Driving long curves


(Lee Swindell) #1

Experts:

What do we need to know about driving long curves?

It’s a question that’s long intrigued me, in view of the impact the long curve theoretically has on lap time.

There’s a sweeper on my local track that one spends maybe 3 seconds in at hire kart speeds. There’s no chance of jacking the inside rear off the deck, so that’s 3 seconds of massive drag on the lap time.

I’ve not tried it, but I’ve wondered whether there might be an advantage to driving the curve in 2 straight lines linked by a sharp turn through 90 degrees. Or several short straights linked my several turns of a few degrees.

Completely counterintuitive of course, but I suspect that most of us just reason that there’s nothing much we can do with long curves, and drive them as They’re shaped.

But if we deconstructed the driving of long curves, would we find an advantage hidden here?

Thanks for your thoughts.

Lee


(Jonthan Stewart) #2

I am certainly not an expert, but I have had some success in rental (hire) karts as well as 4-stroke racing karts.

My main question for you is what does the kart feel like? If you put just a little more steering in, will the back start to slide? Or does it just plow straight ahead no matter what you do? I certainly understand your concern about not being able to unload the inside rear tire and agree that it’s an important thing to be aware of. However, it may not be as big of an issue in some rental karts, at some tracks. Different tracks, or even just different karts at the same track can have wildly different handling. If the kart is somewhat balanced and the rear will start to slide if you turn the wheel more, then I would not be concerned with altering your line in a long sweeper.

Some thoughts about lifting the inside rear tire: to me, it is easier to notice with soft racing kart tires than it is with rock hard rental kart tires. However, with that said, a very tiny amount of steering input may bog down a rental kart significantly, while a normal amount of steering to get around a corner may unload the inside enough to reduce the drag. While this is unproven, I think in some rental karts, in some corners, it can help to be either at “full steering lock” (the max steering you normally get to in the corner) or perfectly straight ahead. No in between. Either unload the inside rear tire as much as possible, or set it down all the way and drive straight. I think you were already kind of thinking about it this way. The main place I think this thought process can help is long sweeping exits, where you can keep turning just a little longer, and then go completely straight to the next corner entry.

In some cases with rental karts I have found unconventional lines to be faster, but not in the way you’re talking about. With such a lack of power, sometimes it can be faster to really try to make the track as short as possible. Not only does this include simply running on the inside of the sweeper for the full length of the corner, but also not using the full width of the track on exit.

I do have an example, which is the closest thing to your suggestion of driving in two straight lines with a sharp turn in the middle. It was not a long sweeper though, but two corners that basically became a double apex corner. Outside of the track, there was a concrete runoff area. In rental karts, in the rain, on slick tires, you could drive into the corner very straight and go off onto the concrete area, suddenly have grip so you could turn, and then get back on the track and drive a relatively straight exit. I have never encountered such a situation in dry conditions in any kart.

So I guess what I am saying is, there is probably not a benefit to what you are suggesting.


(Joseph Costanza) #3

I say give it a shot! See if it does anything to your lap time :man_shrugging:t4:

Report back!

Edit:

Google image overhead shot of the corner in question?


(Dom Callan) #4

With the really long corners the fun is how early you can be on throttle?
And/; can you holfd it all the way out?


(Benn Herr) #5

Usually with any kart but the most powerful, you need to be on the throttle very early in the turn. If you feel one of the rear tires is “dragging” or binding the kart, try leaning outwards while going around the corner. It may lighten the load on the inside rear enough to free the kart up. If you look at pictures of some of the top European guys in the wet, they’ll be leaned out over the outside side pod.


(James McMahon) #6

That’s basically what I do on longer turns, esp if it’s a flat out turn. Lean out to unload the inside rear as much as you can. I can’t say what difference it makes… But it looks cool :smiley:


(Lee Swindell) #7

Some great advice here - especially James your bit about looking cool. :sunglasses:

You’ll find the sweeper in question top left of photo. there’s no driving needed to get through on full noise (85kph - the KZ2s hit this at 170 apparently) - but I’m looking for something to ‘do’ on this piece of track - such as keeping as much load off it as I can.

Benn, you’ve answered that I think - just lean out. Simple as that is, I hadn’t thought of it so I’ll give it a go at the season opener in a couple of weeks and let you know what I come up with.

Johnathan: I subscribe to that ‘all or nothing’ Steering approach too - hence this question. I’ve been tracing the inside of the curve all the way through on the shortest line I can find, with the inside rear on the kerb / grass to minimise the force it feels. Interestingly, a guy in my crew observed one of the fast guys turning in from the concrete apron in our last wet enduro, exactly as you describe. So looks like the word on that is out…

Thanks for your comments.