T@B 400 Suspension

Leaton

I own a T@B 400 which I bought just before the pandemic.  Love the trailer and the quality.   I live in Oregon and travel a lot of dirt roads and prefer to get off the grid.  I have dealt with some dust issues inside the trailer, and got those solved, but dang, the lack of suspension is obvious on the dirt roads, and if there are washboards, you better not go over 5 miles an hour.  With that, I was wondering if anyone has upgraded their T@B 400 with an Axle-Less Trailer Suspension system?  I reached out to NuCamp, for a frame diagram, but for good reason they won't release one, but will communicate to a shop directly if I select to install something.  I am new to this forum, but thought I would ask if anyone has tried to upgrade their trailer?   I saw a thread talking about it, and one person said they were considering air shocks, which I assume is similar to the Timbren Heavy-Duty Axle-Less trailer suspension system.   Thanks in advance for any advice.  Larry

dragonsdofly

@Leaton welcome to the forum and to the t@b family. There are some resident experts here who will chime in soon and help you out. Even if no one else here has attempted what you are considering (and there may be), they'll explain what to consider and point you in informed directions.

Ok experts, your turn!

Grumpy_G

I'm with you on this one.... I live in Central Oregon and deal with the same issue. The rubber torsion spring axles are not suited to rough roads, the manufacturer data sheet lists the up travel at rated load a mere 1.5". T@bs are a German design (originally made by Tabbert) and roads there are generally better. 
I have some background in racing and 4 wheeling (even worse I'm an engineer ) so I've been around suspension modifications. The main problem is that rubber torsion springs are extremely progressive (meaning the spring rate ramps up very sharply). The Timbren solution uses rubber as well, just compressed instead of twisted. I'd expect it to have the same issue. Air springs behave similar so air shocks or axle air bags are not much of an improvement either. That leaves linear coil springs and leaf springs as the only viable solution IMO. The easiest would be to replace the whole torsion axle with a regular trailer axle riding on leaf springs, and adding shock absorbers. That would increase ground clearance as well, at least for non-boondocks models. Another idea I've been contemplating (without much success) is some sort of linear "helper" spring that carries most of the weight and the rubber torsion only functions as a glorified bump stop. However packaging something like this is a real challenge. 

Leaton

Grumpy, wow, that is impressive.  I am a simple hydrogeologist, with limited engineering skills and know enough to ask for help.  Maybe it would be best to replace the trailer axle with leave springs system and shocks.  Any suggestions for someone who could tackle that?  We are somewhat close neighbors -- I live in PDX, but have venturing to the Steens, and beyond for over 20 years.  Thanks again.  Larry

Denny16

@Leaton, do you have a standard TaB400 or the Boondock model?  Our TaB originally had the standard axle and was towed across desert dirt roads and did quite well.  The coastal California fire access roads and some remote areas have rougher roads which is better negotiated with using a higher Boondock type axle.

We had ours changed to a Boondock axle so we could travel these rougher roads around here.  I find the Boondock axle works well, and several TaB400s have gone to Alaska across the dirt access roads to the northern frontier area.
When traveling rough unpaved roads, one has to go slow anyway, even in a Jeep.

The original European axle TaBs had (Dutchman built TaB), an option for road shocks that could be added to these ales to smooth out the ride some.  But the current North American axles will not take that modification, and not sure it would add any benefit anyway.  I find our TaB town very well, much better than other trailers I have towed, even those with springs.  See: https://tab-rv.vanillacommunity.com/discussion/15667/correct-shock-absorber#latest
 Cheers 

manyman297

I have to agree with @Denny16. We’ve been on a few rough and washboarded roads (BLM land) and our 400 BD did really well. Comparing this suspension to the old school leaf spring (and no shocks) was night and day. 

Binghi

I’m with Leaton and Grumpy. I expected that the 400 BD would do well on rough roads but turns out not really. Talk about bouncing and shaking…But on the other hand, what would one expect? Travel trailers are not meant to be high-clearance or off-road vehicles.

