In a seminar at the pri, he stated a coilover spring should be replaced every 20 races, because they lose their frequency not their rate. Agree or disagree?
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In a seminar at the pri, he stated a coilover spring should be replaced every 20 races, because they lose their frequency not their rate. Agree or disagree?
The natural frequency of a spring can be calculated by the equation f= √(k/m)/0.25Quote:
Originally Posted by ZERO25
K is the spring rate
m is the mass of the spring
If the spring didn't lose weight or rate, it didn't change frequency
You can really get down in the weeds about how spring spacing, modulus of elasticity, and diameters of wire and the wound diameter all affect mass and rate. But again, if mass and rate are not changed, frequency is not changed.
I messed the formula up the first time, I used spring mass system instead of just a spring.
I got a question:
1. Where does frank work?
2. What does frank sell?
That's a rhetorical question
motorsports director swift springs
Aka Chief spring salesmanQuote:
Originally Posted by stempy
I asked him to PROVE to me the springs wear out, change rate, blah blah blah along with actual data of spring rebound rate and compression rate differences. He asked to me call him stating it was too much for the forum, I agreed, I called, he never answered or replied to emails after several attempts.
I can't say he's right or wrong, I just wanted some sort of data....just for my own personal curiosity and knowledge. Lots of people throw stuff around and make buzz words out of it like "spring hysteria" but I reserve opinions until I see some data...I never got it, never seen it.
I wasn't even expecting millions of dollars of R@D data either, I figured some sort of generic brochure data could be sent out a "proof" of why they are better than everyone else.
Later, I figured out he was sales.....figures.
They may change. However, rate or mass has to change. Equations that correctly describe physics tell you the variables.Quote:
Originally Posted by Lizardracing
Frank is at Swift now? Nice I delt with him at Eibach. Seemed like a nice enough guy, but a salesman!!
According to the video, him and Bubba Gale have done some extensive testing!
Change your springs every week, get new strange axles and a new shock brand every month and tell me how expensive racing is.
Don't forget the new Longhorn chassis every 8 shows either.
He will gladly tell you how smart he is!
We spoke with him at a track a couple years back and his quote was something to the effect of "They couldn't get a budget together" talking about going to work for a different spring company. Seems a bit slimy to me from the one time i talked to him. As pointed out he's a salesman anything to sell another springQuote:
Originally Posted by Fast3
I bought my first swift springs in 2012 , they were just becoming known in the dirt track world , and if I remember correctly , they guaranteed there spring to stay within one percent for long as you owned it , but any way , dont know this frank fellow , but this goes against their original claims ,
Free spring Frank!!
i have no idea about frank or his claims but i do have a lot of personal experience with springs. i work in the off-road industry (atv / utv) and do a lot of professional tuning work with springs and shocks.
i can definitely 100% feel the difference between some different manufacturers of springs of the same rate. Some springs will feel flat and less responsive, others will react much quicker and feel much more springy so to say. like they are capable of storing more or less energy.
This is especially true when an OEM will be testing with a good aftermarket spring and then go to a less costly production type oem spring. that will often require a damping change.
the math on rate and frequency and what not is absolutely fact. no getting over that. but my professional opinion is there is some vodoo in springs.
ive always felt on car sized stuff its much more difficult to feel that as you are not as connected, i think as long as you stick with a good reputable mfg you should be able to tune any of them up good if they are the proper spring for the job
After watching the video again, I believe you are correct. He used the word frequency but with his hand motion, i believe he was referring to the rebound energy of the spring. He said springs dont usually lose their compression rate just their rebound rate.(paraphrased)Quote:
Originally Posted by outlaw4j
Spring surge is going to effect rebound rate/time way more then the spring being used is.
Are we talking seat of pants feel or actual dyno data?Quote:
Originally Posted by outlaw4j
always seat of the pants for tuning. that's not what dynos are for.
there are all kinds of dyno's...
I would be willing to bet that most all coilover springs have changed height/rate/frequency after 10 races. I do not have access to a smasher, I am just applying common sense. Many spring manufacturers(american foundry conmpany incorporated) claim that there springs are guranteed to not loose over a certain amount of height over the springs life. I am almost sure that these companies make a living off of the fact that almost nobody bothers to check there springs rates as they age. SWIFT
Of course they have changed. If the free height changes 0.1" and all the other values change accordingly, do we care and why? That's the question.Quote:
Originally Posted by LRtireCHANGER
Maybe Mastersbilt can explain it to me better. How much does it really matter if your smashing and resetting springs each night/week for track conditions or different track? So it now takes 1/8 of a turn more to get your numbers where you want them. Maybe if your running weekly at the same track and do not have to adjust anything then yes over time I could see where it might catch up to you.
My argument is it doesn't matter. Good springs, that are designed correctly, are not really wear items. When you notice a significant change in height or rate, or a spring is bent, you need to replace it. Otherwise, it is fine.Quote:
Originally Posted by Mopar DLM
all springs have a cycle life , I will use a valve spring for example , I have had valve springs hold there specs for a long time , then all of a sudden they will drop like 20lbs seat pressure , after that , they drop rapidly , your talking about thousands and thousands of cycles here , it would take a bunch of races for a coil suspension spring to do this , unless poor manufacturing is involved .....
You can't live long enough to cycle a suspension spring like a valve spring. You are correct that "infinite design life" isn't really infinite, but 2 max travels per lap vs thousands is the key math here.Quote:
Originally Posted by fastford
What machine would test the rebound rate, Frank/Bubba is referring to?
You would need to fixture the spring to a plate and impact it with a dropped mass. Then you need a high speed camera to count the oscillations over time. Any type of contacting displacement transducer could affect the frequency and require a way to calculate the effect. If the resistance is low enough, compared to the springs' rate, it can be ignored.Quote:
Originally Posted by ZERO25
I agree , I guess one could confidently say a suspension spring will never wear out , only thing is , do you think leaving a continuous load on a spring will eventually lower the spring rate with no cycles ?Quote:
Originally Posted by MasterSbilt_Racer
If it's poorly designed, you are close to binding it, or it's heated enough, the coil spacing will be permanently altered. That will affect the rate.Quote:
Originally Posted by fastford
How concerned should be be if the springs are losing their rebound rate? Sounds like average Joe couldnt test these springs and we're left to the manufacturers recommendations!
As I've said, they cannot lose this magical "rebound rate" without losing other measurables. Taking the word of salesmen will always cost you moneyQuote:
Originally Posted by ZERO25
Does Bubba Gale have the same credibility issues?
If he's trying to dispute the laws of physics, yes. All the variables of frequency have been laid out from the first page.Quote:
Originally Posted by ZERO25
Quote:
Originally Posted by fastford
I'm imagining a suspension spring in place of a valve spring with a proportionate size.
A valve spring being around 2" tall and around 1.55 in diameter, scaled up a percentage to fit between the axle and frame. Say 500 percent?
If you also scaled up the valve, lifter, keepers, retainers, ect... including what it asked to do, basically a gigantic valve spring and the supplied the same Cycles/time/heat I think you'd find the same thing happening.
A spring is a spring....Valve springs just live much harder lives but they will both eventually suffer the same fatigue.
some valve springs hold there pressure but will break when cycled out , others just loose pressure , and loose it quick when cycled out , guess you will never really know what happens to a spring in the suspension case .