Trail and Lead
- Thread starter Hptqfast
- Start date
paulkish
old fart
IMHO, Trail or lead in the back on either side do two things. They either lengthen or shorten the wheel base and shift the center line projected at a right angle from the axle forward, left and right.
IMHO, in the front they both alter where the front wheel is located in relation to the center of gravity. And in the case of the RF, I think it also alters when the RF will start working more with the bank of the track going into a turn, to help with "turn in".
If they work together depends on what you need to use them for. Most anything will work with everything else, if conditions are right.
I don't think either is better, it's a matter of will either fix an on track problems or help you go faster. With either it's also a matter of try it and check your results with a stop watch or the checkered flag.
What is one of your theories? I like theory. ...
paul
IMHO, in the front they both alter where the front wheel is located in relation to the center of gravity. And in the case of the RF, I think it also alters when the RF will start working more with the bank of the track going into a turn, to help with "turn in".
If they work together depends on what you need to use them for. Most anything will work with everything else, if conditions are right.
I don't think either is better, it's a matter of will either fix an on track problems or help you go faster. With either it's also a matter of try it and check your results with a stop watch or the checkered flag.
What is one of your theories? I like theory. ...
paul
Charliemac115
New member
Different karts have different amounts of lead built in them and most have adjustable lead also. A low lead kart will usually require more stagger but a speed trick is to put about 1 1/4 of lead in it and drop the stagger to 3/4 in the rear and it lets the kart turn well and the lower stagger really helps roll speed down the straights.
Paulkish my theory is. Moving the RR back, the RF forward or both gives you the solo cup affect. If you lay the solo cup on its side it wants to roll in a circle. This is because the right wheel base is longer than the left. Now independently each does something different. Moving the RR back will cause the kart to already be pointing into the corner before you get there. This is caused when you square the kart after doing this it shifts the front to the left to align the wheels. Here is where I struggle. When you move the RF forward it moves it further away from the center. To me this means it transfers weight entering the corner faster but on the other hand takes longer to transfer the weight back exiting the corner.
Charliemac I agree with your statement and think if done correctly can reduce the scrub of momentum. And that is the key to being fast. But understanding all the affects is something I know I do not understand. There is a give and take. Finding that balance is key.
Lead and trail I believe are something most people do not understand fully (me included) but can be a real valuable tool to get you through the corner.
Charliemac I agree with your statement and think if done correctly can reduce the scrub of momentum. And that is the key to being fast. But understanding all the affects is something I know I do not understand. There is a give and take. Finding that balance is key.
Lead and trail I believe are something most people do not understand fully (me included) but can be a real valuable tool to get you through the corner.
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paulkish
old fart
Hptqfast, I think I agree with all you said. The only difference in the way I look at it is instead of thinking in terms of faster, I'd be thinking in terms of making it easier or harder to transfer weight.
... I think pretty much the same idea though as what you said.
Andrew, Mr South recently made me also start thinking about how 'when' g's increase, so does the amount of weight. That means much of the weight is not actually transferring or going to the RF, it's being created at the RF because g's are increasing.
... thanks that a tough thing and a new thing for me to think about. ... weight not actually transferring to the RF, but being created at the RF because g's increased. I hope I have it right about the weight not needing to be transferred, when your in really creating it where it already needs to be.
I'm struggling with it too.
... I think pretty much the same idea though as what you said.
Andrew, Mr South recently made me also start thinking about how 'when' g's increase, so does the amount of weight. That means much of the weight is not actually transferring or going to the RF, it's being created at the RF because g's are increasing.
... thanks that a tough thing and a new thing for me to think about. ... weight not actually transferring to the RF, but being created at the RF because g's increased. I hope I have it right about the weight not needing to be transferred, when your in really creating it where it already needs to be.
I'm struggling with it too.
I really never thought about the g force factor added into weight transfer. I still think some weight has to transfer because you are changing the ride height. And changing ride height should change the weight on each corner without physically moving any weight. But when you add the g force factor it opens up a whole other equation. I have an ideal I have wanted to try for some time but don’t have the funds to purchase the devices needed. I want to put load cells on all four corners of a kart with a data collection device. On the front I think it would be easy. You could put it above or below the spindle instead of washers. The rear end would be a little more difficult. Have the driver cut a few laps. Tie this data to the MyChron GPS data so you can see where the kart is at and how the weight really transfers on parts of the track. I think this data would help you really understand what the kart is doing. I know kart manufactures use the MyChron GPS data to see if the kart is faster or slower in certain sections on the track when making chassis changes. But that alone doesn’t show you why it might be faster or slower.
paulkish
old fart
Instead of load cells you could do similar with accelerometers reading g's at each corner. If I'm remembering correctly Todd (LTG) has done that and more working with Phantom, years ago. ... hummm... I don't think you'd have to put a load cell in place of a washer. All you would need to get a comparison is to have a load cell with the same weight on it at each corner. I don't think it would matter to see what percentage of load increase occurs at each corner, weather the load cell is on the kingpin or just at or near the corner. ... the load cell may need to be angled slightly to increase the effects of the weight. just thunkin about it and writing my thoughts, proly wrong ...
