Home Forums Chassis & Handling OTK Torsion Bars

This topic contains 11 replies, has 5 voices, and was last updated by  Chris Hatch 2 years, 4 months ago.

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  • #49775

    Brock Weiss
    Participant

    I have a 2014 Tony Kart and was wondering if anyone could shed some light on The front torsion bars

    i have the flat torsion bar that comes standard and I also have all three of the round torsion bars.

    Is the flat better than the round and what position do the following do to the kart when it is in the flat, 45 degrees and vertical positions?

    regarding the round torsion bars same question. What does the soft, middle, and stiff round bars do to the kart and when would you use one over the other? For instance when the track grips up do you use a softer bar and when the track lacks grip do you use the stiffer bar and how does the front end width play into it regarding how many spacers you run

    Are the round bars better than the Flat oval bar and is there a certain bar that you use most of the time over the others?

    Also last question do you change the front width when using the different stiffness in bars? For instance do you usually run narrow if you use a softer bar and if you use a stiffer bar would you usually run the front wider?

    im just looking for a good setting that people have found they use most of the time and if I should use the round bars or the flat oval bar since I have all of them.

    I was going to ask about caster and how that plays into it but I figured I have already asked way to much

    Right now I have been running the middle round bar with 1 spacer in front most of the time with about 75% caster but last week I changed to the flat bar and went with just 1 spacer in front and dropped to 50% caster and the kart was faster but I would like to understand why this a happened a little better

    I realize I’m asking a lot of questions so I apologize in advance. There is just so much different combinations to use with caster, stiffness, and width and how they all work together unless I’m making it harder than it needs to be which I tend to do

    #49802

    Matt Dixon
    Participant

    I will answer 1 of the many questions.
    The flat bar is sort of a Multi-bar.
    Flat is softest, 45* is stiffer, vertical is stiffest.
    I always start with it in 45* if I need less grip I turn flat, more grip turn vertical, if I need even more I go to adding caster and even more the go to the stiffer round bars.

    There is no better or worse, its about keeping the kart balanced and fast with the changing track conditions.

    94y

    #49845

    TJ Koyen
    Moderator

    As usual Brock, you’re making it harder than it needs to be 😉

    I run the flat bar all the time. I start with it flat, turn it to 45 if I need more front grip, turn if vertical if I need even more front grip. This weekend I ran it horizontal in the dry, vertical in the rain.

    Anytime you go stiffer in the front, you are adding grip.

    Always set the kart up neutral and tune to the track conditions, as Matt said. The OTK kart works with a neutral setup like 95% of the time.

    From a green track on Friday morning, to a hot rubbered in track this afternoon, I changed from 6˚ of caster to 3˚ of caster and I narrowed the rear 4mm. That’s all we changed all weekend.

    Driver/Coach/Wrench : Innovative Performance/Exprit
    Owner : Oktane Visual - www.oktanevisual.com
    www.facebook.com/oktanevisual
    www.instagram.com/oktanevisual

    #49878

    David Galownia
    Participant

    Brock,

    Below are the bars soft to stiff (someone correct me if I’m wrong in the order here), but the stiffer you go the more front grip.  On greener tracks you’ll be stiffer on “rubbered up” tracks you’ll be softer.    We don’t mess with any bars other than the gold and flat bar.

    flat bar placed flat
    round bar 1
    round bar 2
    flat bar 45 degrees
    round bar 3 (the gold bar)
    flat bar straight up.

    Also, wider front width, more castor, more positive camber equal more front grip.  Less front width, less castor, more negative camber (or less positive than you had) equal less front grip.

    On your changes you made last week, everything you did removed front grip and your kart went faster.   You essentially were “freeing up” the kart.

    I run a Tonykart 2014 in TAG, I’ve been running KRA @ NewCastle.  Track has been green all year.  One race I ran the flat bar 45 degrees, the rest of the races I’ve run the gold bar.  I’m typically at -1 click, neutral, or +1 click camber.

    I’ve been confused as well at how they all work together but if I just need a little more little less front grip I change one click on the camber.  If I feel I’m further off I’ll change the bar.   If you’re all the way soft on the bar I’d change the castor next.  If you still have too much grip your seat may need to be remounted.

    – Dave

     

     

     

     

     

    #49905

    Brock Weiss
    Participant

    Thanks for all the help guys I really appreciate it and TJ you are right as usual I always seem to make it harder than it needs to be. I think I just overthink things and always over analyze everything.  I probably get that from my job.  Maybe I should just stick with fixing people and making them feel better instead of karts.  Lol But seriously I really appreciate all the advice and I will try and keep it simple for the rest of the season.

