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Author Topic:   Storing Car on Jack Stands
sleadhead44
Dirt Maniac

Total posts: 109
posted July 22, 2004 03:21 PM  
Do you all store you cars on jack stands during the week? I am in the habit of this just because the guys I used to pit for did this, but is there any real reason for it?

stic8
Dirt Full Roller

Total posts: 69
posted July 22, 2004 03:34 PM  
no not really, the car gets put on jack stands when we have to work on it or check it over but we seem to move the car aroud enough i dont believe anything really happens to the tires or the suspension from letting it sit for a week. over the winter is different i would take tires off if you plan to reuse next year

hobby39
Dirt Maniac

Total posts: 112
posted July 22, 2004 04:14 PM  
I've been told that it dosen't really matter when your running stock type springs however when your going to the expensive leaf springs they really need to be on jack stands as they wear out quick just from racing and keeping the cars weight on them all week only speeds up the deteriation of the springs.

Special Ed
Dirt Full Roller

Total posts: 63
posted July 22, 2004 05:57 PM  
It does not happen often but we have had coil springs to collapse on us before, so we always put ours up on jackstands. If you are already used to doing it I would continue to do it. It sure won't hurt anything!!

racin2much
Dirt Full Roller

Total posts: 46
posted July 22, 2004 11:25 PM  
Think of your springs as light bulbs, they are only going to last so many hours before they give out. But not being used does not burn up that time. Keep it on stands or jacked up ALL the time they are not in use and you will increase the life big time.

marshalr
Dirt Maniac

Total posts: 148
posted July 23, 2004 08:21 AM  
I was taught to always have the car on the jackstands or on the trailer. Softer racing tires get flat spots from sitting on em it seems.
There is a math formula to determine a spring's rate that takes into account the material characteristics, number of coils....age of the spring is never mentioned. Thus we can conclude that a spring's rate will never change, you only are losing spring free height. I measure a springs free height now right out of the box, record it and periodically check it. If it loses some height adjust accordingly with shims , weight jacker etc...

Whitelightning
Dirt Freak

Total posts: 429
posted July 23, 2004 02:27 PM  
If its dot tire car and coils all the way around I see no reason to put on stands. Afco has a lifetime warranty agaist any spring taking a set. Now leafs it seems to make more since to jack up?

racin2much
Dirt Full Roller

Total posts: 46
posted July 23, 2004 07:36 PM  
My 225 afco after one year was 170 and my 200 couldn't even be measured. So I keep them up all the time. Like I said, if not being "on" you ain't using it.

jay116
Dirt Freak

Total posts: 428
posted July 24, 2004 10:01 AM  
Coil spring rate is determined by wire diameter, mean diameter, and number of active coils. If you had a spring that was a 1100# spring and it rated at less then 900# it was never a 1100# spring. The only potential for a spring to have changed rate on a spring checker is if the spring was bent or collapsed (loss of free height). A bent spring will begin to load the checker off of one side of the spring effecting its rate. If its bent you wouldn't be racing it and you wouldn't have it on a spring rater.
If a spring has lossed free height the spring will actually get stiffer. Less number of active coils will raise the rate given the same wire diameter and same mean diameter. You can't change the wire diameter of the spring so that's out the window. The only other thing that could change would be the mean diameter. The diameter can become larger with an abused spring that has had severe spring height loss. This could happen with the use of, lets say a 500# spring on a RF of a 3400# pavement car. This would coil bind the spring severly and likely cause a loss of free height and increase the mean diameter of the spring which would effect spring height.
Your problem of lossed rate is more likely a mis-boxed spring from the factory or a poor seat in the spring checker.


racin2much
Dirt Full Roller

Total posts: 46
posted July 25, 2004 09:21 PM  
Only one thing beats technical knowledge and book smarts, EXPERIENCE! I respect your opinion, but I have experienced otherwise. That is the loophole on spring warranties and no more. Unless you check what you have, you have NO idea.

merc123
Dirt Full Roller

Total posts: 28
posted July 29, 2004 09:43 PM  
We jackstand ours. It makes it easier to work on as well as saves the springs. Some guys @ the local tracks jack up their rear ends in between heats/features to take the weight off the springs.

Ego Racing
Dirt Forum Champ
Total posts: 724
posted July 30, 2004 12:39 PM  
Crew Chief>>>> DITTO!
I have a 500lb spring in my shop that was on a car for 3 years that sat in the shop on the floor when not used. It has been used on 3 other cars in the last 5 years and it rates as a 498lb spring! If springs went bad from sitting all of our daily cars would be draging the frames on the roads. Leaf springs go bad from being twisted while in use not just from weight sitting on them.
As for what people do at the track Start doing something completely off the wall and win, the next week you will see someone else doing it and then the next week more people will do it. Why? They cant tell you but they will do it. We have dome it before, we got to the track when running asphault and our water bottle would not spray water we used to look at the scribed lines in the tire. We got an empty Coke can and a rag and wiped them down. We won our heat and feature and were accused of treating our tires, they checked and they were legal, the next week we saw 2 other teams wiping there tires down with Coke.

Ego Racing
Dirt Forum Champ
Total posts: 724
posted July 30, 2004 12:45 PM  
One more thing. When your car is on jack stands, if the suspension is hanging on the shocks and they are fully extended they are going to be ruined. Then people will be saying this brand or that brand of shock is junk because they went bad in 3 weeks.

We put the car on stands at the track so we can measure the tire stagger on the car. and get under it to check it out, not for any spring or shock reasons.
Do you guys who jack the car up for the springs let the car bounce around on the trailer by strapping down the tires and not the chassis? If you do you are working the springs and shocks as much or more than when you race.

    

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