Quote:
Originally Posted by FTS
I think you did catch my big mistake in my sentence; I meant "I have NO experience" in setting up karts
|
No big deal. Everyone has to learn from somewhere. There are lots of people far more experienced than me. I've only been racing karts for about 7 years.
Quote:
Your explanation on kart setup is precisely what is so difficult in driving karts competitively IMHO. Thankfully, it is a smaller vehicle and getting on a table/jacks is easier to make setup changes, but you really need to understand the geometric options, which are finite of course. At the same time, not having the help of shock/spring settings makes the whole thing even more difficult.
Do you use A/R bars on karts?
|
Kart setup is not easy.
First and foremost is seat position. That determines pretty much everything (because the biggest lump on the kart is the driver).
Front end setup can be separated into different ways- ride height, stiffness, and alignment. Ride height determines front end jacking, stiffness can be adjusted with a removable bar between the front yokes, and alignment determines camber, castor and toe. There is also track width, hub stiffness, wheel width and steering Ackerman to consider.
Rear end setup is determined by ride height (axle height on most karts are adjustable), axle stiffness, where and which bearings are "locked in", hub stiffness, wheel size and stiffness, and track width. There is also a removable bar in the back that determines chassis twist.
Then there's the kart chassis midsection which determines transient response from front to rear- most chassis' have a removable fourth rail that goes from the midsection to the back, and the front tray can be tightened/loosened according to what the needs are. Not to mention seat stays (adding, removing, loosening, tightening)...
Those are the basics... if you can get a handle on those you're doing better than me!
There are no antiroll bars on karts. Antiroll bars are transient torsion springs that connect the left and right suspension- they are a tuning aid and ideally should be as soft as possible if not disconnected (I know that is a controversial statement), corner spring rate and suspension geometry should determine roll. On my GT2 I have to use them as a bandaid for a conservative setup- the car pushes everywhere. With a more aggressive setup coming (springs, shocks, alignment) I hope to be able to back off the bar settings to get more bump compliance (curb crashing).
For karts you should think of the entire chassis as a giant spring, and compliance for what you want it to do is managed on a micro and macro level. If you get a good handle on how to tune a kart chassis, tuning a car is not much more difficult. Ultimately you need to think about how to work on the end that needs improvement and not take away from the one that works.
Quote:
And driving... OMG, I cannot imagine working within a window of 20 mph; each 1 mph, or even 0.5 mph, must count. So, if you brake 5 ft too early or too late, you can either loose a spot or race, or worse, find yourself moving the lawn. Amazing.
|
Oh yeah! That's what makes it fun (or in my case that weekend, a lesson in futility). Losing 30 ft every tight corner means just keeping up is a W in my book. I'm planning on going to Grattan in a few weeks, let's hope it's better. Check out Grattan if you want to see a crazy track!
edit-
Actually, I was thinking about the "20mph window"... it's actually less than that. Top speed is a given- if you can't keep up you're out to lunch. So the relative operating window is actually your cornering speed- entry, apex and exit speeds. That is probably a much smaller window- 2 to 3 mph at most if you're competitive. It's the same in most motorsports- relative speed differences usually determine the outcome.