Upsizing rear sway bar only on a 325i?

[mach schnell]

Has anyone upsized only their rear sway bar on their 325i?

I have a 21mm front and 14mm rear and the car leans over pretty well.

Anyone have experience with going to a 16mm or 18mm rear bar (and leaving the front bar stock) ?

[moatilliatta]

Sounds counter intuitive, but go for a bigger front bar if you only wanted to choose one. It will kill sway and add front grip due to keeping a better contact patch from loosing camber while leaning. Same issue as E36s E46 McPherson strut single wishbone front ends.

[kronus]

leaning over isn't necessarily bad, if the alternative is just skating sideways. adding rear bar decreases the window you have to catch slides, and increases the effect of the inside wheel unloading on power. this can screw with traction if your LSD is weak.

we found that running no rear sway at all made the car handle more predictably and pull out of medium-speed corners with less drama.

[mach schnell]

Thanks for the replies.

So, I should leave the rear bar alone, and upgrade the front bar instead?

[kronus]

what behavior are you trying to fix?

[mach schnell]

what behavior are you trying to fix?

The car leans over pretty hard. I drive strictly mountain roads every day (no highway). Trying to flatten it out some. It has H&R springs and Koni SA’s, and 16’s running 205 50’s. Not looking for it to be race car stiff though.

[roguetoaster]

Large stock bars seemed reasonable with H&R sports/B8s to me. Are your end links/bushings in fair shape? Are your springs OE sports?

[moatilliatta]

https://www.iemotorsport.com/product/adjustable-front-rear-sway-bar-set-e30-m3/

Some options, If you're on a standard cup kit I would start out with standard bars. If your got a stiffer set up or more power, start downsizing rear or up sizing front.