Leaton

Thanks everyone.  I do not have the BD (should have bought that upgrade), but from what I understand the pitched axel that comes with the BD is simply an angle at the spindle that raises the trailer and allows for taller tires.   I plan to upgrade my tires and if Les Schwabe recommends a new axel, I may upgrade to the pitched axel, or something different. From what I understand the T@B BD pitched axel does not have any added suspension.   

For the most part the T@B 400 is great, and I can easily navigate some tricky roads, but I hate seeing the trailer rattle so much on washboards, even when going very slowly.  Hence the hunt for an upgrade, if possible. 

There are some new small off-road trailers hitting the market, with very impressive suspensions, but they are twice as heavy and twice as expensive and more than what we need since we don't 4-wheel with our unit.

Grumpy_G

T@bs are well constructed and hold up better than most other products on the market. Years ago I had a trailer made by one of the many Forest River brands and I literally had to reassemble it after a mile of washboard on the way to a campground. Still, a better suspension would go a long way at reducing the stress on the T@b. The boondock axles are the same design and have the same limited travel, although airing down the larger tires might help a little. 

@Leaton A trailer repair and/or welding place should be able to modify the trailer. There two challenges: The big one is that the axle is part of the frame structure so it can not be simply removed. Either a replacement crossmember would need to be build, or the swing arms be removed from the axle. I have not found a definite explanation on how the axle is assembled, but if somebody put it together it can be taken apart somehow  The smaller one is that welding on a trailer that can catch fire more easily than a flatbed requires some care. 

Edit: Apparently the axles are assembled by shrinking the rubber in very cold temperature. 

Dutch061

If it makes you feel any better, I too have looked at other "off-road campers". The one I really like has an amazing suspension system, but the inside looks and feels like a 15K Coleman camper.

Out of respect, I will not name the brand but outside of the suspension, they are JUNK.

Brad

Denny16

Grumpy, the TaB torsion bar axle is not part of the frame, and is just bolted in.  It is a one hour shop job to unbolt the standard axle and bolt the BD pitched axle back in.  I had this done, and I was charged on hour of shop time.  What is part of the frame (welded in) are the special brackets nüCamp added to the frame and axle specification.  A off the shelf Dexter pitched axle will not fit.  So yes, our axles are a special order unit made by Dexter.  

I was told the torsion bar is different on the BD axle, and takes more weight than the original standar axle. This may have changed in 2020/2021, as both the standard and pitched axle have the same gross weight rating, but in 2018/2019 they were different.  The standard axle rode a little softer on smooth highways.

The BD axle is stiffer when loaded, and with the off road type tires, are going to be a little more bouncy going down the highway.  On rough and washboard roads, you need to air down the tires a bit to soften the ride.  I do the same on my Jeep tires.  This keeps the road from beating you to death. 

You have to pack the TaB as if you were securing the cabin in a boat for rough seas, or an aircraft being prepared for a landing.  Everything must be stowed, secured and no loose gear left adrift.  Overhead cabinets need to be locked and drawers ser so they will not open.  This applies even for a short trip down the highway.  Don’t ask me how I know this, but learned this lesson from personal experience.  :#
Cheers


 

N7SHG_Ham

I don't know if these guys could retrofit to a Tab, but if so, proably the go to place. https://www.morryde.com/products-cat/is-suspension-towables/

Grumpy_G

Grumpy, the TaB torsion bar axle is not part of the frame, and is just bolted in.

I disagree. Just because it's bolted in does not mean it doesn't stiffen the ladder frame. And if you simply remove it the C-channel frame rail is left with a notch that makes for a nice stress riser causing cracks over time. We're discussing replacing the axle with something else, not like for like. 

Denny16

Yes, I agree with this, the axle or a similar support needs to be in the custom mounting bracket cutout to reinforce the frame at that point.  Not sure how much bracing them axle bar provides, as it is quite small.  TAXA Outdoors uses a similar Dexter Pitch axle for their trailers, and added an Off Roads Boondock option that replaces the Dexter torsion axle with independent suspension (non cross axle) type setup (on a ladder frame simi,are to thenTaB) used on a lot of off road trailers.   

After TAXA installs the Off Road axle setup to their Cricket trailer, it’s approach and departure angles are not quite as good as the TaB400 BD setup.  

