[Gamb1t]

Hi folks. I'm been thinking of replacing my stock staggered setup in my 330i for a square setup. Do you think it would result in skittish handling since it's rwd as opposed to X-drive?
Wheels are Style 193M.

[Welcome to NBA Jam]

Nope. Lots of people switch to a square setup without any noticeable change in handling for daily driving, but a big appreciation from their wallet. Tires are cheaper and you can rotate them to last longer.

[Gamb1t]

Can't rotate them because the 193M wheels have varying widths.

[slupie]

I run square tire setup on staggered 189 rims. Just have to make sure that they put the right size wheels on the same axle. I rotate mine every 6K miles.

[Welcome to NBA Jam]

Originally Posted by Gamb1t

Can't rotate them because the 193M wheels have varying widths.

Do they not fit in the front?

[Phyrexia]

I am already running a square 225 setup on a RWD E90, but I would never do it with two different wheel sizes.

Anyway, the 225/255 setup exists to induce understeer. Going to a square setup should decrease the tendency to understeer.

[johnmyster]

I purchased an extra set of front 18x8" rims so that I could go square. No complaints.

Have run 235/40 and presently 245/40 with only the slightest rub at full lock on the front fender liner.

[Gamb1t]

Nah will not go wide for this car in a square setup. Thinking further, the fact I can't rotate to begin with, I might just remain staggered. I like the 193m too much to switch.

[hassmaschine]

225 seems pretty narrow consider the stock 330i comes with 235 up front and 255 in the rear.

[6ixSpd]

All sport package equipped E90 sedans came with 225s up front. There's no 235 stock front tire size on any E90.

That said, a 45 series 18" tire is super tall up front. Stick with the 40 side profile for the 193M wheels.

[mecheng77]

Do the non square setup really increase under steer that much or is there a benefit from increased power traction that is worth it.

Also, for OEM rims, with the N52 engine, do you guys think 18" rims are too big and to stick with a 17" rim upgrade, in terms of acceleration and handling due to increase in un sprung weight. I currently have ugly OEM 16" rims with RFT but plan to upgrade when they are worn. I want to go summer tire which will be lighter. Looks wise, with a non lowered car, I think both the 17 or 18" will look fine so I'm wondering about performance.

[neilvan]

One of our E90s has the sport package 18"s (same size/offset) with 225 snows front and rear. We bought used and it was a good deal so we didnt get all we wanted.

The car really looks soft with it, Especially in the rear. Just going to 255s make the car look much better which isnt saying much with the stock fitment. We never did push the car much so it is apples to oranges.

Regardless Is stick to oem staggered or bump up to a wider tire front and back.

Edit: You could try to find a pair of rear 193s and run a square wheel/tire set up

[Antetokounmpo]

nothing is stopping you from running 8.5 with a 225 in front and a 8 with a 225 in the rear besides looks. front will still easily fit.

[Phyrexia]

I've read (though I do not have the source handy) that E36 M3 race cars ran faster times with square 225s than with the 225/255 setup. Lots of people with E46 M3s who switch to square setups to decrease understeer. An N52 doesn't have enough power to overwhelm a 225 in the rear anyway.

If you're trying to minimize unsprung weight then just get whichever set of wheels is lightest. I could tell a big difference in ride quality when I moved from 17" RFT to 17" standard tire, but that's the only observation I can give that's close to your potential use case here.

Originally Posted by mecheng77

Do the non square setup really increase under steer that much or is there a benefit from increased power traction that is worth it.

Also, for OEM rims, with the N52 engine, do you guys think 18" rims are too big and to stick with a 17" rim upgrade, in terms of acceleration and handling due to increase in un sprung weight. I currently have ugly OEM 16" rims with RFT but plan to upgrade when they are worn. I want to go summer tire which will be lighter. Looks wise, with a non lowered car, I think both the 17 or 18" will look fine so I'm wondering about performance.

[John 070]

Originally Posted by Antetokounmpo

nothing is stopping you from running 8.5 with a 225 in front and a 8 with a 225 in the rear besides looks. front will still easily fit.

I once got aftermarket rims from one of the biggest online etailers around, and that happened (on a different car). Nobody noticed except me...

[Antetokounmpo]

Originally Posted by John 070

I once got aftermarket rims from one of the biggest online etailers around, and that happened (on a different car). Nobody noticed except me...

99.98 percent of people won't be able to tell

[John 070]

Originally Posted by Antetokounmpo

99.98 percent of people won't be able to tell

Funny and true story. I was about to go into the gym, and I kept staring at my car, very troubled look.

Some other dude in the parking lot goes, anything wrong?

I say, I dunno, something is not right, it's as if my offset is wrong, the front and back wheels just look different.

Guy goes looks fine to me, and walked away. I didn't have to pull them or anything, invoice showed 2 of each rims, same style. They were closeout!

[floydarogers]

I've got two winter sets of rims and tires, both 225 width.

One set is off a 2006-7 325i/328i (not sure which, doesn't matter) that was staggared originally It's a 17" set, with 8" front and 8.5" front. No problems at all with running a 225/45R17 on the rear 8.5" rims.

My other set is 18" rims, all 4 8", running 225/45R18 on all four.

Be sure to check speedo against GPS after putting them on.

[S4NoMore]

Originally Posted by mecheng77

Do the non square setup really increase under steer that much

The staggered setup results in a tendency to understeer rather than oversteer, and this is by design for certain vehicle dynamics, specifically to make for an "easier" or "safer" ride. You have to think in terms of driving on the limit, moreso in a traffic emergency than on the track trying to improve lap times. On the limit, maneuvering around an obstacle mid-corner or maybe just taking a corner too fast for conditions, the front of the car will lose grip first given the smaller contact patch of the front tires. The rear tires with the larger contact patch and more grip will hold on. The result is that the car will slide forward, understeer, until speed is scrubbed enough to regain front traction.

If the tires are square, or if you consider the extreme example of an inversely staggered setup to illustrate the point, the rear tires will lose grip first in oversteer. As we all should know, the result is that the car will rotate and in most cases for non-expert drivers this will mean complete loss of control, sending the car off the road.

This is the same reason why tire shops and manufacturers rightly recommend that new tires be installed at the rear for your average car. Understeer is more controllable than oversteer.

Originally Posted by mecheng77

or is there a benefit from increased power traction that is worth it.

Increasing the contact patch is going to be preferable, yes. Going to a square setup that is smaller than the original rear tires will provide less grip overall.

[Bufalo]

My '09 came from the used dealer with square 225's on the stock staggered style 286's, and I've never wanted for the 255's. I'd rather matched 8" wheels all around so I could better rotate to compensate for wear.

[P4veLow7X]

Hi guys ! I have a 2008 335i e93 with 225/40r/18 all around.

Obviously, the rear should be on 255 but I had a deal on some 225.

Although the car drive perfectly it look silly !

Can I put 25-30mm spacer on the rear ? Will it help ?

Thanks for you help.