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When heavy cargo or a trailer starts to weigh down the rear, these Firestone Coil-Rite Air Helper Springs keep things level. Each polyurethane spring fits inside your existing rear coil spring to add load-leveling support of at least 500 lbs and up to 1,000 lbs. By holding the rear steady, steering and braking stay consistent, headlight aim remains correct, and tire wear is reduced. Whether you’re hauling tools or towing for the weekend, the suspension stays balanced so driving feels controlled instead of saggy and unstable.
The air pressure in each spring can be tuned manually between 5 psi and 35 psi to match your load or road conditions. Inflate evenly for a standard setup or independently side to side to even out an off-center load. Keeping the right pressure helps absorb road shock, reduce body roll, and prevent bottoming out on dips or bumps. You get a smoother ride when unloaded and better handling when carrying weight, all from a simple adjustment at the inflation valves mounted at the bumper.
These Coil-Rite springs are made from tough, elastic polyurethane that stands up to years of heavy loading and rough roads without losing shape. The material resists wear, stretching, and cracking for long-term performance. Even under adverse road conditions, they maintain stability and protect the factory suspension from harsh impacts that can cause bottoming out or premature wear.
The kit includes the brackets, hardware, air line tubing, and separate valves for manual inflation—everything required for installation. The springs fit inside the existing coil spring seats without major modifications. With basic hand tools and attention to routing the airlines away from heat or pinch points, most installs are straightforward for a DIYer who likes doing their own upgrades. Optional switches, gauges, compressors, and air tanks can be added later for in-cab inflation control if needed.
Customer Satisfaction Score:
95% were satisfied with this product
5% of customers were not satisfied
Ratings & Reviews
This was my second order with Etrailer. AWESOME. Product went out same day it was received. Great service and pricing, with service being the most important to me. The air bag support system for my Toyota Sienna van's rear spring coils was easy to install with very minor modications. They made a huge difference on the back end of the van "hitting" the ground when loaded. Just what I needed to pull a trailer.
Excellent product, installed on 2011 Toyota Sienna that tows 3,000# Hybrid Travel Trailer. Works great to keep rear level (along with Anderson Hitch Weight Distribution). We now run air in them without the trailer as well to help prevent typical Sienna sag when loaded with people or loads.
I had these installed in the rear of my 2023 Toyota Sienna Limited after getting it lifted with the Journeys Off-road lift kit. Installation went smoothly with no issues. Initially, there were some squeeking, but that went away after a couple of months.
Etrailer and Firestone have some great customer service. This kit was fairly simple to install
I had these installed on my Toyota Sienna one year ago and I couldn't be happier with the product. I frequently load the vehicle with heavy DJ and sound equipment and when inflated to about 35 psi, the air springs provide perfect support. No more squatting or handling like a boat going down the road. I highly recommend!
These did not fit in my vehicle very well and took much more work than the vague directions explained. Now after a month of use they no longer hold air. This is due to the fact they just don't fit properly on the upper side of the coil chamber in my 2025 Sienna.
All parts there to install, no buying necessary parts that are not included. Instructions and video will make installation straightforwRD
Installed on 06 Sienna. Bought these for towing our 16' boat. Had a mechanic buddy put the bags in and ran air lines myself. Had one initial leak but I recut the end of the air line and it works fine. Noticeable difference when inflated to 25 psi. Some slow pressure loss over 24 hrs but well within driving times needed. Overall excellent service from etrailers and a very good product so far.
Units was fairly easy to install. It was a complete kit and they work great !
I would recommend these air bags to anyone looking for such a product.
David
10/18/2023
They air lifts are working well.
Mike L.
11/9/2023
These were surprisingly easy to install using ramps and a floor jack and really helped with preventing our Sienna from bottoming-out when carrying heavy loads on the hitch mounted luggage carrier. Highly recommended. Be sure to watch the installation video on etailer!
