Let’s talk about rear ride height: the classic theory is that higher ride means more grip, because the inside wheel lift more in the corner and load a lot the outside wheel.
BUT
What about KZ? I mean, in X30 (or similar) you have to free the rear to have a good speed exiting the corner, so in this case too much grip has a negative effect. I think in KZ you have to consider another thing: you need lot of traction to put down the brutal power of the engine (specially exiting from low speed corners when you go from 2° to 4° gear in few metres).
So, if we talk about the grip you need in traction, when you must have all of 4 wheels down to not lose lot of speed, in my mind we have to think in opposite way: high rear ride makes the inside wheel lift too high and for a long time, so you can’t have grip when you go on gas and the only thing you want is traction. Moreover, in KZ the time you spend making a corner is very little if compared to X30, because the ideal line is shorter, so the main type of grip you want is not the grip during the corner (high ride) but the grip in traction (low ride).
If my reasoning is correct we can say that generally in KZ, in normal track conditions, the standard setup is low rear ride height?
For the most part you’re spot on; however, like everything in karting, there are some exceptions here and there based on chassis manufacturer.
Many KZ chassis come with lower rear ride height built in vs their direct drive counter parts. This plays into your points about needing on-throttle traction to best deploy all of the horsepower of the KZ. With many chassis brands, middle ride height is still going to be the baseline setting, because the chassis is already fairly low.
I have found some KZ chassis that still respond in the traditional “lower = less grip” manner, older DR karts being the example. On the contrary, I have also driven X30 chassis that have less rear grip (via more rotation) when running high rear ride height. KR is this way.
It’s really all about finding the correct balance for the conditions. BirelArt nearly always runs low ride height, yet I’ve had times where the rear was not rotating enough on corner entry and the chassis performed better at middle ride height. Lower = more traction is a good rule of thumb, but at the end of the day you may still need to fine-tune based on feel, data, and what the stopwatch says.
IPK is the manufacturer I have the least experience with actually …from what I’ve seen most people run a pretty standard setup, one dot caster pils, plastic front bar, and usually start at middle rear ride height with longer hubs and two sets of seat struts. I’m not sure in terms of axle selection though.
@Andy_DiGiusto has a Formula K, so he might be able to provide some notes for you.
Very easy. Download IPK setup manual, run baseline setup. I know, very boring.
Axle: only use MR (the special medium/race). Road racing/city tracks you may need one step harder
Rear width: max allowed
Front width: test what you like better between 3rd and 4th line (counting out from the narrowest position)
Camber -2mm each side
Toe out: 2mm each side. If it’s a fast track decrease 0.5 if short and twisty add 0.5
Caster: standard insert
Height: middle front, middle rear. During winter months or low grip, I tend to add some rake (lift the rear while keeping the front at mid), the 30/32 chassis seems to like it quite a bit…keeps the front planted and helps with weight transfer at the rear, but you need to be careful not to go too early on the throttle
The above is what I normally run with Evinco (MG) reds on dry. Nothing fancy.
Congratulations, great choice! It’s an awesome chassis!
Thanks a lot, very helpful. Can I ask you where I can download IPK setup manual? On web I find only 2013 manual, I think is old.
For the rest, I use the same axle and the same front setup. Sometimes, with low grip, I go with negative caster.
About the rear: I have to try the middle, I usually go low with 139,5 width (140 is max). With middle you find more traction so you can go 140? Or what?
Yes I like middle because it helps a lot with grip in mid-corner. If you have too much grip and track surface is good, you can lower both front and rear to the max, I normally don’t feel the need to but it’s also because the tracks around here (SOCAL) will literally eat up your seat and chassis bottom in less than a day…IPK lowest setting is lower than the other chassis so you are running really really close to the ground at that setting.
I drive KZ and my chassi just have the high and the low rear height options. What do you recomend me for add or reduce rear grip? I didn’t understand if more height = more grip or more height = less grip.
“Grip” isn’t real. Ride height is changing the amount of weight transfer and flex in the rear of the kart. A kart with high rear ride height will transfer more weight to the outside tire. This can provide more “grip” as the tire digs into the pavement harder. However, if the tire is already at it’s limit, trying to push it into the pavement harder will make it slip, reducing “grip”. Low rear ride height won’t allow as much weight transfer, resulting in the outside tire not digging into the track surface as hard. But it also will keep both rear wheels on the ground for more time in the corner, giving better traction on acceleration.
As with any adjustment that affects the weight jacking of the chassis, going too far either direction can produce the opposite effect you’re expecting.
…from what I’ve seen most people run a pretty standard setup, one dot caster pils, plastic front bar, and usually start at middle rear ride height with longer hubs and two sets of seat struts. I’m not sure in terms of axle selection though.
