Racing a kart

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Hangaku
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Joined: 20 Apr 2009, 16:38
Location: Manchester, UK

Re: Racing a kart

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From the very start, what you need to worry about first and foremost is understanding the track as a whole. As most kart circuits are relatively short, if you mess up a single corner it's very hard to regain the time lost throughout the rest of the lap (either side of the main straight).

Example, if you nail the slowest corner on the track, the next few faster corners you will carry that much more momentum and be ultimately faster. As they are underpowered, it's hard to regain that lost speed within a lap. Consistency is paramount - there is no point in setting a blistering lap time, if the next lap you lose 20% of your lap time due to getting the entry to a single corner wrong.

Also, bananas and red shells are key to winning a race.
Yer.

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Hail22
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Joined: 08 Feb 2012, 07:22

Re: Racing a kart

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Hangaku wrote: Also, bananas and red shells are key to winning a race.
Haha oh dear... :lol: =D>
If someone said to me that you can have three wishes, my first would have been to get into racing, my second to be in Formula 1, my third to drive for Ferrari.

Gilles Villeneuve

JimClarkFan
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Joined: 18 Mar 2012, 23:31

Re: Racing a kart

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Nando wrote:Btw, have you asked for the track record in the rent karts?

i´m 2 seconds of pace but i have only run 10 minute sesssions once a year or so.
20 minutes the time we were 50 guys and ran a tournament.
The lap record was up in a few places. I eat away at that record the longer I race a track, however I don't think I have ever been less than .5-.75 of a second of the lap record on a 40 second lap. That's a lot of time to find, especially on a track where I think I have the racing line figured out

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Edit -

Great info so far... Looks like I have a few new things to try the next time I hit the track.



And sorry to the MODs, I plastered +1s throughout this thread because so much of the info is great

Nando
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Joined: 10 Mar 2012, 02:30

Re: Racing a kart

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beelsebob wrote:
JimClarkFan wrote:Also you lift the rear wheel? That is very counter-intuitive to me, I know it might be hard to explain but can anyone tell me why the inside rear?
You need to lift a rear wheel because turning a corner requires the two wheels to go round different radius turns (because one is further out from the centre). That means that the outer one needs to move further, and hence turn faster, but the two are joined by an axle, and hence can't turn at different speeds. The only way to change this, is to lift one or other wheel. So then the question is, which wheel. To turn the corner you need an inward force, the kart will try to carry on in a straight line. Because of that, it'll lean somewhat out of the corner, and put more weight onto the outside wheel. Because of that, the outside wheel will have more friction with the ground, and provide more inward force to turn you. So, you clearly don't want to lift the outside wheel, because it's what's providing the grip allowing you to turn. Thus, the inside wheel is the one you want to lift.
And how do V8 Supercars get around this problem if you can´t turn the car without lifting a rear wheel?
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N12ck
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Re: Racing a kart

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Nando wrote:
beelsebob wrote:
JimClarkFan wrote:Also you lift the rear wheel? That is very counter-intuitive to me, I know it might be hard to explain but can anyone tell me why the inside rear?
You need to lift a rear wheel because turning a corner requires the two wheels to go round different radius turns (because one is further out from the centre). That means that the outer one needs to move further, and hence turn faster, but the two are joined by an axle, and hence can't turn at different speeds. The only way to change this, is to lift one or other wheel. So then the question is, which wheel. To turn the corner you need an inward force, the kart will try to carry on in a straight line. Because of that, it'll lean somewhat out of the corner, and put more weight onto the outside wheel. Because of that, the outside wheel will have more friction with the ground, and provide more inward force to turn you. So, you clearly don't want to lift the outside wheel, because it's what's providing the grip allowing you to turn. Thus, the inside wheel is the one you want to lift.
And how do V8 Supercars get around this problem if you can´t turn the car without lifting a rear wheel?
v8 supercars have differentials, + you lift the inside rear wheel
Last edited by N12ck on 22 Dec 2012, 00:55, edited 1 time in total.
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Ogami musashi
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Joined: 13 Jun 2007, 22:57

Re: Racing a kart

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The reason why karts need to lift the inner wheel is that they don't have differentials. Cars do.

