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Author Topic:   how to set ride height
HOTWIRE
Dirt Roller

Total posts: 18
posted April 25, 2001 10:05 PM
how do you set the ride height in the car? do yo9u do it with the weight jacks? Doesnt using the weight jacks to set ride height also change the spring rate? where do you measure to on the car. I assume it is from the floor to the frame at a location as near as possible to the centerline of the rear axle and the front end. Thanks in advance.

CUSTOMPERFORMANCE
Dirt Freak

Total posts: 213
posted April 25, 2001 11:15 PM
when i build my mods i set the ride heights at 5.5-6 inches in the front. measured from the floor to bottom of frame rail closest to front tires. in the rear i set the height at 2.5-3 inches from the top of lower rear frame rail to bottom of axle tube.

these heights are also set here according to the geometry that the frontend and rearend is set at. when i have the ride heights where i want them, then i set the geometry around it. if i vary to much from these then my geometry is not the same as what i built it with. thats why it is so important to stick with whatever heights your chassis manufacturer reccomends. if you have a homebuilt car or a no name then you have to go by what someone else is using and then make small changes to them till you have the car working at its best. then record all info

wfoondirt
Dirt Maniac

Total posts: 142
posted April 26, 2001 08:35 AM
Adjusting the weight jacks doesn't change the spring rate but it does change the idividual wheel weights. The only thing i do different than custom is that on the front i weld a tab on the frame above the front of the control arm to measure the ride height off of, same result different technique.

HOTWIRE
Dirt Roller

Total posts: 18
posted April 26, 2001 08:45 AM
Thanks for the info! But how do you actually change the ride height. People at the track tell me I need to raise my ride height in order to get the car to roll over more in the corners. Rolling the chassis over more in the corners will create more downforce on the rr tire and give me more bite coming out of the corners right? I seem to be real loose coming out of the corners. My panhard bar spans from left frame to right axle.

owracer
Dirt Maniac

Total posts: 103
posted April 26, 2001 03:16 PM
How much angle are you running in the panhard bar? You can increase the amount of body roll with more angle.

wfoondirt
Dirt Maniac

Total posts: 142
posted April 26, 2001 03:42 PM
actually you decrease the roll resistance by lowering the panhard bar, normially you dont want to get more that 5-10 degrees of angle in the bar. changing the angle also changes the way the rearend moves laterally in the car so it is usually advisable to lower both ends of the panhard bar.
if you raise the ride heights on the car it will raise the center of gravity of the car and actually hurt lateral acceleration. if your wanting the car to roll laterally more its best to do it with the roll centers and or spring rate changes.

PEDDLER
Dirt Maniac

Total posts: 148
posted April 28, 2001 09:45 AM
5 to 10 degree angle?
With the panhard mounted at left to frame and right to axle, up or down angle to axle?
We currently have frame mount lower than axle mount at a 7 degree angle. We are considering a flat or 2 degree higher at frame.??????????????
Thanks

wfoondirt
Dirt Maniac

Total posts: 142
posted April 30, 2001 12:01 AM
Personally i run the panhard bar virtually flat at all times. normially if angle is put in the bar it is angled down from the left chassis mount. whether you angle the bar up or down will change which way the rear end will move laterally as the chassis rolls. I run the bar level to minimize this effect, also the longer the bar the less movement laterally.

PEDDLER
Dirt Maniac

Total posts: 148
posted April 30, 2001 05:56 PM
Thanks WFO.

Limited5
Dirt Maniac

Total posts: 141
posted May 02, 2001 05:46 AM
As a rule-of-thumb, the difference of angle should be kept close to 10% of bars length. Example: 10% of a 20" bar would be a 2" difference. If you need more, the entire bar should be moved up or down but keeping the 10%.

jammin
Dirt Administrator

Total posts: 3279
posted May 02, 2001 09:35 AM UIN: 16262997
Limited....why would that be rule of thumb? Ever tried more angle?

wfoondirt
Dirt Maniac

Total posts: 142
posted May 02, 2001 11:10 AM
The 10% rule i quite common and an easy way to get close on angle without having a true angle finder and roughly works out to 10 degrees.

Limited5
Dirt Maniac

Total posts: 141
posted May 02, 2001 05:58 PM
Jammin, AFCO also recognizes the 10% rule as a good starting place.

jammin
Dirt Administrator

Total posts: 3279
posted May 02, 2001 06:12 PM UIN: 16262997
Not disputing this. I just like to hear where some of these "rules" originate from. With technology advancing the way it is, I feel that you can throw some of the so called rules out the window. Not saying your wrong here. Just makes me wonder.

bbracer17
Dirt Maniac

Total posts: 168
posted May 02, 2001 08:34 PM
I was also told to keep the bar angle at 10% of the length and I was also told to never ever run a panhard bar shorter than 20 inches. But it's funny that when I look under the cars of the guys that are smoking me they are doing all these things that you should never do. Maybe they are making up these rules of what not to do.

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