Fox Life!!! Anything Related to Fox Suspension

How does it make any difference on an adjustable coilover design where the extra length will just be absorbed by the threaded portion of the coilover? A 13” and 14” spring will both be 600 lbs, the 14 will just move the collar up another inch if you set the preload correctly (which you should.)

 

Correct, but also with a 14" spring you can set more preload then a 13" spring before having worrying about coil bind at full shock compression. (Preload being after the set collar contacts the spring).

 

Very nice setup I have a DCLB as well. How much preload do you have on that setup. Your setup should give me a decent starting point. The Accutune folks made the recommendation shoot for 21" from the top of the coil bucket to the the bottom on the coil where it bolts to the LCA under the eight of the truck for my ext travel 2.5s

 

Well that depends on how the different length is designed. If it's like the same amount of spirals per inch (I just made that measurement up) but stretched, then sure. But if it's the same spirals per inch PLUS the additional height then they can't have more preload without running into the same issue of coil bind.
I would have to see a side by side comparison of the springs to say, and it probably varies by the spring, too.

 

@1:15 "...you want your shock doing the work. All the spring is needed to do is support the vehicle at the ride height that you want."

 

I just swapped out my 13" 600# for 14" 600# springs a few weekends ago. Wish I would have taken a side by side picture, but after putting in the 14" the adjustment collar is an inch higher as mentioned but there is also more space between coils now (I don't have a measurement just a visual). Also seemed to soften the ride a little bit although i admit that it my be just a placebo effect.

Yes, really it comes down the the spring design.

 

So if there is now more room between coils you can add more preload. But if you add more preload, you're increasing the spring rate(not literally but for my lack of technical terms) when you could have purchased 650 lb springs for example and kept the distance between coils reducing your chance for coil bind.

Someone please correct me if I'm wrong. I am not an expert. I'm just babbling on about how I see this to work.

 

Spring rate for a coil spring is determined by the diameter of the wire they turn and the number of turns per inch. I don't know if given two springs of different lengths but same rate if the wire necessarily is the same diameter but I'm fairly certain they would.

When you compare Eibach's data (just for example) it gives the following. The 12" 600 lb/in has a block height of 5.24" and travel of 6.76" and represents a maximum load of 4,069 lbs fully compressed. Compare to a 14" 600 lb/in with a block height of 6.26" and travel of 7.62" and represents a maximum load of 4,638 lbs.

So since spring rate is linear the longer spring compresses less per inch at a given rate and load because it will have more length, turns or however you want to think of it. IOW, a going from a 13" to a 14" spring in the same rate will sit higher and compress less over its length with the same conditions otherwise. So you will preload the coil slightly less to start.

 

It's been talked about a few times in this thread

https://www.tacomaworld.com/threads/fox-life-anything-related-to-foxs.536036/page-54#post-19349110

https://www.tacomaworld.com/threads/fox-life-anything-related-to-foxs.536036/page-54#post-19349269

 

A 14" spring will sit higher in a fixed position coilover assembly, but not in an adjustable coilover (like Fox 2.5) where the threads will absorb the extra inch. This is where people get confused, myself included.

The maximum load comparison you just made means the longer spring takes more weight to fully compress even though they're both 600lb springs, but I wonder if that matters on an adjustable coilover where the extra length is almost a moot point at the same preload.

 

I’m traveling this week but will take exact measurements for you when I return. I believe I set for 2” of spring preload. I don’t worry about the number of threads showing since it’s hard to for me to count them. I measure the spring.

 

All the universal fit, double ground springs are designed for max travel, so a longer spring will always have more travel than the same rate shorter spring.

 

Skimming through that I'm starting to see what they're getting at. So many variables I think I need another morning coffee.

What do you all think about my situation?
I have the Fox 2.5 coilovers in the front (non-ext travel) that come with the 600 lb 13" springs I believe. Even with a little additional preload I'm sitting at like 1.5" (advertised 2") of lift. I was thinking I would want to upgrade to the 14" 700lb King springs once I get a bumper, winch, sliders, skids, etc. But now I'm feeling like I'm back at the drawing board after this conversation.

