Coil spring rate

Im in a DCLB 3rd gen and went 730lb Dobinson coils. Rides much better than OME in my opinion. Stiff at first but once worn in it rides very well

 

Uhh.. thats why you have shocks to dampen the springs....

I have 700lbs and if I did it again I would bump to 750 and I'm running 1000lb leaf packs and my truck rides better than our Lexus

 

According to the testing Toytec did, the factory front springs are 717lbs.

https://www.tacomaworld.com/threads...2016-tacoma-presented-by-toytec-lifts.395798/

You 2G guys just don’t know what it’s like to have a real truck with real truck coils.

 

All the 3rd gen coils are the same AFAIK. I was going post a link to that thread until I saw you did. There is very little info online about the stock springs.

 

The stock is about 700 lbs according to the thread already posted above. I went with 600 lb king springs when I upgraded. High spring rate doesn't always equate to good ride quality. That's partly why pickups don't ride like Cadillac's. If you are mostly looking to increase ride height as opposed to load capacity, consider a coilover with adjustable preload or a longer spring instead of a spring with a higher rate. Note that I mean a longer spring with the same spring rate (e.g. larger diameter wire), in case that wasn't obvious.

There is good info here:

https://accutuneoffroad.com/articles/coilover-spring-rates-for-toyota-tacoma-4runner/

 

Interesting. I hadn't heard anything about the Pro springs, but I also never looked for it explicitly. It makes sense to me that Toyota went with a smaller spring rate with the fox shocks on the Pro. I did the same with my Kings.

 

Although it is likely an over simplification to use the damped forced simple harmonic oscillator as a model, I agree with you that a higher spring coefficient requires a higher damping coefficient to maintain critical or over damping (assuming that is one of a suspension designer's goal), however increasing either of those also decreases oscillation amplitude and that does not lead to a good ride quality unless you have the mass and/or big enough bumps to drive the increased spring and damping coefficients. Think of replacing the spring with a granite rock and cooling the shock oil to near its freezing point to smooth out the oscillations when you drive over a curb at 30 mph. I'd rather have a softer spring with more damping; at least if my goal is off road ride quality instead of load capacity. Pick the softest spring that gets you to your desired ride height and then get a nice shock to stop you from bottoming out. I have a vague memory of a Filthy Motorsports video on youtube that says something along those lines.

 

Hence why people increase coils and leafs when adding armor, winches, gear etc . . . Hence why they increase coils and leafs for off-roading purposes . . .

 

Then watch the non OEM coils sag. Its happening a lot lately. I stayed with the stock coils as what Bilstein recommends with the 5100s and no sag. Mine has maintained the same height for over two years.

 

Here's the email and contact, in case you or anyone else has more questions.

 

Hence why in some cases they are trading off-road ride quality for load capacity. I think people often jump to the wrong conclusion that heavier springs are the solution. I'll relink this article in case you didn't see it.

https://accutuneoffroad.com/articles/coilover-spring-rates-for-toyota-tacoma-4runner/

Joe, you were one of the people advocating expensive shocks to me a while back before I upgraded my suspension and part of the reason I ended up with Kings.

I went with the 600 lb springs based partly on that article and some additional thought and research.

 

Wouldn't spring free length also play a big role in the rate at ride height? It would seem a higher rate spring would firm up more through the relatively short travel of our front coilover setups.

 

Have you ever been watching an off-road race and a (garage built) truck lands off a jump and bounces into the air? Probably yes. Have you ever seen a (factory built) dirt bike bounce off the ground in a motorcross race? Probably not. The bouncing is undesirable and caused by too much spring and too little shock. Correct me if I'm wrong. I'm starting to get drunk.

 

I don't think I understand your question. A longer coil spring with everything else the same has a lower spring rate (e.g. 100 pounds will compress it further than a shorter spring). Coil springs are harder to visualize. Think of a leaf spring as you make it longer (and move the mount points farther apart). It bends more. Another analogy would be a single box spring mattress vs two on top of each other. You are going to sink in further with two.

 

stock TRD OR coil is a 700# coil. 3rd gen only. Other 3rd gen models may be less but the 3rd gen is considerably heavier than the 2nd gen (about 330lbs in the nose). I ran OME 600# and the sag after a year was bad, like 1.25”, been there done that. I run 14” 700# coils now but will be switching to 650’s on my next rebuild

 

I've read it before and there is some truth to it but you have to take it with a grain of salt. Accutunes bread and butter is their tunes and selling tuned shocks so of course they are going to market tuned shocks over other options. There entire argument is also based on adjustable struts and coilovers which kind of negates their argument, they assume people are going to a heavier spring rate to achieve desired ride height but also call out that you need a spring rate thats appropriate for your trucks total weight

Cadillacs don't ride like Cadillacs because they have soft springs, they were giant boats that prioritized ride handling.

Their spring rate recommendation based on approximate added weight is grossly undersized as well. We all know sliders and skids arent approximately 100lbs but close to 300. Using their 600lb example actually equates to 1200+ lbs.

If 700lb coils are recommended for 600 pounds then what are they recommending for those with 1000+.

I think we all agree that throwing in 700lb coils on stock tacoma will not ride the same, same with adding 1400lb leaf packs and no weight, but no one is doing that.

EDIT: Most people don't understand digressive, linear, and progressive valving and many or just throwing on some bolt on shocks they bought from some random drop shipper. I think the key is ensuring you have shocks that are tuned specifically for your application. I had King tune my shocks based on my specific setup and my truck does truly ride better than our RX. I don't think you can look at coils and not shocks or vice versa.

Let's look at a static example:

If you add 250lbs to the front of a stock Tacoma the front axle weight increases and the coils compress (causing "sag"). Tuning the shocks doesn't fix the increased compression or weight, it simply compliments the new weight. Adding longer springs may bring the vehicle back to stock ride height but at the risk of potential coil-bind on compression. (If adjustable, adding preload would risk coil-bind). The only solution is to increase coil rate to bring the truck back to stock geometry to offset the added weight, however your stock shock tune no longer compliments the coil rate.

 

I don't completely disagree with you, but I think I haven't explained my point well enough. Critical damping (which is approximately a goal of a suspension designer) is the product of vehicle mass and spring coefficient (b^2 = 4mk). If you increase your spring coefficient you need to also increase your damping coefficient, if you don't want to bounce off the ground after landing a jump. The problem is that both decrease your amplitude (the amount of suspension travel for a given bump). So you have this multiplicative effect. Combine this with that fact that most pickups probably come over sprung from the factory because their primary customer is looking to haul or tow weight on the road as opposed to hitting whoops in the desert. I lost my train of thought. Too drunk. Anyway, while the exact numbers in the accutune article might be inaccurate, the theory of big shocks and small springs for getting crazy in the desert is a sound one me drunk mind thinks. My experience with purpose built off-road machines (i.e. dirt bikes) makes this intuitive to me.

 

I would look for longer coils not higher spring rate. Factory 700lbs coils (if factory coils are 700. Seems kinda high to me) are shorter than OME 887 590lbs coils. 2” lift and rides better.

 

great point, and nobody ever brings up preload which factors in hugely along with spring rate and length. Like you said factory 700 springs are shorter than OME887s but also have less preload. For example OME 887 and 888 have the same spring rate and same total assembly length but the 888 have 5 mm more preload and ride noticably differently.

Have to consider spring rate AND preload when comparing setups