I was just thinking if you zero all load cells with driver in kart not moving then you could see how each corner loads and unloads. I have never worked with accelerometers but when measuring g forces would you not get more of a side force from that? When i think of g forces I imagine the entire kart haveing the same g force. Is that wrong can each part have different g force readings? G force is one thing i really do not fully understand. To me in a nut shell it is the force generated from movement in the oposite direction. Hmmm This really opens up an entire way of thinking about it.
Mr South 59
New member
See Paul, planting a little seed can grow into a whole tree.
I would have though that the seed I planted about stagger not causing any drag on the straights because of the surface speed and g's would have helped with your stagger thread. Try to use some of it in that thread and you might plant a seed in
a few of those guys.
I am putting so much time on this new car build that I have much time for Bobs. I will try to keep up.
Something to think about. Having RF lead and RR lag does not cause a solo cup affect. If you had lead and lag with zero stagger the vehical would still roll straight. It would not roll in an arch.
RF lead changes the timing of weight transfer to the RF. RR lag changes the center line of the rear axle to the front axle.
The longer right side wheel base does help on the tighter radius corners because the vehical will always turn better in the direction of the shorter wheel base but it is mainly a driver comfort thing and not so much a speed tuning tool.
I would have though that the seed I planted about stagger not causing any drag on the straights because of the surface speed and g's would have helped with your stagger thread. Try to use some of it in that thread and you might plant a seed in
a few of those guys.
I am putting so much time on this new car build that I have much time for Bobs. I will try to keep up.
Something to think about. Having RF lead and RR lag does not cause a solo cup affect. If you had lead and lag with zero stagger the vehical would still roll straight. It would not roll in an arch.
RF lead changes the timing of weight transfer to the RF. RR lag changes the center line of the rear axle to the front axle.
The longer right side wheel base does help on the tighter radius corners because the vehical will always turn better in the direction of the shorter wheel base but it is mainly a driver comfort thing and not so much a speed tuning tool.
paulkish
old fart
"Is that wrong can each part have different g force readings?"
I'm not a person to ask for answers, only opinions. But I'm pretty sure each end, front and back, will have different acceleration. And there's also vertical acceleration, to consider too.
___________________
and thanks Andrew for the post, I think both Hptqfast and me will both think on it awhile.
I'm not a person to ask for answers, only opinions. But I'm pretty sure each end, front and back, will have different acceleration. And there's also vertical acceleration, to consider too.
___________________
and thanks Andrew for the post, I think both Hptqfast and me will both think on it awhile.
Bergh223
Member
When you pull the RR back, doesn't it make the rear end track towards the wall? Hence indoor racing or at a 1/10 mile bullring its an excellent tool. If you are running on a 1/5 mile or a 1/4 hard and fast track, you will want to keep the RR in a neutral position so the track is pointing straight ahead.
If you run more stagger instead of more lead, I would think the benefit is the tires are at least pointing straight? Like you both said, its a balancing act based on the track you are on any given day.
If you run more stagger instead of more lead, I would think the benefit is the tires are at least pointing straight? Like you both said, its a balancing act based on the track you are on any given day.
Mr south. Never thought about the solo cup idea like that. But I see what you are saying. Because they are not spinning on the same axis that changes everything.
Paulkish I really didn't think of g force in a vertical direction. But I can see where that would be going on at the same time at a horizontal g force occurs.
Paulkish I really didn't think of g force in a vertical direction. But I can see where that would be going on at the same time at a horizontal g force occurs.
wade tumblin
New member
tony.. realy ??? come on.. all of this to out run a lil yellow kart.. you can already outrun.. you think way to much ... lol.. good points though.. thinking outside the box
wade tumblin
New member
yea.. that's why we trail more than we lead !!!! lmbo !!!!!
fastbraden11
Last of the originals
best thing to do is leave the lead alone,
Lead/lag, I look at it much like Andrew. I also think of it relative to the CG, moving the RF forward or the RR back moves that tire away from the CG therefore causing it to be delayed in dynamic loading and the amount of load. A quarter inch or so may not seem like much but it is. Now on the rear you have two choices, to not re-square the chassis or to re-square the chassis. Re-squaring the chassis will move the chassis relative to the way the tires are running. It also moves the roll centers relative to the CG and the centerline of the chassis.
Caster trail, the best way to describe it is to actually feel it. Say you run caster of RF 10 and LF 6. Just flip your caster numbers. One thing you will have to do is check your steered camber gain. Reset your camber to match your steered camber gain before the change. You will feel the difference as soon as you go onto the track. Also think about running caster as low as you can run it. Running the caster lower will better allow you to "feel" the way the tires are gripping the track. It will also let the kart glide over bumps better due to less feedback through the steering.
And that is just my opinion.
Mike McCarty
Chassis Manual (Only $17.95)
www.kartcalc.com
Caster trail, the best way to describe it is to actually feel it. Say you run caster of RF 10 and LF 6. Just flip your caster numbers. One thing you will have to do is check your steered camber gain. Reset your camber to match your steered camber gain before the change. You will feel the difference as soon as you go onto the track. Also think about running caster as low as you can run it. Running the caster lower will better allow you to "feel" the way the tires are gripping the track. It will also let the kart glide over bumps better due to less feedback through the steering.
And that is just my opinion.
Mike McCarty
Chassis Manual (Only $17.95)
www.kartcalc.com