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BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Technical Forums > Wheels and Tires Forum Sponsored by The Tire Rack > Spacer question for Kosei K1 wheels



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      03-26-2012, 09:33 PM   #1
will.c
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Spacer question for Kosei K1 wheels

Intro:
I had stock 189s with Hankook Ventus V12s (245/35 front; 265/35 rear). I just purchased a square set of Kosei K1s (17x8.5 ET40) with 245/40 Star Specs all around. Stock sport suspension on E92 335i RWD, pins removed, max neg camber at around -1* front, -2* rear.

Quick Review:
The difference in the amount of grip is shockingly different even at low speeds. It only feels slightly quicker at lower speeds due to lighter weight, but not much difference as I expected. Despite taller tire sidewall, the tires are very stiff and I'd say they do not compromise steering response, if not better (hence harsher ride). On the other hand, I don't know how, but the steering quickness is now similar to an M3 (smaller steering input, larger output). Perhaps it's due to square setup, grippy tires, or another reason. Whatever it is, it almost caught me off-guard in the highway trying to dodge a pothole. Steering effort is higher. Road noise is quite a lot more, kinda drones during highway speeds.

Concern 1:
I know that the stock sport wheels I had were 18x8 ET34 front; 18x8.5 ET37 rear. Which means, now I have about 12mm LESS clearance from inside of the front wheels to the strut, and 3mm LESS in the rear. So far, I don't hear anything rubbing, but I'll have to check if there's any rubbage on the strut. I did, however, test that I could barely stick a cardboard paper between the front strut and the rim. Well, as long as this is not gonna rub, I'm fine with it.

Concern 2:
Because of the new offsets, it is my belief that the suspension geometry has changed. The center (of force) of the wheel has now gone more inside due to more positive offset, and I think a few things have changed as the result:
1) car sits higher due to shorter moment arm of car weight pushing the tires up around the control arm joints
2) steering effort is more
3) turn in is fast (could be good or bad)
4) other handling dynamics probably have changed

Question:
Should I get spacers (6mm front, 3mm rear) to replicate OEM offsets? And ultimately would this relieve the changes I feel now? Or should I just embrace the new feel of the car because the are "improvements?" If rather I should get the spacers, what brand and where can I buy them from?

Premises:
I don't care about car height in terms of looks; I only care about handling dynamics, performance (whatever that means..), predictability, reliability; I believe in OEM/BMW engineering for the most part; I will be tracking my car a LOT, during which my rims, hubs and suspension parts will undergo a LOT of stress

Sorry for the long message...... Thanks for your expertise!
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      03-28-2012, 03:19 PM   #2
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Bump.. Maybe I wrote too long... Ill stay concise next time
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      03-28-2012, 03:51 PM   #3
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Quote:
Originally Posted by wonho View Post
Question:
Should I get spacers (6mm front, 3mm rear) to replicate OEM offsets? And ultimately would this relieve the changes I feel now? Or should I just embrace the new feel of the car because the are "improvements?" If rather I should get the spacers, what brand and where can I buy them from?
A 6mm and a 3mm spacer would work to bring your car back to stock track width. You could definitely fit a bigger spacer though and make those wheels fill the fender. As for spacers we carry Macht Schnell. If you have any questions feel free to PM me directly!
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      08-21-2012, 06:42 PM   #4
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I just got the same wheels for my 335i, what spacers did you end up using? I am planning on using 15-18mm spacer upfront.
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      08-21-2012, 07:42 PM   #5
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Quote:
Originally Posted by n55PR View Post
I just got the same wheels for my 335i, what spacers did you end up using? I am planning on using 15-18mm spacer upfront.
actually none. It's been perfectly fine so far. But that's considering I'm only running 245s. My next set of 255s will require at least 3-5mm spacers to clear the struts, depending on the tire. I only have about 1-2mm right now.

I don't know too much about fitments, but 15-18 sounds pretty aggressive to me.

right now I'm thinking H&R.
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      08-22-2012, 08:35 AM   #6
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I have e92 with Kosei's running 255/40's for track events. I have 10mm spacers up front and 12mm's in the back...... same ones I use for my stock 19" 225m daily driver wheels.

And yeah, with the 255's i needed at least a 5mm spacer up front to clear my coilovers.
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      08-22-2012, 12:14 PM   #7
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I have 18x8.5 with 35mm offset with 225s and I have about 10-15mm strut clearance. I must have made a mistake calculating the fit the 245s on the Kosei's. My thought process was that the Koseis have 40mm (lose 5 mm clearance) and the 245 are 20mm wider (lose another 10mm) I would be rubbing strut.

I guess a 5-10 spacer would be a good investments....specially when I go with 255s in a month or so.
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