I don't have the engineering answer for you. It could be the diameter of the coils, diameter of the wire, number of coils with this wire or that.
I'm the type of Guy who pays attention to my setup and I will try things to see how they effect the truck. I'm a firm believer in knowing what I use and what I did and how it improves or even worsens the truck. But I can say they are an improvement. I didn't do the Losi springs since all I read was that they don't rub the shock body. Well I didn't have a rub problem so I didn't bother. I keep reading and reading about these Avids and every single one noted improvement. So I tried them and they have not come off since. Sorry I don't have that exact answer, but I've been on the hunt for information and landed on suspension designs and theories hoping to have an explanation for the hype.
Equal drivers on the track, the one with the better truck is going to win.

Pretty much making and testing springs have come a long way from the days when the AE springs were made. Those springs were not even made with the extra weight (top heavy) of the SC truck in mind. The new Avid springs fix a lot of that with current spring technology.

From a physics point of view springs are not too complex. Has the technology associated with manufacturing and testing really changed that much? Or is it just that rc company (or companies) have a better understanding?

I would like a little more detailed info if you have the time/inclination.

Could someone explain to me what Bump steer is doing to my truck. Also, what am I doing by adding or removing bump steer spacer's?

Reminds of the story of the Princess and the Pea. How is that anyone can feel the difference of a set of springs?

I'm not trying to insult anyone who believes in Avids and I agree with all the rave reviews are success stories. My point is that the Avids are simple non-progressive springs as far as I can tell. There is no pre or post tension "technology" in them. Spring materials haven't changed a great deal and even if they did, the modulus of elasticity doesn't change with time. My best guess is that they are made with more precision. More precision in the wire diameter, shape, and length and that's about it. This would result in better corner balance and possibly more consistency.

Jbone,
I assume the rate from AE to Avid is not exactly the same. Is there any possibility that a softer or harder spring can be attributed the increased performance? Again, I'm not trying to start a fight here. This is all food for thought and bench racing!

Respectfully,
Tom

Bump steer changes the toe as the wheel travels up and down. Adding will make it move more and less will make it move less.

Grab your front and watch how the top moves. Add some or remove some and see the difference.

I notice your lap times improved by about a second from one race to the next, but you're not the only one with the improvement. There are three other guys who were there both nights, and two of them have very similar improvements, the third also if you just look at top 5/top 10.

I'm not trying to cause a problem, just saying that your improvement from one week to the next may be due, in part, to other factors. If people love the avid springs that is great; I just would like a reasonable explanation as to why they would be better.

Keep in mind this is coming from someone who can barely get around a track, let alone have consistent laps.

i was wondering do you guy have a link for those avid spring you are using for front and rear? Second question is do you guy build like the manual say with the dead shock ? and third what is up with the lower spring retainer it like my springs can fall off to one side they dont hold in place good at all or not like im used to for 1/8 scale truggy any way. i built this for the wife and she was happy i spent all day getting it done while she was out. i just have to change the stuff i dont think is right. i did not have a problem with the steeing bell crank that people said they had to cut for. so iguess i lucked out there. i did have a bad futaba horn which sucks do the make an aluminum servo horn for this or not? I could use a link for that also the plastic one dont seem to fit the savox to good so i dont trust it will hold. thanks rob.

what kind of body cut outs are you guys running on large tracks? ive been hitting the local 1:8 track and it has some larger sized jumps. im good on all but the largest jump. i have the speed easily but once in the air i have ZERO control and get massive parachute effect.

im running the AE body with the top 2 triangles cut out and cut the very back out by the bumper.

Here is the link for the avid springs:

http://www.avidrc.com/product/19/springs/

While you are there, check out the site, the format and products are definitely easy on the eyes. You will need to get different shock spring retainers; check earlier posts (page or two back) for options (including Avid).

Yes, I made my shocks as instructed in the manual. I think 1/10 scale shocks typically have no bladder and zero rebound, but a more experienced rc'er can correct me.

Make sure your spring retainers are on correctly. They should slide over the eyelet with a nice sliding fit and hold the spring quite reliably. Maybe you have them upside down?

Regarding the horn, were you using the one as instructed by the manual? There is maybe a little aluminum ring that keeps the plastic gear in tact. I am not aware of an aluminum horn, but with something like the sc10, chances are there's an aluminum anything somewhere. Maybe someone else will point you there.

Hope your wife enjoys it.

IMO the only 2 guys who made big improvements were me and Jbone. Oddly enough, we both switched to Avid springs and Bypass1 pistons between races. The other guy was 8 seconds faster overall, and the other guy was slower and all over the place. But they're all my buddies. This was just an illustration of lap times. It seems we all get to a point where we are stuck at making gains. I'm now stuck at 21/10:00 even through a perfect race. Every week its 21/10:00 give or take a few seconds. So when I make a change and I'm consistantly running 22/10:20, then I know it was an improvement. So, as far as why, I dont know why. But they are not comming off until I feel something may be worth trying, and then it will be back to the score card.

what did u think of the bypass pistons? and what type of track are u running on ?

One thing I can tell you is Avid matches their springs. Spring rate tests have been done to other manufacturers springs and people found a lot of variance between springs that came out of the same package. Kyosho's typically were closest and maybe thats why they are $20 a pair. But the Avids are matched and rated and also have a printed label they stick to each container showing the exact rate. Tested to be accurate also. Any other info should be best explained by Kurt "Coach" Wenger. He designed then

Well Mike answered most of the question, but a few things to add.
-Track conditions were identical for both races.
-I already had the Bypass1 pistons in for both races.

I like them a lot. You can go to http://realshocks.com and read up on them. I have a setup for my SC10 on there as well.
I run on a outdoor clay track that can get dusty and is ran Wet majority of the time. It's got a lot of jumps and technical type jumps and sections.

Yea, I'm waiting for an overtray and Flotek body before coming back out.