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Review of RAS Vehicle Suspension - Rear Axle Suspension Enhancement - RAS4611TD

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RAS Vehicle Suspension - Rear Axle Suspension Enhancement - RAS4611TD Review

Randy: Hey guys, it's Randy here at Today we're taking a look at a rear suspension upgrade for the Toyota Tundra. This is the Roadmaster Active Suspension system, and essentially this is going to turn your static or your passive style leaf springs into an active mechanical suspension system. We'll have two connection points. One's going to go around our spring blocks, essentially where the axle and the spring meet. It's going to sit right in here just like this.

So our leaf spring has a contour to it of course, this portion goes underneath, this portion goes above rather, and this is going to sit underneath it. The other end is going to go right around the end of that leaf spring.Now, this gives us a great advantage in a lot of areas, especially when towing and hauling. Depending on how you set it, you can get 25 to 40% improvement on your suspension. They're rated for a 2,000 pound capacity, so a thousand pounds a piece is how much weight they're going to support. This does not increase your capacity by 2,000 pounds of your truck.

Truck's rated for what the truck's rated for. This just takes a lot of that wear and tear off of that rear suspension. It's taking a lot of that brunt from it. As a byproduct of that, the ride quality and the handling of the vehicle go up significantly. I've installed these on several different vehicles.

One of them is one of our programmers. He's had them on there for about five years now and they work really well and they've really tightened his Silverado up. You turn the wheel, it just feels more direct. It just wants to travel.Also during accelerating, we're not going to have the axle wrap. A lot of times when your wheels turn, it wants to twist that axle.

This is going to eliminate that. Whether it's aggressive starts where you're trying to get out of the hole really quick or trailing, when we've got a force pulling rearward on our truck as we're trying to drive. Helps to eliminate that, which is going to help to eliminate any wheel hop if we're doing quicker acceleration stuff or bottoming out when we've got a load on. It's going to reduce any sway and any body roll out while cornering. As you go to take a turn, in a truck, a lot of times they want to lean a little bit. They kind of want to fade off. This helps keep everything nice and solid.This is a constantly active system so we don't have to wait for anything to engage and I like this system for certain things. If I we're always going to be hauling the same load in the same trailer, things like that, I like the system a lot. If I constantly switched to different trailers over and over and over and over again, I think airbags are a better way to go. They allow you a little bit quicker and easier adjustability. Now, those don't necessarily turn your suspension into an active system, but they have a lot of the same traits that these do. I think you'll like airbags in that situation. Whereas for just hauling the normal trailer that you usually do or staying within certain loads, I think these are a better way to go.Now, these are adjustable, so if you have these installed on your truck and you've got a 3,500 pound trailer and you're hauling around a UTV, then you decide you're going to go to a 7,000 pound trailer and haul around your Jeep or something like that, these are going to work for that. You can just tune them in to that load. Takes a little bit more effort than what you do out of airbags, but I like not having to constantly monitor their pressures in air bags, to make sure we've got enough pressure in there, make sure we're maintaining our minimum. I think the maintenance-free aspect of this adds a lot.Another thing I like about this, it's just a bolt on application and it bolts on very quickly. There's not a lot of stuff to do, once you get this part put around your leaf spring, get this part put around the leaf spring, then it's just a matter of making your adjustment. They're going to send two adjustment tools, they're just round disk. As you adjust these out, now keep in mind your rear axle needs to be hanging, completely hanging when you make your adjustment. But if we use the narrower one here, gives us about a 25% suspension improvement. The thicker one's going to give us about a 40% suspension improvement and that's when it fits down between the coils of the spring.The ones that we're installed on that Silverado I talked to, they've been on there for about five years. They've experienced some rust. I mean, we're in the Midwest here in Missouri, so we got a lot of salt and stuff like that on our roads, but it hasn't been so bad to where it's compromised any of the integrity. They use a durable epoxy E-coat finish on it and then of course, the yellow zinc on all of our other components. If you live in an area where rust is very common, I think these things are going to rust on you. I don't think it's going to compromise anything, like I said, but eventually they're going to have a little bit of rust to them.Another aspect of this, similar to what we get out of airbags, if we install them correctly, the airbags, is that we do have independent adjustability from side to side. So an in-bed camper, let's say, where you've got a water tank on one side or a maintenance truck, you know, the big box trucks that have the tools and stuff like that in them, sometimes those can be a little bit offset. You can adjust these independently from one another to where you could help that one side that sags. You can help that out a little bit. You can get it a little bit more even, spread that load out more even. I really like how this works. The more pressure that we put down on that suspension, the more we're going to get out of the system. It's a variable rated coil so they're automatically going to adjust to the load when you put them in. I like that.Again, load your truck up, hit the road. You don't really have to worry about stopping by a gas station or anything like that for air. It's going to level your ride out, of course. And overall I really like this system. I really like the way they've designed it and I like how easy it is. It's going to go on very quickly, it's going to solve a lot of the common problems we get from hauling typical trucks, typical loads, or the problems we have with that body roll. So it's kind of a double edged sword. It's going to improve the ride quality of your vehicle and then when it's time to start towing, you're going to have that additional support there to take all the wear and tear off a lot of those components.Be sure to use our fit guide. You want to put in your exact year, make, and model. As I said, these are going to be for the Tundra trucks, but they make them for all different varieties of vehicle, too. So put in your year, make, and model. Just ensure that you're going to get the perfect set for you, it's designed for your vehicle, they've made it in a way that it's going to bolt directly on and it's not going to interfere with anything. But again, overall, I think this is an excellent solution to beef up that rear suspension a little bit and get a lot of improvements in the ride quality.

Larry H.


I tow a 28 foot pull behind RV trailer with a tongue weight of about 900 lb. I use a Blue Ox stability / load leveling system but dont like torquing up the Blue Ox so much to significantly reduce rear sag. Blue Ox also sets ball about a foot further back from truck bumper further increasing rear sag. Considering the Roadmaster RAS4611TD or possibly even the 3000 lb Roadmaster. Would either level up the truck rear end to near level with my situation. Also, I have a TRD rear axle swY bar kit installed. Will there be interference between this and Roadmaster? Looks like vertical rod from sway bar to frame is far enough away from leaf spring so there should not be an issue with Roadmaster. Would I be better off with air bag system instead. Like the idea of no maintenance with Roadmaster if they will work for me. Thanks.

Etrailer Expert

Chris R.


I do think the Roadmaster # RAS4611TD will do a great job of reducing a lot of that rear sag caused by the trailer. I'm not sure it would totally eliminate it, but it will definitely bump it up enough to make adjusting your Blue Ox system a lot easier if you continue using it. As long as the existing sway bar kit doesn't take up any space around the leaf springs there won't be any interference. Your best chance of really eliminating that sag is indeed with an air bag setup. Like you mentioned though, the initial install is more in-depth and it would require maintenance/adjustments thereafter, so it's completely up to you. I honestly think the RAS system is definitely worth trying.

Info for this part was:

Employee Randy B
Installed by:
Randy B

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