And that's an excellent transition...the most critical part in karts past the racing lines (like cars they are different whether you're in a rental kart, a non shifter kart or shifter kart) is to have that wheel lift and that far harder than you may think.

The ideal is to lift the wheel just a few inches of the ground and maitain it through the corner; here comes one of the great thing about karts, it is that the drivers makes up for a large part of the package (sometimes weighing more than the kart) and thus is a large contributor to the handling and that wheel lift.

Anything you can find both by set up and driving position/style to maintain that wheel lift up to the exit point will warrant you a good lap time.

Other than that, the basic rules are:

-Turn the steering wheel as little as possible and pay great attention to unwind the steering wheel as soon as possible.
-Turn it firmly for the first few degrees else the inner wheel will not lift, then turn smoothly and gradually for the remaining degrees
-Avoid any tail slide, you're loosing power, non shifter karts do not have a lot of power.
-On braking, smash the pedal until the wheels lock, then immediately release a bit of pressure to be just under the lock pressure, then release the pressure gradually to always be under the lock state (as your speed decreases it is easier to lock the wheels so you need less pedal pressure)
-If the kart has only rear brakes you can extend your back and head towards the rear on braking this will stabilize the kart
-If the kart has three brakes (front and rear) you can trail brake, if not refrain from doing so
-You can bend the head and torso on straight lines if your kart does more than 70km/h this helps not only drag but reduces lift.
-You can, especially on rental karts jump at the exit of a turn if the RPM went too low. The transient unloading of your kart will make the rear wheels spin a bit thus bringing the RPM up closer to the powerband.

and much more...Kart driving is an art...

About differencies:

Rental karts: Racing lines must be of the minimum curvature type (turn the wheel as little as possible) because you have very little grip and stability as well as low power for exits.

Non shifter karts: Racing lines can be a bit more aggressive on entry (especially in corners series) but exit must be smooth as possible.

Shfiter karts: Do an extra turn after the apex to straighten the kart and re-accelerate hard, throttle application is later than with non shifter karts.

hope this helps.

Nando
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Joined: 10 Mar 2012, 02:30

Re: Racing a kart

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N12ck wrote:v8 supercars have differentials, + you lift the inside rear wheel
It´s a solid axle, it sends equal power to both wheels at all times.
(i.e. both wheels spin identically)

Never seen a rear wheel lift in V8 supercars, although i have seen it in DTM.

[...]
Last edited by Steven on 26 Dec 2012, 14:26, edited 4 times in total.
Reason: Removed derogatory remark to other members
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"2% of the world's population own 50% of the world's wealth."

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N12ck
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Re: Racing a kart

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Nando wrote:
N12ck wrote:v8 supercars have differentials, + you lift the inside rear wheel
It´s a solid axle, it sends equal power to both wheels at all times.
(i.e. both wheels spin identically)

Never seen a rear wheel lift in V8 supercars, although i have seen it in DTM.
they do have differentials, a spool differential, not as effective as a normal differential, but none the less a differential
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beelsebob
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Joined: 23 Mar 2011, 15:49
Location: Cupertino, California

Re: Racing a kart

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Hail22 wrote:A bit of rear slide into corners can help by the way, also it depends how aggressive some corners/kerbs are, I try not to ride all the kerbs on the tracks I drive on (purely because two of those kerbs are replicas of the sausage kerbs used in the Indian GP) They're used as a deterrent as some racers have exploited said kerb (all 3 wheels off due to its width the 4th is the right rear wheel as its a left hand corner/turn, hence sausages are there to prevent said...bunny hoping). ;)
Heh, certainly where I go, there's no way to ride kerbs – the corners are bordered on both sides by tyre barriers, no kerbs to be seen.

Scootin159
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Joined: 06 Aug 2009, 21:09

Re: Racing a kart

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V8 supercars have a spool diff, which basically functions like a kart axle. They may not be lifting a wheel, but they are certainly shifting the weight off that inside wheel in slower corners.

