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Author Topic:   bar angles
rpm20
Dirt Freak

Total posts: 338
posted May 12, 2005 07:41 AM  
what are the effects of lowering and raising lr and rr bars on a 4-z setup car.
i have short(13") lower left at 5* up and a longer 15" upper at 15*

on rr i have lower long (19") at 5* up to front and upper 20" long at 5* down to back.

just wondering what the effects of lowered or raised bars have on car so now i can tune it with a better understanding.

dirtbuster
Dirt Forum Champ
Total posts: 2007
posted May 12, 2005 08:35 AM  
Thats tought to answer and be somewhat breif. IF you havent read the tech article in the tool box i would reccomend that for starters. IT will get youthe basics to start with anyway.

In very general terms top bars for exit, bottom bars for entry. More angle=more traction. Z link is the same except you lower the top rod on the frame for more bite instead of raise it.

Any time you increase angle up on a 4 bar you increase traction but you also increase roll steer. Thats why you use more angle in the top for traction, but less angle in the bottom to control roll steer. if you raise the bottom bar you will gain some bite, but you will also loosen the car by adding roll steer. Same with the top bar, more angle, more bite but you gain roll steer that may or may not hurt you.

If you have springs floated on the BC then you also add in another element of indexing due to differences between top bar angle and bottom bar angle and its effect on the springs. This can be used to tune traction as well. Thats why some of the adjustments for LR clamped and LR behind are opposite of ea other.

Its all a fine tuning act. Thats why when changing something you have to be aware of everything that changes with a 4 bar car.

If you have more specific questions you know how to get ahold of me....

dirtbuster
Dirt Forum Champ
Total posts: 2007
posted May 12, 2005 08:54 AM  
also forgot to mention that shorter bars react faster so they will gain or lose angle faster as well. So when you are comparing notes with others make sure you take that into consideration.

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