REVIEW 3rd gen suspension on 2nd gen

I just changed to 3rd gen shocks and Icon AAL's after getting a topper. So much better now, like a new truck even with 80,000+ on the clock, drives like new.

 

Eh, your maths seem a teeny tiny bit off...
35.25 - 34.5 = 0.75
35.75 - 35.25 = 0.5

That's not an inch. That's 3/4 inch on one side and only 1/2 inch on the other side.
And it didn't do anything with regards to "lean". I see a measurement increase of +1/4 inch on the LR and a corresponding +1/4 on the RF (opposite corner). Because the increases are on opposite sides, it means that the entire difference is either measurement error, or the spot you parked on is very marginally different.

I'd call this an even half inch on the front and obviously nothing on the rear.


Now with the increased number of winds of the coil (1 additional wind), the consequence of that will be a REDUCTION in the spring rate. I don't actually see any change in the thickness of the coils, which isn't to say that they aren't thicker, just that I can't tell visually -- a measurement with a caliper would be helpful in this regard. But assuming NO change in the coil thickness, the following will hold;

With more coils and an increased "free length" presumably, you can simultaneously have a little bit of "lift" along with a lower spring rate. It means that these springs will tend to compress more with an equal increment of force applied to them. That should make them feel a bit "softer" and will increase articulation for offroad scenarios. For anybody considering increasing the weight load on their front suspension, for example, steel offroad bumpers, snow plow, this change will NOT be well received, since the lower spring rate will increase the tendency to bottom out.

 

2016 Factory TRDOR springs have another wind and also have a reported spring rate of 717lbs...as measured by Toytec. Seems hard to believe they are that high, but I will try and add my review soon when I install a very low mileage set on my 2015. I have a 100+ Lb Warn Trans4mer hanging off the front and will report back with measurements (both installed Warn and uninstalled). I am also installing 1/4 inch spacers so I will need to adjust approx 1/2inch to compare to non spacer trucks with 2016 OR Springs/2nd gen.

I think the fact the springs are the same exact length but lift the truck some measurable amount supports the higher spring rate observed by toytec.

https://www.tacomaworld.com/threads/2016-yrs-or-factory-spring-rates.490719/

 

Spring rate and lift have some physical relationship, but are not the same thing and can be controlled independently.

The "lift" is going to be the inverse of compressed length, which will be equal to FREE LENGTH - WEIGHT / RATE. There will be one additional consideration, which is PRELOAD. That is just the amount that the spring is already compressed before the weight of the vehicle is added to it. That just factors into the FREE LENGTH figure. So if you have, for instance (totally made up numbers) 3 inches of preload, and a preloaded-free-length of 17 inches, then you just use a FREE LENGTH figure of 20 inches.

Now lets just imagine for a moment that we have 2 springs. Both of them have linear rates (you can tell a progressive rate spring easily by looking at it -- the coils will be spaced tighter on the ends than in the middle), and both of them have a rate of 500 pounds per inch, but they differ in their FREE LENGTH. One of them is 12 inches free length, the other is 24 inches free length. Now give them each 1000 pounds to support.

12 inch - 1000/500 = 10 inch.
24 inch - 1000/500 = 22 inch.

So you can see that even with identical spring rates, one of them will have an additional lift of 22-10=12 inches when supporting the same 1000# load.

Now in comparing these springs -- the older vs newer, there is one piece of information that we don't yet have: The free length. We have only the preloaded length, which isn't enough to base any calculations. IF the rate is really ~200 pounds/inch higher on the newer springs, then they *must* be under much less preload (meaning that their free length is shorter). However, I wonder if that is really the case. I wonder if the 700 pounds/inch figure is actually a measure of the rate, or if is a measure of the preload-force? Or the force required to compress it 1 inch FURTHER than the preloaded length? Again like I mentioned, more coils points towards having a LOWER rate (all else being equal) and not a higher rate, because it means more leverage. Basically, imagine stretching the entire coil out straight, clamping one end in a vice, and sitting on the other end. The longer it is, the more leverage you have, and the further it bends under the same weight. So with just looking at them visually via pictures, the most likely guess is that the newer ones are actually a LOWER rate spring with a longer free length, and are thus under a greater amount of preload.

But there could also be metallurgical differences, such that despite the greater number of coils, they *may* be a higher rate spring under *less* preload.

I would be very interested to see the source material indicating that the 700# is rate, and not just preload. If they really are that much higher of a rate, then I could use a set of those for supporting the weight of my snow plow.

 

How did you cut the OEM nuts on the coils?

 

I just used a cut off (air) tool. Installed the spacer and nuts, marked the studs with a sharpie, removed the spacer and nuts and cut away.

 

Thank you. Picked up a 3rd gen set for my bro in law today and am going to use the same size spacer. Appreciate the info.

 

I’m not following what you trimmed off or why? Are the 3rd gen oem strut bolts longer than a second gen? I thought they were short and only work with 1/4” spacers. Sorry if I’m missing something obvious here....

 

1/4 spacer can place over the directly over the OEM studs no problem. 1/2 spacer can be placed directly over the OEM studs but some will advise against it (I did it with them and got plenty of turns on the OEM studs 15k miles ago). 3/4 spacer you will have too shorten the OEM studs and use the additional studs that came with the spacer. They will not let the spacer sit flat against the mount on the truck unless modified.

 

Gotcha, okay. I just misunderstood what was said. Thanks!

 

You mentioned adding a spacer. Did you add a 1" thick spacer? Or a 1/2" spacer to add 1" of extra lift?

Thanks!

 

@Tacohumper13 did you ever end up selling your front struts/springs?

 

Looks like a great affordable option to upgrade or simply replace worn suspension at a killer deal.

 

1/2 inch spacer for 1 inch of lift. My brother in law just got 2018 and we are going to put 3/4 spacer on his.

 

I'd be curious to see those pics when it's done.

So your front end has pretty much settled about 2 inch Lift overall up front?

Did you do an AAL in the back? Or just the stock tsb?

 

As soon as I find time, I’ll be installing my 3rd gen suspension with a 1/2” DS spacer and 1/4” PS spacer. I also bought 1.5” AAL for the rear as I’d like to keep a slight rake.

 

Post pics when you do. I'd be curious how it looks with 2" lift DS and 1.5" lift PS

 

Yes I did...sorry

 

I didn't measure but I think I am at 2. I have a toytec aal in the rear but I had to put a couple bags of sand in the bed to make the ride softer. You may want to get a progressive aal instead of the single. They ride better from what people say.