Z4 Autocross Setup

Sirius19 · 03-03-2025, 11:13 AM

Hello everyone, I just recently purchased a Z4 3.0si that I'm going to start autocrossing in the street/stock SCCA class.

The first purchase is going to be a dedicated set of autocross wheels. I can go up or down 1 inch in diameter, so I'm thinking about going with the 17" rims.

The front rims are 8" width and rear ones are 8.5", but I have been reading that keeping the same size tires on front and back is the way to go.

I'm interested in getting feedback about wheel/tire size selection and anything else autocross related. I like the feel of the Bridgestone RE-71RS, so I'll probably stick with that brand.

Sirius19 · 07-25-2025, 11:11 AM

Looks like there are not many Z4 owners autocrossing their car. It's not really competitive versus the Miatas at the national level, but it will surprise you.

I decided to go with 17" rims with Bridgestone RE-71RS installed. 245/40/17 on the front and 255/40/17 tires on the rear wheels. The front tires are slightly pinched, but work for autocross.

I did install Koni Sport shocks/struts. I'm still trying to find the right shock and tire pressure settings. After I get more seat time, I will decide if I need to upgrade one of the sway bars.

Burnt C6 · 12-15-2025, 06:41 AM

Quote:

Originally Posted by Sirius19

Looks like there are not many Z4 owners autocrossing their car. It's not really competitive versus the Miatas at the national level, but it will surprise you.

I decided to go with 17" rims with Bridgestone RE-71RS installed. 245/40/17 on the front and 255/40/17 tires on the rear wheels. The front tires are slightly pinched, but work for autocross.

I did install Koni Sport shocks/struts. I'm still trying to find the right shock and tire pressure settings. After I get more seat time, I will decide if I need to upgrade one of the sway bars.

Just ran across your post. I'm picking up an 06 3.0i that I'm turning into my AutoX and HDPE track car. I'll be running with my local BMW group on AutoX and different track days. are you planning on doing a big brake upgrade? I'm looking into it. would be interested to see what else you have done and how it worked out. I'm planning on a different spring just wasn't sure if I really wanted to go adjustable stuff or just put in new H&R springs

Sirius19 · 04-16-2026, 11:13 AM

The only mods I have done is Koni Sport shocks and the 17" wheels. I didn't like the feel of the brake pads, so I switched to Hawk HP Street 5.0 pads.

It does understeer some on the sweeping 180 degree turns so I'm thinking about upgrading the rear sway bar. The stock/street class limits you on the mods, but I can change either the front or rear sway bar.

One other problem that occurred was the issue with the sticky steering. It only happens when it's out in the sun during the summer. I was able to make the adjustment described on one of the web sites that fixed the issue.

03-03-2025, 11:13 AM	#1
Sirius19 Registered 4 Rep 4 Posts Drives: 2007 Z4 Join Date: Feb 2025 Location: Kentucky iTrader: (0)	Z4 Autocross Setup Hello everyone, I just recently purchased a Z4 3.0si that I'm going to start autocrossing in the street/stock SCCA class. The first purchase is going to be a dedicated set of autocross wheels. I can go up or down 1 inch in diameter, so I'm thinking about going with the 17" rims. The front rims are 8" width and rear ones are 8.5", but I have been reading that keeping the same size tires on front and back is the way to go. I'm interested in getting feedback about wheel/tire size selection and anything else autocross related. I like the feel of the Bridgestone RE-71RS, so I'll probably stick with that brand.
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07-25-2025, 11:11 AM	#2
Sirius19 Registered 4 Rep 4 Posts Drives: 2007 Z4 Join Date: Feb 2025 Location: Kentucky iTrader: (0)	Looks like there are not many Z4 owners autocrossing their car. It's not really competitive versus the Miatas at the national level, but it will surprise you. I decided to go with 17" rims with Bridgestone RE-71RS installed. 245/40/17 on the front and 255/40/17 tires on the rear wheels. The front tires are slightly pinched, but work for autocross. I did install Koni Sport shocks/struts. I'm still trying to find the right shock and tire pressure settings. After I get more seat time, I will decide if I need to upgrade one of the sway bars.
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04-16-2026, 11:13 AM	#4
Sirius19 Registered 4 Rep 4 Posts Drives: 2007 Z4 Join Date: Feb 2025 Location: Kentucky iTrader: (0)	The only mods I have done is Koni Sport shocks and the 17" wheels. I didn't like the feel of the brake pads, so I switched to Hawk HP Street 5.0 pads. It does understeer some on the sweeping 180 degree turns so I'm thinking about upgrading the rear sway bar. The stock/street class limits you on the mods, but I can change either the front or rear sway bar. One other problem that occurred was the issue with the sticky steering. It only happens when it's out in the sun during the summer. I was able to make the adjustment described on one of the web sites that fixed the issue.
	Appreciate 0 Quote