torsion bars
08-24-2008, 12:47 PM
#21
I'm also interested. Does the Downey flex as well at stock height? I disconnected the swaybar on my truck last night and it seemed to crawl up the rock I was flexing on easier, but it didn't look as if it were flexing much better when I got out and looked.
08-26-2008, 01:16 PM
#24
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08-26-2008, 01:31 PM
#25
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unless you modify the suspension (such as with TC or downey kit, or possibly ball joint spacers), there's no way to get more flex regardless of the bars installed. the bump stops limit how far the suspension travels. the downey and TC kits get more travel mostly because the a-arms are longer; ball joint spacers get more because they increase the angle between the upper and lower arms, which pushes the lower arm farther from the stop allowing it to move farther upwards before it hits the stop.
the uprated torsion bars are analogous to going to stiffer leaf or coil springs and require more weight to compress, and can actually fight flex.
the uprated torsion bars are analogous to going to stiffer leaf or coil springs and require more weight to compress, and can actually fight flex.
Last edited by abecedarian; 08-26-2008 at 01:33 PM.
08-26-2008, 01:32 PM
#26
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08-26-2008, 04:15 PM
#27
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unless you modify the suspension (such as with TC or downey kit, or possibly ball joint spacers), there's no way to get more flex regardless of the bars installed. the bump stops limit how far the suspension travels. the downey and TC kits get more travel mostly because the a-arms are longer; ball joint spacers get more because they increase the angle between the upper and lower arms, which pushes the lower arm farther from the stop allowing it to move farther upwards before it hits the stop.
the uprated torsion bars are analogous to going to stiffer leaf or coil springs and require more weight to compress, and can actually fight flex.
the uprated torsion bars are analogous to going to stiffer leaf or coil springs and require more weight to compress, and can actually fight flex.
I have plans for the BJ spacers at the same time, and I just figured throwning these in with a little crank would give a little lift, a bit more flex, and a near stock feeling ride...
08-26-2008, 04:29 PM
#28
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what preload? the preload is the same with whatever bars are installed. the only preload is the weight of the truck and that doesn't change just by changing bars. yeah, maybe I'm arguing semantics, but the devil is in the details. truth = truth.
I'm not trying to be argumentative or anything like that, but it is that sort of disinformation that people hear that biases people into buying product X over Y or not buying anything at all.
The larger bars have a higher initial spring rate (and a higher rate under load as well) than the stock springs do. So to install the larger bars means you have to adjust the adjusters differently so the truck sits at the same height. there is no change in preload. the 'preload' on the springs is the same with the stock springs as it is on the new springs. The difference is in the spring rates, not some magical 'preload' value. On the same truck, the preload is exactly the same, no matter where the suspension is adjusted to sit.
I mentioned earlier about leaf springs.... now if preload was a consideration, why would chevy springs be a worthwile addition to a truck that weighs less? Obviously, it's not preload. It's the load placed on the spring, and the rate at which the spring responds to a load. Chevy springs have a high static load rating, so the truck sits well, but under compression, the chevy springs 'give' and allow flex. That tells me that Chevy springs have a lower dynamic spring rate than stock Toyota springs do, since Toyota springs don't give as easily.
Get what I'm saying?
Stock torsion bars give more under load than the oversized bars do. They ride softer and will consequently allow the suspension to flex more easily than uprated bars.
*edit- in the end, is how far will the suspension travel when compressed and unloaded... THAT is flex.
I'm not trying to be argumentative or anything like that, but it is that sort of disinformation that people hear that biases people into buying product X over Y or not buying anything at all.
The larger bars have a higher initial spring rate (and a higher rate under load as well) than the stock springs do. So to install the larger bars means you have to adjust the adjusters differently so the truck sits at the same height. there is no change in preload. the 'preload' on the springs is the same with the stock springs as it is on the new springs. The difference is in the spring rates, not some magical 'preload' value. On the same truck, the preload is exactly the same, no matter where the suspension is adjusted to sit.
