m416 swaying on highway (1 Viewer)

[Bloomer]

Have a new M416 with SOA and equipped with RTT. Took out on first trip and experienced significant swaying on the highway. We had a bumper carrier with a cooler and 5 gallons of water on the back of the trailer. Once we removed these, it seemed to help considerably. I'd like to use the bumper carrier to store things during road trips. Any thoughts on how to improve this (heavier leaf springs)?

Tend to think the weight hanging off the back balanced the trailer enough to allow then lunette to raise in the pintle and the trailer to be more unstable. That's my guess anyway. Maybe more weight in the front is needed?

 

[ntsqd]

More tongue weight is needed. Assuming that you aren't exceeding the tow rig - trailer combo's critical speed, trailer sway is nearly always not enough tongue weight.

 

[titanpat57]

13%-15% of total trailer weight for adequate tongue weight.

I always go 15% minimum and never had a problem

 

[Helipilot]

Trailer sway is very dangerous and can easily lead to an accident. I used to own a trailer manufacturing company and the rule of thumb was from front of trailer to center of axle should be 60% of the length of the trailer. This should place 60% of the load over and forward of the axle thereby providing a stable towing experience with proper tongue weight. Another reason for trailer sway is low pressure in the tires or an over loaded trailer. Good luck with your trailer building project.

 

[Bloomer]

Thank you so much for the replies. After shifting the weight off the cargo carrier mounted to the rear of the trailer, the swaying almost all but stopped. Never much exceeded 60 mph (maybe got upto 65 occassionally but not sustained). Tow rig today was a 3/4 HD Diesel so not even close to exceeding towing capacity. Tires on the trailer are less than desiresw so they'll be replaced before the next trip.

I'm a little concerned about the overa weight with the top and RTT and everything I would like to haul in the trailer. 50% of the objective in purchasing a trailer was to free up space in the land cruiser during trips, with the other 50% being a carrier for the RTT.

Along with the SOA it also has Rancho shocks. Any suggestions on how to increase the payload capacity to improve towability?

 

[cruiserpilot]

I would consider flipping the axle to SUA, lowering center of gravity will improve dynamics.

 

[ntsqd]

Sounds to me like you just need to re-think how the trailer is loaded. Put all of the heavy stuff up front, lighter stuff towards the rear. Maybe shift the RTT forwards as well.

One of the factors in the formula that predicts the critical speed (the speed where it will sway regardless of loading) of the tow-rig/trailer combo is the stiffness of the trailer tire's sidewall. I've never seen a number for that, so the formula is useless to me, but that tells me that anything that adds lateral compliance to the trailer's suspension is important to when the trailer will sway and when it won't. This is part of the reason why I don't think same size tires as the tow rig, when they're over-size, is a good idea. It is also why I think SOA on a trailer is usually unnecessary.

 

[Living in the Past]

Just saw your other thread about extended tongue. Just remember if you decide to lenghten the tongue you reduce tongue weight because of leverage. My M416 is SUA with stock wheels and tires. I used a 60 series spare tire carrier mounted in front of the axle. A tire carrier mounted to the back would have been more convenient in the present location it helps with both tongue weight and center of gravity.

 

[Bloomer]

Thanks again for all the feedback. Really good stuff!

The thread on the extended tongue was a trailer that was more local (a few hours away) I was considering. The one I actually ended up purchasing is the red one with the RTT.

I'd really like to keep the SOA configuration, particularly since it is already done and it sits almost level with the tow vehicle. If I could figure a way to make it level with the tow vehicle without a towering pintle adaptor I would lean toward going SUA. I actually like the way SUA looks and it would actually tow better (more stable).

It is way overdue for new tires. The ones on it may not be 1967 vintage, but likely pretty close. I plan to use the original rims and have been thinking about going with a slightly larger tire. (On a side note, discount tires mentioned they can install tubeless tires on the original rims as long as they are not split rims. Not sure what split rims are. Can anyone confirm whether this is possible with the original rims?). My plan is to go with a tire with a stiffer sidewall; maybe 8 or 10 ply BFG AT/KO.

Since I will not have matching tires with the tow vehicle, I plan to carry a spare on the trailer (I have a 3rd rim that is in ok shape). As of now, I am going to try and fab a mount that will attach to the tongue of the trailer, to help keep the weight distributed more towards the front.

Thanks again for all the feedback. Please chime in if you think of anything else.


...via IH8MUD app

 

[ntsqd]

On the Cheap Utility Trailer we used an S-10's spare tire cable winch/carrier (we had it) to hold the spare under the trailer. If you stay with skinny tires you could do that under the bed, forward of the axle.

 

[hey you]

As mentioned, the tongue weight is the issue. I have a simular setup as you and have learned to pack the trailer with the heavest items forward. The other issue is too much tongue weight and not being to un-hook the trailer from your tow vehicle and developing a hernia. Instead of using the stock landing leg, I installed a rotating trailer jack (#2000) which helped to solve the issue.

 

[Dell]

Just remember if you decide to lenghten the tongue you reduce tongue weight because of leverage.

I'm going to disagree with this comment.

my tongue extension weighs more then the original lunette assy.
also... an extended tongue improves trailing.

As others have stated...
load balance is what the OP's issue is.

 

[Living in the Past]

I'm going to disagree with this comment.

my tongue extension weighs more then the original lunette assy.
also... an extended tongue improves trailing.

As others have stated...
load balance is what the OP's issue is.

I brought this up for two reasons. OP's other thread he mention changing the tongue on the trailer he didn't buy. So he may thinking of changing the tongue on this one. He is also already having issuing with he current trailer.

While load balance is important so is tongue weight. These trailer are really set up as a lever. If you had problems lifting the tongue of the trailer and adding a cheater like you do on a wrench you have reduced tongue weight. Just try lifting your trailer at the front of the box and then at the end of the tongue. The tongue will be easier to lift. So extending the tongue will reduce that tongue even more. Since a percentage of the overall trailer weight needs to be on the tongue a longer one may not be better if your already having load balance problems. It means even more weight needs to be moved forward of the axle (fulcrum).

Lot of information here. http://en.wikipedia.org/wiki/Lever

As for trailering with proper tongue weight I've never had a issue towing. Backing up is easier with a longer tongue but so is a ball hitch compared to a lunette. For off road I like the shorter tongue towing with my FJ40s. Can turn sharper and the trailer follows right along. Since the Forest Service in my area allows taking your vehicle off the trail to pick up your firewood I can get into some pretty tight spaces.

 

[Bloomer]

Thanks for all the feedback. Load balance seems a to be the main issue I was having. I'm happy with the current set up and am not interested in extending the tongue at this time. While I see some benefits to a longer tongue, it doesn't fit into my short term plans for the trailer. I'll likely adjust some of my storage plans and place some of the times I planned for the trailer into the cargo area of the land cruiser. The swaying all but stopped when I moved my cooler and Walter off the cargo carrier on back of the trailer.