The wonders of trail braking and understeer biased setup (rental gokarting)
11-06-2006, 06:05 AM
#1
Race Director
Thread Starter
The wonders of trail braking and understeer biased setup (rental gokarting)
I participated in a 2 hour race (2 drivers) yesterday in Halmstad, Sweden.
New track for me, I ususally race 3 hour races (3 drivers) on another track that is less forgiving to variations - there really is only one way to drive that track fast. This new track (for me) allows more variations in lines.
I was going around the track the traditional way when braking straight for about 25 minutes and reached my limits to how fast I could go around it that way. Once I started trail braking in two of the turns I slashed my lap times with 2/10 and 3/10 of a second in the two individual turns.
Since I could move the seat back and forth I was able to change the under- and oversteer balance of the kart while on the go. Normally in a car such a dramatic changes are impossible without stopping but now I could test it at speed and do 5 laps one way and 5 the other and watch the lap time trend.
Combining the two factors of trailbraking and having a understeer balance I was .8 of a second faster per lap (37-38 second lap times). There were three sweepers on the track where the kart felt faster when it was loose in the back but the lap times told me it was slower.
I am sticking to the statement I did a while back - understeer is fast and oversteer is slow.
Now I know that there are siginificant differences to a car and a kart, mostly regarding power, differential and brake balance but this sure was an interesting test since the driving basics are the same.
New track for me, I ususally race 3 hour races (3 drivers) on another track that is less forgiving to variations - there really is only one way to drive that track fast. This new track (for me) allows more variations in lines.
I was going around the track the traditional way when braking straight for about 25 minutes and reached my limits to how fast I could go around it that way. Once I started trail braking in two of the turns I slashed my lap times with 2/10 and 3/10 of a second in the two individual turns.
Since I could move the seat back and forth I was able to change the under- and oversteer balance of the kart while on the go. Normally in a car such a dramatic changes are impossible without stopping but now I could test it at speed and do 5 laps one way and 5 the other and watch the lap time trend.
Combining the two factors of trailbraking and having a understeer balance I was .8 of a second faster per lap (37-38 second lap times). There were three sweepers on the track where the kart felt faster when it was loose in the back but the lap times told me it was slower.
I am sticking to the statement I did a while back - understeer is fast and oversteer is slow.
Now I know that there are siginificant differences to a car and a kart, mostly regarding power, differential and brake balance but this sure was an interesting test since the driving basics are the same.
11-06-2006, 06:57 AM
#2
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Anders
An oversteering car feels faster that an understeering car. BUT the only measure of performance are lap times and not how wild or on the limit a car feels. An oversteering car would generally feel like you are driving on the edge compared to an understeering car. Is it too simlistic to say that if you have used up all you rear grip in sideways movement - there is less to propel the car forward?
Give me an understeering car on fast corners and I shall give you quick times. In some slow corners you may want an oversteer characteric built in to help the car to rotate.
I think no less of an authority than Carroll Smith said that it is a pity that even though an oversteering car looks fast that it is in fact slower than an understeering car.
Johan
www.almost.co.za
An oversteering car feels faster that an understeering car. BUT the only measure of performance are lap times and not how wild or on the limit a car feels. An oversteering car would generally feel like you are driving on the edge compared to an understeering car. Is it too simlistic to say that if you have used up all you rear grip in sideways movement - there is less to propel the car forward?
Give me an understeering car on fast corners and I shall give you quick times. In some slow corners you may want an oversteer characteric built in to help the car to rotate.
I think no less of an authority than Carroll Smith said that it is a pity that even though an oversteering car looks fast that it is in fact slower than an understeering car.
Johan
www.almost.co.za
11-06-2006, 07:27 AM
#3
Race Director
Thread Starter
Originally Posted by Flat Top
Anders
An oversteering car feels faster that an understeering car. BUT the only measure of performance are lap times and not how wild or on the limit a car feels. An oversteering car would generally feel like you are driving on the edge compared to an understeering car. Is it too simlistic to say that if you have used up all you rear grip in sideways movement - there is less to propel the car forward?
Give me an understeering car on fast corners and I shall give you quick times. In some slow corners you may want an oversteer characteric built in to help the car to rotate.
I think no less of an authority than Carroll Smith said that it is a pity that even though an oversteering car looks fast that it is in fact slower than an understeering car.
Johan
www.almost.co.za
An oversteering car feels faster that an understeering car. BUT the only measure of performance are lap times and not how wild or on the limit a car feels. An oversteering car would generally feel like you are driving on the edge compared to an understeering car. Is it too simlistic to say that if you have used up all you rear grip in sideways movement - there is less to propel the car forward?
