J-bar

[pa_dirt]

Can someone explain in simple terms what a j-bar does and what affects it has by lowering/raising it on both the frame and the pinion?

[Jim11h]

Changes roll center of rear. Down pinion/up chassis "tighten car or stick rr harder. Opposite loosen. Pinion bigger adjustment then chassis typically. There's a point where have too much angle in j bar and then your really chasing your tail.

Afco used to it believe had good article explaining j bar in their tech section

[pa_dirt]

Thanks for the reply... that’s what I thought but wanted verification on it...

Un j-bar related...any thoughts on being able to get the car up on the bars but car seems to unload and “slam” back down as soon as you get out of the throttle

[Basecircle]

Driver new to late models? If so, that’s usually driver induced. There’s things you can do to help. What car, springs, bar locations, track configuration/surface conditions etc?

[Roudy73]

Have a similar problem too, car sticks the rr good to the center. After that it feels like it looses the rr an skates just a little to much.

[Jking24]

Have a similar problem too, car sticks the rr good to the center. After that it feels like it looses the rr an skates just a little to much.

Before or after you pick the throttle up

[Roudy73]

It would be on the throttle.

[Jim11h]

Typically slamming back down is Driver letting out of throttle to fast but with today's shock valving it should still hold car up on lr.

[Jking24]

It would be on the throttle.

This would typically indicate that the car is too tight on the throttle. At that point you need to decide weather or not you could afford to be tighter in on decel because many of the adjustments that generally loosen accel generally tighten entry. You need to identify what is actual happening at initial throttle pick up

[Roudy73]

It feels like when I get the car loose enough on entry the car just skates through the corner. It could be the way i drive too. I drive the car to straight people have said. If I enter sideways it will just keep sliding. By the time it catches everyone is a car length ahead.

[CCHIEF]

It feels like when I get the car loose enough on entry the car just skates through the corner. It could be the way i drive too. I drive the car to straight people have said. If I enter sideways it will just keep sliding. By the time it catches everyone is a car length ahead.

How are you "loosening the car on entry"?

[Roudy73]

We were taking lf spring out. But its almost like it took the drive out if it too. Thanks for the responses.

[Roudy73]

What would be a better to free up entry at the track?

[grt74]

We were taking lf spring out. But its almost like it took the drive out if it too. Thanks for the responses.

lf spring for the most part is an entry only adjustment

heres what i recommend
go test and be honest with yourself (go pro looking at the steering wheel)
almost 99.9% of the time the car is too tight and breaking loose in the middle = killing drive off
I'm guessing this is when its slick and you will have to give out all info to help
but test when slick and drive straight, fix entry, then middle should almost fix itself (little tweak at most) then work on exit
if you trip at entry you'll fall at exit

[CCHIEF]

What would be a better to free up entry at the track?

What are you doing on the RF/LR/RR? single spring, bump stop/spring/etc.