J bar adjustment

[W2racing]

I just bought my 1st late model - 05 2" black front. I've seen it on other cars and it's on mine too. The j bar mount on the frame has a mark about 1/4 - 1/2 inch above the standard mounting position. I've never seen anyone move the j bar on the frame. What conditions would dictate moving the j bar mount on the frame up rather than moving the j bar down on the pinion?

[hpmaster]

J bar on frame adjustment effects the entry thru the middle on most cars. The short version is lower on frame to loosen entry raise to tighten entry. According to many you are changing leverage and the rear roll center location both right and left and up and down of the rear suspension of the race car BUT each drivers style, on gas off gas entry and the car's other adjustments can determine how these adjustments will affect the car. Please beware that depending on the type of mount on the car when you adjust the height of the J bar on the frame you may also be moving the rearend left or right in the car changing several other aspects of the cars handling. Sometimes a change in how the car is driven is more important than an adjustment or just having a driver who really knows if the car is really loose or tight. JMHO.

[W2racing]

J bar on frame adjustment effects the entry thru the middle on most cars. The short version is lower on frame to loosen entry raise to tighten entry. According to many you are changing leverage and the rear roll center location both right and left and up and down of the rear suspension of the race car BUT each drivers style, on gas off gas entry and the car's other adjustments can determine how these adjustments will affect the car. Please beware that depending on the type of mount on the car when you adjust the height of the J bar on the frame you may also be moving the rearend left or right in the car changing several other aspects of the cars handling. Sometimes a change in how the car is driven is more important than an adjustment or just having a driver who really knows if the car is really loose or tight. JMHO.

Ok, so what is the difference between raising the jbar on the frame and lowering it on the pinion? It seems as if you're basically doing the same thing?

[Matt49]

Ok, so what is the difference between raising the jbar on the frame and lowering it on the pinion? It seems as if you're basically doing the same thing?

They are "basically" doing the same thing but there's a lot more going on with j-bar than most people think about.
There was a good discussion on this on the Modified forum recently. Here's the link:
http://www.4m.net/showthread.php?324...nhard-bar-tech