Weight Transfer Part 2: Does the Racing Driver Control the Weight Transfers?

Uncategorized Jun 20, 2018


What do these three F1 racing drivers have in common?  Kimi Räikkönen, Valtteri Bottas and a young Nico Rosberg (when he drove for Williams in 2006).

They’ve all been coached by Rob Wilson – “the F1 drivers coach”.  He’s also coached many other professional drivers, racing in just about every pro racing series around the world.

Rob knows weight transfer.  Most times, when he is talking about driving, he’s talking about weight transfer.  He says that “the rate at which you transfer weight”, is just about the most important thing you do in a race car. 

For a quick look at what he does, check out this video with Formula E driver, Karen Chandok.  It shows Rob's great sense of humor as well:
2017 Belgium - Rob Wilson Driving School

Rob is teaching smooth introduction of the steering brake and throttle so as to maintain maximum grip.  From that perspective, talking weight transfer does make sense. 

But the issue I have with putting weight transfer at the centre of our thinking about race car driving is that weight transfer is not related to the motions of the car the driver can feel.

In my blog article, Weight Transfer Part 1, we discussed the motions of the car of that give the driver feedback directly from the tyres.  They happen as a result of the forces acting at the tyres in the ground plane.  There are three motions felt by the diver - the lateral and longitudinal G force, and a very subtle rotation of the car about its vertical axis, while the tyres continue to grip the road.  

It’s this small rotation of the car that’s the most important feedback to the driver.  It’s what the driver feels, interprets and responds to as the “rate of cornering” - whether you’re cornering up to the limit, or whether you could push harder – or, are you cornering too hard?    

(Basically, when the steering wheel is in motion, you control the car by feeling the rotation, the rate of turning the corner.)

If driving coaches talk weight transfer, whether the speaker intends this interpretation or not, the inference most driver's will take away is that we can feel the weight transfer and use this information in controlling the car. 

Rob Wilson does talk weight transfer almost exclusively.  He says, “When we get everything else done, the line and so on, we bring it all back to this rate of weight transfer thing.”

Rob Wilson’s “Flat Car” Concept

Here’s a brief run down.  My purpose in doing this is to discuss his use of weight transfer as a way of describing what is happening,

Now, I’m not for a moment suggesting that I have studied his techniques, or that I am in any way qualified to critique what he does.  He’s hugely successful, with a long list of satisfied clients, including Formula 1 drivers, and drivers in all forms of professional motorsport.  But because of the volume of video content on YouTube showing his work, it's a good opportunity for us to look at the language he uses.

Rob uses the expression “Flat Car”  as a code word to represent the idea that you need to have as little steering in the car for as long as possible to gain the greatest speed in the corner. 

In the traditional way of racing driving, in corner entry, you use just the one smooth turn of the steering wheel. 

Rob’s recommended steering technique is as follows:
1. Initial slow turn in (momentary).
2. Blend into a full movement of the steering wheel
3. Then apply extra steering at the apex of the corner. 

The idea is that you can have more speed in corner entry with less steering in the car up to the apex.  Then approaching the apex, or even at the apex, you apply more steering for a short time to get more turning done quickly, while the car is traveling at its slowest speed.  Having pointed the car better on corner exit, you can get the steering out of the car earlier, and get on the power earlier.

With the “Flat Car” code word, Rob is suggesting to get the car flat (ie as little weight transfer as possible) at least a couple of car lengths before any maneuver - either braking, accelerating or turning. 

So, for instance, on initial turn in, Rob suggests to momentarily initiate a little weight transfer with a small amount of steering, to “introduce the car to the corner”, as Rob puts it.

On corner exit, to get the steering out of the car and back on the power as soon as possible, he suggests you think “Flat Car”- get the car turned mid corner, get the steering out, get to a flat car as soon as possible (with weight distributed as evenly as possible, so as to give maximum grip for acceleration).  

The weight transfer thinking might work OK in these instances.  But sometimes it doesn’t.  

What’s especially confusing for me, is on corner entry as you approach the apex, Rob still wants you to momentarily think “Flat Car” – to run the car “flat”, even if it’s only for a couple of car lengths, prior to adding the extra steering wheel movement you need to get the car turned in the third phase of steering.

But far from having the car flat, approaching the apex, this is just the point where you have maximum weight transfer, maximum roll angle on the car.  The car is a very long way away from being flat.

Then I realized what he’s really talking about is stabilizing the car for a moment on the suspension.  Towards the end of the second phase of the steering, you slow down your hand speed, or even stop turning for a moment, before the final third phase of the turn in.  Just to let the suspension settle. 

What’s happening as you stop turning your steering (assuming you have a constant throttle and you’ve finished your trail braking) is that the rotation you feel goes to zero, while the lateral G, the cornering force, is at a maximum.  You feel no rotation inside the car, yet the car is cornering big time.  From outside the car, you can see the car rotating about a turn centre somewhere inside the corner.  But from your world inside the car, you are in tune with the car, and it is not rotating about it's own axis when the car is in "steady state".   

F1 2017 Onboard Kimi Räikkönen Fastest Lap Of Testing: 1:18:634

You’ll notice it’s not always going to work, but much of the time, in slow and medium speed corners, you can see the three phases of the steering in corner entry.

In Weight Transfer Part 3, we're looking at the change in perspective needed for us to take advantage of this new thinking.  Knowledge always evolves.  Our position on any subject might change.  We can never be absolutely right.

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