Just getting back in the sport, new to me comp kart, was described “light use, practice only etc” by looks I believe what I was told. Did set up with sniper on the stand. Had to move the Left side adjuster one hole to get things matching left to right. Camber, toe, caster and sweep all good. Put the kart on the ground, the wheel goes left hand down slightly.
Sitting in the kart if I turn the wheel 45 either direction and release the natural resting spot is that same left Hand down and feels “snappier” releasing from right hand down.
Drove the kart for the first time yesterday, tracked straight, didn’t feel different turning left or right, from what I could tell. First time in a kart in 20 years, so it was a lot to take in.
The left hand down natural resting position makes me think something could be tweaked . I come from the car racing world where all set up is done on fixtures with the car loaded (on the ground) with driver weight and fuel load weight, so for me it seems weird to not do that with a kart, obviously
This seems to be the norm so it must work, but that could be because of the change I am seeing from stand to floor.
I read that having a small difference (1) in pills is not the end of the world, is this accurate?? How concerned should I be with the situation I am seeing?
Even in street cars alignment is done with the weight on the suspension and ideally the weight of the driver in the seat. However, this is not really feasible with karts, plus the lack of suspension will keep things from changing much if at all. For me personally, once I have a baseline setup making changes to the pills is more about looking for a feel or handling change versus what it shows on the sniper.
TJ, no scales yet, I think I have a bit more rust to knock off before I get to that point. When my driving is more consistent and closer to the limit I will get it on a scale set. Seeing as there was nothing drastic going on I.E. tracking straight and feeling same left turn vs right turn I will drive it as is and chalk it up to it is what it is. First time after 20+ years I’m kicking myself for not doing this sooner!!!
If you really want to, you could do the aligment on the ground and arguably you’d see more consistent results… BUT to do it right can be arduous. You’ll have to remove all variables by using a scale stand (or similar dead-nuts flat surface), stable tire pressures and tire circumference will be important too.
So in a counter-intuitive way, doing the alignment off the ground can often work out better as it’s easier to get repeatable results.
Im surprised fixtures aren’t a thing, or common thing. I understand karts aren’t cars for many reasons, obviously the main one being no suspension. The kart frame is the suspension, and when you a human in the seat things flex and move and change. My car mind says you should do the set up the way the vehicle will roll down the road. I guess as long as you do whatever you do every time it doesn’t matter, it’s your baseline.
In top level racing all teams have gone away from doing set up on wheels and tires and now use fixtures in place of wheels, measure camber electronically and toe with lasers, kind of like the snipers. Much easier and efficient once you go through setting them up for the car/tire you run. I even had a set for my 1/10 RC Touring car at
One time.
If you breathe a different way while you sit in the kart, it can change the alignment. Lean 1" forward or back and your weight distribution changes. I imagine that the body in the seat is so variable it’s kind of pointless to try and set everything up with a statue-still driver. The driver is such a big part of the equation when it comes to handling; their posture, weight, CoG etc. How you sit has such a big effect on all aspects of how the kart is at “rest”.
I think most people (myself included) set it all on the stand and then have an idea in their head from experience what it’ll be on the ground. Front end alignment is really the only thing you need to worry about changing once the kart is on the ground.
That makes sense. With such a small item and the driver being half of that weight. Just like anything in motorsport, do what you do and do it the same every time, set up, tire psi, tire temps etc.
Motorsport also has a tire model where you know what camber angle is ideal for the tires, so the camber angle has real, physical meaning. For us, it is entirely relative. “1 box of camber” of physically meaningless.
In other words, a proper fixture would get you an exact measurement of camber, but you’ll still be adding a subtracting camber as you figure out the setup. It won’t get you any closer to knowing what number to hit. What the true camber is does not matter nearly as much as the relative camber. Like TJ said, a reliable, repeatable measurement is easier on the stand, so when you add or subtract a unit of camber, you get a predictable outcome.
Still, it is helpful to always keep in mind that the stand is not the same. When changing the front bar, you may have to revisit alignment since the dynamic alignment will change.
I take the steps necessary to set the alignment neutral on the ground once, with me in it. Then I put it on the stand and note what has changed. From there I know what changes to make on the stand to get the desired driving geometry.
You’ll find that unless you are on dead flat ground the wheels will want to skew one way or the other. Just an effect of the built in geometry.
A sanity check would be that the sweep is correct and you haven’t offset to one side or the other.
Also I find I get a more accurate and repeatable setup by pulling the hubs and putting the lasers on the spindles. Roughly place the laser in between where the two bearing sit.
This all stems from a driver friend of mine coming over and sitting in the kart and pointing out the snap back of the wheel and getting me all wound up about something being bent or not right and then the wheels got turning about set up procedure. You guys answered the questions, on the stand it will be for sure.
TJ explained it better than I did. Karts are so much easier to “upset” that aligning them on scales or with plates is tricky. Not to say it can’t (or isnt) done. It just a fiddly pain in the arse
As has been said, setting up on the stand is done for 2 reasons - ease, and more importantly, repeatability. Camber, toe, caster might all change slightly when the kart hits the ground, but that doesn’t really matter as long as you can consistently make changes with predictability and return to your baseline when you need to.
It’s the same reason that you always use the same tire pressure gauge. Does it really matter if my gauge reads 10psi, while yours more accurately reads 11 psi, for the same tire? As long as my gauge consistently reads 10 psi for that same tire, I can tell what impact going up or down 1 psi has on the stopwatch (like moving one box on the snipers), and I can always go back to my baseline, if need be.
That’s probably from the (comparatively) massive amount of caster karts run with. I do agree that using “squares” and millimeters to measure geometry is a bit odd. Esp when the front track width often changes so often that a given number of mm will have varying amounts in actual degrees.
That’s one thing that’s nice about the likes of the sniper laser tool. In theory you should be placing it on the front spindles at the same position each time…
One thought that continues to come to mind here… is the steering wheel actually mounted straight? I’ve had this argument a million times (+/- 999,950) with my 5-13yr old kids telling me the wheel isn’t straight so there must be something bent. “does it go straight when you let go of the wheel?”
“I dunno. I never let go of the wheel”
In many cases, it turned out to be the slop in all of the bolts between the steering wheel, hub, and shaft. when the kart gets bumped, those little gaps shift a little and now the wheel isn’t straight but nothing’s actually bent.
In a number of other cases, I did a poor job of setting the sweep and it was a lil off, causing the steering shaft to be off while the wheels pointed “mostly forward”
And then there’s “yup, it’s bent [again]. Go get the crash box”.
Those Comp Karts I believe are symmetrical, but I’ve also run into a few chassis where the steering is offset to the left a little to better align the seat and steering wheel. now you have different tie rod lengths and getting the sweep to match is a fruitless endeavor! I straighten the steering shaft by eye, clamp it in place, then set the toe.
. I come from the car racing world where all set up is done on fixtures with the car loaded (on the ground) with driver weight and fuel load weight, so for me it seems weird to not do that with a kart, obviously