Give me an understeering car on fast corners and I shall give you quick times. In some slow corners you may want an oversteer characteric built in to help the car to rotate.
I think no less of an authority than Carroll Smith said that it is a pity that even though an oversteering car looks fast that it is in fact slower than an understeering car.
Johan
www.almost.co.za
Yes, exactly. I posted this since I got a bit flamed a while back when I stated the same without having lap times to back up the statement. Now I do.
In the slow hairpins I really had to wrestle the kart when it was understeering compared to rotating by a simple lift off when it was oversteering. Through fast corners where a confidence lift came into play it actually made a difference when it was understeering but was a disaster when it was oversteering.
11-06-2006, 09:04 AM
#4
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Interesting, Anders;
What it may boil down to is that there are many more ways to manage slight understeer; Turn in style, TB, chop throttle rotation, etc. It is not a catastrophic event to try and manage at a very high speed. The worst you get is a front end washout, i.e. slow.
There are far fewer ways to manage oversteer, and it is much harder to maintain high speed during the management phase, both in terms of effectiveness, and scaring yourself silly... or worse!
What it may boil down to is that there are many more ways to manage slight understeer; Turn in style, TB, chop throttle rotation, etc. It is not a catastrophic event to try and manage at a very high speed. The worst you get is a front end washout, i.e. slow.
There are far fewer ways to manage oversteer, and it is much harder to maintain high speed during the management phase, both in terms of effectiveness, and scaring yourself silly... or worse!
11-06-2006, 09:43 AM
#5
King of Cool
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Originally Posted by sweanders
I am sticking to the statement I did a while back - understeer is fast and oversteer is slow. ...
...
OK, OK, I agree, in principle, in some (usually faster) corners, understeer gives you more "options" and is faster but IMO you can't generalize that understeer is always and everywhere faster.
There are drivers who are/were very good (and fast!) with oversteer handling cars.
I personallty prefer very little understeer (or neutral) handling in fast corners and oversteer on slow corners.
11-06-2006, 10:46 AM
#6
Race Director
If the understeer gave you confidence that alone could make you faster.
Confidence = speed. If you can still be confident in the car and have a bit of oversteer you are probably the fastest. The problem is that in a fast corner most people are not confident to push the car hard if it has oversteer. So they go slower.
So in the end what is fastest is what the driver can get the most from. That is why even the pros have different set-ups.
Confidence = speed. If you can still be confident in the car and have a bit of oversteer you are probably the fastest. The problem is that in a fast corner most people are not confident to push the car hard if it has oversteer. So they go slower.
So in the end what is fastest is what the driver can get the most from. That is why even the pros have different set-ups.
11-06-2006, 11:16 AM
#7
Race Director
Thread Starter
Originally Posted by M758
If the understeer gave you confidence that alone could make you faster.
Confidence = speed. If you can still be confident in the car and have a bit of oversteer you are probably the fastest. The problem is that in a fast corner most people are not confident to push the car hard if it has oversteer. So they go slower.
So in the end what is fastest is what the driver can get the most from. That is why even the pros have different set-ups.
Confidence = speed. If you can still be confident in the car and have a bit of oversteer you are probably the fastest. The problem is that in a fast corner most people are not confident to push the car hard if it has oversteer. So they go slower.
So in the end what is fastest is what the driver can get the most from. That is why even the pros have different set-ups.
Whenever I am on a track my first sessions I build confidence and go faster and faster until I overdo it and am to aggressive (wide and deep). Then I back off and start modulating. I am a firm believer in the saying that you have to go over the limit to truly define it.
I would guess that on a track with plenty of room oversteer can be fast since you can allow the rear to hang out longer. On a track with barriers it is IMHO advantageous to keep the car pointing straight(er) so that you can have the whole side of the car aligned with the barrier.
Interestingly I found it very easy to keep the grip on the edge whith an understeer setup because it keeps the suspension (tires on a kart) loaded better than when oversteering. It is hard to keep the front hooked up while the rear is sliding.
As I wrote before it took a considerably higher amount of work to rotate the kart in the hairpins when I had it setup for the fastest laptimes. I did most of my passings in these tight turns though since I always had the rear planted and could power through the turns instead of just out of them compared to when I was driving with more oversteer bias.
To clarify - I still drive with oversteer but only when I want it and found it much easier to control when the kart was easier to bring back.
