[Jme_be]

I agree with the review of the basic balance of the E92 as Birds BMW (BMW tuning specialist) have found - i.e. understeer -

"anti-roll stabilisers complement the chassis balance and trim. Fast drivers will immediately note the prevalent under-steer inherent in the standard BMW chassis. As a consequence we provide significantly more rear stiffness than the front, biasing away from understeer.."

http://www.birdsauto.com/sites/www.b...9210928311.pdf

..whilst I save my pennies for their "B3-3.5 Dynamics Package 1" I thought about how I might try to address the understeer balance without spending too much cash. Although spacers don't affect the stiffness of the springs or antirollbar, they do effectively lengthen the wishbone which achieves the same result. Moving the wheels further apart reduces roll.

My car is fitted with standard offset 18" wheels (225 fr / 255 r) I opted therefore to leave the front alone and add 15mm hub-centric spacers to the rear axle only. The theory being that doing this reduces roll on the rear axle, whilst maintaining the existing front balance.

Initial drive, and I can immediately feel a difference - slightly less roll at the back, less understeer into the bend and more steering 'feel' with better precision. On acceleration out of a bend, the rear feels better also - the only way I can describe it is as if I'd put much wider tyres on.

Cosmetically, the car also looks great, more squat. The tyres look almost flush with the arches now. For me, the front tyres look fine as they are without spacers. Besides, adding spacers to the front also, would arguably restore the original balance which is what I was trying to get away from.

For an investment of around £55 it has been well worth it. Cynics, as I did, will say why don't BMW just supply the standard alloys with an offset that achieves this without the need for spacers - i.e. I can't believe it would work. It does! I very much doubt that it achieves the same or anything near the change in balance new springs, shocks and antirollbar would achieve but it does get some-way there for a fraction of the cost.

Notes: only buy "hub-centric" spacers / ensure you have correct length (longer bolts) / clean the hub of rust dirt etc. and apply something like copper grease to surface before fitting the spacer, otherwise it will not come off again easily / torque the bolts to the OEM specs and recheck after first drive, and recheck a week later / most chain/franchised garages won't help you fit, so unless you have your own torque-wrench you'll need to find a local/independent garage, and even then some may not want to assist - whatever, you must use a torque-wrench to fit and check / spacers may affect insurance.

[Jme_be]

..profile pic and previously posted pics are car before spacers. Will post new pics shortly

[GI335I]

[dsuraci]

Any picture update?

Originally Posted by Jme_be

..profile pic and previously posted pics are car before spacers. Will post new pics shortly

[CombatNinja]

OP probably oversteered into a tree.

[Jme_be]

No, still here

Having had the 15mm spacers on the rear for a while now, I've just put 12mm on the front also..

Having initially been happy with the balance and having basically convinced myself that my *theory* was correct, I realised that whilst the rear was more planted, understeer hadn't really gone ..and may have even got worse - so much for my own uneducated theories!! I also found that whilst the rears looks nice and flush, the fronts looked inset. Sounds obvious now..

I've seen E92s with 15mm on the front which for me looks like they stick out too much. I went with 12mm on the front which looks just about right.

It is quite surprising how such a seemingly small change can have. Turn-in is more positive and understeer is significantly reduced. Steering does feel everso slightly heavier but I haven't noticed any steering *issues* such as full-lock arch rubbing etc.

In my experience, spacers do reduce roll, do improve grip and will effect the balance of your car. I guess that If you want to keep the same front/rear balance you have and want to put spacers on, you need to put the same on front/rear - in which case, I'd recommend 12mm front and rear (for the non-M3 E92) with the standard offset wheels and standard profile width/profile tyres.

I've gone 12mm front and 15mm rear, and car feels great. Front and rear look are pretty good too.

I'll get some photos when it stops raining!