 

I know it seems like you're increasing tension when you crank the coil spring down, and it's compressing more or changing, but it's not. When you turn the collar the spring does not compress any more, it just raises the vehicle.

There are two scenarios where increasing preload can increase harshness:
1. Lift height too high and no room for droop - tires can't follow the road and clunk on extension
2. Spring goes coil bind and runs out of travel before suspension bottoms out (extremely bad)

 

Adjustable coil overs don't change the spring characteristics, you're primarily adjusting ride height. You want your ride height to put the spring and shock travel somewhere in the middle, so you have the up and down travel you expect. Too much lift means you have less down travel.

So I shot for being about 2" higher than stock with my extended travel coil overs. I give up a little down but not a ton and try to run my shocks as close to the middle of their travel as I can. I have about the same number of threads exposed now as FOX did when they built the coil overs. I don't want the shock hitting its internal limit at either extreme and acting like a bump stop before the actual bump stops get engaged.

You don't want to use the collar to compensate for the wrong spring rate. If you're cranking the collar down you have too low of a spring rate. Vice versa if you run the collar way up the body you have too high of a spring rate.

You want to have just the preload you need to hold up the truck without consuming too much or too little travel. Preload is the amount of coil travel you use to hold the truck at its static height. It takes the same amount of force to go the next inch as it took to get to its static height (e.g. 600 lb/in x 3 inches took 1,800 lb and another 600 lb gives you 4" of spring travel). So how that factors out might result in soft ride, coil bind or a hard ride depending on what you're after.

You never want a coil to compress completely but leaving too much unused is wasting travel capability and is probably a comparatively harsh ride. It's ultimately subjective and conditional, other than never binding a coil. One person's ideal ride and travel won't be the same.

I run 14" 650 lb/in coils on my truck with extended travel 2.5" IFPs and I find them acceptable but slightly harsh (partially it's because I need to further soften the tune in the shocks). But I don't want to run a sway bar so having a slightly stiff ride is alright and I don't want to bind a coil. I think 14", 700 lb/in coils are overkill on a Tacoma, you've overloaded the truck if they are needed. But that's just my $0.02, clearly a lot of people disagree and it works for them.

I have an ARB bumper, XD9000 winch w/ synthetic rope, a 3/16" front skid, dual batteries, sliders. I do not have tranny or xfer skids, though. It's an intentional decision since I want to conserve payload for gear. I don't use my truck for super hard trails and prefer to base camp and hike/ride/ski instead.

BTW, travel limiters and travel stops factor in here, too. Having active bump stops let you bias more for travel because hitting the limit isn't a hard stop. I haven't yet had the money for better overload and bumps options, so I tend to be over sprung as a result.

Consider too that the spring is pushing back when you unload it, so having a high spring rate might require more rebound damping to prevent being jarring after you've input a lot of energy to compress it.

 

How do you add more preload if you're saying the collar doesn't compress the spring it just raises the vehicle?
I'm pretty sure mine is preload adjustment only. On a coilover like this for example: (just a similar one from a quick google search)

 

As you turn the collar the shock shaft is moving within its body. The spring length isn't changing from it's static loaded length until you run out of shock travel.

 

Preload is how much the spring is compressed at full extension, so you are increasing preload.

But I am saying at ride height you are not changing how much the weight of the vehicle compresses the spring by threading the collar up and down.

 

So in my case going from 13/600 to 14/650 will have the advantage of higher spring rate PLUS the possibility of adding more preload?

And preload doesn’t increase spring rate, rather it just increases the force needed to start compressing the spring right?

I think my brain is starting to hurt less.

 

Less preload. You will turn the collar down less for the same ride height with a higher rate.

https://www.youtube.com/watch?v=YkJqxMVM3v8