Is this a suspension issue? 500 Miles on new suspension and it's ROUGH.

Update.

All the suspension was looked over, and whatever I’m experiencing is not coming from that.

I’ve done a bit more observation, and I believe I have a better understanding of what I’m experiencing

So, I had a chance to drive my truck on many roads, highways, backroads, bumpy roads, smooth roads. Issue occurs on them all.

My issue occurs right around 30MPH, though it’s much less noticeable, and intensifies around 50-60+

While driving, especially when it is going uphill, the rpm’s seem to.. slowly drop and the speed begins to drop as well. Mind you, my foot is on the peddle in the same position it was to maintain the speed. If I do not give it more gas, I feel the shudder begin.

I’ve also noticed the same behavior while turning (45mph+ following the natural curve of the road)

So, while I’m no tech, I can’t help but think my transmission is the root cause. So, I’m going to take it to Toyota, and hope they use their computers to monitor the actual stats the transmission is feeding.. undressing just attempting to duplicate and go from there.

It’s got 58,550 on the odo, so fingers crossed they play ball and cover whatever it causing the issue.





(Weirdest thing though. I drove it home from the shop, an hour drive, ran perfect. Let it sit for an hour or so, took a drive, issue returned.)

Just feel defeated at this point, y’all.

 

Well, pretty good account of your observations on when it occurs. I would check the trans fluid level before taking it into the dealer. I would hate to look back and wonder if that could have been the cause all along. IMHO.

 

The reason perch setting doesn’t preload the coil once it’s installed is because the weight of the truck “loads” the spring way past the point of what the perch “preloaded” the coil when it was off the truck, so it makes it moot. However, it’s not 100% correct to say the perch setting doesn’t preload the coil at all, because when the shock is fully extended, THAT is the only time when the coil is compressed more than it would be compared to a lower perch setting. And that means when the shock is extended out (and the weight of the truck on them is reduced), they will be a bit stiffer to get back to the resting point where the trucks weight is back on them. This will be most noticeable when driving over large ruts at speed - large enough for your shocks to extend to full droop. That’ll make the ride stiffer in those situations. But… over the course of normal everyday driving, the front suspension isn’t reaching full droop, so the weight of the truck is compressing the coils to the exact same point regardless of perch they are on (and the ride most of the time remains unchanged). So with the weight of the truck on the shocks, the perch setting just lengthens/shortens the overall shock, which provides the amount of life you have. The lift on 5100s doesn’t come from coil compression whasoever.

This diagram should help make it clearer..

 

You just defined what spring preload is.

"Preload is a measurement of how much a spring is compressed at full extension of the shock."

https://accutuneoffroad.com/articles/spring-preload-matters/

 

You missed my point as it relates to ride quality 99% of the time.

 

Finally someone else gets it too.

 

Sorry, I guess I don't understand your point. You seem to be saying that the Bilstien 5100 shocks do not preload the springs, but at the same time using the concept of preload to support your argument. But anyway I digress. I know I'm going to regret getting into another thread about preload. lol

 

My point was that the preload on the coils from higher perch settings is moot once the shock is installed on the truck, because the weight of the truck squishes the coil way past that little bit of preload anyway, and the length of the coil under the weight of the truck is the same regardless of perch setting, and therefore the ride quality stays the same (the diagram I posted illustrates this - the overall shock length is longer/shorter depending on perch setting, but not the coil under weight). It’s only when the weight is alleviated, and the shock is fully extended so the suspension is at full droop, that the preload caused by the perch setting comes into play. And if you think of how much time the suspension is at full droop compared to not, that’s less than 1% of the time, meaning the ride quality isn’t affected the other 99% of the time.

Another way to help understand this is comparing adjustable shocks to spacer lifts. The reason spacer lifts affect the ride quality far more than a perch setting on a 5100 or similar (the ones where the spacer goes between the coil and top plate - as opposed to above the top plate) is because once the weight of the truck is on the struts, that type of spacer lift has to fit in that space so it squishes the coil way more at rest, making the coil much stiffer in order to achieve the lift - as opposed to a perch setting increasing the actual overall length of the strut at rest to achieve the lift (see the left side of my diagram again, how under weight, the struts are longer at rest, depending on perch setting, but the coil length remains the same at rest). Hope that helps.

 

I understand what you are trying to say, but not with how you are saying it. Preload is not moot after installation. It raises the ride height, which is its purpose. What it doesn’t do is change the spring constant. In other words, it doesn’t make the suspension stiffer. It has some other effects such as the one you mentioned about the force to the ground at full extension.

 

You don't understand what he is saying but you seem to think you know what he is saying and you disagree?

 

This has been explained a few times on here, I totally understand it but I get tired of repeating it and I thank you for clearing it up in this thread. Like I have said I have been on different settings and they all ride the same to me but some won't believe it because they have read it somewhere on the internet.

 

Your words, not mine. Anyway, I think all three of us agree that preload is not evil. Let’s fist bump and call it a day.

 

Are you sure about that?

I always thought the stock coils were 600lbs. Always seen 650 as a "medium duty" and 700 as a "heavy duty" option when choosing springs.

 

The best information we have about the stock coil springs is in this stickied thread.

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

 

I think the “disconnect” between us is that the preload on a 5100 or similar adjustable shock is not what raises the ride height at all - the perch setting lengthens the actual strut at rest and under load, which raises the ride height (with the coil squished exactly the same amount that a stock coil is compressed on a stock strut - once it’s under the weight of the truck). The preload is out of play now until the suspension is extended to full droop.

In contrast, a spacer in between the coil and top plate creates so much preload that the weight of the truck does not fully overcome it like it does with a 5100, so the coil is squished more at rest, which puts more force against the weight of the truck, resulting in lift.

 

Its all good

.

 

I see what you are saying about the spring seat changing the shock's position relative to the spring once it has weight on it. I had not thought of that before. I think you are missing the fact that you put the same spring in a smaller space when moving the seat, so you are starting with increased preload before you ever put weight on it. Since a coil spring requires more force to compress the further you compress it, you are left with an effectively higher spring rate by raising the seat, resulting in the truck not compressing the spring as much as it did with less preload. I think this is observable when you see people using higher rate coil springs to achieve lift on the same shocks with the same spring seat height. I can see how both concepts affect ride height.

 

I don’t agree. There aren’t different types of preload nor does it matter how you apply it. It is the compression of the spring at full extension of the coil-over measured in length or force. You can apply preload with the perch on a Bilstein 5100, with a spacer between the top hat and the coil, or a threaded collar like on King, Fox and other high end shocks.

Are you perhaps thinking of spacers between the top hat and upper shock mount?

 

Same coil spring in smaller space means greater preload. You can't put weight on the suspension without engaging the spring, so I cant see how preload COULDN'T affect height. Though I'm not sure how you could rule out his theory as a contributing factor, although it could only apply under weight since you can't change the extended length of the shock.

Hmm...spitballing here...if preload doesn't matter, then changing the position of the spring seat on the shock body shouldn't matter either, since a shock doesn't support hardly any static weight. It would still drop to the same place where the spring meets equilibrium, which only leaves spring rate and preload as ways to alter height.

 

Since you installed new coils and shocks, have you checked the upper ball joints, wheel bearings, and sway bar connections at the spindle?

If you havent, I'd make sure those things are good to go