Home Forums Chassis & Handling Low HP and very hard tire tips?

This topic contains 12 replies, has 4 voices, and was last updated by  Richard Gordon 1 year, 1 month ago.

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  • #55363

    Richard Gordon
    Participant

    for fast sprint track with 3 tight turns, are there any settings that would be different from the norm for a LO206 with a Duro concession tire?  We had the kart working well with fast lap times using a 1″ narrower rear tire (Burris B44A).  We lost 3 seconds when we switched to the Duros with the same setup.   We have to use the Duros for our class.  Great for keeping cost down as a $100 set will last for multi seasons.  Not so great for handling and figuring out a good setup.  I have tried a lot of settings and have got the kart a little better, but still way off pace.  The top karts are running about the same times as we did on the Burris tires.  At a loss as to what to do.  Want to get in the ball park before going back to the track to test.  Don’t get there very often as it is a 2 hour drive one way.  Our season is over, so hope to get one or 2 tests in before winter sets in.

    #55367

    Richard Gordon
    Participant

    Would the setup be similar to an SL spec tire?  Would rear track be narrow, front wide, chassis stiffer in front, rear, CGH raised, more weight forward or back?  How about front end geo?  More, less Ackerman, more or less toe, more or less caster, camber?

    #55379

    TJ Koyen
    Participant

    Being 2-3 seconds off the pace isn’t likely the kart setup. It’s probably a driving issue.

    What is the kart doing?

    Team Driver - Innovative Performance/Tony Kart // Owner - Oktane Visual Custom Helmet Paint and Graphic Design

    #55380

    Richard Gordon
    Participant

    Mostly feels like the front end is over responsive then the rear breaks loose.  Going down hill into off camber turns it is very tight and won’t turn.  One of those is a high speed turn.  The other tight and slow.  I drove it and my son. We had the same times within .3 seconds.  He was much faster when we ran the other tires on it with similar weather and track conditions.  Over 3 seconds a lap with same driver and set up.  Only difference was tires and added 19lbs of lead to make class weight.  5 lbs in front of tank on floor, 7 on lower left front of seat, and 7 on back of seat up high a little off center to the left.  I didn’t get to scale with the weights since we didn’t know about the weight limit until we got to the track.

    #55388

    TJ Koyen
    Participant

    It sounds like you’re simply lacking grip. But if the tire really is that much harder than the previous tire, the other guys shouldn’t be going the same speed as they were before either. Can we confirm it’s not a bad set of tires or something? I have no experience with Duro tires but do you know if you are you running the correct pressures? Also, that 19 pounds is really going to hurt in a low power class on hard tires so don’t underestimate that time that’s going to cost you. That’s a lot of weight to add.

    With hard tires sometimes it is more a matter of getting the kart to slide in a controlled manner rather than trying to generate lift because you simply won’t have the tire available to get the kart to jack mechanically and hold the wheel up. You’ll also need to be much smoother on the wheel/brakes if you’re experiencing the rear kicking out on entry.

    If the top guys didn’t slow down much on the new tire, then it clearly isn’t that much harder than the old tire. I would check for obvious things like flat tires or broken chassis or something first if you lost 3 seconds overnight.

    Team Driver - Innovative Performance/Tony Kart // Owner - Oktane Visual Custom Helmet Paint and Graphic Design

    #55389

    Richard Gordon
    Participant

    The guys and gals that have been running for a while are 1.5 seconds faster with the same tire.  Some are even heavier than us and they are all bunched up running about the same speed.  Talked to one of the drivers and they said they had the same problem when they switched to the Duro tire from MG whites. Said it took a lot of testing and practice to learn to drive with the tire and set up the kart.  Kart is brand new with 2 races on it now, so don’t think there is anything wrong with the kart other than set up.  One other big difference is the fronts are a total of 2″ narrower and the rears are 2″ wider (both tires combined) than the Burris.  Thinking to use a green track, low grip set up?  Have tried different pressures.  Anywhere from 12-26 psi.  Made a little difference in time (few tenths) and made it easier to drive, but no big gains.

    #55407

    TJ Koyen
    Participant

    I for sure agree you need to tune grip into the kart. I’m just saying it’s likely a combination of that plus learning to drive the harder tire.

    Team Driver - Innovative Performance/Tony Kart // Owner - Oktane Visual Custom Helmet Paint and Graphic Design

    #55415

    Patrick Roth
    Participant

    Do you have a reference as to what tire pressures others are running?  I see where you have tested a pretty wide range but in my opinion you should get a ballpark of where others are running and then start tuning from there (try to take this out of the equation so you can focus on other things).

    I recently attended a race (new track to me on tires harder than I’m used to) where I would’ve chased my tail if it weren’t for a friendly competitor letting me know the tire pressures he was running.  Once I set the tire pressures it became tuning myself and then a little on the kart (balance felt good still, just needed slight tweaks in front and rear width).

    #55422

    Richard Gordon
    Participant

    Yep, not sure of what to do differently driving wise, but need to try something different.  Also think something is missing from the set up.  Will try a low grip set up to the extreme and back off from there to see what happens.  Did get good info from a trusted source on psi and it is at the low and high of the range we used.  Some like the high and some the low.  Would guess that a lot would be dependent on the kart setup?  I’m going to try testing without the extra weight since I have good numbers on the scale that way and know it did work work well before.  Then scale with the extra lead bolted on to see where it’s at.  Have the kart stored at the track right now and can’t weigh it until we bring it home.

    #55430

    Barry Hastings
    Participant

    Do you know where you are slower compared to the competition?  The 206 is not happy with junk in the carb, and the clutches can be a pain as well.  Have you done the maintenance to the engine?  Just asking to make sure it is truly a chassis thing.

     

    I have seen the clutches work work work then turn to crap as well.  bog way way down.

     

    Just a couple other things to think of…

     

    #55431

    Richard Gordon
    Participant

    It might need the clutch cleaned as it has run a couple of races since it was apart, but when we put the Duros on it was a lot harder to drive.  My son spun out a bunch of times when he has rarely spun before.  Made some psi adjustments and got it better, but it just seems to lack grip.  Going to try wider front track and. Narrower rear.  Might also put the front torsion bar in.

    #55457

    Richard Gordon
    Participant

    Not sure on where they are better?  Engine seems to run fine and is hitting the limiter at 6050 at about the same point as everyone else on the longest strait.  Think I really need to work on side bite.  The Burris tires were feathering on the inside edge about equally all around.  The Duros are doing nothing.  What would be the best way to get side bite without binding the chassis up?

    #55464

    Richard Gordon
    Participant

    So with losing .5″ on each front tire of contact patch it also narrows the front track width 1″. So I should need to move the fronts out .5″ on each side? Also the rear gained 1″ per wheel so in order to get the same rear track width I should pull the rear wheels in 1″ on both sides? This would take the track width back to the way it was on the Burris tires. Does this sound like a good idea?  Also, wouldn’t the front lose some grip due to the tires being narrower?  The rear should gain from the extra rubber?

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