I installed Firestone Coil-Rite Air Helper Springs and they work great. With minimum air pressure they improved the unloaded ride and driveability. Loaded the van for vacation, added air pressure to bring the ride height back to the normal ride level and the van drove and handled better than when it was new.
Followed your on-line installation video and installation was a breeze.
The installation instructions with the kit were poor and incomplete.
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Still holding pressure and does what I need. Van is more stable unloaded, even with new shock dampers it's better. With a full load of hundreds of pounds in back the van is much more stable and does not wallow like a whale near as much. Towing trailers is much better too. Didn't expect airbag pressure to hold for months and months but no leaks so far. Only issue was as expected...little bit of elbow grease to install bags and find best airline routing. some bag rubbing squeeks in the coils but I did expect some inherent to it's design. Nice product I would recommend to friends.
I use my Toyota Sienna as my work van, so it's loaded with tools and supplies. It's heavy enough that the rear suspension sags, and the car rocks forward and back on rapid deceleration. I was almost ready to pay for a custom suspension before I found this product. I've been using it for a year and I can't say enough good things. It was reasonably easy to install, had to get some ramps and a creeper, but the rest of the installation was tool free. I measured the height of the front fender to the ground (highest point of the gender) and inflated the system until the rear fender was within 1/2"of that. For me it wound up getting 28 psi. Just short of the 30 psi max working pressure. The benefits were immediate. My acceleration improved, because the car didn't rock back as much when accelerating. Surprisingly, my breaking got better, which makes a little sense, since the car was only leaning forward, and not teetering back and forth. Best of all, the van was no longer leaning like a motorcycle every time I made a turn. The entire driving experience improved massively. It's been a year, and things are still going strong. Well worth the money.
Product works as advertised. Surprising held most of its pressure after a year without further inflation. Provides very good suspension assistance when trailer tongue hitched to minivan.
Bill
10/22/2022
Air bags are still performing as expected. The additional surprise is how well they hold their pressure with time. Thanks again for a very good product.
My 2023 Toyota Sienna AWD was having major problems with the rear sag when we put a hitch and a bike rack on. The bike rack would sag so bad that it would scrap on the smallest of bumps. I am still worried it has damaged my nice bike rack pretty badly. I had a friend of mine help me install these on my van and it has worked much better now. I am still debating lifting the van a little but that is not the Firestone helper springs problem. They have worked great so far. I also installed the tee so that I just have to air it up from one valve.
Lazer S.
4/21/2026
Glad they are working well for you, Larry! Sorry to hear you having so much sag beforehand though. It is a fairly common occurrence, especially with bikes and cargo. How many bike are you typically carrying? And did they affect your unloaded ride at all?
This Firestone #F4155 air-bag product is excellent. The fit to my 2011 Toyota Sienna was just as described. I installed the bracket and the two air-fill valves in the jack compartment, easy to get to and out of the weather. etrailer has been a pleasure to deal with.
Bruce B.
2/1/2016
Love the product. Had it installed by my favorite local Toyota dealer. Makes a nice difference towing our Park Liner Fiberglass Egg Camper. Would certainly recommend.
I'm very happy with my Firestone Coil-Rite kit for my '06 Sienna. I added a
"Tee" to join the bags together and routed the schrader valve to exit inside my fuel fill door. It was a little extra work, but well worth it as it's out of the weather and sight, and I don't have to scrabble around on the ground in the slop to check / adjust the pressure. I run 15 -17 lbs when I'm not hauling a load and that seems to help with body roll, and up to 25-28 psi fully loaded. The kit does the job it was intended for, and hasn't leaked a snif of air since I installed it a year ago. Three thumbs up!
Cal P.
3/11/2018
Two years out, and still happy as a clam. Just do it!
I did not actually time the install but I believe it was less than an hour. I have been loading my 2008 Sienna very heavy when going on vacation. This last time my trailer hitch that I use to haul 5 bikes dragged leaving the driveway and was just a few inches off of the pavement when sitting on the level. I installed this system and tested the load with live body weight, I had a family visiting, they crawled into the van and it did not sag half as much as before. My next big trip is coming up in a week, so we will be giving it the full road test then. I recommend this product.
