My new to me 2020 Trd OR has been modified by previous owner

I believe that is a SSO front bumper and a Heise light bar.

I installed an SSO bumper with winch as well, the bumper seems well built but haven’t needed a good pull yet. No experience with the Heise lightbar.

 

I have done several internet searches looking for an authoritative article that says leaf springs wear out a significant amount over the lifetime of an automobile and I have not found one.

Yes steel can suffer a fatigue failure, but that does not mean a spring's rate or shape changes an appreciable amount.

I have read that fatigue causes microscopic changes in the steel, but the same article did not say anything that would cause me to suspect these changes were visible to the eye.

I also have read articles about changes in the shape of a steel part called "creep". However, as I remember creep only occurs at temps well above those experienced by a leaf spring.

In any case, the proper way to inspect the leaf pack, according to the article you posted, is to measure the ride height; not look for a W or flat shape. This aligns with my understanding. They do use the term "sagged" but they don't define it, so I'm not sure what they mean.

Personally, I have taken ride height measurements of my truck several time and kept notes. I have not seen any decrease in ride height in 3 years.

 

This conversation motivated me to do another search. Here is a discussion of coil springs on physicsforums.

https://www.physicsforums.com/threads/how-to-tell-if-a-spring-is-fatigue-creep-or-degrade.891665/#:~:text=The principal failure of this,spring rate and free length.

"If you referring to wire coil compression springs, these will principally only lose their initial set (free length and spring rate) if they are exposed to extreme temperatures that can anneal the material or to an environment that is corrosive to their material. The principal failure of this type of spring due to cycling fatigue is fracturing of the wire in one of the coils not loss of spring rate or free length; but extremely rapid cycling over an extended period can result in internal heating of the spring wire that can result in a loss of spring rate and free length. For critical applications, presetting (compressing the spring through its full travel for a few cycles) is a standard step during the spring manufacturing process."

It's easy to find scientific articles on spring fatigue failure like this one, but it's hard to find anything that mentions spring length or spring constant changing.

https://www.sciencedirect.com/science/article/abs/pii/S135063071831611X#preview-section-references

I'm either bad at searching or this a rarely studied subject because it doesn't happen.

One the other hand, it's easy to find zillions of influencer videos, advertisements, etc. that assume "spring sag" is a real thing. I suspect many of them are just regurgitating stuff. Yeah, internet!

 

I can, without a doubt, tell you leaf springs wear out over time. Perfect example is my fj60 Land Cruiser, which is now almost 41 years old on original leaf springs. I have a pair of helper airbags in place to take some load off the springs, but without them, the factory leaf pack is so weak they’re inverted and it would ride on the bump stops. Call it whatever you want, wear, fatigue, creep, etc, but they don’t hold the weight they were designed to originally hold any longer.

 

Most of the info I've read over the years regarding replacement, comes from commercial truck maintenance articles.

Most of the technical papers I've read, seem to be from foreign engineers/students...

 

Go down to your local 4x4 shop and have them show you their pile of bent, twisted and broken leaf springs - then you will be a believer. With the common on road use the springs will last the life of most vehicles. I have both S wrapped and broken springs - use to reassemble springs packs from multiple individual springs to run with. Don't do that any longer, can now afford complete sets. My application is a 1986 Samurai which I rock crawl - it takes a lot of abuse. Hope my Tacoma, once I have it outfitted will not require that level of maintenance. Before I 4-wheeled I had no idea leaf springs wore out. There doesn't need to be any studies where the evidence is very clear. Will most people in their Tacoma's bend or break their springs; highly unlikely as they will not be putting their trucks through the stresses needed to bend or break them.

Agreed 1000 percent!

 

I didn’t see it mentioned so I’ll throw in a recommendation for the Icon Add A Leaf (AAL). It replaces your overload with three additional leaves and improves ride and load carrying. It will restore the arch to your leaf springs. I’m very happy with mine.

 

Looks fine. Just run it. I doubt someone dumb enough to buy $600 dollar fog lights is going to also buy a $60 dollar lift and put it on. I bet someone got that lil lift from the dealer or something, and then added the fog lights and bumper winch themselves. Or more likely had someone put the lights and bumper on for fashion.

 

Here is my personal example: Even unloaded and uninstalled you can still see the residual "W." Over time, springs do develop memory (plastic deformation) which in turn accelerates fatigue.




^^^That was not a fun day.






Here is how the like-for-like replacement sat:




The trailer was running full tanks/full weight in that photo (which made the roadside repair even more fun ).



And to be clear, I am NOT saying "omg, OP is on the verge of snapping a spring." But I am saying that a W shape is the most visible clue that might suggest fatigue and/or excessive use and/or damage from overtightening.

If it were my truck, I'd have my credit card out for a replacement pack and I wouldn't be running heavy loads until it was installed. If anyone else is comfy with letting it ride and sending it, cool. I personally wouldn't be. I'm a fan of replacing things early when its on my terms and in my garage.

