Understanding Weight Transfer

[boxsey]

I would like to start by saying how interesting and informative this forum is. I have already spent many hours reading the different threads, taking in the advice and having a few chuckles along the way. Now onto my question.

Is it possible to 'manage' the weight transfer of a car or can you only react to it? I'm interested in both front and rear engined cars but mostly mid-engined cars with RWD (i.e. my own car).

My guess is that some management of the weight transfer is possible. My reason for thinking this is that on an S bend (left then right) after steering through the left bend, I momentarily turn the wheel to the straight ahead position before turning into the right section of the bend. By doing this I feel that I am bringing the weight of the car back to the middle before steering in the opposite direction i.e. trying to avoid throwing the weight from one side to the other too quickly.

I look forward to hearing your thoughts and descriptions of what is actually going on with the weight of the car whilst driving.

Edited by boxsey on Wednesday 29th November 16:51

[boxsey]

Cheers guys. I haven't read the thread above yet, it was already on my list but I got too engrossed in a number of others especially the 'Headlight flash' one. I did a search on both 'weight' and 'transfer' during the last year but nothing came up. Hence starting a topic.

[boxsey]

willibetz said:

I particularly like your use of the word "manage", Boxsey.

The weight transfer is an inevitable consequence of the forces acting on the car.

As a driver, awareness of this phenonenum is prerequisite to "managing" the rate at which weight transfers to provide better grip. It's particularly important in cars which pitch, lean or have an odd weight distribution. Your Boxster is taut and has wonderful weight distribution, so if you want to experiment try to get an old 911 as a loan car when your Boxster is next serviced!

Indeed, I am very lucky because of the superb handling that the boxster provides the driver with. Getting the boxster has brought the joy of driving to me and the desire to get better at it rather than just using a car to commute like I guess 95% of drivers do. I've already experienced it on a track and loved it. I guess that's when I first really appreciated the weight of the car shifting around and prompted me to think that I would be able to drive the car better if I understood what was going on with the weight shifts.

My particular model, although an auto that I drive mostly in manual mode, has no other driver aids and is the first RWD car I've had since a MKII Escort Mexico when I was a youth. Therefore, although the boxster handling is very neutral and flatters the driver, I know it has the potential to bite me if I abuse it.

Already, I've committed the above 5 points to memory and put them into practice on my commute to work this morning. For example, by using smooth and progressive steering inputs (as per point 3) at a roundabout, I felt a sensation of grip and control that was very, very satifying. Totally different to the feeling that I normally have which is one of tensing up in preparation for the back end to break away and having to correct it.

I like the advice about the 911 and would be interested to hear more about how to manage that heavy back end swinging around as an old one (993 or 964) is on my future shopping list!

[boxsey]

willibetz said:

Older 911's pitch quite dramatically. So, for example, it's important to load the front end before braking heavily. They will slow very quickly if driven in this way, but lock a wheel even more quickly if you panic and just hit the middle pedal.

WilliBetz

Ahhh. The mist has suddenly cleared! I was wondering what was actually meant by 'loading up'. From what you say above, you load up the front of the car by progressive braking and once the weight has moved forward, brake harder to set your road speed for the bend. So again, smoothly on and off the brakes is a key to managing the 'front to back' movemnent of the weight.

Right, I'm off to do some more testing.

[boxsey]

willibetz said:

On the road, grip is changing all the time and sometimes dramatically within the course of a single bend. Skilled drivers that I've been fortunate enough to sit with use observation to predict the available grip and then manage the car without troubling those limits (acknowledging that the available grip may disappear suddenly).

I think this great common sense approach also applies to those of us who would not claim ourselves to be skilled drivers. In addition to observing the road conditions, I also pay close attention to the feedback I am getting back from the tyres (a bit like GreenV8 but perhaps less extreme). A small twitch is enough to tell me that these are not the conditions to get too exuberent in so back off.

Personally I think the tyres I use are an important factor in being able to feel the level of grip. Mine are Conti Sport Contact 2 all round. I've stuck with these because I find they have a progressive loss of grip. By this I mean a little too much gas at the wrong time and you can feel them go, a little bit more gas and they'll slide more, etc. Yet, I'm constantly being told that other tyres (particularly Michelin PS2) are much better because they have so much more grip in the wet. That may be so but I prefer a tyre that tells me grip is not good here so slow down rather that a tyre that keeps on gripping until....it suddenly doesn't grip

[boxsey]

victormeldrew said:

Someone who can get the brakes to the point of locking and hold it there without ever actually locking has to outperform ABS.

This is nicely illustrated in the Car Limits 'bending the rules' DVD for anyone who wants to see it in action. An ABS equipped car is shown to stop in a shorter distance by not allowing the ABS do all the work.