I mentioned earlier about leaf springs.... now if preload was a consideration, why would chevy springs be a worthwile addition to a truck that weighs less? Obviously, it's not preload. It's the load placed on the spring, and the rate at which the spring responds to a load. Chevy springs have a high static load rating, so the truck sits well, but under compression, the chevy springs 'give' and allow flex. That tells me that Chevy springs have a lower dynamic spring rate than stock Toyota springs do, since Toyota springs don't give as easily.
Get what I'm saying?
Stock torsion bars give more under load than the oversized bars do. They ride softer and will consequently allow the suspension to flex more easily than uprated bars.
*edit- in the end, is how far will the suspension travel when compressed and unloaded... THAT is flex.
Last edited by abecedarian; 08-26-2008 at 04:33 PM.
08-26-2008, 04:47 PM
#29
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Yeah preload isn't the right term, but what actually changes as you crank the t-bars up is the angle of the upper control arm. As the angle of the UCA gets away from 90* to the ground its takes more force to move it (ie stiffer). To increase the preload of the t-bar you would have to adjust the UCA so far down that the upper bump stop was being smashed just sitting there.
Last edited by mt_goat; 08-26-2008 at 04:53 PM.
08-26-2008, 05:00 PM
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Here's an analogy that some may understand even better: fishing line.
Lets grab some 5lb monofilament and some 20lb monofilimant.
Let's tie nice bolline knots and suspend equal lengths of each from eyebolts in the ceiling.
Let's put 5 lbs on each line.
Which has more preload? (neither)
Which gives more easily as more weight is applied? (5lb test)
The 20lb test line needs exponentially more weight to stretch as much as the 5lb test line.
There... problem explained.
The 20lb test is stronger, not by virtue of having more preload, but by the fact it needs more tension to break.
Lets grab some 5lb monofilament and some 20lb monofilimant.
Let's tie nice bolline knots and suspend equal lengths of each from eyebolts in the ceiling.
Let's put 5 lbs on each line.
Which has more preload? (neither)
Which gives more easily as more weight is applied? (5lb test)
The 20lb test line needs exponentially more weight to stretch as much as the 5lb test line.
There... problem explained.
The 20lb test is stronger, not by virtue of having more preload, but by the fact it needs more tension to break.
Last edited by abecedarian; 08-26-2008 at 05:05 PM.
08-26-2008, 05:07 PM
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if you find yourself bottoming out the suspension, maybe higher rate shocks are in order so that you can slow down the suspension movement before it hits bottom. if that doesn't help, then maybe higher rate torsion bars are needed.
08-26-2008, 05:11 PM
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@iamsuperbleeder-
my goal wasn't to get you to choose stock t-bars over larger bars, but rather to get people to think about what is needed, from a logical standpoint. mt_goat has lots of good information and I consider what he says quite often. he also has a heavy front bumper and probably needs the higher rate t-bars to compensate for it.
@mt_goat-
I hope there are no hard feelings or animosity towards me. I know you know what you know, and what works for you.
my goal wasn't to get you to choose stock t-bars over larger bars, but rather to get people to think about what is needed, from a logical standpoint. mt_goat has lots of good information and I consider what he says quite often. he also has a heavy front bumper and probably needs the higher rate t-bars to compensate for it.
@mt_goat-
I hope there are no hard feelings or animosity towards me. I know you know what you know, and what works for you.
08-26-2008, 05:30 PM
#34
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@iamsuperbleeder-
my goal wasn't to get you to choose stock t-bars over larger bars, but rather to get people to think about what is needed, from a logical standpoint. mt_goat has lots of good information and I consider what he says quite often. he also has a heavy front bumper and probably needs the higher rate t-bars to compensate for it.
@mt_goat-
I hope there are no hard feelings or animosity towards me. I know you know what you know, and what works for you.
my goal wasn't to get you to choose stock t-bars over larger bars, but rather to get people to think about what is needed, from a logical standpoint. mt_goat has lots of good information and I consider what he says quite often. he also has a heavy front bumper and probably needs the higher rate t-bars to compensate for it.
