[spiike32]

I came across this blog and it made me wonder. What is it exactly that makes our cars handle so well? I always thought it was the weight distribution and wheels pushed out further...

What is the weight bias of our 335's? I thought it was near 50 50...

http://automotivethinker.com/chassis...s-not-optimal/

[M340i Pride]

I believe the biggest part is the chassis. our cars (e90 e92) have awesome chassis that are stiff and agile at the same time.

RFT are not the greatest tires for producing high g's but they are still above average. if you have money to switch to better tires, it will perform even better on curves...

fact is e90 produced better lateral g figures than e46 m3. awesome chassis.

[noro]

It's not secret that 50/50 is not the most optimal weight distribution. 911 and Formula 1 cars are a good example.

50/50 is overall the safest distribution. Try abruptly lifting in a 911 in a turn.

[Cygnusx1]

Chassis, suspension geometry, bushing compliance, struts, springs, quality of construction, weight bias, center of gravity location...are all factors.

[Tag]

335i Weight distribution, front/rear Manual 51.2/48.9, Automatic 51.4/48.6

MT Unladen weight 3,560 lbs.
AT Unladen weight 3,582 lbs.

MT weight lbs. Front 1,830, Rear 1,730

Gas weighs roughly 6 lbs. a gallon and being the car holds 16.1 gallons that equals 96.6 lbs. on a full tank. Add that to the rear weight and you get 1,827 lbs. which is pretty much 50/50.

Automatic weight lbs. Front 1,841, Rear 1,741

Add 96.6lbs which is roughly the weight of a full tank to the rear and you get 1,837 lbs. which is pretty much 50/50.

This by no means is an exact science but simply illustrates how well these cars are balanced.

[F32Fleet]

Originally Posted by Cygnusx1

Chassis, suspension geometry, bushing compliance, struts, springs, quality of construction, weight bias, center of gravity location...are all factors.

+1

It's easier fro the average driver to drive faster in a balanced vehicle vs one with a heavy rear or front bias.

Someone's comment about lifting up on the throttle in a 911 is a case in point.

Not to mention the relationship between the Porsche Cayman and 911.

The Cayman is a better handling car because of it's weight distribution which is why Porsche priced it so high with a lesser powered engine and why some Porsche guys are dropping 911 engines into the damn things.

[Legion5]

50/50 weight distribution is the optimal for handling actually. I used to work helping to design supercars so maybe I can shed some light on all this.

For those that mention rear biased weight distribution as being optimal, it's not. The Porsche 911 is also the worst example to use for any superlative. Almost everything is wrong with it. It's not a good car because of it's design features, it's a good car, DESPITE them. Race cars have a rear biased weight distribution for acceleration, not handling.

Anyways BMWs aren't really all that great in the handling department, most BMW drivers severely overestimate the handling of their cars. The fact is that BMW's cornering performance is more or less average. Economy cars can match it and BMW uses inferior Mac Pherson strut technology. With that said what BMW excels at is composure, driver feel and feedback. They manage to make a luxury car with decent but not amazing handling performance and then make it feel like the best car to drive in the world.

The 50/50 weight distribution certainly contributes to the way the car feels "balanced" but there are many factors that contribute to the end result of the way the car feels. The results are mostly as from the tuning of the car though, and BMW obsesses over chassis tuning so they get the desired results.

Mitsubishi, besides their evo/lancer really tend to make cars a lot like refrigerators. They don't really lavish the effort onto the handling. If it doesn't have any glaring issues or explode, they put it into production, so that's the difference.

[Michael Schott]

People are confusing weight distribution with moment of inertia. The 3 series handles well because most of the engine is behind the front axle making it more like a front mid engine car. You don't want weight at the ends of the car which is the reason that the Porsche 911 can be diabolical if not driven properly. All that weight in the rear is not optimal. The mid engine design of the Cayman makes it an inherently better handling car. There's a reason 3 series BMW's handle better than 4 series Audi's. Audi does not mount their engine's behind the front axle. The S4 works well because it has the electronic differential which compensates for the design issues.

[Michael Schott]

Originally Posted by TrackRat

^^^^ Polar-moment of inertia is not the same as weight distribution. There are benefits to both high and low polar-moment of inertia for excellent handling depending on the objectives.

The point is they are not the same. Having the moment of inertia near the centerline of the vehicle is good for handling especially versus a front or rear engined car. When you have a chassis that has a good basic design like most BMW's (rwd, good weight distribution, stiff chassis, front mid engine placement) you have the basis for a good handling car.

[TheRox]

Originally Posted by spiike32

I came across this blog and it made me wonder. What is it exactly that makes our cars handle so well? I always thought it was the weight distribution and wheels pushed out further... but in the end my 2004 mitsubishi eclipse gts has a similar length and wheel location... but handles much differently. It's not responsive, sloppy, and has lots of body roll.

What is the weight bias of our 335's? I thought it was near 50 50...

http://automotivethinker.com/chassis...s-not-optimal/

Yea, its gonna depend on a lot of things.

Someone also mentioened that while a lot of other cars have similar tolerances to BMW's...the FEEL of BMW is much tighter and agile, and powerful.

Responsiveness has to do with the tolerances of components, the way the suspension is tuned, the chassis.

Weight distribution is part of it; BMW tries to be almost mid-engined by placing most of the weight of the engine behind the front axle (they push the front wheels out further for that)

[Tom K.]

Originally Posted by tag824

335i Weight distribution, front/rear Manual 51.2/48.9, Automatic 51.4/48.6

MT Unladen weight 3,560 lbs.
AT Unladen weight 3,582 lbs.

MT weight lbs. Front 1,830, Rear 1,730

Gas weighs roughly 6 lbs. a gallon and being the car holds 16.1 gallons that equals 96.6 lbs. on a full tank. Add that to the rear weight and you get 1,827 lbs. which is pretty much 50/50.

Automatic weight lbs. Front 1,841, Rear 1,741

Add 96.6lbs which is roughly the weight of a full tank to the rear and you get 1,837 lbs. which is pretty much 50/50.

This by no means is an exact science but simply illustrates how well these cars are balanced.

IIRC, BMW quotes weight per the Euro standard which includes a 90% full gas tank. So their quoted distribution figures will be accurate, unless the tank is low.

Tom

[accel]

Doesn't euro standard also include the driver

[hipnotic]

chasis