What does right rear lead do
- Thread starter kart49
- Start date
Moving the RR back helps turn in and loosens throughout the corner. If you move the whole axle back you just change wheelbase assuming you move it back the same amount on both sides.
racing promotor
Moderator
Moving 1 side of the axle back or forward changes Lag or Lead .
racing promotor
Moderator
Lead is if the right side of the kart has a wheelbase GREATER than the left side of the kart, USUALLY at the RF or LR , most really smart guy's say ( and I agree ) best ones adjust at the LR because it doesn't alter the front end geometry itself, and the amount it affects misalignment at the sprocket is such a miniscule amount it ends up no effect on chain alignment , and if the chassis manufacture doesn't provide a reference point so that you can visually see a marker and know how much lead or lag you're utilizing rather than having to measure always, scribe a reference point location on yourself. But not all chassis give the the LR option .
LAG is just the opposite, the right side of the kart has a wheelbase LESS than the left side. when adjusting lead or lag always make sure that the steering geometry has not changed, changing lead or lag will not affect the caster, camber, or KPI , changing lead or lag will affect toe, front end alignment, and static weight, so all should be reset to desired setting or placement.
MOVING the RF forward will tighten the chassis
Moving the RF towards the rear of the kart will Loosen the chassis
Moving the LR forward will Loosen the chassis
Moving the LR towards the rear of the kart TIGHTENS the chassis
Dynamic weight Transfer and the timing of depends, yes on Frame design, and INITIAL turn in.
What happens when the kart turns left :
The LF spindle pushes the outside of the LF tire into the ground and reduces the pressure that the LR tire is exerting on the ground ( the "effictive " Cross ). The further out that LF tire is located on the spindle, the more this effect will be multiplied. The greater the amount of POSITIVE LF Camber, the more this effect will be Multiplied also. As the LF is forced down, the RF is raised up, and for a split second the instantaneous reduction in speed caused by the forces acting upon the kart from changing directions, the kart acts like a see-saw teetering the weight forward and onto the RF, The weight at the LF & RR will Increase while the weight at the LR and RF will decrease, however the RF and RR weights will increase proportional to the G - Force transferred while the LR & LF decrease.
When the weight is increased on the LF from turning left, the LF tire becomes the pivot point and largely controls " turn in " into the corner, that is until weight is transferred from the LR to the RF. As weight is being transferred from the LR to the RF. VCG begins to play a vital role in the chassis set-up. a LOWER VCG will transfer less weight from left to right when cornering. What your trying to achieve is " PROPER " balance.
( and is the toughest thing to accomplish ). A set up with LOW VCG will usually be best when combined with HIGH Caster settings, because although the VCG isn't transferring weight the Caster is. The inverse is also true. Set ups with HIGH VCG usually will be best with LOWER Caster settings. Frame " FLEX " at the LR has a major effect on whether the kart is tight or loose. for a " Loose " lower grip track where you would need the kart to " BITE HARD ", you would want the area at the LR to be STIFF. For a " TIGHT " higher grip track where you would NOT want the kart to " BITE HARD " you would want that same LR area to be " LIMBER "
Went a little beyond just Lead & Lag info only to point out the fact that only moving just lead or lag, does not always net result what happens at turn in, what happens there is more about just that, " TURN IN " , which starts the whole process.
Disclaimer this Info comes from someone whole lot smarter than me, although I did tweak it some adding in some years of experience, which also automatically adds in some GRAY Hair , which in a perfect world = SOME WISDOM .
Now remember ACCURACY with out CLARITY is a WASTE of TIME, So let the DeBate Begin .
LAG is just the opposite, the right side of the kart has a wheelbase LESS than the left side. when adjusting lead or lag always make sure that the steering geometry has not changed, changing lead or lag will not affect the caster, camber, or KPI , changing lead or lag will affect toe, front end alignment, and static weight, so all should be reset to desired setting or placement.
MOVING the RF forward will tighten the chassis
Moving the RF towards the rear of the kart will Loosen the chassis
Moving the LR forward will Loosen the chassis
Moving the LR towards the rear of the kart TIGHTENS the chassis
Dynamic weight Transfer and the timing of depends, yes on Frame design, and INITIAL turn in.
What happens when the kart turns left :
The LF spindle pushes the outside of the LF tire into the ground and reduces the pressure that the LR tire is exerting on the ground ( the "effictive " Cross ). The further out that LF tire is located on the spindle, the more this effect will be multiplied. The greater the amount of POSITIVE LF Camber, the more this effect will be Multiplied also. As the LF is forced down, the RF is raised up, and for a split second the instantaneous reduction in speed caused by the forces acting upon the kart from changing directions, the kart acts like a see-saw teetering the weight forward and onto the RF, The weight at the LF & RR will Increase while the weight at the LR and RF will decrease, however the RF and RR weights will increase proportional to the G - Force transferred while the LR & LF decrease.
When the weight is increased on the LF from turning left, the LF tire becomes the pivot point and largely controls " turn in " into the corner, that is until weight is transferred from the LR to the RF. As weight is being transferred from the LR to the RF. VCG begins to play a vital role in the chassis set-up. a LOWER VCG will transfer less weight from left to right when cornering. What your trying to achieve is " PROPER " balance.