Don R.
10/11/2017
I just came back from another trip and it worked well.Once installed it is easy to inflate and deflate as needed.
This system require drilling on even though this item says no drilling is required, the 2021 and newer Toyota Sienna FWD models require drilling. This is direcred in the toyota minivan specific instructions. You have to download the specific instructions for the Sienna that are linked in the description of the item.
Jenny N.
5/23/2023
I understand where you are coming from as at first I believed that we needed to update the site. However when we mean no drill in this application we mean that you do not need to drill bolt holes into the vehicles frame. All of the air springs kit will require a hole to be made for the air line nozzle.
I have purchased 3 sets of Coil-Right. The product is very good but the installation instructions were terrible. The first set (2023) I installed per video instructions and it failed. The puck that is placed at the top of the bladder fell of and caused a catastrophic failure. The bladder was punctured and was basically destroyed. The second set (2023) I installed per the video but I enlarged the hole in the puck to help is stay on top of the bladder It failed also. The third set (2024) installed per the new installation instructions which removed the bump stop at the top of the tower. So far they seem to be working better but I think eventually the puck will diappere because there is nothing to hold it inside the spring. Time will tell. This is the only product for my vehicle I can use. 2021 Toyota Sienne LE.
I put these on two Toyota Siennas ('06 and '09). Installation was "easy" without any special tools to speak of. I didn't have to remove the bottom bolt of the shock. If you collapse the rubber and use the red plugs to hold them without air, they will fit between the spring coils with a little coaxing. So far very happy with both. Have had the vehicles loaded heavily multiple times and the difference in load capacity and handling while full is impressive. Ride can be a little stiff if you leave the air pressure at 35lbs without a load. I find around 25lbs is perfect for average use. Anyone with a Sienna knows that loaded down and the trailer hitch will drag in and out of parking lots etc. No longer with these on! Drilled through the bottom of the plastic bumper on one for the valves. The other one I attached an angle bracket to the plate where you would mount a larger trailer power plug.
Would absolutely recommend these to anyone with a Sienna.
JL in SC.
Installer couldn't get them to hold air for more than a day.
And if pressure falls below 5 psi, there's a risk of damaging them.
Installation was difficult.
But they do fix the ride height issue when towing.
If I had it to do over, I'd get Sumo springs.
Mike L.
7/14/2026
I'd make sure that the tubing that goes into the air spring's fittings are cut so they're perfectly square. That is the main culprit when it comes to leaks....
I've yet to install these, I will update once complete. But I've heard from numerous people that if you life the van at the jackpot and let the weight of the tire extend the spring, you can remove the stopper with channel locks and slide the bag in using a liberal amount of soap, so you don't need to disassemble the axle. Again, I will update when completed.
The airbags is working out well so far. Install video was a great representative of what it took. Only reason I didn’t give it 5 stars was the packaging. Outer box was perfect, actual product packaging looked like it was used a soccer ball. .
The airbags were difficult to install on a 2021 Sienna. It required removing the rubber stopper from inside the coil spring. Once that was out, install was easy. However, these need to be installed with the valve down as the plastic spacers fall out when the van is lifted for service when installed right side up as recommended. Upside down the air hose is routed thru the center of the plastic donut spacer which holds it in place when the van is lifted. However, once installed "upside down" the valves tend to pinch on the suspension as they move around. The pinching lets the air out and requires the bags to be frequently repositioned especially after the van is lifted for service. It is a good product, just unreliable and requires much inspection and maintenance to work properly. Will be loading up again for a summer trip and will need to reposition them so they work as I just had the oil changed.
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Karl
1/23/2023
Working great, keeps tail of car at correct height. Cut the air lines when installing as directed. Do not use sidecutters.