Page 3 of 3 FirstFirst 123
Results 61 to 70 of 70

Thread: Jr2 Driver needing more weight xfer to RR?

  1. #61
    Join Date
    Oct 2013
    Posts
    4,081
    Quote Originally Posted by paulkish View Post
    You suggest this even though he told us previously the LR tire was in more then the manufacture recommended as a minimum?

    "I went ahead and pulled the LR out last night to the MIN suggested spec from Prowler, moved it a total of 5/8"."


    _____________________


    just yada yada and proly more useless yada below because the response got me thinking about it. no argument intended, just offering what it made me think about which probably ain't right anyway.

    IMHO the position of the tire in or out has nothing at all to do with the effects to rotation caused by stagger. The ONLY thing which effects how stagger will work, unless your traveling in a perfect circle is the loading of each rear tire and the direction forces act on the tire. Moving the axle out effected tire loading and because it slightly lowered the LR corner of the kart it effected the direction forces acted laterally to pull the LR tire to the right. The key IMHO is did moving the LR out cause an increase or decrease in the amount of slip at the LR.
    Well you're wrong paul, its easy to prove drawing a line from the top of the right tire to the top of the left, then move the left tire out and draw the same line you see the angle of that line has changed where they intersect.
    Moving the tire in increase the effect, and out lessens it
    It didnt lower the left rear, it moved the left rear farther out from VCG which slowed weight transfer from and to the LR

  2. #62
    Join Date
    Oct 2013
    Location
    Poland
    Posts
    4,967
    Quote Originally Posted by XXX#40 View Post
    Well you're wrong paul, its easy to prove drawing a line from the top of the right tire to the top of the left, then move the left tire out and draw the same line you see the angle of that line has changed where they intersect.
    Moving the tire in increase the effect, and out lessens it
    It didn't lower the left rear, it moved the left rear farther out from VCG which slowed weight transfer from and to the LR
    Your right I was looking at it wrong. Moving the LR out raises the LR corner and does not lower it. thank you


    corrected my reply with the words >raised< and >tire< it now reads:



    IMHO the position of the tire in or out has nothing at all to do with the effects to rotation caused by stagger. The ONLY thing which effects how stagger will work, unless your traveling in a perfect circle is the loading of each rear tire and the direction forces act on the tire. Moving the >tire< out effected tire loading and because it slightly >raised< the LR corner of the kart it effected the direction forces acted laterally to pull the LR tire to the right. The key IMHO is did moving the LR out cause an increase or decrease in the amount of slip at the LR.

    How's what follows? It changed the position of the karts rear roll center in relation to how it is working the LR tire. Not by lowering the rear roll center but by raising the point on the chassis which pulls or works the LR tire. You end up with not only a longer lever to operate but where the lever is operated is placed in a better position to be pulled downward. ... again not arguing, your letting me see it better and thanks.

    -----------------------

    edit and added on: "it moved the left rear farther out from VCG which slowed weight transfer from and to the LR"

    Weight created at the LR transfers instantly per g's created. Weight physically located at the LR cannot leave the LR without also having a loss of grip. It's how much you cause the LR to slip and loose grip that lets physical weight leave the LR tire. If the LR does not slip(loose grip) physical weight cannot leave. The only timing involved is with when you cause or lessen slip/grip. That is the only reason more grip/bite allows you to go faster. ... maybe???

  3. #63
    Join Date
    Feb 2014
    Location
    Ocala Florida
    Posts
    172
    Update: 3/15/19

    We came to the track with the same setup as we've been running here and out of the gate the kart was pushing on entry VERY badly. My little guy had a terrible time. I chased it with minor air pressure adjustments which didn't seem to help in the heats so I pulled the RR hub out 1/2" and moved a 5lb lead puck to the nose for the feature. It took most of the push out but seem to "Lock" the kart down. He said he was running flat out and not lifting but the kart just wouldn't gain speed. Ended up running 5th out of 11 karts.

    My question is how?? why?? RPM's were same as normal 5880-6000 peak. Same gear, same tires etc. We have had incredible luck at this track all season and know the setup we have on this kart works, I just can't see what caused such a drastic change.

  4. #64
    Join Date
    Oct 2013
    Location
    iowa
    Posts
    6,984
    My initial thought is . After all the changes on the left rear , you moved to the right rear for a fix.
    The left rear seems like the logical place to start.

  5. #65
    Join Date
    Feb 2014
    Location
    Ocala Florida
    Posts
    172
    So you're thinking I should move the left rear hub back in to the frame as it was before? That thought has crossed my mind but all my knowledge tells me push on entry is solved with other means... I forgot how fun it was to chase your tail with dirt karts...

    If the LR is moved back in tight, wouldn't it have more weight on it and not want to rotate allowing the kart to turn in?

  6. #66
    Join Date
    Oct 2013
    Location
    Poland
    Posts
    4,967
    "If the LR is moved back in tight, wouldn't it have more weight on it and not want to rotate allowing the kart to turn in?"

    Either the fronts turn the thing and/or/or both normally it rotates around a LR which is pinned enough both on entry and exit to act like a rudder letting the RR either roll around it decelerating or out accelerate the LR.

    If it's pushing either you have to make the fronts turn better of get the LR pinned/ruddered/acting like a brake enough to let the RR do it's thing.

    ... all just IMHO and ain't necessairly right anyway. ...

  7. #67
    Join Date
    Oct 2013
    Location
    iowa
    Posts
    6,984
    Honestly I always threw the kitchen sink at it.
    The two main things you've changed are the tire and its location. At least that we know of . Same prep same air same gear , nothing else ?
    Did track conditions change ?

  8. #68
    Join Date
    Feb 2014
    Location
    Ocala Florida
    Posts
    172
    We put a new LR tire on 2 races ago and ended up moving the LR out some. Other than that, nothing has changed. The track was a tad wetter this time than it has been. Looked like they really poured the water to it but nothing unusual for this place.

    I did notice I had lost some stagger in the rear, hadn't paid the closest attention to it but realized last night that we're setting at 1" in the rear now, where as before we had 1-1/4- 1-3/8" That old worn out LR was in effect giving us more stagger. Odd thing is, on a track this size I wouldn't think you'd need much stagger.

  9. #69
    Join Date
    Feb 2014
    Location
    Ocala Florida
    Posts
    172
    Looking back, I think I know what happened... I moved the LR out and by using a new LR tire I lost some stagger. This is where my push came from. I plan to shrink the LR down to what the old one measured or Increase the size of the RR and move the LR back in some. That should get me back to square one....


    Thanks for all the help fellas!

  10. #70
    Join Date
    Oct 2013
    Location
    Marysville, Pa
    Posts
    6,681
    Quote Originally Posted by 1fasttiller View Post
    Looking back, I think I know what happened... I moved the LR out and by using a new LR tire I lost some stagger. This is where my push came from. I plan to shrink the LR down to what the old one measured or Increase the size of the RR and move the LR back in some. That should get me back to square one....


    Thanks for all the help fellas!
    Don't move it back in to close or you'll still be chasing it.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •