This may be my most controversial article. Why? Because if you go to any kart shop, go online, or talk to people at the track, they will have conflicting views on how to tune with axles. Some will tell you that if you want to reduce rear grip, you have to soften the axle. Others will tell you, quite categorically, that the only way to reduce rear grip is to stiffen the axle. So who is right? Funnily enough, depending on which chassis you run, they could both be right.
I will give you a perfect example of how this is possible. In the Tony Kart chassis lineup, they have two chassis that share the exact same frame geometry but have different tube thicknesses. The Racer EVR uses 30mm tube thickness while the Krypton KRX uses 32mm tubing. I have attached their homologation photos below. (For those skeptics in the audience, print them up on thin paper, hold them over each other, and yes, it’ the exact same geometry.) Anyway, if you want to reduce rear grip with the 32mm Krypton chassis, you need to soften the axle. If you want to reduce the grip with the 30mm Racer chassis, you need to stiffen the axle.
Great, you say, that doesn’t help me at all. You’re right, it doesn’t, and this is where the websites, shop owners, and fellow drivers end the conversation. It’s their way or the highway. So how do you tell which direction to go on the axle, I’ll tell you and the answer is simpler than you would ever imagine…
TonyKart Racer EVR (30mm Chassis) Homologation Drawing. Same geometry as the chassis below but uses exactly opposite axle change to achieve the same goal!
TonyKart Krypton KRX (32mm Chassis) Homologation Drawing. Same geometry as the chassis above but uses exactly opposite axle change to achieve the same goal!
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As I mentioned in last month’s FKI, a reader requested I do an article on what a good handling kart feels like. When I read the request I immediately thought, what a great concept! Everyone talks about the changes you can make to make your kart handle better but WHAT are we trying to achieve. As far as I know, no one has ever tried to define it. While the topic is of course a little subjective, there are some things you are looking for. So, I will do my best to put into words what you are trying to feel on the track. Hopefully, by the end of the article, you will have a better idea or at least a wider perspective of what you are looking for from your kart…
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