm spacers, I guess that is difficult or impossible. Use thicker spacers or none.

I use some spacers also on other cars, but I don´t have anytime the problem that I cannot centered the spacers. They are automatticly centered.

[ovekvam]

Originally Posted by MightyMike75

I use some spacers also on other cars, but I don´t have anytime the problem that I cannot centered the spacers. They are automatticly centered.

If they are automagically centered, you have the hub centric type.

[Noggie]

I guess the point here is:
Hubcentric spacers on the left, non-hubcentric spacers on the right