It’s easy to go fast in a straight line in a go kart. Whether you are driving a Honda powered Cadet kart or a 26bhp Dmax kart, you just put your foot down and accelerate – but the key to a fast lap time is always about the corners. The biggest mis-conception about cornering quickly is that you need to enter the corner quickly – whereas the rule is that you need to enter the corner at the correct speed for that bend in the current conditions.
There are very few corners on good kart circuits where drivers don’t need to moderate their entry speed to maximise their exit speed. You can enter the corner flat out but, if the kart cannot maintain grip and accelerate through the bend, you will either spin out, run wide, or simply scrub off all your speed and be swamped by loads of drivers passing you on the exit. It’s so much better to be one of the drivers doing the overtaking on the way out of the corner.
So entry speed is important in order to maximise exit speed and the trade-off between the two can make a huge difference to your overall lap time and to your ability to overtake/avoid being overtaken. As I watched the final ten laps of the exciting Bahrain grand Prix at the weekend, where Lewis Hamilton and teammate Nico Rosberg were having an epic battle for the lead, we saw lots of examples of how to use corner entry speed correctly – and incorrectly.
There were two examples of Nico outbreaking Lewis to pass inside him into T1 and on both occasions Lewis was able to immediately pass him back again as Rosberg ended up running wide and slow as Lewis swept through on the exit of the bend with seriously better grip and speed. Elsewhere on the circuit, Lewis was able to simply defend corners from the attacking Nico by holding the inside line on the entry to the corner, effectively parking himself on the apex, taking the corner slower than usual but covering the entry, mid-point and exit lines to avoid Nico using them to pass him.
Lewis also had the benefit of his ERS boost – he would have been delighted when his engineer confirmed he could use it on the exit of corners – as this gave him slightly more confidence that he could block the entry to the corner by going offline but still have power on the exit.
Kart drivers don’t have ERS and DRS etc but the basic principles of fast cornering are exactly the same. You should try to “straighten” the corner as much as possible. So, if its a tight hairpin bend, you will see quick drivers sweep out wide on the entry, clip the apex of the bend and then run wide on the exit. Even mid speed corners will be taken a lot quicker if you use as much of the track to straighten the bend. The only time that one changes the entry line to a corner is when one is either attacking the driver in front or defending from an overtaking driver – and if you do have to take a defensive line, the key is to avoid sudden changes of direction or zig-zagging. Karts slow down when you change direction and Race Directors don’t like watching drivers changing lines more than once or twice when defending.
The final rule to follow when trying to corner quickly in a kart is to avoid leaning in. It seems counter-intuitive as we are used to leaning in to cancel out the cornering forces acting on us, but leaning in actually unsettles the kart. If you sit in a stationery kart in the pits and turn the steering wheel from side-to-side, you will see the front wheels lift one at a time. This steering design enables a kart to overcome the fact that its back wheels are fixed together on a solid rear-axle and thus have to rotate at the same speed, even when cornering.
Your road car will have a differential fitted to the drive shaft/axle arrangement. This allows the drive wheels to rotate at different speeds and thus allows the outside wheel go further/faster around the corner than the inside rear wheel. Racing cars often have a limited slip differential – which allows the engineers to find the perfect balance between cornering ability and outright acceleration in a straight line. A go kart doesn’t have a differential – its has a solid metal axle. When you turn in to a corner, the steering is designed to lift the outside front wheel. As the various forces acting upon you and the kart push everything to the outside of the corner, the outside front wheel is forced down and the chassis thus lifts the inside rear wheel. By doing so, this allows the kart to corner quickly on three wheels effectively. By leaning in, like a motor-cyclist, you are countering the karts design to corner better.
The answer isn’t to lean out, it is simply to allow your upper body to rest against the outside side of your seat as you corner. As you take the bend, the forces pushing your body against the seat increase and this actually helps the kart’s geometry to do what it is supposed to do.
All of the above should help you to corner better on a dry circuit, or on a wet circuit if you have wet tyres. If you are stuck on a wet circuit on slick tyres, then slightly different rules apply. Firstly you need to understand that you will be cornering slower. Secondly you will be using slightly different lines around the corner and thirdly, and most importantly, accept that once you commit to the corner, you are committed!
The trick in the wet is to slow down in a straight line to the correct entry speed for the corner. Then turn the front wheels in to the bend but don’t be alarmed if you go straight on. Now apply some throttle and that will get the rear wheels to lose some traction which will enable the front wheels to actually turn the kart. Again it may seem counter-intuitive but you do accelerate into the corner, albeit gently and with care.
Once you have mastered the skills above and started to win races, maybe you will get noticed by Ron Dennis and one day you may have your F1 engineer telling you that you can use your overtaking boost to defend the lead in an F1 race!
Jim Graham
TEAM DAYTONA