There is none, you arnt going to find an equal. Springs are wound with spring steel, the characteristics of the spring rate are determined by the wire diameter, and the overall spring diameter. So unless another company copies it exactly, and uses the same material forget it.

Losi Yellows are close.

Also this talk about progression is entertaining. All springs are progressive by nature, to some extent. Its inherent to how there made, all your doing is bending spring steel aka a spring.

A spring is rated, usually, by distant over resistance.

Example: Colapse a spring .1" how much weight does it hold, or pressure does it exert? say 1lb for ease of numbers. Move the same spring another .1 (.2 total now) if its a truly linear spring it will 2 lbs.

Problem is alot of MFG's do not compare the entire range of motion of the spring for one, and two they average out all the measurements and give you a avg rate. Which is a wildly misleading.

If you want to see if a spring is progressive, measure it thru the entire range of motion, right up to coil bind, and chart it out in excel or something. Then set it up to show you a curve, the curve will not be linear, if your lucky it will be close.

Dual Rates? only if there is a stop. 2 springs stacked do not make a dual rate. Only if there is a stop on one spring, and or if one coil binds before the other. Anyone out there know how to figure spring rates of 2 springs stacked?

Can you post a picture of a spring that you suspect is progressive? I'm not trying to trap you here, but I'd like to see what you see that you think is progressive. While your at it (just food for thought), have you ever seen a progressive torsion bar? How about a progressive anti sway bar?

I don't want to mince words here - some users will argue that all springs are progressive, meaning that as you compress them, they store an increasing amount of kinetic energy. As a result, they all get "stiffer" the more they are compressed. But they do so at a linear rate, right up to the point where you put them into coil bind (or bottom out the shock the spring is mounted to) and the absorption goes to -0-

People get all fired up over springs. I contend they should not - it's just a piece of wire - it has an overall length, it has a certain diameter, the metal has a certain modulus of elasticity because of it's temper. You can measure all of those.

Why get your panties in a bunch when you wind that wire up in a coil and call it a spring?

I'm not arguing that the size of the coil doesn't matter - it does, but for packaging reasons. You only have so much room to fit the spring in there. Problem is, as the spring diameter gets smaller, spring stability becomes an issue because the coil starts to deflect in directions you don't want it to (i.e., buckling in the middle). Sometimes you can use that buckling to your advantage (for example, they preload the buckling force in the spring on a stock car when they do a coil bind setup because the rules require some insane long spring), but for RC applications, it's almost always bad.

Yes - it's the rate of the softer spring until that spring is can no longer any more energy (coil bind or otherwise). Then it becomes the rate of the stiffer spring.

At first it was entertaining but this whole spring discussion is getting carried away. Let's be honest who really gives a $hit. It's an Rc car for Christ sake. Losi spring work for some and ae springs work for others. The spring charts are all over the Internet. Do some testing and figure it out.

For the guys running ghea pistons,which ones do you prefer?I run at Westcoast so the track is super smooth with not alot of big jumps

In real racing (not toy car racing lol) a progressive spring looks like this. Never seen one of these in rc racing. Schumacher big bores might be considered progressive springs as the spring circumference gets smaller at the bottom but to my knowledge I have never seen an actual associated, losi or kyosho progressive spring. A true progressive spring has two rates depending on where it is in the compression or retraction.

The tapered pistons are usually used on rougher tracks, flat pistons are used on smoother tracks and big jumps with harder landings.

Hole size will depend on how you track is setup.

Here is a good resource for spring information, and to learn about how the work.

http://www.afcoracing.com/tech_pages/spring.shtml

Alot of great info here.

I know its RC cars, but its interesting to figure things out. I come from, and still set up and work on Dirt Late Models, so alot of this i researched for a reason.

Stacked Spring rates, very popular right now in DLM's:

http://www.jimmyjudd.com/jimmy/spring_rate_cal.htm

Only after one spring can not compress anymore, or its movement stops does the other springs rate takes over. Most off road application, the shorter spring has a limited amount of movement, once it hits a stop the spring that is active takes over the spring rate.

Here is a good resource for spring information, and to learn about how the work.

http://www.afcoracing.com/tech_pages/spring.shtml

Alot of great info here.

I know its RC cars, but its interesting to figure things out. I come from, and still set up and work on Dirt Late Models, so alot of this i researched for a reason.

Stacked Spring rates, very popular right now in DLM's:

http://www.jimmyjudd.com/jimmy/spring_rate_cal.htm

or

(Spring X spring) / (Spring + Spring)= stack rate

200 X 400 / 200 + 400 = stack rate
80000 / 600 = 133.3333.....

Only after one spring can not compress anymore, or its movement stops does the other springs rate takes over. Most off road application, the shorter spring has a limited amount of movement, once it hits a stop the spring that is active takes over the spring rate.

hideeho
nope, got that beat!
I last rebuilt the dif in my XXT-cr graphite kinwald edition in '94 or '95. I rebuilt it again last september when I found a new local off road track. Believe it or not, I put new oil in the shocks & new grease on the dif (still the old stuff I didnt buy any new stuff) & it was still smooth as butter! now, my 21.5t stock brushed motor & 2000mah nicads were a whole different result

I have an extra set of Losi 56 pistons I can test with. How much different did you have to change the oil/spring combination? Right now I have stock AE springs, #2 pistons, and 30f/27.5r oil.

Craig, I would say a spring of similar design to what tuner66 posted would function progressively. The coils would quickly bind on a few winds, leaving the remaining action to fewer coils. I can't say I've seen any like that on a b4.1 though.

Lol that was my first kit... brings back memories!

hideeho
I started w/ a grasshopper. found out very quickly a live axle does not do very well in off road racing! I went through 2 rc10 (original gold chassis!)
one got swiss cheesed, the other got a fiberglass!? chassis then a graphite chassis & mip tranny.

Been there, lived that! Good times!

You mean bound and rebound. Spring RATE is controlled by wire thickness ONLY.

A true progressive automotive spring is coiled smaller at one end and larger at the other (or any variation by design) and rate can change ONLY if the wire thickness is progressive as well. Like so...



Notice the wire size tapers along with coil size? If your RC car spring does not look like this then you do NOT, by definition, have true progressive rate springs. This is fact by definition, not assumption or hearsay.