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When the road gets rough, you don’t want your trailer bouncing around or your cargo taking a beating. The built-in AEON rubber jounce springs absorb road shock and carry the load, while the rebound springs cut down on body roll, rattle, and bottoming out. Together they keep the ride stable and quiet whether you’re running loaded or empty.
Traditional axles hang low and tie both sides together, but this axle-less setup gets rid of that beam completely. Each side works on its own, so one wheel taking a hit doesn’t upset the other. The independent action smooths out turns and helps the trailer track better. With no axle hanging down, you gain extra ground clearance for off-pavement travel.
The built-in 4" drop spindle brings the trailer deck closer to the ground, making loading and unloading a lot easier. Its long spindle design fits wide off-road tires, and the E-Z Lube grease zerk keeps bearing maintenance simple. The 5-bolt brake flange is ready for compatible hub and brake setups, so you can build it out the way you need.
This suspension is made from heavy-gauge steel that’s built to stand up to off-road abuse. A black powder coat finish fights rust and corrosion, so it keeps its strength season after season. With a 3,500-lb total weight capacity and 2-5/8" of suspension travel, it’s ready for demanding loads and long stretches of rough terrain.
Each of the two suspension units bolts right to the trailer frame and fits any frame width. If your frame doesn’t have a crossmember, you can run a piece of 2" x 3" steel tubing through the built-in holes for support or reinforce the frame from the inside. The setup keeps the frame square while maximizing clearance and flexibility for custom builds.




