Sponsored by The Tire Rack

[Drivaar]

Hi everyone,

I'm trying to switch out my current sport package 2007 E90 335i to soften it up.

Currently it has 225/40/R18 fronts and 255/35/R18 rears, plus Koni FSD shocks. Everything else is stock.

I want to switch the shocks + springs to non-sport OEM... where should I be buying these parts? I was told that the Bilstein B4 is exactly the same as stock, but Tirerack says it's 10% stiffer than stock... and I think "stock" there is referring to "sport package stock".

Also, I was looking at potentially getting some 17" wheels, but everything I saw on Tirerack was pretty expensive. Where should I be looking?

Finally, there's the question of aspect ratio. One forum member suggested that I could simply stay with my 18" wheels, but just widen the aspect of my tires, going to 225/45/R18 + 255/40/R18. I love that idea... it will have the same amount of tire cushion as the 17" setup, so will it be just as comfy as 225/45/R17 + 225/40/R17?

Can I go as far as trying 225/50/R17 + 255/45/R17??? I figure that would be pretty comfy!

Sorry for all the questions, and thank you for your advice.

[BM3Rrrr]

Are you tires runflats?

If so get rid of them for some non-runflats, you will notice a difference in comfort right away

[Drivaar]

Yup, removed those 1 month after I got the car, almost 10 years ago.

[Wolf 335]

Regarding tires:
----------------------------------------------------------------------
Your current setup
Fronts 225/40/R18 Sidewall height = 40% of 225 = 90mm
Rears 255/35/R18 Sidewall height = 35% of 255 = 89.25mm

Option 1
Front 225/45/R18 Sidewall height = 45% of 225 = 101.25mm
Rear 255/40/R18 Sidewall height = 40% of 255 = 102mm

Option 2
Front 225/45/R17 Sidewall height = 45% of 225 = 101mm
Rear 225/40/R17 Sidewall height = 40% of 225 = 90mm
This option is not favorable as sidewalls are not close to each other and your speedometer will read wrong.

Not sure if you meant 255/40/17 which would be a more favorable option with 102mm sidewall.
----------------------------------------------------------------------
So what can we conclude from this is that, by increasing the tire sidewall percentage number, sidewall height is increased. You will need to ensure that you have enough clearance for increased sidewall height (no rubbing).

However, changing the wheel diameter will not affect sidewall height. What wheel diameter will affect is the height of the car in relation to how low it sits to the ground.

So with that said, if there is potential for rubbing with 225/45/18 and 255/40/18 then in order to maintain that same desired sidewall height you would need to drop down in wheel diameter to 17". That would give you 1" clearance from the overall tire diameter while maintaining equilateral sidewall height.

[Drivaar]

Thank you so much, Wolf 335. After a lot of thought, and a nice conversation with a great guy at TireRack, I ended up with 225/45/R17 + 245/40/R17, which should give me nice comfort while allowing the use of 17x8 wheels both in front and back to match.

[Wolf 335]

Originally Posted by Drivaar

Thank you so much, Wolf 335. After a lot of thought, and a nice conversation with a great guy at TireRack, I ended up with 225/45/R17 + 245/40/R17, which should give me nice comfort while allowing the use of 17x8 wheels both in front and back to match.

I think that's a good choice for comfort ride

I think you first need to be realistic when setting expectations as it relates to "comfort." What is your goal here: Lincoln Town Car type comfort or just having a car that's composed enough to not have the suspension completely crash over every bump like it does stock?

Sometimes peeps will drive and Audi or a Lexus then jump back into their E9x and be like "I wanna make my car ride like that" and that typically results in setting a goal that is impossible to achieve.

Furthermore, just adding taller tires could end up being a step in the wrong direction; instead of creating a more comfortable ride, you could end up with a floppy wet noodle version of what you already had.

[Jeff@TopGearSolutions]

First question is what kind of tires are you on currently and are they run flat?

Also have you considered Koni Orange? They are OEM Equivalent and you can select between non sport and sport options.

[VTECaddict]

Originally Posted by FCobra94

I think you first need to be realistic when setting expectations as it relates to "comfort." What is your goal here: Lincoln Town Car type comfort or just having a car that's composed enough to not have the suspension completely crash over every bump like it does stock?

Sometimes peeps will drive and Audi or a Lexus then jump back into their E9x and be like "I wanna make my car ride like that" and that typically results in setting a goal that is impossible to achieve.

Furthermore, just adding taller tires could end up being a step in the wrong direction; instead of creating a more comfortable ride, you could end up with a floppy wet noodle version of what you already had.

This. Even the non-sport E9x suspension is stiffer than a lot of other cars on the road, so there's a limit to how "soft" you can get with this chassis.

If you want something that rides like a Camry, you need to get a Camry. Or a non-sport F30.