Home Forums Chassis & Handling Axles?

This topic contains 16 replies, has 5 voices, and was last updated by  TJ Koyen 3 years, 10 months ago.

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  • #25309

    Joe Morales
    Participant

    Will A softer rear axle help loosen up the kart in high grip track?

  • #25358

    TJ Koyen
    Moderator

    Sometimes.

    Sometimes it will make it worse. It depends on what the actual issue is with the handling.

    On OTK karts we usually would go harder on a high grip track. Soft axles can get really soft and squishy in the corners if the grip level goes up.

    Is the kart just flat and boggy through the whole corner or is it specific to the entry, apex, or exit of the corner?

    Driver/Coach/Wrench : Innovative Performance/Exprit
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  • #25368

    TJ Koyen
    Moderator

    If it’s pushing on entry then generally you’d want to add caster to fix that, but if it’s hopping mid-corner, you would want to reduce caster so that’s a little puzzling.

    When you say “extra seat braces”, how many additional seat stays are you running besides the factory chassis ones?

    Driver/Coach/Wrench : Innovative Performance/Exprit
    Owner : Oktane Visual - www.oktanevisual.com
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  • #25377

    Joe Morales
    Participant

    4 Seat braces. Im thinking of going with a soft axle.

  • #25424

    TJ Koyen
    Moderator

    Try it and see, no harm in testing a few things. What works for one person might be different for another.

    Driver/Coach/Wrench : Innovative Performance/Exprit
    Owner : Oktane Visual - www.oktanevisual.com
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  • #39243

    Jay Sinon
    Participant

    We have a hopping problem going into turns on a high grip track. We are running a  Yamaha on a OTK Kosmic Mercury I have the wheels set to 54 3/4″ and we are using the gold stabilizer bar in the front and none in the rear. I tried raising the axle in the frame that seemed to help but was destroying the bottom of the frame over the rumble strips( I know stay of the strips)  So I put the axle back to the middle setting. What would you try next? I’m not sure from these posts if I should try a harder or softer axle to fix this.

    Thanks

    TaG Sr.

  • #39247

    Jay Sinon
    Participant

    Does a hard axle = more grip on a track without grip or a track with a lot of grip?

    When do I use a soft axle? or is the question not that straight forward to answer?

    TaG Sr.

  • #39250

    TJ Koyen
    Moderator

    If it’s hopping on entry, you have too much initial flex and lift. You’re probably too soft.

    The answer isn’t straight forward because it completely depends on what the kart is doing. What axle is in there?

    Driver/Coach/Wrench : Innovative Performance/Exprit
    Owner : Oktane Visual - www.oktanevisual.com
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  • #39252

    Jay Sinon
    Participant

    It has the type N stock axle now

    TaG Sr.

  • #39253

    Jay Sinon
    Participant

    My 14 year old daughter drives the kart so I don’t get much input from her yet but were working on that. She used to have steering issues and they seemed to go away when we put in the gold/stiff stabilizer bar but that created the hop in the back. Most everything I am trying to adjust is coming from what I see her do on the track or though the GoPro camera.

    TaG Sr.

  • #39257

    TJ Koyen
    Moderator

    If a kart is setup properly, it should be allllllmost on the brink of hopping, because that means you’re getting maximum usable grip.

    I would suggest tightening up the 3rd bearing and seeing if that fixes it. It’s a small change but it’s best to try something small in that direction before going gung-ho and changing an axle. The axle might be too much. From personal experience, it’s very easy to make too big of a change, gain nothing in lap time, and end up on the opposite side of the issues you were trying to fix.

    It sounds like you needed more front grip, so you added the gold bar, which then made the rear flex too much on entry, resulting in a hop. Widening the rear by 5-10mm would probably help too, but 54 3/4″ is pretty baseline so I would just leave it for now. Maybe if the 3rd bearing helps but doesn’t quite fix it fully, you could widen the rear out just a bit.

    Driver/Coach/Wrench : Innovative Performance/Exprit
    Owner : Oktane Visual - www.oktanevisual.com
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  • #39258

    Jay Sinon
    Participant

    TJ,

    That’s interesting. Not only due I not have the third bearing in the axle tight I do not even have it on the kart. Someone told me a while back to take the bolts out of that bearing so I did (no one else seems to run them bolted in) and they said it would free the kart up. Then it bothered me just rattling around and I was already heavy so I took it off completely. I imagine that this has the effect of stiffening the axle?

     

    TaG Sr.

    • #39261

      TJ Koyen
      Moderator

      Having it out will soften the rear up, giving you more lift and flex, which in many cases does free the kart up. Putting it in stiffens the rear slightly, correct. You can also run it with just 2 bolts in as well, to give a very very small change in stiffness from the 4 bolts.

      In lower horsepower classes, it isn’t uncommon for people to take it out completely and never use it. Personally, I always keep it in because it doesn’t hurt to have an extra tuning tool. Plus, I need the weight.

      Driver/Coach/Wrench : Innovative Performance/Exprit
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  • #39263

    Kirt Burcroff
    Participant

    Of course – Why didn’t I think of that? I’m adding weight to get my son up to senior weight this weekend and I’ve been running without the third bearing. It’s going back in Saturday. Thanks for the inadvertent tip T.J. :)

  • #39386

    Barry Hastings
    Participant

    One thing to also think about is the karts dont like to always off the throttle all the way thru the turns.  An OFF throttle will tend to have the kart kind of flop until the throttle is picked back up.  Not 100% but just a crack can really settle that kind of hop down.

  • #39387

    TJ Koyen
    Moderator

    Good note Barry. The kart frame is a spring. If it isn’t fully loaded, it will start rebounding.

    A kart might be set up technically perfect for the track conditions, but if you aren’t loading it just the right amount by driving on the limit, it could react poorly to inputs.

    Driver/Coach/Wrench : Innovative Performance/Exprit
    Owner : Oktane Visual - www.oktanevisual.com
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  • #25360

    Joe Morales
    Participant

    Here is the problem,entry the art has a push that i kant get red of. Its not really bad i just want the kart to rotate easier getting to the center so i can drive off smother. The kart bogs getting to the center. The kart has a small hop when i put the extra seat braces on. It fells like it has allot of rear grip. I have the caster set to full and the rear of the kart low.  I have moved my seat all around the kart and still with the problem that the kart has to much rear grip.

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