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Join Date: Oct 2006
Posts: 315
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Ride Height
I own a restored 1973 911S with 22mm front and 26mm rear torsion bars along with new bushings and Koni's. I know that these cars should have approximately 25 1/2 in. front and 25 in. rear fender measurements. My question is, Should this measurement be taken with a full tank of gas or closer to 1/2 tank? The reason that I ask is the front of the car will raise up at least 1/4 or more when the tank is 1/2 empty and also, as the front raises up the rear drops a little. This is more evident at high speeds and acceleration as the front lifts up and feels a little light and unstable.
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02-06-2007, 05:31 PM
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Join Date: Nov 2006
Location: Studio City, Ca.
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Good question. I'd like to know the answer as well. My car is going to the suspension shop on 2/19.
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87 Carrera Cab GP White 01 740i Sport 03 Honda Odyssey |
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02-06-2007, 06:24 PM
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Location: TX USA
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What tire and wheel sizes do you have on the car? That makes a significant difference in where you want the ride height.
Personally, I would set the corner balance with a half-tank of gas ... more likely closer to where most driving will be done with than a full tank!
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Warren Hall, Jr. 1973 911S Targa ... 'Annie' 1968 340S Barracuda ... 'Rolling Thunder' |
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02-06-2007, 06:41 PM
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Home of the Whopper
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I am just throwing some numbers out there so I may be off a little, but...
The difference between a full tank and half a tank is about 10 gallons? So about 80 pounds? Divide that between two front 'springs' at a rate of about 400 #'s per inch? You're talking about 1/10th of an inch in deflection at each front corner? For a street car I don't really think you'll notice much of a difference. Some (many?) may disagree, but corner balancing a street car is a waste of money. Set the ride height so it looks good and I doubt you will notice any difference hitting the on/off ramps at speed. If you're tracking the car, then nevermind.
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“The wave is not the water. The water merely told us about the wave moving by” – Buckminster Fuller |
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02-06-2007, 07:31 PM
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3 restos WIP = psycho
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Location: North of Exit 17
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I did mine with a half tank; when in doubt, regress to the mean.
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- 1965 911 - 1969 911S - 1980 911SC Targa - 1979 930 |
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02-06-2007, 07:43 PM
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Location: Galivants Ferry, SC
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BK911.... the stock front "wheel rate" ( not spring rate) is about 100-120 lb/in.
- Wil
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Wil Ferch 85 Carrera ( gone, but not forgotten ) |
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02-07-2007, 12:47 PM
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Home of the Whopper
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Well there I go showing my ignorance again. So what is a wheel rate? Does it account for the suspension geometry?
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“The wave is not the water. The water merely told us about the wave moving by” – Buckminster Fuller |
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02-07-2007, 01:27 PM
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Think of this..... what matters is how much resistance force the wheel sees as it moves up and down. The spring rate is simply that... the spring. If it's located (say) on an A-arm with the lower mounting point near the balljoint....it will make for a "stiffer" suspension than if the lower mounting point was more inboard....where more leverage is imparted on the same spring.
See...? The point is that a stock wheel rate is nowhere near 400 lb/in. More like 100-120 lb/in. - Wil EDIT...see what I say here and the embedded links, even though I ( too!) used the wrong term "spring rate", at the time I wrote it. --> http://forums.pelicanparts.com/showthread.php?threadid=329018
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Wil Ferch 85 Carrera ( gone, but not forgotten ) Last edited by Wil Ferch; 02-07-2007 at 01:47 PM.. |
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02-07-2007, 01:43 PM
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