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Heavy cargo, campers, or trailers can make the rear sag and steering feel light. The Timbren Rear Suspension Enhancement System adds up to 2,400 lbs of rear axle support to keep things level under load. Its hollow rubber springs sit above the axle and get more rigid as weight increases, keeping your ride height even so braking and handling stay predictable.


When the road gets rough or uneven, these Aeon hollow rubber springs take the hit before it reaches the cabin. They act like built-in shock absorbers, softening bumps and helping your suspension avoid bottoming out. You get a smoother, more stable ride while reducing wear on your factory suspension components.

Each spring works on its own, so side-to-side loads or sharp turns don’t throw the vehicle off balance. This independent action helps control body roll when swerving or cornering and keeps things stable when a trailer starts to sway from wind or passing traffic. The result is less bounce, less lean, and a more controlled feel behind the wheel.


There’s no compressor, air hose, or gauge to deal with—just bolt the custom brackets onto the frame rails using the included hardware. The springs replace your factory bump stops and sit about 1" above the axle so your stock suspension still handles light loads normally. That inch of clearance gives you a comfortable unloaded ride with instant support when weight is added.
Customer Satisfaction Score:
91% were satisfied with this product
9% of customers were not satisfied
Ratings & Reviews
very good
Works great! Fits Great! overall excellent quality!
good product
Add stubility to your van.
Does exactly what it's supposed to do.
did not do what I wanted it to do.
Needed this to lift and stabilize the rear end of my 2012 Sienna. Works very well!
I just received it today, and asked the shop to install it for me:
1. The two plate washers were missing (NOT in the package)
2. The top 2 nut / plate weld is poor quality. The screws cannot go through the nuts easily
3. The rubble looks pretty cheap and not worth the $XXX I paid for
NOT RECOMMENDED
Very Poor and unsatisfactory. Box arrived unsealed with no attempt to tape box closed from shipper or manufacturer. Hardware is the worst quality control I have seen in 25 years of working with automotive parts. The 3/8 nut welded to the flat bar was painted inside 75% of the threads and the nut and bolt are stripping trying to clean up the threads. The welding and painting is very poor quality on all parts. Paint shows bare steel in many locations. The nuts and bolts are plain steel and not protected from corrosion at all except where they got paint from the flat bar inside the threaded nut!

Sierra K.
12/7/2021
Customer Service will reach out to you.
Tried to order part first time, rotten customer service. Called back spoke to manager, much better service received part very quickly. Unfortunately part had bad bolts and or nuts, would not work together. Manager said if I had any problems I could call her number directly and she would take care of it. Have tried to reach her for three days no response. Called regular etrailer number and they want pictures sent to them and then it would have to be reviewed and I was informed I they were behind schedule, so only could guess how long it would take. Sending parts back and demanding refund. Have been doing business with etrailer for many years and this is the thanks I get for being a long time customer. Will not be shopping with etrailer ever again

Brooke M.
5/4/2022
Thank you for letting us know. Our customer service team should be reaching out to you soon.
Great products and great service! Fast shipping is a major plus!
Put this on our Sienna van to help tow our pop-up camper and it worked great. The rear of the vehicle did not go down over the wheel like it did before, and it feels more confident when towing too.
I purchased the Timbren suspension booster to reduce the sag when pulling our pop up trailer behind our 2010 Sienna. It works well for that. The Sienna rides quite firm however even when we are not pulling the trailer.
This is a great product. I installed it on my 2006 Toyota Sienna with new shocks. We tow a pop-up camper and would bottom out sometimes. It also improved the way the van drove with a load attached to it. Well worth the money.
Out of the box I was not impressed with this product. I had the spring removed from the van upon their arrival. After looking at the manufactures instructions, which were minimal. And a size up, holding the parts in place. There was no way the springs were going back in after this thing was installed, even after compression.
Go for the air bags, which for me have worked well in the past on other vehicles. There adjustable, and have longevety and installed without spring removal. Sorry I tried something different.
Use my van for deliveries from time to time. It feels more stable with the Timbren system. There is less sway under heavy loads and the suspension doesn't drop as much. Would buy again if needed.
I installed these on a customers Toyota Sienna and to be truthful I didn't think he would be happy with them. The next day he had seven adults in the van to go on their weekly hike and when I asked him how he likes them he couldn't be happier. So apparently they do what they are supposed to.

