What does right rear lead do

My take is that, for instance, trailing the rr moves the steering requirement to the right to travel down the straight.
Which changes camber on both front wheels.

Which changes the weight on both front wheels.

Which affects transfer and timing.

Kind of like cross, there are phases of such where it seems there is a dead spot.

Knowing what you want can help.

It sometimes seems like no one wants to give you a straight answer. Which is not true, because there can be more than 1 correct answer.

Fun to think about though.
 
Yes, I agree that the changes made in doing so are static changes in weight and dynamic changes in weight and timing.
 
Here's a simple exaggurated diagram to help think about lead:
In this example, LR lead was added. This, in effect, shifted the Cg to the LEFT relative to the old Cg. It also required the driver to "steer right" relative to the chassis centerline, adding some jacking effect (as if the driver was turning right.) This preloads the RF and LR tires relative to a "square" setup. Also the left side wheels are marginally on a shorter wheelbase than the right sides. If the RF had been moved BACK (lag) instead of the LR, this would ADD some wheelbase, affecting stability and leverage ratios somewhat.

Hope this helps you picture what's going on.

1705519168585.png
 
While adjusting rear tracking does result in a total chassis lead change, it shouldn't be called lead or lag. That's like saying caster and camber are the same thing because adjusting one will directly effect the other. But, I know it's slightly easier to explain when it's just referenced as lead. It's a tracking change and rear tracking effects chassis yaw, which directly effects Lead unless lead is then taken out of the front.
 
Last edited:
How are yall adjusting for lead or lag? Is it slightly moving the cassettes or are we working with adjustable cassettes?
 
Always need to keep minimum wheelbase in mind when leading or trailing rear axle.

Some chassis can already be close on one side, so need to pay attention.
 
1. Tracking is whether the rear tires are rolling in the same path as the fronts.
2. Lead or lag is whether the rear axle side is moved front or rear of its' initial (Assumed perpendicular) position relative to the chassis.
3. Wheelbase is the distance between the wheel centers on the same side.
4. Track width is the distance between tread centers at the front or at the rear. (Note: this is why #1 is called what it is.)

In a kart, lead or lag fundamentally misaligns the gear to the clutch and the rotor to the calipers....
Some chassis can also have lead or lag "built-in", meaning the chassis offset position is intentionally producing the same effect, but with the axle squared to frame. It's the "design intent" from the beginning. If you took every chassis and took only the 2 kingpin locations and rear cassettes and mapped them, you'd see some interesting results.
 
Ted Hamilton said:
1. Tracking is whether the rear tires are rolling in the same path as the fronts.
2. Lead or lag is whether the rear axle side is moved front or rear of its' initial (Assumed perpendicular) position relative to the chassis.
3. Wheelbase is the distance between the wheel centers on the same side.
4. Track width is the distance between tread centers at the front or at the rear. (Note: this is why #1 is called what it is.)

In a kart, lead or lag fundamentally misaligns the gear to the clutch and the rotor to the calipers....
Some chassis can also have lead or lag "built-in", meaning the chassis offset position is intentionally producing the same effect, but with the axle squared to frame. It's the "design intent" from the beginning. If you took every chassis and took only the 2 kingpin locations and rear cassettes and mapped them, you'd see some interesting results.
Click to expand...
This would probably would have been a good start. Seems the largest discussions on here get confusing because we use different terms.

One question, you define track width as center of tread, I thought it was outside edge of tread in karting? At least that is what phantom shows on their setup sheets.
 
Surveyor said:
This would probably would have been a good start. Seems the largest discussions on here get confusing because we use different terms.

One question, you define track width as center of tread, I thought it was outside edge of tread in karting? At least that is what phantom shows on their setup sheets.
Click to expand...
For dirt oval racing we use the outer most edge that touches the ground under race conditions.


All oval chassis are built with up to a ¼ inch longer wheel base on the right than the left.
There was a time we squared the axle off the inside engine rail at 90*, but still maintained the ¼ offset in wheel base.
Lead an lag is more a front end term that got adopted to the rear.
Truth? More do dads to sell chassis.
 
I feel that this option for the rear end would be more beneficial on small bull rings and indoor coke syrup racing. Or does it work well on the bigger tracks as well? Is there essentially a time to try this during certain track conditions or is it more of a preference thing?
 
I pretty much agree with
XXX 40.
I liked to fiddle with it, the driver hated it .
He`d always go straight out and bend the axle .
 
Colt sr said:
I feel that this option for the rear end would be more beneficial on small bull rings and indoor coke syrup racing. Or does it work well on the bigger tracks as well? Is there essentially a time to try this during certain track conditions or is it more of a preference thing?
Click to expand...
It all depends on what the chassis needs to time correctly. Certain chassis in certain weight classes would need a tracking adjustment on bigger tracks. But, generally smaller tracks and tighter corners this tends to help.
 
Best hope is the discussion understanding it or not has led to a lot of racers understanding stuff in general better.

"in general" means ya had to go to War College to have a grip on it. ... :)
 
shiftyag said:
The Cup guys were also using it to get more or less air on the spoiler
Click to expand...
Exactly they did it to get air onto the right rear and when cornering it provided more air to the spoiler. And in return created more downforce and could drive car harder. Sam hornish is the reason nascar made a rule about it.
 
Wa15h said:
Sam hornish is the reason nascar made a rule about it.
Click to expand...
Anyone else's kid get to race a kart with him?
We did one time. ... :)

Thinking back seems like he showed up with more motor then the rest of the kids running junior box stock.
Don't remember if he won or not but was competitive.
Had good stuff to ride.
 
Last edited:
Wa15h said:
Exactly they did it to get air onto the right rear and when cornering it provided more air to the spoiler. And in return created more downforce and could drive car harder. Sam hornish is the reason nascar made a rule about it.
Click to expand...
Difference also being how the right side loaded and unloaded.
A kart doesn't have an aero component.
 
You must log in or register to reply here.
Back
Top