I am a knowledge freak and I would like to know in what order you change front end and rear end
For example…
The kart needs front end, What to change first and why?
The kart needs rear end, What to change first and why?
What does it mean when people say they make minor tweaks to their chassis?
Like is an axle considered a minor tweak? What is OTK Neutral on caster camber pills? Is it full caster or neutral caster, or half caster?
Thank you for your time.
Ideally I think you might want to break it down a bit more granular.
For example…
More front end (Grip)… But at what turns and at what stages of the turn(s) will influence the change(s) you try.
I’d consider an axle a majorish change. Ideally you will have tried a couple of hubs first if you have some available.
What to change first really depends on how the kart is behaving, where that behavior is happening and how everything is setup already.
Maybe we could to a list of possible changes from mild to wild in terms of impact?
While it might seem odd given the question is about OTK… I’ll ask anyway… Have you read CRG’s handling manual? It’s worth a read. It’s listed here along with some others:
The most important thing I’ve found with karting is that there are really very few rules other than the willingness to experiment, often in ways that defy logic and “just work”.
Yes I have, Do those changes work for an OTK? I know the axle theory is that a hard axle frees up the kart and a soft axle tightens the kart up. Is overall or for just high grip or low grip tracks? And by the “willingness to Experiment”, what do I experiment with? For example low grip situations? The kart is not turning in to corners, and sliding out?
We’ve discussed this a few times before I think, but @KartingIsLife is right, it isn’t so cut and dried. What to change completely depends on how the kart is reacting at every stage in the corner. If the kart is truly understeering, you start by widening the front to increase the amount of geometry in the front end and give you better weight jacking.
Axle would be one of the biggest changes you can make. Small changes are track widths or small caster/camber adjustments.
Neutral is neutral on caster/camber.
I think you need a team Noah 
Any suggestions???
I’m pretty sure you know what my suggestion would be!
Other than Innovative, there are plenty of good teams to choose from. You should make sure that you’re able to get support at the events you’ll be attending, so whatever series you run next year, it would be good to have the team there.
What is Scott charging? You gonna be at Route 66?
You would have to ask Scott. And yes, I will be under the tent again this year to providing tuning and coaching help.
So, I’m trying to wrap my head around all of this, because once I think I finally have it “right” in my head, I hear someone explain it exactly the opposite in regards to “too much/little grip” or “hard/soft” or “free/tight.”
Here is my most recent experience/knowledge (I don’t remember much from when I was a teen. I think about things a lot more logically/theologically):
When I was racing 206 a couple of years ago, I had a new 32mm Righetti (Extreme) chassis while everyone was running 30mm or smaller chassis. I was told that my chassis and set up was too stiff, thus too much grip, so it was binding things up and bogging down the motor. That’s how I interpreted it: stiff meant grip as the lift rate is faster. The analogy I was given was a knife blade. Having a stiffer set up meant that knife edge was more perpendicular to the asphalt to dig in, whereas a soft set up would make that knife be more parallel to the pavement and thus cut the grip. Based on recommendations, I did pretty much everything I could to soften the set up. Lowest ride height possible, as wide at the rear as possible (55"), super short rear hubs, soft seat, soft axle, higher rear tire pressures, and no additional seat struts. As I made these changes, I progressively got quicker and got within a quarter of a second of the leaders. To me, a “soft” set up meant less grip and more free, and resulted in more speed.
And I know @tjkoyen that you’ve said it all depends, so I know that experience can’t exactly relate to my current situation, but based on that, I’m trying to dial in my current chassis, a 1994 Tony Kart with a KT100 on it. Right now, I experience understeer on corner entry, particularly into our tightest couple of corners. I feel like I’m not getting that inside tire to lift like it should, thus the kart is not rotating like I’d want it to. I also feel that I’m not getting the power down as well as I should on corner exit. So, I’ve gone wider at the front and narrower at the rear (was at 53, then down to about 52.5" and it seemed to be faster) with as much caster as I think there is. I’ve put in the rear torsion bar and slid the side bar over the joint. I have two additional seat struts on the left side and one on the right by the motor and dropped the rear pressures a bit. It seems to be getting better. My next steps are to add toe out, drop tire pressures all around to increase side bite, and I just purchased long rear hubs to test (currently running fairly short hubs, so I’ve been working with what I have). Basically, my thought process to get better turn in and lift is to stiffen the chassis. However, when out at the track last, I was talking to a guy that said I should be going the opposite direction, that I need to take away rear grip in order to give the front more grip relatively.
I forget what thread it was on, but I thought I read that someone was saying a “free” kart has more “grip” and so on. So, do you think my thought process is correct and I’m on the right track? Or, do I have it backwards? I guess it depends…
It’s a lot to take in, so you’re right, it’s hard to wrap your head around it all. It can be difficult to decipher because with all the variables at play within the chassis (not to mention the engine and tire combination which can completely flip everything), many things can seem contradictory.
Now, first I would say that trying to tune a 1994 Tony Kart is going to be completely different to tuning a modern kart. Nearly everything has changed since then in terms of chassis philosophy, driving styles, engines and tire compounds etc. Just look at a top-level driver of 1994 compared to a top-level driver of today and look at their posture in the kart and the karts attitude is on-track. Totally different. Modern karts have become heavier, wider, softer, and smoother.
In general, I really try to get people off the idea of “grip” and whether you have too much or not enough. In reality, the more grip you have, the faster you can corner, right? The reason the kart has “too much grip” is because both back tires are on the ground and it’s binding. It’s not a case of “too much grip”, it’s a case of not enough lift. So if you’re trying to free the kart up, you’re trying to adjust the rate at which the inside rear lifts, to get it to lift more/sooner in the corner.