    Or at least until next week when I come up with another overcomplicated question that will have Ten questions for one answer

    #49980

    Chris Hatch
    Participant

    I believe we often simplify our understanding of “adding grip”.   The where and how it adds grip is often more important.

    FOr example, adding castor really doesn’t add front grip.  It increases the weight jacked on the inside front tire as well as increases the speed at which that weight transitions.  This will help the initial turn in (which people often think of as grip but isn’t).  However, be aware that it also increases the weight that arrives at the right rear.   Turns in good but may bind and even hop.  Get it right it turns in well and then returns the weight it the right time to get good forward bit off the corner.

     

    COnversly, stiffing the front bar doesn’t actually add front grip.  It stiffens the front and resists weight transfer.  In doing so, you help prevent some weight from moving to the outside front tire that can cause overload it causing it to slip.  This helps the front primarily at apex and exit but will do nothing for turn in.   I like to think if the front bar as a broom handle, which one adds more grip to the broom head?

    #49985

    Brock Weiss
    Participant

    Thanks Chris explanation was very helpful.

    Last question I have.  so if I have more grip in the front does that take away grip from the rear?

    If I have less grip in the front does that add grip to the rear?

    someone at my track said that is kinda how it works and I am just wanting to clarify that if you want to free up the rear then you could do that by running a stiff front end.

    Or am I wrong on this?

    just trying to see how the front effects the rear

    #49989

    TJ Koyen
    Moderator

    Chris is correct.

    The tires always have the same amount of grip. You are never adding or taking away grip from the tires unless you are changing the compound or softness of tires. The only adjustment that affects that is tire pressure.

    You are only affecting how the chassis flexes and uses the grip available. This is why I don’t like talking about adding or removing grip; I prefer to talk in terms of adding or taking away inside rear wheel lift. Because it isn’t always cut and dry. Sometimes a handling adjustment might have the opposite effect you were expecting.

    If you are “taking away grip from the front” you aren’t always “adding grip to the rear”. You are just changing the relative balance.

    For example, adding caster increases your perceived front grip on turn-in. This isn’t because you are adding grip to the front tires, you’re just increasing the weight jacking to the rear, allowing the kart to react quicker. This can either dig the outside rear tire in harder, resulting in a better “dig” in the corner and more side bite. OR, it can result in you overloading the outside tire too quickly, making the kart lose traction and slide. These are two opposite handling issues caused by the same adjustment, because it all depends on track conditions and the rest of your setup. There’s always so many variables at play.

    Driver/Coach/Wrench : Innovative Performance/Exprit
    Owner : Oktane Visual - www.oktanevisual.com
    www.facebook.com/oktanevisual
    www.instagram.com/oktanevisual

    #50027

    Chris Hatch
    Participant

    Adding grip to the rear does not mean taking it away from the front unless you are moving the seat back (or forward).

    Most kart adjustments are not about adding or taking away grip but rather where/what you are doing with the weight that is unloaded from the inside rear.    For example, adding more negative camber as the track grips up means moving less weight to the outside rear and towards the outside front.  The weight may not always get to the outside front because once the driver unwinds the wheel, the weight is being shifted back to the inside rear.  Therefore, I have taken away weight (grip) from the outside rear, moved a little to the outside front, and kept much of it suspended in the frame = free.

     

    #50028

    Chris Hatch
    Participant

    TJ,

    I am curious about your comment about moving the rears in 4mm when the track gripped up.  While this is a very slight adjustment, I am curious as to what the purpose was.  Conventional wisdom of course is to run full width (lower center of gravity, more resistance to weight transfer) when things grip up.

    Not questioning the effectiveness, just what to understand your theory.

    #50049

    TJ Koyen
    Moderator

    Chris,

    We’ve found the MG tires to start to fall off pretty quickly, especially at Shawano, and as the day goes on, we start to lose sidebite and the kart begins to sit flat. We narrowed the rear to try and get more sidebite. The tires were falling off quicker than the track was building rubber.

    Driver/Coach/Wrench : Innovative Performance/Exprit
    Owner : Oktane Visual - www.oktanevisual.com
    www.facebook.com/oktanevisual
    www.instagram.com/oktanevisual

    #50052

    Chris Hatch
    Participant

    Thanks, that’s an interesting observation.

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