| A | B | C | D | E | F |
|---|---|---|---|---|---|
| 14-5/16" | 18-3/8" | 1-1/2" | 6-1/4" | -3/8" | 5" |

| G | H | I | J | K | L |
|---|---|---|---|---|---|
| 5-5/8" | 8" | 5-3/4" | 2-1/4" | 3-1/4" | 5-1/4" |


Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.
Today we're going to be taking a look at, then we'll show you to install the Timbren Axle-less Trailer Suspension System. These are available in multiple configurations to fit most applications. Just check our website out for details. Today specifically we're going to be using part number ASR3500S05. This is a spindle only configuration for 3,500 pound axles. With the spindle only configuration we're going to be reusing our bearings, we're going to be reusing our brakes and our drums.
You may want to pick up some new seals if you're going to go this route. We also have the full kits available with the brakes, the drums, and everything that you'll need. The Timbren Axle-less Suspension is an excellent, excellent product. You can tell an immediate difference as soon as we start hauling our trailer with the items installed. It's much, much quieter, much smoother, you don't feel the weight in the truck nearly as much as you did with that standard suspension. You can see as we're cornering there's no transfer of weight.
They're working independently to keep our trailer nice and level. Here's what our kit's going to look like installed. This axle-less suspension system from Timbren is kind of a solution for all that noise and everything that we typically get with our trailers; real rough ride. Now, they use 2 rubber springs essentially, they're Aeon rubber springs. We've got our larger one here in the back. This is the main body of the system, and as we load it more and more and more it constantly kind of adapts to that to give us just the ride of support that we need. To keep this constantly under tension so we don't have to ever worry about a lot of that rattling and stuff, we've got a rebound spring right here in the front.
These are designed to work with really any style of trailer frame, no matter of the thickness here. Depending on the application if you've got a really wide trailer, well then you're just going to put the 3 bolts in the side, 3 bolts up through the bottom. We're dealing with a little bit narrower angle channel here, so what we've done is we've put the square tube across the front. You could also design a bracket to go on the side, if you wanted like a gusseted bracket. There's a lot of options out there. We went with the spindle only design.
It's really heavy duty, too. You can really tell about the quality that they've put into the design of it. Going to have a black powder coat finish on all of our surfaces and this real nice thick steel fully welded around all of our points with reinforcement gussets right where we want them. You can just tell it's a really well built system. Another advantage that we're going to see with the axle-less suspension is going to be increased ground clearance. We don't have that axle that typically hangs down here lower. Even with us using the cross tube design or the cross bracing design, it's tucked up right underneath of our trailer. It's even up higher than what our cross members are here for our flooring, so really tucks it up. Then this area down here, you can see smooths off. The axle-less suspension system can also help us with getting our deck height of our trailer where we want it. These are available in both drops and lifts. One of the added benefits that we get out of this axle-less system is that we're not tying this side of the trailer to that side of the trailer with one of those through axles that are going to go right through down here where all our movement's going to actually take place. This allows these to work independently of one another. If we hit a bump on that side it doesn't transfer all the way over here and then cause this side to go too. Now, they've set this up with tow and camber adjustments aligned 00:04:02 already, so we should have great tire wear as we track down the road. However, if need be they do provide us with some nice alignment shims here if we do want to change it up a little bit, or maybe our trailer's frame wasn't exactly square. Another great thing about the Timbren Axle-less Suspension set up is that they use urethane bushings here at our pivot point. It's going to be very very long lasting. It's going to keep everything nice and tight, and we don't have to worry about lubrication. To begin our installation we need to get our factory axle out. Now if you are going to reusing hardware off of the original axle it's best to do it when it's still on the trailer. That way you're not fighting the roll. All right, now you'll notice here on the frame of our trailer, this is our rear spring perch. We've removed the front to allow room. You may have to do that on yours, and there was a couple welds here and then here that kind of stuck out on the frame rail. We've gotten rid of those. Just use a grinder, get it nice and clean. We want a nice smooth surface for this to mount up against. We're going to mock it up now just by bringing this edge up and letting it sit on our trailer. You can see the 3 holes we're going to use for attachment. Now the key to getting this set up properly, you can see we've got some plumb bobs here. Basically it's just a string with a nut tied to the end of it. We've gone off of both of our spindles here in the same location, and then we've gone from the center of our coupler in the front so we've got them at 3 locations. Now we're going to measure from that string back to this string, and then we'll measure from the front over to the other side. It's very important for us to have these within an 1/8 of an inch. What this means is that we've got the perfect triangle from the coupler back to each of our spindles. We won't have to worry about any kind of side tracking. It's going to keep our trailer running straight behind us, and it's going to make sure that we're getting proper tire wear. Adjust as necessary. We want to make sure if you're using plumb bobs that your trailer's level. After that it's just a matter of getting them lined up to where they're going to be just right. We'll measure, mock it up, measure, mock it up, and then once we have it right where we want it we can get our holes drilled. Now we want to take a punch and I'm going to mark the middle of my rear hole. Then we can start stepping up to a 1/2 inch hole diameter is what we want to end up with. We start with just an 1/8 inch and then kind of move up as we go. All right, that created a little too much movement, so we want to get this hole drilled perfectly to get that suspension out of the way and get our hole drilled out. We'll bring it up, slide our bolt through the hole there, and then put our hardware on the inside. That's going to do a good job of holding that in place while we get the rest of our holes marked. I'm going to use a jack stand again here just to apply some upward pressure. I'm going to tighten this nut down temporarily. That's going to draw it right over into position we want to make sure it's pressed up firmly all the way in the front. We don't want any kind of gaping between the top of our enhancement here and the bottom side of our trailer. Now we can use our center punch or our 1/2 inch bit here and get the center of our holes marked. You see I've already mocked up what would be the passenger side of the trailer. Anything I do on this side, I'll do the exact same thing on the other side. Now we're ready to get these pulled down and we'll get our holes drilled out. All right, now with those holes drilled out let's get our suspension back up into place here. What I want to do is just get these 3 started and I'm going to get them snugged down. This isn't a permanent mount, so we don't want to torque them all down. We've got to measure for that cross tube. We're going to be using this opening here for a 2 inch by 2 inch cross tube section that's going to give us additional strength. There's a few options on the additional strengthening process that you can check out in the instructions. That's mainly for just like the trailer that we've got here, just your simple utility trailer that just has an angle iron frame. If you see channels and things like that, typically once we're putting these on the heavy-dutier trailers there's going to be plenty of thickness in the frame. You really don't have to worry about having that cross tube. Now to figure out how long of a pipe that we're going to need here we're just going to measure inside to inside. There's going to be a couple little lips there. Right here there's a little bit of a lip. We just want our pipes to sit just inside of those, and we'll want our square tube to fit right inside of that. Now with our pipe cut to size all we'll need to do is slide it in all the way across, and we'll want to make sure that it engages our other side as well. All right, that's held in place there kind of by those little lips we saw in each end. We need to get our bolt holes here marked so we can drill our holes and install our hardware. Those should be marked so let's pull our tube back out of there, get those holes drilled, and we can put it back in. Now we can get our center punches taken care of here. Just like before we'll just step up our bit size as we go, makes it a little bit easier. Now with the tube back in we'll take our hardware, got kind of a tight squeeze here but we're just going to place that through. Place that flat washer inside of there on the bolt, then we need to get our nut started. One of these little flexible magnets is a really good way that bolts quite a ways back in there. If you've got a different method that works for you, great. My fingers won't reach in there. Maybe a pair of needle-nose you could get to work in there. These little magnets are pretty readily available and pretty handy to have, so that would be my recommendation. We'll just leave that one loosely installed. Now we're going to take our other bolt, we want to place it through both of our holes but we don't want to have it poked all the way through. What we're going to do is have that stay there as we get our spindles torqued down, as we get our brackets to our frame torqued down. Then we'll torque down our inside bolt, then we'll be able to get to this and torque this down. We'll just at that point either thread it in by hand or with a wrench, put our stuff on it and get it torqued. If we we're to leave this out completely so we could get to that back bolt, it's likely that our holes would then be slightly misaligned and it would be real difficult to get it in. Now we want to look in the instructions and find our torque specifications and we want to go through and torque everything down in the appropriate order to those specifications. I had these pretty snug when we we're doing the install just so we wouldn't have to worry about any movement or anything with the spindle. With those done we'll move up to the 3 here in the side. Once those are properly torqued we'll go to the ones that we've got inside of our tube. With everything torqued down that's really all there is to the install. I would here on this cut piece of tubing, just a little bit of black spray paint there. Just kind of seal that up, prevent any rusting there. Then, depending on your set up if you're using, if this is on a braking axle then you'll put your brakes back on your flange and then rebuild your hub per the instructions. If this is on a lighter-duty trailer and if you don't have brakes then you're just going to rebuild your idler here. Good time to replace the seals, repack the bearings, inspect those bearings, or just order a new kit to fit right on here and then you'll know you're going to be safe as you go down the road. All right, now we'll lower it down until the tires touch the ground and you'll want to be sure to use a torque wrench and get all of your lugs torqued down appropriately. That's going to complete our look at the line of the Timbren Axle-less Trailer Suspension Systems.
Ratings & Reviews

