Review: First trip after shock install

[Lowmiler]

A couple weeks ago, I installed the Roadmaster 7k lbs axle shock kit on my 2018 377. This weekend was the first tow after install, 400 miles round trip.

Verdict: awesome.

I run a Goose Box pin box, which has an airbag and shocks, so I’ve never gotten a lot of chucking, and bumps weren’t overly harsh due to the pin box cushioning. What I hoped to solve was the behavior of the trailer on bridge expansion joints. Even towing with my Ford F450, bridge joints tended to be a little white knuckle as you could feel the trailer almost launching up in the air and bouncing up and down a bunch after hitting a big joint.

With the shocks installed, not only is the amount of bouncing seriously reduced, but the bounces themselves are much milder. Instead of bouncing three times, the first two being severe, now the trailer bounces once, and the bounce is greatly diminished. Rides really great.

Bought the kit on Amazon, $488. Took me a day to install, I decided to weld the top plates after using the self tapping bolts. The square tubing wall thickness is a little less than a frame i-beam, so the welds add peace of mind. I had to buy longer u-bolts to accommodate the thicker lower bracket, and that added another $50 to the project.

Whacked myself hard in the head too, when the half inch ratchet slipped off one of the axle plate nuts, gave me a nice shiner.

I started a thread previously here:

https://www.jaycoowners.com/forums/f...ion-71020.html

FYI, AKRUEBBE, I think your installers measured the angle wrong. I used your photo in that thread to guide my install, and yours are installed at a 56 degree angle from vertical. The shock is installed at a fixed length and using the top bolt of the lower bracket requires the shock to be tilted towards horizontal at 56 degrees. Using the bottom hole gives a 32 degree angle, which is well within the recommend spec from Roadmaster. I think your guys measured the angle from the horizontal, not vertical, plane.

Here’s mine:

[Lowmiler]

Just noticed my leaf spring clamps are out of place in that photo. Interesting. Took that photo after the road trip. Need to look at that next time I’m at the rig. Anyone know the 7k axle leaf spring width? Might buy some new ones.

[Magnolia Tom]

Todd

Now that you’ve got a smooth towing rig you’ll never get another trailer without shocks! Next up is disc brakes and you’ll be set! [emoji3]

[Cannon]

Originally Posted by Lowmiler

Just noticed my leaf spring clamps are out of place in that photo. Interesting. Took that photo after the road trip. Need to look at that next time I’m at the rig. Anyone know the 7k axle leaf spring width? Might buy some new ones.

My axles were bottoming out on frame and rubbing slide floor when it was new. Jayco replaced with 8000lb springs.

[Mopar_Earl]

That shock kit has been on my mod list for sometime. Just waiting on myself to pry my wallet open. That and just not having the time to do the install.


Earl

[AKRUEBBE]

Originally Posted by Lowmiler

A couple weeks ago, I installed the Roadmaster 7k lbs axle shock kit on my 2018 377. This weekend was the first tow after install, 400 miles round trip.

Verdict: awesome.

I run a Goose Box pin box, which has an airbag and shocks, so I’ve never gotten a lot of chucking, and bumps weren’t overly harsh due to the pin box cushioning. What I hoped to solve was the behavior of the trailer on bridge expansion joints. Even towing with my Ford F450, bridge joints tended to be a little white knuckle as you could feel the trailer almost launching up in the air and bouncing up and down a bunch after hitting a big joint.

With the shocks installed, not only is the amount of bouncing seriously reduced, but the bounces themselves are much milder. Instead of bouncing three times, the first two being severe, now the trailer bounces once, and the bounce is greatly diminished. Rides really great.

Bought the kit on Amazon, $488. Took me a day to install, I decided to weld the top plates after using the self tapping bolts. The square tubing wall thickness is a little less than a frame i-beam, so the welds add peace of mind. I had to buy longer u-bolts to accommodate the thicker lower bracket, and that added another $50 to the project.

Whacked myself hard in the head too, when the half inch ratchet slipped off one of the axle plate nuts, gave me a nice shiner.

