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Author Topic:   j-bar ????
akadirtracer7
Dirt Freak

Total posts: 217
posted August 03, 2005 10:29 AM  
I have a couple j-bar questions.If I raise the both ends of the bar equally that should raise the roll center and give it more body roll.????what effect would just lowering the pinion mount? Right know its even with the pinion gear and has 5 5/8 rake.Everybodys telling me it should have about 6-8 inches of rake. What might be the complaint from the driver if theres not enough rake on the j-bar [IMG]I guess maybe it would help to know what I'm trying to improve on.the rear of the car hangs out alot coming out of the turn and I can't get in it hard.Last time we run my buddy was behind me and he thought it might be tight in the middle ,I had the left upper in the bottom hole on the birdcage and have put it back up to the top hole but haven't tryed it yet, i hear that can cause tight in the middle.Heres last scaling. 57.1 rear 54.6 left 50.2 cross yet.http://www.thedirtforum.com/ubb/smilies/cwm12.gif[/IMG]

[This message has been edited by akadirtracer7 (edited August 03, 2005).]

rocket36
Dirt Freak

Total posts: 209
posted August 05, 2005 08:11 AM  
i have found that usually not enough rake in the j-bar will make the car loose in the middle and exiting the turn with little forward bite. when mor bar angle is added it seems to plant the right rear harder (increase side bite). personally, we rarely move the slider on the frame, but regularly alter the pinion mounting point of the j-bar. it seems to have more of an effect. if your a really good/experienced driver you will notice a slider move on the frame alot more.
lowering both ends of the bar equally, with less angle (lower roll centre only) is more common on rough, wet race tracks.

GO 24
Dirt Freak

Total posts: 366
posted August 05, 2005 01:33 PM  
Generally you raise the whole bar for wet/real tacky tracks which raises the roll center. It will help free up the car going in and through the middle.
Dropping the whole bar of course lowers the roll center and tightens the car up (slick track).
Lowering the pinion mount or raising the frame mount will give the car more body roll.
8in of rake should be right in the ballpark.

racer68
Dirt Roller

Total posts: 7
posted August 08, 2005 04:22 AM  
Put the Jbar at chassis specs then move the frame slider 1 inch at a time up or down until you find what you like. Up on frame to tighten car up (push off corner to far). Down on frame to loosen car(backend hanging out to far). Just mark the positions on the frame for reference points.

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