An example of poor frequency would be rear springs that have a lower rate than the front spring.
Do I have news for you.
An example of poor frequency would be rear springs that have a lower rate than the front spring.
I’m not sure exactly how the factors interact with one another, but you can change the spring material, the thickness of the wire from which the spring is wound and, diameter of the turns of the coil, the number of turns per unit length and the overall length of the spring. Manufactures like savvy and Currie try to work those to get a spring that has the longest free length, while still providing the correct ride height. Those two factors in and of themselves can be achieved by modifying the above listed parameters.I've been reading up on frequency.
If I am looking for a spring that provides a certain ride height along with a sufficient free length to support the shock travel, how do I also include frequency in my decisions? Does changing the frequency effect the ride height and/or the free length?
I’m not sure exactly how the factors interact with one another, but you can change the spring material, the thickness of the wire from which the spring is wound and, diameter of the turns of the coil, the number of turns per unit length and the overall length of the spring. Manufactures like savvy and Currie try to work those to get a spring that has the longest free length, while still providing the correct ride height. Those two factors in and of themselves can be achieved by modifying the above listed parameters.
Fascinating stuff huh. But honestly, it's fun to know but not practical. The answer is you buy a quality set of matched springs that meet your other criteria
Good point. Here is a comparison to consider. Let’s say that your Jeep while empty gets 4” of lift with a TJ spring. Now let’s say you add enough weight that a 1” spacer on top of the tj spring nets you 4” of lift. Although the ride height is identical, the weight of rig changes, and the spring is operating at a different frequency due to the added weight affecting it and compressing it. Spring tuning is more common in the coilover world, but that doesn’t mean it has no effect in the spring+shock world. But there isn’t a manufacture out there making custom spring for our application, so comparing the spring rate of various spring with the same final ride height is really not going to get the results. Going with a standard spring (Currie, savvy) and using shocks to tune ride is way more feasible.From what I've been reading, watching and grasping, it is all tied together into the same discussion. Low frequency suggests a longer and/or lighter spring, while a high frequency spring suggests a shorter and/or heavier spring. Describing this through frequency is a way to compare the relationship between rates and lengths. One cannot be changed without affecting the other. One also cannot change the vehicle weight without also changing the frequency of the existing springs.
... Spring tuning is more common in the coilover world, but that doesn’t mean it has no effect in the spring+shock world. But there isn’t a manufacture out there making custom spring for our application, so comparing the spring rate of various spring with the same final ride height is really not going to get the results. ...
I'm not sure that this is adding anything new to the spring debates other than a bit of a distraction by throwing in another way to describe the same sets of relationships that she of us have always been trying to describe. One cannot change one thing without changing other things. This includes adding spacers to make up missing ride height compared to another spring. Adding spacers is changing the suspension design and is consistent with the recommendation to build the ride height with springs first and fine tune with small spacers if needed.
I’ve only done COs with dual rate nuts, where spring selection affects a good portion of handling - shock valving does do the most.Spring tuning with CO's largely consists of establishing the tide height along with creating enough spring length to support the shock travel. Sound familiar? There is a relationship that is created. The rest is controlled through the valving.
Spring tuning with CO's largely consists of establishing the ride height along with creating enough spring length to support the shock travel. Sound familiar? There is a relationship that is created relative to the vehicle weight. The rest is controlled through the valving.
Here is a link.
https://fliphtml5.com/khqr/dimm
I would be surprised if Currie did not take care of all these things you are asking about.
I noticed that in their bumps, front trackbar, and AR. Even the new rock nuts.Having done a few outboards, I would agree. And I would further argue that Currie knows a few things about maximizing the potential of the TJ suspension that most don't.
It does sound familiar. I thought in was unfortunate then and still do.
Check out Billa Vista's coil spring bible. I don't claim to be an expert on any of this, but he has a chapter dedicated to suspension frequency that made me understand this stuff way better than I did an hour ago.
I've been reading up on frequency.
If I am looking for a spring that provides a certain ride height along with a sufficient free length to support the shock travel, how do I also include frequency in my decisions? Does changing the frequency effect the ride height and/or the free length?
From what I've read and understood on this topic, suspension frequency is how fast the suspension travels up and then back down to the same point when you drive over a bump. If our Jeeps did not have shocks, the springs would continue to bounce up and down at this rate for quite some time.
The suspension frequency for each corner is your standard classic spring equation, f = 1/2pi *sqrt(k/M), where k is the spring rate and M is the total sprung mass in that corner, which is calculated as half the axle weight minus some calculated amount for unsprung mass (wheels, tires, suspension components ...). I would assume you want this number to be even left to right and front to back unless you have a special case vehicle.
To give perspective, passenger cars today have that number less than or around 1Hz. High speed race cars (think F1) that generate a lot of downforce will be around 5Hz. That's a five fold difference.
It is not clear to me how perceivable the difference in front vs rear susp frequencies in an hypothetical Jeep with different springs (and same shocks) will be. But, us humans are surprisingly sensitive to some things and I would not be surprised if you can feel (but not clearly explain) a difference like that. It might come out as just an uneven feeling ride. The springs we choose will very much have an impact. Shocks complicate things quite a bit on top. I think Currie knows about this much more than we do.
@Mike_H may know more than I do. Did I say anything incorrect here, Mike?