@mt_goat-
I hope there are no hard feelings or animosity towards me. I know you know what you know, and what works for you.
And the shocks need to be changed anyway, so I'll keep that in mind.
Thanks again!
08-26-2008, 05:40 PM
#35
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@iamsuperbleeder-
my goal wasn't to get you to choose stock t-bars over larger bars, but rather to get people to think about what is needed, from a logical standpoint. mt_goat has lots of good information and I consider what he says quite often. he also has a heavy front bumper and probably needs the higher rate t-bars to compensate for it.
@mt_goat-
I hope there are no hard feelings or animosity towards me. I know you know what you know, and what works for you.
my goal wasn't to get you to choose stock t-bars over larger bars, but rather to get people to think about what is needed, from a logical standpoint. mt_goat has lots of good information and I consider what he says quite often. he also has a heavy front bumper and probably needs the higher rate t-bars to compensate for it.
@mt_goat-
I hope there are no hard feelings or animosity towards me. I know you know what you know, and what works for you.
Not at all Abe, I think you're right on. I agree that many people would find the bigger bars too stiff.
08-27-2008, 01:14 AM
#36
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Yea, theres some confusion going on here. Cranking your T-bars doesn't "stiffen" them. It just changes the angle of the A-arms. I think folks get that confused quite often. If you turn the A-arms, you limit your flex only by getting it closer to being maxed.
In other words, the travel doesnt change, just the ride height.
I for one swapped out my 26mm in favor of stockers. I find very little reason to use a larger T-bar in any case. The ride sucks, the flex is HaHa, i mean the flex stock is pretty weak, throw on a stiffer torsion bar and things just get worse.
IMO stock is the best. The only real practical reason I think Downey offers the larger T-bars is for more "pre-runner" type applications. Where the loads on the front end are more important... a larger bar would reduce the possibilitys of bottoming out (which is bad) say after getting air over some narly hill.
**stock with balljoint spacers:
In other words, the travel doesnt change, just the ride height.
I for one swapped out my 26mm in favor of stockers. I find very little reason to use a larger T-bar in any case. The ride sucks, the flex is HaHa, i mean the flex stock is pretty weak, throw on a stiffer torsion bar and things just get worse.
IMO stock is the best. The only real practical reason I think Downey offers the larger T-bars is for more "pre-runner" type applications. Where the loads on the front end are more important... a larger bar would reduce the possibilitys of bottoming out (which is bad) say after getting air over some narly hill.
**stock with balljoint spacers:
Last edited by drew303; 08-27-2008 at 01:17 AM.
08-27-2008, 05:06 AM
#38
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Lots of guys have twisted them to the point of permanent deformation. In fact, that's a good way to tell if you need bigger bars. If after wheeling you have to re-adjust your t-bars to get your ride height back to the way it was before you probably need bigger bars.
If you wheel on steep trails its not just the weight of the front bumper that loads the t-bars. On steep decents the weight of the whole truck is on the t-bars to some degree. That's where I've bottomed out the most, fully loaded down with gear on a out-of-state trip and going down some really steep trail. I had one trip where I hit the bump stops so hard one broke off (Superlift bump stop). After that I re-designed all my lower bump stops with beefier ones.
Last edited by mt_goat; 08-27-2008 at 05:27 AM.
08-27-2008, 05:09 AM
#39
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You mean besides the OP in post #1 hehe.
Lots of guys have twisted them to the point of permanent deformation. In fact, that's a good way to tell if you need bigger bars. If after wheeling you have to re-adjust your t-bars to get your ride height back to the way it was before you probably need bigger bars.
Lots of guys have twisted them to the point of permanent deformation. In fact, that's a good way to tell if you need bigger bars. If after wheeling you have to re-adjust your t-bars to get your ride height back to the way it was before you probably need bigger bars.
08-27-2008, 05:30 AM
#40
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I might just add, if you snap a t-bar in half that's an indication you may need bigger bars, or an indication that maybe the previous owner needed bigger bars, LOL.
Last edited by mt_goat; 08-27-2008 at 09:23 AM.
