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Old 12-23-2009, 11:17 AM   #1 (permalink)
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Minimum ride height?

What is a good minimum ride height to shoot for on a vehicle? I have seen 15deg as the minimum infront of the front tires and behind the rear tires, but I don't think I have heard mention of a "minimum ride height". Certainly you want some for clearing debris and such on the road, for taking corners (spring compression), or for speed bumps (the ones I cross every day are about 3 inches tall). I am looking at this from a side skirts/catamarans point of view. Thanks.

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Old 12-23-2009, 11:32 AM   #2 (permalink)
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I think the answer is "it depends".

SAE may have a rule of thumb answer. (By the way, I thought aerohead has said 10 degrees for approach/departure angle?)

But sports car owners tolerate below average ride heights. They just have to watch out more for debris, bumps & driveway angles.

Makes me wonder what the lowest, non-adjustable OEM clearance is...

basjoos would probably tell you to make the low-hanging bits sacrificial. His pontoons are coroplast. Inexpensive and not a lot of work required to replace.
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Old 12-23-2009, 12:08 PM   #3 (permalink)
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SAE and Custom by Crunch

SAE recommends an approach angle ahead of the front wheels of 16-degrees.Between the wheels,up to the rocker panel bottom,10-degrees,and behind the rear tires,10-degrees.
GM has adopted a partial solution with cars like Camaro,Firebird,Corvette,allowing the road to eat away the parts which extend too low.The New Beetle also utilizes this technology.
The Ford Probe-IV had active suspension which allowed the nose to drop,and front spoiler to deploy to a ground clearance of only 3.5-inches ( 87.5 mm ) above 40-mph.
Many supercars utilize active suspension to lower the car at speed,then raise it for urban warfare.
Here in Texas,engineers must design for roadkill,where the occasional dog,cat,skunk,possum,raccoon,armadillo,hog,white-tail deer,or tire-gator might take out a car's undercarriage.
Always travel with spices and condiments in Texas,as you never know when you might be preparing a roadside delight!
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Old 12-23-2009, 12:51 PM   #4 (permalink)
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aerohead -- what did that SAE paper for the NASCAR Dodge Daytona 500 show as best nose-down rake for racing?
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Old 12-23-2009, 01:12 PM   #5 (permalink)
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Sae

Quote:
Originally Posted by Old Tele man View Post
aerohead -- what did that SAE paper for the NASCAR Dodge Daytona 500 show as best nose-down rake for racing?
Rat's,after all the trouble we went to,to get me access to it,I left the thing at home and it will be maybe 2-1/2 weeks before I can post on that.
My memory should not be trusted,but I do recall from the paper that the Dodge was very sensitive to rake angle,and a change of even a degree made a great difference to downforce and drag.
I'll bring that with me when I get back,sorry for today's empty hands.
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Old 12-23-2009, 03:01 PM   #6 (permalink)
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If you want to add side skirting, or a front lip why not make it out of stiff rubber like mud flaps are made out of? you can get it at farm farm stores.
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Old 12-23-2009, 03:34 PM   #7 (permalink)
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Quote:
Originally Posted by aerohead View Post
My memory should not be trusted, but I do recall from the paper that the Dodge was very sensitive to rake angle, and a change of even a degree made a great difference to downforce and drag.
...that's what I recall too. Sorta like Goldy-locks and a "...not too much; and not too little" situation..." where either side of "...just right..." isn't gonna help you.

...just wanted to make the point that "sometimes" the "good spot" (vehicle rake angle) isn't something you want to arbitrarily be playing with, unless you know what you're getting yourself in for.
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Old 12-24-2009, 10:28 PM   #8 (permalink)
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I can't comment on the minimum ride height, but I have the 5" lawn edging from Home Depot for a front air dam on my car. It is about 3-4" off the pavement. It rubs all the time. Speed bumps, driveways, etc... I really like it because it is very durable. The snow and ice recently hasn't even cracked it in 20 degree weather. The asphalt has been the most abrasive on it by wearing it away. At $13 a roll, it gives you enough for two front air dams, so it's a great deal. I'd also use it for side skirts...
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Old 12-25-2009, 10:39 PM   #9 (permalink)
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so after smoothing the under belly all the way back, would a 3'' dam negate that work?
the bottom of my front lip is 7 3/4 inches to the ground. I could ratchet my springs down maybe one inch. But I had lowering springs for about 1 yr and I was ALWAYS scrapping my front lip.
What angle are you measuring?


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Old 12-26-2009, 09:04 AM   #10 (permalink)
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I've worked on a few lowered cars that scrapped bumps and damaged their bumper covers.
It seems 4" will scrape regularly and 3" will scrape daily.
That said, if its lawn edging, etc., it will just flex out of the way and spring back.
One older large car (Buick?) if you let some air out of the bags then let off the gas hard and swerved over the line , the steel bumper would pop off the road reflectors ! Thats too low!

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