( and is the toughest thing to accomplish ). A set up with LOW VCG will usually be best when combined with HIGH Caster settings, because although the VCG isn't transferring weight the Caster is. The inverse is also true. Set ups with HIGH VCG usually will be best with LOWER Caster settings. Frame " FLEX " at the LR has a major effect on whether the kart is tight or loose. for a " Loose " lower grip track where you would need the kart to " BITE HARD ", you would want the area at the LR to be STIFF. For a " TIGHT " higher grip track where you would NOT want the kart to " BITE HARD " you would want that same LR area to be " LIMBER "
Went a little beyond just Lead & Lag info only to point out the fact that only moving just lead or lag, does not always net result what happens at turn in, what happens there is more about just that, " TURN IN " , which starts the whole process.
Disclaimer this Info comes from someone whole lot smarter than me, although I did tweak it some adding in some years of experience, which also automatically adds in some GRAY Hair , which in a perfect world = SOME WISDOM .
Now remember ACCURACY with out CLARITY is a WASTE of TIME, So let the DeBate Begin .
Had no idea changing lead or lag affected toe and front end alignment.
racing promotor
Moderator
But have changed it and was confused about results ???
Nope. Every time I changed it one way or another it done exactly as thought it would.
racing promotor
Moderator
Are you still going to racing events now , or are you pretty much Idle till Spring 2024 ??? I'd be curious just to test if your happy where your at now , if not happy guess it's worth trying move Lead or Lag then ReSet Toe and front end alignment and confirm if it ends up doing exactly what you thought it would do .
I don’t see how moving the axle forward, back, in, out, up, down, or out does anything to the front end statically other than maybe wheel weights. Dynamically I can see where it may change weight transfer ect. Ive pretty much been idle for a couple of months but I will try anything that makes sense or not. Sometimes the stuff that don’t make no sense makes me faster. I’m not trying to argue with you Racing Promotor, I know you are a very smart man who has done a lot for the sport. I’m here to learn too. Say I have 1/16 toe out and I move the LR forward let’s say a 1/16. What do I reset the toe at because it is still at 1/16?
So moving lr forward to loosen has same effect as moving rr back correct
paulkish
old fart
Easiest way to see it is to understand my concept of what is going straight in an LTO kart or car.
I define "going straight" to be the direction or how the staggered solid axle wants to roll if you took it out and just rolled it.
The direction the axle rolls is "straight" and all your front end geometry is setup based on where the axle is heading or going to roll.
Got it?
Now you got everything up front aligned with the axle toe, caster, kpi, camber, ackerman etc..
... and then you move the left end of the axle forward, ok?
When you moved the left end of the axle forward you caused the whole front of your kart to move over towards the left because the axle is still going to roll straight but since you moved the left end forward it moved the center line of your kart over to the right so now you got to 'maybe' reset all your front end adjustments to be setup now heading to the right a little.
clear as mud?
flattop1
Dawg 89
It is .
Put your laser or use string .
In the right rear . Project the line forward . Measure the right front inset .
Next move lf rear axle forward , re-masure the inset .
....
Something tells me moving either side would produce slightly different effects .
Any thoughts on that.
Put your laser or use string .
In the right rear . Project the line forward . Measure the right front inset .
Next move lf rear axle forward , re-masure the inset .
....
Something tells me moving either side would produce slightly different effects .
Any thoughts on that.
racing promotor
Moderator
Just what It reads yes its the same, However since there are VERY few Gospel written in stone do this and this will happen or the same will happen ALWAYS, I'd say there would be slightly different net result.
I will play with the toe a bit when I get a chance, but I would think relative to the way we typically check it, it would have to change the readings. If you measure the actual toe out, say with toe plates, it very well may be the same, but since we use lasers off the rear axle a change of lead or lag there is going to change the angle of the laser compared to the front.
Skidude
Member
Yes, but your geometry is now off. In relation to squareness to the axle, the front end geometry needs to be reset. For squareness, the LF would now be toed out, your RF is less than 1/16 also. That’s assuming your Ackerman is 90* to both tie rods and checking toe in relation to the axle.
racing promotor
Moderator
Don't take it as trying to argue at all, my post ended by saying let the DeBate Begin, that's how I take what were doing now.
So Let's break this down little better, Most now set toe out on the right side, and use a laser device that is mounted on aluminum stock that inserts into the rear axle, so you set the toe based on a laser red line projecting forward and reflecting back in some cases, the location of that laser line ends up because of where rear axle just happens to be when you decide to set toe, to make Clarity easier later lets assume that rear axle location at the time of the intial set of the toe was exactly 90* or Square to the length of the chassis , and you set toe out on the RF based on that 90 * square laser line by adjusting tie rod on the RF spindle.
You then MOVE ONLY the LR forward , would that NOT change the degree of the new laser line projecting forward from being square of that same rear axle, which when projected forward after moving would move that line to the right slightly, thus net result in changing the RF toe out ??
" FOR SURE " or " MAYBE "
As far as me being very smart, there's NO Debate needed for that one, I'm not very smart, not even AVG smart, I could list a few things that would prove just how dumb I've been, but that's a whole different conversation for a different forum.
Would't say I've done a lot, just try to be Help where I can and make a difference.
racing promotor
Moderator
I think the same provided you only change ONE side of the rear AXLE , are we both not thinking right ?? I feel little better now because BRAD here is a lot SMARTER than I am !!