Dependable A.
4/25/2015
Apparently still good, I havent heard otherwise and I have seen my customer since then.
This did the trick. My 2007 Toyota Sienna rides higher when I tow my popup. I installed myself at my friends house. Do both sides at once to make it easier. When both wheels (hubs) are off the ground and both rear shocks are removed it makes taking the spring out alot easier. We struggled with the first spring because we didn't do this.
I bought the Timbren rear suspension enhancement system because my Toyota Sienna was often bottoming out whenever I had my trailer hitch bicycle rack loaded up. It was a gradually-worsening problem. Eventually I bought new shocks, but also wanted to protect the minivan from harsh roads and heavy loads. The Timbren bumpers seem to work well; I've noticed that bumpy roads seem less jolting when my bikes are loaded onto their carrier, or when I am carrying five or six people. I wouldn't hesitate to recommend them to any other Sienna owners.
Very hard to install and top bolt was turning by self when I try to tite at main bolt. So I did welding another peace of metal on top bolt for not turning bolt by self. This product need to modified top bolt. And Bottom unit are also hard to organize standing right. If they can make a air suspension between spring it is better than this. anyway it works but not satisfied 100%.
Painful to install because of poor design.
If you are installing this on an AWD Sienna, don't bother. Take it to a mechanic. They have a lift and all the necessary tools.
I work on everything on my own cars, the only thing I don't do is alignments, because I don't have a machine for that.
But this was an absurd installation. The components are low quality and the design could use some improvement.
The nut with the backing plate you see in the picture is full of paint. I've had 2 kits and they all had the same problem. You might think you can push through the paint with the bolt, but you can't, at least not safely. So you'll need a tap and die kit. Then you'll need a bench vise to hold the nut in.
There are tons of older reviews mentioning this, but the manufacturer must not read reviews because they haven't fixed the issue.
Then you'll need to buy or rent a spring compressor set because the rear axle won't let the suspension down low enough as in the video of the FWD Sienna.
You'll also need some large prybars or wrecking bar, but for one of my springs I had to use a ratchet strap to pull it out, and on another spring I had to use it to pull it back into place. You'll definitely want some solid jack stands if you don't have a lift, like the ones with the locking pin in them, and get some pinch weld pucks, and of course you'll need a floor jack, preferably 2.
But the stupidest part of the design is the thin backing plate on the nut. I can't believe how easy it is to bend as you tighten it. The used kit that was sent to me once was already bent so I know I'm not the only one that has seen this issue. The trick is to put your finger up behind to feel it while you tighten to make sure it doesn't bend. It also has no lip on it to hold it into the upper spring mount, so if it's not tight enough, it could just get in the right position and wiggle out and then your rubber piece would be flopping around in your spring. A simple lip and thicker metal would solve these problems.
Then you have the odd sized 5.5mm allen key for the lower piece. A lot of hex key kits don't come with 5.5mm
If you don't already have all of these tools mentioned, just take it to a mechanic. Even if you do have all of these tools, you might still want to take it to a mechanic, unless you actually like your mechanic. If you have a FWD Sienna, then maybe it's tolerable.

Jenny N.
4/8/2022
The manufacturer will reach out to you.
I did not encounter any issues with the install on my 2011 Sienna awd. However, in order to do the install you need a spring compressor, which I did not feel comfortable with so I ended up taking my van to a 4x4 shop. I like the do nothing/maintenance free aspect of the kit over airbags.
My van never scraped my driveway, but comes very close. The steering was effected by power a wheelchair in the trunk. The kit gave me 1 more inch of clearance. Installation was was easy with a spring compressor. However I needed to tap the nut on the T nut plate insert for both sides. The nut was not threading on to retain the rubber spring until I tapped it.
Did not get delivered on time. The screw would not go all the way through for the nut that’s wielded on with the washer so I had the worst time with it. It turned out that the nut needed to be rethreaded all the way through because of the coating of the paint that got stuck inside the thread. Therefore, I had to purchase a brand new threading kit to make this work. It was very frustrating during the installation process having to take an extra step of ordering a rethreading kit. I wish the nut would’ve been threaded all the way through prior to shipment to avoid having to rethread.
Other than the installation issue, the product worked as intended with towing a small trailer. It did not sag and was nice and stiff.
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Jenny N.
5/23/2022
I will have our Customer Service team reach out to you.