hello dear frinds.can anybody hepl?
we have a tony kart chassis mini rookiee, our track is a low greap and can you advise what setting is better for low track?we have rear 109 cm and front wildth 15 cm.canber 1/1/ CASTER 45.and our kart goes slow:((((
You’re better off asking this on a new thread
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yes you are right 
otherwise i have another t thing to ask?
how can i make tony kart fast? is there any secret about it? 
The largest gains are made by the driver. After that, there are small tweaks to improve handling for different conditions. Best to focus on Driving first.
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Lower steering shaft mount looks like it has provisions for one. I’d check with Birel or maybe look at the aftermarket (Righetti Ridolphi, etc).
Here is a thread on that:
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I want to widen my rear track width but I don’t know how much the axle/hub overlap should be. Or how much of the axle should be in the hub.
As long as you stay under the maximum total legal width (Usually 140cm or 55.25") you should be fine.
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Evan, I assume you are racing the kart so most rules limit rear width to 55" and axles are usually 1040mm or less. Unless your axle has been cut a lot or you have really short hubs you should be okay. Personally I would like to have at least half of the length inserted on the axle.
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My apologies, I should have clarified, the hubs are 80mm and the axle is 1030mm. I’ll try it with 40mm of the axle in the hub, Thanks for the advice!
You need AT LEAST the whole cinch area in the hub. Easiest way to tell is to look in the split of the hub and make sure you can see axle all the way. If you see air, you are bordering on too far out. I’m not saying I haven’t done it, but would never recommend it to someone else.
My grandpa always said “If you’re going to be dumb, you gotta be tough.” I’ve gotten really tough over the years…
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I would go with 40 or 50 mm of axle / hub overlap as a minimum to feel comfortable. You can probably go with less, and I am sure others do, but me no likey.
When I ran a cut axle (1000mm), with 95mm hubs, and wheels with a 58mm backspacing (std), I had 40mm of overlap and got to 1395 rear width. If I recall correctly.
80mm hubs and a 1030 axle with 40mm of overlap you should be able to get to 1400…
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Taking advantage of this thread, I want to share a question that I am struggling to answer myself.
Reading some thoughts, especially from KP, Tkart.it and flowracers.com I concluded that, when we widen the front track, a lot of reactions happen, but let’s focus just on the ones that impact weight transfer, as follows:
a) Rate of lift: wider front track lifts inside rear tire higher increasing weight transfer from the inner rear tire to outer rear tire increasing OVERSTEER
b) Flexibility: The further we put the front tires away from each other, the more flexible the front of the kart becomes. Consequently, the load transfer capacity from the inner tire to the outer tire is reduced. That is, with the load better distributed between both front tires, the grip in the front increases resulting in OVERSTEER
c) Center of gravity: The further the tire is from the kingpin (wider front track), the greater the lever and consequently the greater the slope at the front of the kart causing the load to be transferred from the inner front tire to the outer front tire, resulting in UNDERSTEER
We know that if we want the kart to turn, we need to lift the inside rear tire, so item (a) in the list above is the most important of all. Does anybody disagree? I believe no.
But, if we exclude item (a) from the discussion, which one do you believe would impact most in the front grip, item (b) or item (c) of the list above?
In my opinion, item (c) has greater influence, but there is a moment where the front track is so wide that the front is so flexible that item (b) starts to overlap item (c). Makes sense?
I don’t think front center of gravity is that important. The center of gravity in the front of the kart is already incredibly low. Plus, center of gravity in this context is only important because of how it affects inside rear lift. Center of gravity has very little bearing on the front end of the kart and how it works.
It would have to be a very wide front end as well to affect flexibility in a noticeable way. In the rain you run the front end at max width, and there isn’t a real big affect on how it flexes. Surely there is some increased flex but it is outweighed by the benefits of increased weight jacking.
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The thing is that front track width impacts a bunch of things including effective rake, scrub radius, camber change, lateral load transfer and diagonal load transfer.
On the rear it’s primarily a change in lateral load transfer and arguably a change in flex/damping.
As for A, B or C, I think I’d encourage people to not constrain their thinking to any single one as it will vary depending on many variables.
I will go out on a limb and say that if you go lock to lock with a kart set min front track, then do same at max, you’ll find that the change in rake (which gives the diagonal load transfer) is pretty significant.
Whereas if you run a calculation for center of gravity height change due to the same change it will be pretty small.
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Thanks @tjkoyen and @KartingIsLife for the comments.
Maybe I did not make myself clear about the thought regarding the center of gravity. What I was trying to say is that the further the inner tire is from the kingpin, the greater the lever and the greater the load transfer from one side to the other, and consequently the grip at the front is negatively affected.
So, in my point of view, when we widen the front track, we improve the oversteer due to the rate of lift (item a), but it does not necessarily mean we increased the front grip.
In other words, what I was thinking is that, by widening the front track, we are reducing very little grip in the front due to the lateral weight transfer, but at the same time we are reducing a lot of the rear grip due to the rate of lift, so there is a perception of grip improvement in the front, but actually, it is just a perception since instead of adding grip in the front we are just changing in the weight balance between front and rear.
What is the problem that you are trying to solve? Is is a slow 180 corner or a fast corner?
I believe that if the front track is increased the amount of lateral load transfer to the outside front tire is reduced but the IR lift is increased, at least during initial turn-in.
It might be better not to use the term “oversteer” without context as it creates a misconception that it’s a always good thing. I think there are situations where the sliding balance is important where the term oversteer and understeer make sense and other turns (slower) in which one needs to think about getting the kart to roll.
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Actually, I am not trying to solve a specific problem. As I am an engineer and I learn better when I understand something instead of just memorizing, I am just trying to understand the physics and dynamics around each setup so that I can improve the conversation with my mechanic and help to find good setups for my driving style.
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Ok that I understand. I spent much of my earlier life as an engineer, so I have the same problem as you do and want to understand the fundamentals, not just the solution to a situation.
For Ademir’s Front End Questions: Just some food for thought. Last weekend’s race I focused on the where the kart was not behaving as I think it should. I picked a slow hairpin turn which leads to fast corners and a short straight. The kart was not rolling as it should and the kart felt grabby and consequently was boggy out of the hairpin. The next time through, I tried to sense what was going on. What I realized was that the IR was lifting, the kart was turning in nicely but IR set down way to early in the turn, just as I started to turn the steering wheel back to neutral. So the question was should I widen or narrow the front. I narrowed the front because there was plenty of turn-in and narrowing the front would reduced the rate at which the IR would set down. It worked and it went faster. 5mm spacer in front of an OTK.
Does this logic seem right?
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