[Rottweiler]

I’m a man without an X4M40i allocation YET, but that doesn’t keep me from planning. It’s about all I can do at this point, along with trolling this forum

Part 1 : 15mm spacers seem to be the most popular choice here. My guess is that going thinner will not bring the sidewall out enough to provide the desired “look” (a wider stance). Is going thicker than 15mm not recommended due to handling issues or perhaps it could cause too much road debris (pebbles or puddle/rainwater) to be thrown up on the sides of the vehicle? I believe I saw 17mm and 20mm both available on the Burger site

Part 2 : I’ll likely run the factory wheel/tire set rather than going aftermarket. If I go 21” rims, does the low profile tire leave an unsightly gap in the wheel well? I wasn’t thinking of lowering the ride with a spring swap. Does the 20” wheel option fill the well better? Purely aesthetics at play here, though I’m leaning towards 20’s for ride quality and future tire availability

Thank you

[Rottweiler]

https://x3.xbimmers.com/forums/showt...=Burger+Tuning

Lots of good info here :~}

Unless talked out of it, I might look for 16-17mm now, provided they’re from a reputable maker

[M6csi]

Whether you go with 20” or 21” rims, the overall tire/rim diameter remains the same at about 28.7 inches. So in essence, the bigger the wheel, the shorter the sidewall and the smaller the rim, the taller the sidewall. So there will be no height difference between the fender lips and top of tires, assuming the correct tire sizes are chosen.

The chart below illustrates the numbers In relationship to rim/tires sizes. These are the factory spec tire sizes for both the 20/21” rims

[Rottweiler]

Originally Posted by M6csi

Whether you go with 20” or 21” rims, the overall tire/rim diameter remains the same at about 28.7 inches. So in essence, the bigger the wheel, the shorter the sidewall and the smaller the rim, the taller the sidewall. So there will be no height difference between the fender lips and top of tires, assuming the correct tire sizes are chosen.

The chart below illustrates the numbers In relationship to rim/tires sizes. These are the factory spec tire sizes for both the 20/21” rims

That’s hugely helpful…thank you

Now I’m only wrestling with the spacer thickness issue…15mm or 18mm or perhaps 15/18 f/r

Just keeping myself occupied while waiting for “the call”

[huggy509]

what do spacers actually do ?

[AllBlackBimmer]

I run 15mm spacers... honestly, if I were to do again, I might go 18mm or 20mm... but 15mm is how the car should have came from the factory. 18/20 might be a little more aggressive. I like the 15mm but would like a little more aggressive look I think.

The issue with spacers is actually running TOO SMALL of spacers... with say, a 5mm spacer, there sometimes isn't enough lip for the wheel to safely rest on - which can cause vibration or worse and sometimes a reason spacers get a bad rep.
Not sure what "too small" on our X3's are, but on my E90 any spacer less than 6 or 7mm is an issue with the car.

Spacers make the track of the car wider, which makes it handle better.
It also makes the car visually look better (subjective) by pushing the wheels our further to be flush with the fenders.