I've recently aquired an 1994 Sonoma with a cam'd 5.3 and built 4l60, it's nothing crazy but a fun little truck to rip around in. One of the first things I'm wanting to do is lower it, somewhere around a 3/3 drop. The front is easy, some 2" spindles and 1" springs takes care of that. Usually the rear would be easy as well except the truck has what you'd call 'diesel style' traction bars which creates an issue when lowering the rear. The usual options are either lowering leafs or blocks, both of which seems like they'll cause issues.
you can see here the bar's I'm working with. With a 3" drop leaf I have concerns of the bar hitting the front leaf mount during regular suspension travel. And you can see in the next picture that any kind of block over ~2" would put the back of the bar below the wheel line and would make or an 'interesting' experience if I were to ever get a flat on the rear. I initially wanted to use a combo of zq8 leafs (~1.5 inch drop) and 1.5-2" blocks to get my desired drop but I cant find anywhere that produces new zq8 leaf springs.
I had a thought of a possible solution but I figured I'd check with people smarter than me to see if it's a bad idea. I had the idea of using 3" drop leafs then using a 2" lowering block between the bottom of the leaf and the leaf spring plate/shock mount. That would lower the bar back close to where it currently sits and should avoid any bar clearance/ground clearance issues. Is it dumb to put a block on that side of the leaf? are there any other concerns using a block there that I'm not thanking of?
In typical budget fashion I'd like to keep the current bars since they are already there, they work great, and it still rides like a stock s10. Bigger wheels would gain me some room to work with when using blocks but that's a future plan. I though caltracs might be a solution but from what I've read/seen it still presents similar issues with lowering, for example:
STM317
PowerDork
3/20/24 8:59 a.m.
Aren't you kind of halfway to a 4link as it is?
In reply to STM317 :
you're not wrong... it's just the whole rest of the setup that's the issue
That's a tractor pull traction bar. Caltracs/assassin bars end at the spring eye.
looks like homemade junk to me.
In reply to Ranger50 :
I'm aware these aren't caltracs or caltrac style bars, I didn't think I implied that at all in my post, my only mention of caltracs was that they have similar issues when lowering a truck. This set up is very much homemade but still does it's job of preventing axle wrap and wheel hop and still gives a good ride so I figure why not try to utilize them?
my buddy Jay fabbed a set for his lowered LT1 S10 that install above the spring. i'll see if he can chime in.
edizzle89 said:
I had a thought of a possible solution but I figured I'd check with people smarter than me to see if it's a bad idea. I had the idea of using 3" drop leafs then using a 2" lowering block between the bottom of the leaf and the leaf spring plate/shock mount. That would lower the bar back close to where it currently sits and should avoid any bar clearance/ground clearance issues. Is it dumb to put a block on that side of the leaf? are there any other concerns using a block there that I'm not thanking of?
In typical budget fashion I'd like to keep the current bars since they are already there, they work great, and it still rides like a stock s10. Bigger wheels would gain me some room to work with when using blocks but that's a future plan. I though caltracs might be a solution but from what I've read/seen it still presents similar issues with lowering, for example:
I am having trouble visualizing how this will help ground clearance. The front of the bar is going to be lowered by whatever amount you lower the truck. Putting spacers between the axle and the shock plate will lower the rear of the bar, and cause it to sit even lower. The only thing that it could help is if there is interference between the lowering spring and the bar.
I am curious to see what AngryCorvair can show. I have a set of low profile Caltracs for my S10, but haven't installed them yet, as I am waiting until I put my 3" drop springs back on, which will require some other work first.
In reply to edizzle89 :
As long as either mounting point is shorter/smaller than the ride height of the bottom of the rear rim, aka flat tire, use whatever you like. Dont overthink this.
In reply to AngryCorvair (Forum Supporter) :
I'd be interested in seeing what his set up looks like
In reply to eastsideTim :
I should have clarified I'm not concerned with the front mount of the bar, I know that will get lower with the rest of the truck. The spacer under the leaf would be so the middle part of the bar doesn't interfere with the front leaf mount when using a 3" drop leaf, in the full pic of the truck you can see the bar and the front leaf mount are only around 3" apart as it sits now.