I started a thread previously here:

https://www.jaycoowners.com/forums/f...ion-71020.html

FYI, AKRUEBBE, I think your installers measured the angle wrong. I used your photo in that thread to guide my install, and yours are installed at a 56 degree angle from vertical. The shock is installed at a fixed length and using the top bolt of the lower bracket requires the shock to be tilted towards horizontal at 56 degrees. Using the bottom hole gives a 32 degree angle, which is well within the recommend spec from Roadmaster. I think your guys measured the angle from the horizontal, not vertical, plane.

Here’s mine:

Todd, if that's the case then I'm way out of the desired angle. Don't think I can adjust them. They also welded the top brackets. Your thoughts? Nice job..........I knew you would notice the difference.

[Lowmiler]

Originally Posted by AKRUEBBE

Todd, if that's the case then I'm way out of the desired angle. Don't think I can adjust them. They also welded the top brackets. Your thoughts? Nice job..........I knew you would notice the difference.

I can't tell from your photo if the tops of the shocks are in the middle or and outer hole in the bracket (the one furthest away from the equalizer).

If they are in the middle hole, you may be able to move the top shock bolt to the hole further away from the equalizer and drop the bottom shock bolt to the lower hole on the adapter.

The fact that they improved the ride for you is great, I'd just hate to see them wear prematurely from side loading.

The ride really was dramatically improved for me, and I found myself wondering how to soften the rear axle feel on my tow vehicle to match the trailer! I already have Bilstein 5200s on there, so I guess it's as good as it gets.

[Lowmiler]

Originally Posted by Cannon

My axles were bottoming out on frame and rubbing slide floor when it was new. Jayco replaced with 8000lb springs.

I don't see any tire contact with the camper. But the fact that the leaf spring clamps moved has me intrigued. Pretty sure they were in the right place before my last trip.

[Big1]

Wow, that look good I would love to do this but this is on my list to do, thanks for the pics.

[Lowmiler]

So short update to the “shocks on a trailer” story.

We’re on our return leg of our annual Florida trip, about 2100 miles total, so I’m doing a really long shock test drive for sure.

Trailer behavior remained composed over expansion joints, but since installing the shocks, the rear of the truck seemed more unsettled over same joints, like it was porpoising.

Since I’m driving a new F450 and pin weight is just 3100 lbs, and I have Bilstein 5100 on the truck, this porpoising feeling was surprising. It was so common that it had me entertaining putting timbrens on the truck to minimize squat over bumps.

After pondering my situation further, I wondered if maybe I needed to soften up my pinbox by letting some air out of its bag, I keep it fully inflated to maximize bed rail clearance on my truck. But the porpoising had me thinking that maybe the airbag wasn’t able to absorb bumps and was transmitting direct force to the truck.

So this morning before pulling out of Charleston, I bled 10psi from the bag, which only reduced bed clearance by maybe 1/8”.

Wow! What a difference! 350 mile tow today and the truck didn’t porpoise anymore and the trailer remained compliant on expansion joints. The rig was like a magic carpet ride on I95.

Now I’m ready to tackle our 8 week road trip this summer.

[Jeffur]

Not sure how letting air out of the air bags would affect bedrail clearance on the fifth
Wheel. Please explain.

[Lowmiler]

I run a Reese Goose Box, not a conventional hitch.

[ShotgunZ71]

Originally Posted by Lowmiler

I run a Reese Goose Box, not a conventional hitch.

What was your PSI after letting air out, compared to normal? Also, where is your "bar" in the sight on the Goose Box?

[Lowmiler]

Originally Posted by ShotgunZ71

What was your PSI after letting air out, compared to normal? Also, where is your "bar" in the sight on the Goose Box?

I have the Gen 1 version. The lower edge of the top of the pin box now sits halfway down across the sight hole on the side sticker, used to sit above. As running max psi of 50, now running 40. Huge difference.

[ShotgunZ71]

Originally Posted by Lowmiler

I have the Gen 1 version. The lower edge of the top of the pin box now sits halfway down across the sight hole on the side sticker, used to sit above. As running max psi of 50, now running 40. Huge difference.

Ok. I've been running mine at 48-50 for my 355MBQS. The ride has been great, but I may try to bump it down as you did to see if it gets even better. My bar is usually right in the middle, going from bottom-left to top-right.

[Jeffur]

Sorry, I thought you were referencing the air bag over the leafs spring type install.