Another thing to remember is that v8 supercars are running tracks with significantly larger radius corners, so the side to side speed difference is less significant. The inside wheel is still slipping, but to a much lesser degree.

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strad
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Joined: 02 Jan 2010, 01:57

Re: Racing a kart

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If I may...It's not that it won't turn but what happens is that the inside rear skips sideways.
Have none of you ever run a car with a spool or welded spider gears?
I seriously doubt V8 Supercars run a spool that locks the axles for that reason.
Usually reserved for drag racing and Some oval track and dirt racing. imo
edit
just checked :
Differential-9 inch
in other words,,,they run a ultra dependable 9 inch Ford diff.
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krisfx
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Joined: 04 Jan 2012, 23:07

Re: Racing a kart

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My friends all drive differently, the quicker ones tend to push their weight into the seat, toward the outside, ie: left hand corner, push into the wheel with your right hand so your body is pushing weight onto the rear axle and shift your weight to the outside.

I've found if you lean too much the back tends to step out in rental karts especially if you're tall or heavier, it's not so much a problem in faster karts.

the thing they hammer into me the most is conserving speed, and if you raced more competitive than rental, everyone is leaded to the same minimum weight so it's about carrying maximum apex speed using the brakes to get the kart turned in on a gradual slide, in rental as well you need to keep the revs up, they bog down so easy it's untrue.

The guys I race and teach me are either ex Formula Kart stars, club champions and one now even races super cup

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Tim.Wright
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Joined: 13 Feb 2009, 06:29

Re: Racing a kart

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strad wrote:If I may...It's not that it won't turn but what happens is that the inside rear skips sideways.
Have none of you ever run a car with a spool or welded spider gears?
I seriously doubt V8 Supercars run a spool that locks the axles for that reason.
Usually reserved for drag racing and Some oval track and dirt racing. imo
edit
just checked :
Differential-9 inch
in other words,,,they run a ultra dependable 9 inch Ford diff.
They have been running spool axles for years
Not the engineer at Force India

Raptor22
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Joined: 07 Apr 2009, 22:48

Re: Racing a kart

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JimClarkFan wrote:I do a bit of kart racing, not all that much though, but I like to get as often as I can and money allows it.

My question, to all those who race karts, is just what is the best way to drive the thing;

Are there any tricks that you know of, that you have seen, or do yourself to make the kart go faster?
Is the old adage of loose is fast by and large true?
Are there any good video which demonstrate how ex kart masters, such as Lewis and Vettel, to illustrate your point?

Anyway, post up what you think, I want to wipe the floor at my next meet up :mrgreen: and given that I can't be behind the wheel as often as I would like, I would prefer to learn from others that can.

It really depends on the kart, tyres, tyre pressure and engine you are using. My favourite technique is oversteer into the corner, balance on the throttle and steering easy onto the throttle form apex. A brief choke just before entry halpes to richen things up a bit but I seldom needed it.
I also tend to steer very little. Short sharp actions on the steering wheel. The longer the wheels are straight the faster you will go.
Use the track and find the line that works for your kart set up on the day.

Tommy Cookers
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Joined: 17 Feb 2012, 16:55

Re: Racing a kart

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Tim.Wright wrote: They have been running spool axles for years
IIRC Paul Frere drove the Le Mans winning Porsche (solid ie spool type diff action) in the mid 70s and said the likliest place to fail to turn in was the pit lane (journalists had crashed these cars going slowly)
in other words even the hairpin was ok in race conditions because the driver went in hard and used plenty of throttle, stealing grip from the axle's attempts to disagree with the bend (Porsche liked the exit traction, the solid diff was their secret for years ?)
most karts dont have the power to do this

IMO the better the driver is cornering the less an LSD is needed (an open diff tells the driver how well he is cornering)
someone should tell this to Clarkson, (when he rubbishes as unsafe American cars that don't have LSDs)
the LSD is the one that is potentially unsafe, it's a machine for breaking loose the rear
of course if you are cornering too slowly you can use the LSD to hang out the rear and pretend this is good driving

the kart might do better with a ratchet ?/overun type diff functionality, like the Detroit Locker etc ?