February 20, 2007

DE Smooth vs Race Smooth

Invariably, when we submit a video to one of the many internet discussion forums, someone will declare that our driving (or whoever is in the film) sucks because the steering wheel moves around too much.
"The driver looks like he played too much Playstation" is a predictable barb and while in the ideal world smooth IS the ideal, the reality of tires, surfaces and trajectory are such that at the limit a driver is ALWAYS making corrections.
Club racer and frequent Bimmerforum poster Bryan Watts put it very well and very clearly:

"Someone driving at/near the limit won't be making a single steering input to apex and never move their hands except to unwind the wheel for the exit...that's what I like to call "DE smooth". That generally means they aren't pushing hard enough. If you're at the limit, you'll be making changes constantly as each few inches of pavement has different grip characteristics due to camber, roughness, wear, material, etc, etc and the amount of grip available from the car changes as it rolls into and out of the turn while the geometry changes and weight transfers. The really good drivers are the ones who can make these small changes so precisely and so instantly that the tire is always happy and the car looks "smooth" from the outside because of how much work they are doing on the inside."

(Editor's Note: "DE" stands for "Driver's Education" a short hand for club organized track days with instruction.)

To illustrate the above I dug up two video of the same pro driver in different situations.

This driver is a great example since his style is so exaggerated: Wolfgang Kaufmann has been racing for 20 years everything from Polos to Porsches. The video of his astounding laps of the Nürburgring in a Donkervoort racer are legendary.

In the first video below he is driving, presumably some acquaintances, around the Nürburgring in a ... VOLVO!

The video is very shaky but you can get the idea. Watch his hands, perfectly "DE Smooth", one input and then held steady.
If you think he's just going slow you're right, Kaufmann did have the 'Ring record in a Gamballa GTR at 7 minutes and 32 seconds, still a sub 9 minute lap in a Volvo with at least 3 people on board is not too shabby!
There is plenty of good commentary about the track and "Bonus points" for racing the Ring Mini at the end of the lap!

Contrast that with the video below where Kaufmann is at Spa, driving an FIA GT Porsche 996 GT3 RSR. The hands speak for themselves.
CG will probably chime in on this but I'm guessing that the RSR is so stiff in the front that it needs to be thrown and caught to make it turn.
Notice also that if you look at the track the car is smooth, this is because at the very limits of adhesion the effect of steering angle is much less pronounced.

I would love to see some comments on this subject either here or in the Axis Forum.


I found a different onboard from the same FIA GT race as above, this time from a GT2 Ferrari 430.
Not much flailing going on there!.

Below the Ferrari clip, we find out more about why exactly Kaufmann is in a Volvo... and as you see from his driving in that clip, no drama.

At this point I'm leaning towards the conclusion that that the setup on the 996 RSR above blew chunks...or maybe the tires were completely gone.

The guys over on Rennlist are adding lots of useful comments take a look.


  1. That is a lot of words - to sum up:
    The limit of adhesion is defined by the tire and the ROAD and so is a variable. You have to continuously correct inputs to compensate for surface changes or you will fall off the "limit" on one side or the other.

  2. When I go the Subaru, I thought I'd forgotten how to drive, because I looked like a rookie in my in-car videos, with my hands all over the place. You cannot drive that car at the limit with smooth hands. Too many variables affecting the limit, as Walter said, and with lots of power, a not-quite-perfect suspension, and AWD, it just changes everything.

  3. ...and you must get torque steer too...weeeee!

  4. Right on... This is what I've been saying for quite a while in all forums.
    It all depends on the car. What I notice through time and experience (both driving and watching is the following rule:

    Smooth steering:
    -Usually on nicely setup cars with street suspension and predicatble tires (Differences in surface grip usually get soaked up by some rubber in the suspension or suspension movement and there's little you can fix/improve wiht the steering.

    -The driver that drives at the limit this way is usually very good applying multiple corrections through the turn with the tw other steering controls: brake (LFB mostly) and throttle.

    "Jerky" steering:

    -Most stiffled sprung racecars (or DE cars) with stiff bushings (or none wathsoever - metal yo metal). All surface changes go through the steering and so require fast correction when at the limit. Unforgiving tires with a narrowband of good slip coeeficient (grip while sliding) will also require very fast corrections.

    - Cars with poor handling (IMO) that require to be thrown into the turns (like the AWD Subaru STi... sorry Josh...) and then be caught

  5. Thank you for putting up this interesting post! I've noticed that in my M Coupe with an aftermarket setup, although better, is still forgiving like a stock car. It was easier modulating the throttle during mid corner corrections than using the wheel. In the Skip Barber RT2K, however, I used the wheel more. Since the RT2K throttle is sensitive, I lost quite of bit of speed when easing off. I only had two days on that car and it's vastly different than the one they used in the basic 3day school. I know I'm not nearly driving at that car's limit but I can see how car type plays a role.

  6. Great post AC!

    Keep an eye on The Garage, as you've stirred some thoughts! I have more than a few words brewing in regards to smoothness, not to mention a few comparisons.


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