Frank Simonetti

[outlaw4j]

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

[ZERO25]

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)

[billetbirdcage]

Spring surge is going to effect rebound rate/time way more then the spring being used is.

[Henry Every]

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

Are we talking seat of pants feel or actual dyno data?

[outlaw4j]

always seat of the pants for tuning. that's not what dynos are for.

[Henry Every]

there are all kinds of dyno's...

[LRtireCHANGER]

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

[MasterSbilt_Racer]

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.

[Mopar DLM]

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.

[MasterSbilt_Racer]

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.

[fastford]

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 .....

[MasterSbilt_Racer]

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.

[ZERO25]

What machine would test the rebound rate, Frank/Bubba is referring to?

[MasterSbilt_Racer]

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.

[fastford]

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.

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 ?