Conrad S.
4/1/2015
HI Matt,WHat size wheel did you use and which hub did you get to match?Appreciate the info

Matt N.
2/6/2016
They are GREAT! I put them on a small offroad trailer that has followed me all over some really rough roads in remote Oregon, Washington, and Idaho. They have performed flawlessly, helped the trailer tow extremely well, and were the single best upgrade I did to that trailer. Very much looking forward to another summer of exploring! Massive upgrade to the stock axle leaf spring combo, and I have had the opportunity to show it off to alot of fellow overlanders. I cant speak high enough of them. I also purchased a set of airbags for my vehicle which unfortunately have not held up terribly well. I have had to field repair one once already, and neither holds air terribly well. Truth be told they seem very underdesigned for the job they perform. From my super secret high tech pocket internet window.

Michael
1/15/2016
Ashley, the 4 version doesnt actually give it more travel. Its the same was the standard or the system as far as suspension travel. What the 4 system does it lift the height of the trailer from the ground, depending on what youre doing with the trailer. For an off road trailer I personally would do the 4raise for added ground clearance, just gotta make sure the trailer doesnt get top heavy. The standard system is good for pretty much all uses and the system is for when you need a really low deck height for a lawn mower or go kart for example. I appreciate your review as I am going to be building a small off road campingbug-out trailer to tow behind my lifted FJ cruiser. I havent decided if I am going to go with the standard height or the 4 lift as I am going to be running the same off road tires toyo RT that I have on my FJ on the trailer and I want the trailer to sit around the same height. Did you add brakes to yours? Im planning on either running electric brakes or if available in am going to run surge brakes.

Ashley
1/18/2016
Michael, My trailer was so light even fully loaded that I didnt see the need for brakes and never missed having them.I stand corrected: We did get the 4 lift, but the non-HD instead of the HD because the specs said that it had a bit more travel. and we didnt need the weight capacity. That being said, Im still happy with how this suspension performs. My trailer is on 31s on a stock Cherokee.

Gwendolyn Y.
10/23/2025
Can't wait to hear how the install goes, Christopher! What kind of trailer are you going to install them on?

Steve
9/11/2025
It is perfect.

Quality M.
9/26/2013
Your comments regarding the Axle-Less Suspension are greatly appreciated. To address the issues you have pointed out, we have carefully reviewed our assembly. While we did not come across any major issues, we did however discover a few areas where the quality could be improved, specifically in the areas you brought to our attention. The following improvements have been made to improve the manufacturing process: - Robotic welder gun re-programmed so that it stops from getting too close to the areas adjacent to the mounting holes of the outboard arm and control arm. This will minimize weld spatter. - The distortion of the flat plates is due to the high degree of heat generated during welding. We conducted experiments, changing the sequence of welding operations until we were successful in minimizing the distortion. We apologize if our customer service in addressing your concerns was insufficient at the time of your phone call. Timbren is an ISO 9001:2008 company with an excellent reputation for providing customers with quality products that are well-performing and easy to install.

Larry D.
9/28/2017
WORKING GREAT MUCH BETTER RIDE STILL 5 STARS

Robert
3/7/2021
Fantastic O will ONLY use Timbren Axles on my Overland Campers

Robert
3/7/2021
Fantastic O will ONLY use Timbren Axles on my Overland Campers

Philtreeman
11/20/2019
We just drove 1200 miles mostly at 75mph. The axles work very well in all conditions, trailer ride very smoothly.
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Pat A.
3/15/2018
Its been a year since Ive installed the new axles on my trailer my comments above still hold true. Im very pleased with the ride quality of the system after a year. The trailer tracks true and has hauled many things other than my motorcycle. Even empty it doesnt hop around like the original stock straight axle did. No regrets on the purchase.