E30 Zone

what is the preferd drop on a 1992 BMW 318 I CONVERTIBLE and what size of wheels can i go for ? i dont want to do any arch work.and are they four stud or five stud (i havent got the car yet)its just to make it sit better and look a we bit nicer

Wheels are four stud. A drop of more than about 30mm and/or wheels greater than 15" (16" at a push) will start to adversely affect handling and safety.

so if i drop it 40mm and put 16s on is that good or bad and thanks for that

its neither good or bad, its up to you but it should be fine with that.

Brianmoooore wrote:Wheels are four stud. A drop of more than about 30mm and/or wheels greater than 15" (16" at a push) will start to adversely affect handling and safety.

yeah anything bigger than 15's turns the car into a wild handling death trap. It will snap around and you'll be doing 360's as soon as you turn the wheel or push the accelerator.

if you drop it more than 30mm without changing the shocks, their effective operating range will have been reduced - (this means you will probably have to replace them after a few 1000 miles - depends if they are O/E at the moment or not) - and they may not be able to function as effectively. This will effect the handling (on our lovely UK roads).

IF you drop it by more than 30mm at the back without adjusting the rear suspension/camber/castor, the rear wheels will effectively be running more on the inside edges - you will tend to wear out your tyres somewhat faster, but also it means (especially in the wet) that the back end will have less grip - a bit like the old Triumph Spitfire transverse-leaf suspension.

IF you keep the correct rolling diameter but fit wheels of more than 16", the sidewall is going to become rather small and stiff - this will also have the effect of the back end going before you realise it, and again going sooner in any given situation.

These are the points Brian was making, and only so that you are aware of them.

Alpina had 16 inch wheels on MTech suspension (lowered 15mm) but they had modified shocks to complete their package.
Mine's lowered 40mm with 16" wheels but I have Bilstein Sport shocks to control it all and it goes round corners on rails! (I've got an LSD as well). It will be safe if you go for the whole handling package and not just looks.

The point is that if you drop 60mm by cutting springs, use original shocks and put 17" alpina reps on it (the ones with extra wobble!) you're not going to be getting improved handling. Just "gangsta" looks. If thats what you're after, thats your call and noone is going to stop you. But if you're after handling you're going to have to think about things a bit more carefully.
People report good results from uprated rollbars, and also report that its worth reinforcing the rollbar mounts if you go down this route.