So how do we actually get lift? Well the chassis has to flex. This is a pretty simple concept; softer chassis will flex more, stiffer chassis will flex less. The goal is to get the waist of the kart to twist, so that the inside rear can come off the ground. Take a popsicle stick and try twisting it. Now take a 2x4 and try twisting it. Obviously the popsicle stick twists more easily because it’s softer. It becomes difficult when we start adding components to the kart which can interfere or contradict with the action of the chassis.
Now it’s really important to distinguish between stiffening the frame vs. stiffening the axle. By adding long hubs, you are not stiffening the frame, you are stiffening the axle, and not only are you stiffening the axle, you are only stiffening the very end of the axle. In my very humble opinion with only my personal experience to back it up, long hubs do not add increase the sidebite on the outside tire. I feel like they alter how the tire flexes and reacts/deforms with the track surface, but they don’t let the tire dig into it’s sidewall like a standard hub does. This is just me though. I always run medium hubs, 100% of the time. Rain, dry, sleet, snow… However, pretty much every other tuner I talk to (including my team) disagrees with my assessment, so take it with a large grain of salt.
And this is where we get into the debate of why OTK recommends a hard axle to “free” up the kart. My theory is the way their chassis is constructed, the materials they use, they put the hard axle in to get the frame to flex more. The stiffer axle is going to absorb less of the load, and transfer that force through the frame to twist it more. Some constructors with a stiffer frame might suggest a softer axle, because they are trying to get the axle to flex more. I truly don’t know, this is mostly speculation.
I should also note, that on a green track and hard tires, it’s totally viable to run a super soft setup, and basically slide the kart around the track to keep it free. This is exactly what we did when we ran club races on B’stone YDS tires. Soften everything, get the thing to squat in the corner and just slide ever so slightly to keep the kart from binding. This only works on a really green track though. Once it starts to grip up, you can’t slide anymore, the kart will just be flat and boggy.
If you’re struggling to get front grip and then struggling to get back on the power, I would say address the understeer first, because late corner oversteer generally stems from lack of front grip on entry. Push-kick or snap oversteer is usually what it’s called. It sounds like you’re making the right adjustments, especially if you’re getting faster, so that’s sort of the end-all-be-all of whether it’s working or not. The stop watch is the best judge of what’s working and what’s not.
I sort of rambled but hopefully there’s something useful in there.
I can certainly see that and figured there would be a quite a learning curve. Hard to beat a $500 deal, though, for something that’s still in good shape, so I’ll take the trade off.
This is where my thinking has been backwards! I guess I’ve always thought that a stiffer chassis would lift the inside tire better. In my thinking, a soft chassis would flex down to keep the inside rear on the ground, but your logic makes sense now that I think of it, that the inside would flex up.
That makes total sense to me, so thank you for explaining that! I certainly would believe this to be the case, because with that 32mm Righetti chassis, that is exactly what I needed to do. I honestly have no idea what axle I have in the kart right now, but I may look for a hard axle to try next. I currently have 75 and 82mm(I think?) rear hubs, so I figured I’d get some 115mm just to try, but that’s why I bought used so it’s not a huge investment if it doesn’t work out. Though the longer hubs will help me get to a wider rear if that’s where I end up needing to go. The short hubs don’t have a whole lot of room to go out on the axle without losing their bite to the axle.
I kind of miss those YDS days. Good times! But yes, even though we’re in California, the track has been pretty green and I’ve been practicing on what were brand new YKCs just as I learn the chassis. Tomorrow, it’s supposed to be sunny and in the 70s and there were a good amount of karts out at the track last weekend. I put on some slightly used YLCs to try, and I have a set of 6 inch rears to try out as well (currently 7 inch rears).
Thanks for the reply TJ! I’m trying to approach this season in a totally different manner than in the past by learning more and doing more testing than I ever remember doing when I was younger.
@dagee2 interesting discussion above! I think @tjkoyen is 100% right–usually driving and handling problems begin in the first 1/3 of the corner. If you as a driver carry too much speed into a corner, the kart will be unhappy. If the kart does not turn in well, the rest of the corner is compromised. Widening the front end to increase the ‘jacking’ effect is a common fix to this. So is stiffening the front by addition of a front bar, or increasing geometry jack by adding caster. It sounds like you’ve tried these things, with some success.
By adding a rear bar to the kart, you are hindering the ability of the rear area of the kart to flex, which causes it to remain flatter. As TJ said, it is more a flexing issue than an overall grip issue, as the tires will have so much grip, the track likewise.
By adding a rear bar and the seat struts, the kart may have more grip coming out of the corners. However, if the kart isn’t happy on the entry to the corner, having grip coming out won’t matter, because you won’t be able to really capitalize on it.
The common sentiment among many LO206 racers is that ‘softer is better’ in most applications. As TJ mentions, this is really a very global statement. If you are running a 32mm frame compared to 30mm frames that most are running, you likely already have a significantly stiffer chassis in some areas. This all depends on the manufacturer, material used, ‘ideal’ class the kart was designed for, etc.
Just so everyone knows. My seat was 20mm forward of where it was supposed to be. Maybe causing handling issues.
lesson: put seat in right spot.
Try it and see. One thing to keep in mind… The measurement from the manufacturer is a recommendation for a starting point. With different tracks, tires, motor packages and human body compositions it can vary. If you haven’t already, it’s worth asking someone who’s running as close to your situation as possible: Tires, motor package, body composition etc.
Now having said all that, it may actually be that the standard position is working well for them. My main point is that It’s worth checking.