In reply to edizzle89 :
That makes sense. I think that your idea should work, then, might require a little work to make sure everything gets located properly, but the clamping forces should probably take care of that. I suspect you won't really need too large of a block to get it to stay clear. I agree with Ranger50, just make sure the rear rim extends lower than anything else, and you should be good to go.
JT
New Reader
3/20/24 3:01 p.m.
In reply to AngryCorvair (Forum Supporter) :
Guilty as charged; these are my creation. I came up with this design to curb wheel hop and maintain ground clearance at the same time. Additionally, because I like a stock looking sleeper build, and traditional slapper bars or caltracs just scream to me "look at me, I go fast!" (or hope you think I do). Whenever I get around to v2.0, I'll utilize a rubber/urethane bushing at one end to improve NVH. I'll also powdercoat the links black so they're even less noticeable.
In reply to JT :
I like that a lot, is that just a standard steel lowering block you welded tabs to?
Can you adjust the length of the bars to fit the lower ride height?
JT
New Reader
3/20/24 4:43 p.m.
In reply to edizzle89 :
I made the lowering block too, starting with the appropriate size steel rectangle tube (I forget the dimesnisons now). I've thought many times I should sell a kit for this.
JT said:
In reply to edizzle89 :
I made the lowering block too, starting with the appropriate size steel rectangle tube (I forget the dimesnisons now). I've thought many times I should sell a kit for this.
When we set up shop building high-end bespoke S trucks for 90s kids done good, you'll have a captive market for these. 🤘🏻
In reply to MadScientistMatt :
The bars have heim joints that can be adjusted on both ends so they have a good bit of room for adjustment
When the axle-end of the "traction bar" can pivot, the job is not being done. That axle can definitely still pivot all over the place with that heim underneath, and the springs will still definitely wrap like Christmas presents. Think in terms of needing to trap the top of the axle housing when preventing axle twist/leaf spring wrap--look at it from a side view under tension when accelerating or downshifting hard. Those super-long bars just look cool in a 7-11 parking lot . . .
(Note: This is only applied to the OP's example, not the one attached to the lift block.)
A good learning device might be looking at an under-axle third link (torque arm) that only pivots in the middle of the car, AKA Gen IV Camaro suspension.
In reply to rustomatic :
my understanding is that the rotational point is more-or-less around where the axle sets on the leafs, so any bar mounted below that line will help prevent rotation through a push motion as the bottom of the center of the leaf tries to rotate and move forward. The bars I have below the axle are just a simplistic version of caltracs, which still pivot on the axle side and in the same location as my bars in relation to the axle, and once under load and the front plate of the caltrac pivots and sets against the top of the leaf it's essentially the same as the straight bar on my truck by just preventing the under-axle mounting point from pushing forward. I'm not saying my bars are the best set up, but on drag radials it doesn't wheel hop at all from a launch, so it's doing something right.
Here's a random picture I found and drew on to show my thought process
I don't see how the long bars in the original post, heim joints on both ends and all, would allow for spring wrap. The bar would have to grow or shrink in length to allow for that. Right? I think solid mounting the axle to the bar, like truck arms, would not be preferable due to greater change of pinion angle as the axle moves through its available suspension travel.
I'm not sure how the longer bars are so inferior to the others that were shared which run from the frame to the lowering block. Neither run through the same arc as the axle due to different lengths of front-spring-eye-to-axle vs. bar lengths which makes me think the longer bar would cause less bind.