 

One question and one observation/question if I can.

You mention over tightening, I presume of the U-bolts, I do not understand how that would lead to spring bending. Under tightening would lead to shifting and wear of all components in contact with the springs.

The observation is: I was under the impression the spring locating pin round head should be located within the spring perch hole, not the nut holding the spring pack together. Your pictures of the original springs I believe show the nut was in the hole in the spring perch. Is your understanding different?

 

That was the factory setup, and I noticed that the replacement springs were bolted the same way: where the nut indexes into the axle and the round pin connects to the bolt plate. I think it's weird too, but I never bothered checking if that's just the way it's supposed to be on trailers.

 

I wouldn't think there wouldn't be any difference between trailers and tow vehicles. Looks to me the springs were expected to be used on Spring Under Axel application, while your trailer and our Tacoma's are Spring Over Axel.

You didn't comment on the "Over Tightening".

 

Plastic deformation occurs when the force on the material exceeds its yield strength. Under normal circumstances, this does not happen to a leaf spring.

https://en.wikipedia.org/wiki/Yield_(engineering)

I’m not seeing an obvious W shape in your pics. I think a better way to inspect spring is to measure their spring rate and length/displacement at rest.

https://www.youtube.com/watch?v=Yl1FNX08HFc

 

Everyone else is already covering the spacers, so not beating that dead horse.

Just and FYI, those fog lights are CaliraisedLED and, though their fabbed stuff is good, their electronics are cheap chinesium that breaks easily. Be prepared for that.

Also, if the speedometer hasn't been calibrated to the larger diameter tires, then you are going faster than it says and have more miles on it than it says. Basic math is that if the tire has say a 10% increase in circumference, then you are travelling 10% further than it says. Not a big deal short term, but it adds up over time.

So for example (all these numbers are pulled out of my ass just to illustrate) if the stock size was a 30" tire and it now has 33" tires, then the 25,000 miles it was driven since the new tires were put on isn't 25,000 miles, but rather 27,500 miles. That would also mean that when your speedo says 75 MPH you are actually going 82.5 MPH (75+7.5) and it'll throw off the fuel economy numbers as well.

Whether or not you care about that stuff is up to you. Just giving info.

 

@Defcon ... The discussion on the status of the springs is actually pretty interesting and provides some valuable information, but @Toycoma2021 has offered up a excellent piece of advice that shouldn't get lost in the rest of the discussion...

You've started in a great place here on TacomaWorld and I can guarantee you that everyone here will do their best to help you out and steer you in the right direction, but joining a local 4WD club is the next thing you should do. Having one-on-one access to the combined knowledge and experience that a --LEGITIMATE-- club will give you is everything you need to start having fun with your new truck. It doesn't matter if it's not a Toyota-specific club, any real 4WD club with an avid group of 'wheelers will do...if there's more than one club around you, then try them all out...you'll know when you've found the right one for you.

As far as your rig goes...one of the first things I ever learned about racing and 'wheeling... run whatcha brung!
You've got a very capable vehicle right out of the box, and I'm pretty sure everyone here will back me on that!! So don't sweat the upgrades, go have fun! Fix what breaks, ideally with better parts, and get back on the trails. Again, a decent club, as well as everyone here on the forum, will be more than happy to share advice and help you to learn and grow your knowledge, but main thing is get out on the trails!

As for getting stuck...well, if you run with a club I guarantee you there'll be at least five winch cables battling to see who can get you hooked up first and pulled out! They'll also show you how to safely self-recover with your own winch as well!

Lastly, I need to chime in on the springs...sorry, can't help myself... Those rear leaves are shot! Lift blocks have that effect on springs. Now, as some have offered up, if you need to go the least cost route then I agree that a good set of helper springs would most likely be the way for now, but a good quality lift kit would be the direction I would go.

Hope this helps,
-Rob

 

Really appreciate the discussion and information you folks have provided, everyone here is such a great resource, thanks again guys!

I figure I'd bump this thread instead of making a new one. I just had a customer and his stock Tacoma come by, and I'm scratching my head again about this truck.

So a customer pulled up today and asked about my truck. We got to chatting, eventually he started the truck to show me a front camera he had. I immediately noticed the sound his truck made, it was super quiet... when my truck starts up it roars to life and when its idling it sounds like a truck, his idles... super quiet.
So I figured I'd snap some pics of the engine bay and again, see if anything sticks out to you folks.

Here's me tapping the accelerator from below the truck
And from above

 

I wonder if my truck will end up on one of these threads.

 

@Defcon
Your intake seems to be stock, at least by the pictures; Have you checked to see if you have an air filter in place? If your vehicle sounds different it is most likely in the exhaust system underneath the truck.

You have the transmission oil cooler was about all I saw different between your truck and mine. You haven't added your truck's particulars to your signature - I wish this forum would make that a requirement of joining. It tells people immediately just what you have and may help answering questions. For you I realize you truly do not know what the truck is equipped with.

 

Vin shows all