Ask TJ, second round

[JIM SILVERHEELS]

From the Arrow Guide

Problem: “There’s no traction/the kart is oversteering coming from the apex out of a corner”
Solution: Reduce the rear track width by 5mm on both sides at a time.

Problem: “The back slides/the kart oversteers going into the turns”
Solution: Increase the rear track width by 5mm on both sides at a time, being careful
not to exceed the maximum regulation width overall of 1400mm.

Problem: “There is understeer all the way through the turn.”
Solution: Increase the rear track width by 5mm on both sides at a time, being careful
not to exceed the maximum regulation width overall of 1400mm.


Why would narrowing the rear track make more grip if the kart is oversteering coming out of the apex? Wouldn't a wider track hold the inside wheel from lifting more?

Ok, if the kart oversteers going into the corner we would widen the rear to hold the inside tire down making it harder to jack. So why going through the apex WITH IT WIDE make it loose?

If there was understeer all the way through the turn why would widening the rear track help? You'd think that narrowing the rear would make it easier to jack with a longer duration of lift.[/i]
_________________
Don't get stuck in someone else's discarded chewing gum with your thought process.

[TJ Koyen]

Narrowing the rear track creates a quicker lift and shorter lift duration. Like stiffening the axle. It can also give you more side bite and get the kart to dig better mid-corner though too.

Oversteering into the corner usually means you have too quick of a lift action causing the kart to get twitchy immediately at turn-in. The wider rear track will slow down the lifting action and get rid of some of the quickness of the lifting action.

I don't necessarily agree with widening the rear track for understeer all the way through the turn. If you're understeering immediately on turn-in, you need MORE jacking so I'd think you'd want to narrow it up slightly.

[Paul Makarucha]

You don't want to jack it too much or for too long a duration though. You'll go blind.
_________________
CKR/KZ
CRG/ICA
http://WWW.ACTIONKARTRACING.COM/
http://neshifterkartseries.com/
http://Jaymotorsports.com
Do you have any special rituals when the helmet is concerned like many have? - "I wipe it so that I can see better." - Kimi

[JIM SILVERHEELS]

Paul, the doctor gave me the same advice so I only did till I needed glasses.
_________________
Don't get stuck in someone else's discarded chewing gum with your thought process.

[Keith Mattoon]

So I am new to karting & have been reading what you guys have been saying about lift & lift duration.
How much does chassis flex play a roll in the lift?

[TJ Koyen]

[Keith Mattoon]

I am 225lbs & I am running a Leopard engine.
One of things I have been trying to figure out is a good starting point. As far as chassis size, should I be running the stabilizers, caster, camber, etc.

[Randy Mckee]

Keith, you should start a new thread with the appropriate title so people with similar build can provide a baseline setup.
_________________
Randy
#123 TonyKart - S4 Stock Honda

[Tony (Toe-Knee!) Morrison]

First things, first; Seat location makes the single biggest difference; SCALE the chassis, with you in it, before you do anything else, so that you have a starting point. Ask you local kart shop (LKS), or a disinterested, friendly, experienced fast guy, about corner weights/front rear percentages... The seat has to be correct before you can make real progress.
Then it is time to test, document it, make a change, test, document it, make a change, test, document it... Until you get it figured out.
Do you have a soft, medium, or hard axle? (Note 1; Try them ALL, before you decide) Borrow from a buddy, or share resources... Some LKS have loaner axles, or they will rent/trade depending on you relationship with them.
Short Medium, or long hubs. (note 1 See above)
Chassis up, middle or down, in the front? (see note 1 above)
Chassis up, middle or down, in the back? (see note 1 above)
Start with the rear at 54.75, and don't worry about FINE tuning, with the track width, until you get the big things (seat, axle, chassis height) sorted out.
When you get to a good BASELINE setting (repeatable lap times, within .25 sec's), you can try to adjust, to changing track conditions, when there are MANY karts running.. That is the realm, of the experts.
All it takes is time, money, diligence, and intelligence. If it was easy, everyone could/would do it!
_________________
-Toe-Knee!

[Gary Lawson]

Instead of only thinking of lift/duration think about the vertical center of gravity in relation to rear track. Most karts have a tuning window where if you go too wide/narrow you will have opposite or negative effects. Ie. wider in rear will reduce exit grip but if you get too wide it will push from lack of lift on entry and through most of the corner

[TJ Koyen]

[orlando figueredo]

TJ, in your experience what is your method for kart tuning ? Do you start with tire pressure, track width, etc.. I have read a few of the tuning guides and they all give you a list of what to change for specific situations, but not a specific order. Just wondering what progression you use. Thanks, Orlando

[TJ Koyen]

I start on the baseline and go from there. I can't really give you a specific guide to what I tune first or second because it's completely dependent on the conditions and what I feel the kart needs.

Simple track width adjustments is usually my first go-to though, because it's quick and easy.

My most common adjustments are front track width, caster/camber, and tire pressures. With those 3 things, I can usually tune out 80% of any handling issue I might have, I can drive 10% better, and the remaining 10% of big handling issues I might have to go with different axles or torsion bars.
_________________
T.J. Koyen
OKTANE VISUAL - Custom Helmet Paint & Graphic Design
www.oktanevisual.com
www.facebook.com/oktanevisual
--------------------------
DB Motorsports
Exprit/Leopard