Lock out nut is where the spring rate changes over to the non-locked out spring?
My question, when 2 springs are ran in conjunction via a stack, do both compress an equal distance?
Example, 500lb top spring, 600lb lower spring rate together is 273lb. Lockout nut is set to 2" travel, if you compress it 2" inches do both springs see the same amount of movement?
Looking at the math, 273lbs @ 2" movement would be 546lbs on the spring. Once it locks out, shifts to the 600lb spring is there already 1" of travel there, so your beginning rate is 600? aka 600lb spring compressed 1" has 600lb load on it.
Lock out nut is where the spring rate changes over to the non-locked out spring?
My question, when 2 springs are ran in conjunction via a stack, do both compress an equal distance?
Example, 500lb top spring, 600lb lower spring rate together is 273lb. Lockout nut is set to 2" travel, if you compress it 2" inches do both springs see the same amount of movement?
Looking at the math, 273lbs @ 2" movement would be 546lbs on the spring. Once it locks out, shifts to the 600lb spring is there already 1" of travel there, so your beginning rate is 600? aka 600lb spring compressed 1" has 600lb load on it.
Thanks, Krom.
The springs compress very close to what they would individually.
400/200 stack = 133.33 rate
400# on this stack (133.33#) = 3" of travel
400# on 400 = 1" of travel
400# on 200 = 2" of travel
So, you can do the math and don't really need a spring smasher. When you get into bump stops, if you have the curves, you can mesh that in too.
The first time I ever ran a dual stage rf, I started with the travel I was getting with a conventional spring. I calculated a dynamic load at max weight transfer. I installed the stack. I calculated an expected shock travel based on all these knowns. I set the lockout to get what I wanted. Put the car on the same track. I was off on travel by 3/16". This was without actually rating the springs and using nominal values. And the car was several tenths faster and a second place car instead of 5/6.
Last edited by MasterSbilt_Racer; 01-29-2016 at 09:07 AM.
MBRacer is exactly right. You can do the math can calculate how far each spring travels (and hence how far the slider move relative to the nut) relative to the compression of the entire stack. I created a spreadsheet that did it for me and then I could enter the gap and it would tell me the exact amount (from ride height) the entire stack would compress before the lock-out nut was engaged. So then if you knew the combined spring rate (which you would) and the spring rate of the primary spring, you could essentially map the load just like a spring smasher.
All good data to have but it's simply a line graph with a bend it it
The only problem we had really getting the RF dual-stage deal dialed in was lack of track consistency. If you have a track that is the least bit choppy, it is difficult to tune the shock to make the RF behave the way you want it to. It's best used on a really glass slick track with consistent banking top to bottom so that the compression travel on corner entry is very predictable and repeatable. A spring smasher won't really help you with this. Data acquisition and a 7-post shaker rig maybe would get you the data you need :-)
Care to share that spreadsheet LOL? I could ask one of my Eng buddy's here at work to make me one i guess.
We race mainly at Florence Speedway (North / South 100 track), its not always smooth, but thru the summer it pretty much is every week.
I actually don't mind sharing it at all. What I need to do is make it a little more user friendly first. I'm semi off work today so I may work on that this afternoon.
Well, u got a good start then. MB had his car rolling pretty good last year.
I would like to see my Brother get a win this year, but it's getting harder each year $ wise. Doing it yourself on your own dime is rough, but it is nice to see the car run well and finish top 5 to 10.
About this spreadsheet... I spent several hours last weekend tweaking on it and I was showing it to somebody to get a second set of eyes on the math. He asked why I was doing this and suggested that I get a copyright on it and sell it rather than giving it away. I haven't done that and may never but what I have done is created a password protected copy with most everything hidden except the data entry and the results graph.
At this point, I want to figure out a way to publish it online so that I can take it down in the event that I feel someone might take it and use it for profit. What I've also considered doing is creating additional useful spreadsheets (or ultimately having a program written) and packaging that as something that could be sold (by me) in the future. Kind of like a dirt racers math application. I could provide all of the formulas for how to calculate all kinds of things but ultimately, most people just want to input some stuff and see the results. The fact there is an actual MARKET for that makes me hesitant to publish my work for free.
Anyway...more to come on this as I think more about it.
If I can figure out how to post a picture on here I'll provide a screenshot of what it looks like with some sample output to see how interested folks really are.
Here is the trouble with things today. At first you say you don't mind sharing then get the idea that there could be a profit to be made and want to test the water to see if any fish will bite. Now to be honest I would want to get compensated if I thought I had something that could be marketed but I was tought to be of my word and if I said I would share my pappy would smack me if I backed out on that.
Looking at it on my phone, but it looks really cool. I wouldn't mind paying for it at all. I would think alot if big teams would have something like this already.
I like the graph alot. Package it up better and sell it, I say.
Yes, at first I said I didn’t mind sharing. My initial spreadsheet was unreadable to anybody but me. I spent several hour cleaning it up and making into something that a person might actually be able to use (the screenshot I provided is an example). I then had it reviewed by somebody that I trust (mostly to verify my formulas) but they made the suggestion that I copyright the material before sharing it because it could reasonably be considered “intellectual property”.
I’m sorry if you think that “my word” on 4m means something but I assure you it doesn’t (in this context). If a handshake is what you need, I’ll give it to you…but not online. I don’t owe anybody anything for reconsidering my willingness to give away what I spent significant time developing.
To Lizard’s point, you can’t “patent” math. That is true. But you CAN copyright materials (that includes software or files) that generate output based on math. This is the entire reason the idea of a spreadsheet distribution stopped. Because you can’t copyright a spreadsheet. You can however copyright software code which is what I’ll take this to if that is required.
I know there will be people that say, “we’ve done this already”. Call them and have them share their results for free and please let me know how that phone call goes.
Actually Matt I wasn't even judging you directly. And this was not meant to seem like a personal attack. You seem to try and help folks when you can with a simple answer to their questions. What I am pointing out is the way things are today. I run a successful business and if I say something on the phone or even on the Internet I feel I have to honor it even if I realize later that I made a mistake. Again Matt it was nothing personal.
Market it as a cell phone app, with the ability to email the results to yourself. That concept works great with some of the scaling calculators out there. Id spend under $10 for that app in a heartbeat. Not worth my time, and you can make some coin!
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Originally Posted by Kromulous
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