I've never engineered on this stuff so take everything I just wrote with a grain of salt.
edizzle89 said:
I've recently aquired an 1994 Sonoma with a cam'd 5.3 and built 4l60, it's nothing crazy but a fun little truck to rip around in. One of the first things I'm wanting to do is lower it, somewhere around a 3/3 drop. The front is easy, some 2" spindles and 1" springs takes care of that. Usually the rear would be easy as well except the truck has what you'd call 'diesel style' traction bars which creates an issue when lowering the rear. The usual options are either lowering leafs or blocks, both of which seems like they'll cause issues.
you can see here the bar's I'm working with. With a 3" drop leaf I have concerns of the bar hitting the front leaf mount during regular suspension travel. And you can see in the next picture that any kind of block over ~2" would put the back of the bar below the wheel line and would make or an 'interesting' experience if I were to ever get a flat on the rear. I initially wanted to use a combo of zq8 leafs (~1.5 inch drop) and 1.5-2" blocks to get my desired drop but I cant find anywhere that produces new zq8 leaf springs.
I had a thought of a possible solution but I figured I'd check with people smarter than me to see if it's a bad idea. I had the idea of using 3" drop leafs then using a 2" lowering block between the bottom of the leaf and the leaf spring plate/shock mount. That would lower the bar back close to where it currently sits and should avoid any bar clearance/ground clearance issues. Is it dumb to put a block on that side of the leaf? are there any other concerns using a block there that I'm not thanking of?
In typical budget fashion I'd like to keep the current bars since they are already there, they work great, and it still rides like a stock s10. Bigger wheels would gain me some room to work with when using blocks but that's a future plan. I though caltracs might be a solution but from what I've read/seen it still presents similar issues with lowering, for example:
Do you know where that front bumper (cover) came from?
In reply to gsettle :
no idea unfortunately, was on the truck when I got it, seems like just some generic drag bumper.
rustomatic said:
When the axle-end of the "traction bar" can pivot, the job is not being done. That axle can definitely still pivot all over the place with that heim underneath, and the springs will still definitely wrap like Christmas presents. Think in terms of needing to trap the top of the axle housing when preventing axle twist/leaf spring wrap--look at it from a side view under tension when accelerating or downshifting hard. Those super-long bars just look cool in a 7-11 parking lot . . .
(Note: This is only applied to the OP's example, not the one attached to the lift block.)
A good learning device might be looking at an under-axle third link (torque arm) that only pivots in the middle of the car, AKA Gen IV Camaro suspension.
I disagree. In order for the axle to wrap, the bar would have to grow or shrink. The further away from the fulcrum it is, the better. OP's bars would prevent more wrap than JT's spacers by a little.
If the axle were to wrap on either, it would require the axle moving forward or backward, but since it's anchored to the shackles, it can't. Same goes for the traction bar. If you try to rotate the axle, you would be pushing or pulling on the bar trying to change it's length.
Take a look at this sketch below. If you put the traction bar on the red line, you'll maximize the amount of wrap you permit before you reach the end of the tolerances in the joint, but it will still work. If you put the traction bar on the blue line, it severely limits the amount of axle wrap.
Not to mention, you MUST have a pivot point to allow for suspension movement.
In reply to edizzle89 :
Caltracs have a feature that traps the front portion of the leaf (pushes down on it) when under torque, i.e., when your differential tries to pivot backward; this helps limit the twist of the axle. Yours do not. I really didn't intend to begin such a debate here . . . I am someone who fought leaf springs for years for every little bit of traction, and I generally hate them.
Shelby had a version of your bars called "underrider" traction bars that went on early Mustangs. They didn't do a whole lot, but people liked the way they looked. The race cars had overrider traction bars that actually located to the top of the axle (and inside of the car), hence providing the ability to limit the twist under power or braking. For practical purposes, the overriders made the leaf springs act like a four-link.
Leaf springs will twist and flop around in ways most of us can't imagine. Their ultimate purpose is only to suspend weight. Traction has rarely been a factor.
In reply to Curtis73 (Forum Supporter) :
The blue bar does indeed help in avoiding shock to the front half of the leaf spring, which technically aids traction by making it take longer to lose. Nevertheless, the axle will still twist the spring fore and aft--all the same weakness still resides in the back half. Old-school Class 8 tractors would break leaves all the time from just such a shock.