My original point was that the Dexter axle, whilst bolted in does reinforce the frame at the mounting point, is not a permanent structural component, but a bolted in replaceable component.
 Cheers 

atlasb

Grumpy_G

N7SHG_Ham said:

I don't know if these guys could retrofit to a Tab, but if so, proably the go to place. https://www.morryde.com/products-cat/is-suspension-towables/

That's an interesting solution, up to 5.5" of travel would be a great improvement. However the only applications I found are on expensive 5th wheel trailers so it probably won't work on the light weight T@bs. 

manyman297

Here in Utah we have the Escapod teardrop trailer (https://escapod.us) that uses a proprietary independent suspension that's supposedly really good. I also think Ember and Black Series trailers use an independent setup as well. 

Denny16

Black trailers use an Australian axle setup developed for the Outback where paved roads are few and travels are often without graded roads.

You do not need a huge swing travel, unless you are leaving the road and going over an area with dips, hills and gully’s to navigate, or climb up over rocks.  A trailer designed for roads, like the TaB can work with a well dampened limited swing movement, enough to smooth out the small bumps, and right spots in unpaved graded roads, and normal street travels.  
Cheers

Leaton

I will reach out to the Morryde to see if their system would work on a T@B 400. The 5.5 inch travel is nice, but it would need to be verified that it would work on a T@B at roughly 3,000 lbs.  Thanks

Mickerly

There is a mod available for the Casita to add shocks to the Dexter axil. One shock mount attaches to the brake backing plate, the other bolts to the axil frame mount. I looked at it for a while. Their axil mount is different from ours. It couldn't be that difficult to change the bolt pattern. The kit is sold through "littlehomeontheroad.com".

Leaton

https://youtu.be/MzDW1OUbmHc
https://www.youtube.com/watch?v=MzDW1OUbmHc

I checked on the Morryde axle and it does not work for the T@B 400 since it requires at least 10,000 lbs to work properly.   Good point Grumpy.

With that, does anyone know if the T@B 400s are equipped with the Dexter Torflex suspension axles?  I tried to copy and paste a link to Dexter's video of the axle (see above).   That could be a nice compromise to add some suspension to the T@B 400 if it isn't already equipped.  I crawled underneath and noted the axle arm, but not sure it swivels like the Dexter Torflex does.

Denny16

That is the Dexter axle the TaB400 (and 320) uses, I believe Torflex is Dexter’s trade name for the torsion bar type suspension.  I believe this is one of the best types of axle for lightweight trailers like the TaB. 
 Cheers 

Leaton

Cool so the trailer does have "some" shock absorption.  Thanks 

Leaton

No it is time to see what are the tallest and best offroad tires I can put on my non Boondock T@B 400 since the tires that came with it are sure to fail on all the dirt roads I travel.   Again thanks everyone, my first time on this Forum.  Learned a lot

Denny16

You are not going to get a much bigger tire the the stock one on a standard axle TaB.  If you want to go down undeveloped roads, you are going to need to switch ykur axle for the additional lift Boondock axle, which has more swing motion, and raises the TaB around 2” for improved clearance and allows larger off road tires.  

This is what we did to our 2018, which originally did not come with a Boondock axle option.  See your TaB dealer for cost, or message atlasb in above post showing the axles.  He did the change out on his TaB also, ordering the axle from Dexter directly.  

I got the nüCamp provided package sent to our dealer in a standard trailer shipment to save shipping, and got the axle, Boondock wheels and tires, which the dealer put on the trailer.  Changeover takes about one hour of shop time.
 Cheers 

Leaton

Great advice.  Thanks.   Larry

Denny16

You are welcome Larry.  However, when I am going on a trip using mostly highways and paved roads, I plan to put road tires (Goodyear Endurance) on the original rims I took off, and mount the road tires to the trailer.  The original road type wheels do mount on the Boondock axle quite nicely, and still has a little extra clearance.  This also reduces the trailer height to make highway towing more stable and balanced, and should increase mpg a bit.

Short trips on the highway with the off road tires is fine to get to my off roads trails, so I will use the Boondock tires/wheels for these trips.  Since I have the option to use both, I will use the highway type tires when I am just going to a camp site via paved roads and highways, like our upcoming trip to Lodi, CA, which will be using paved roads all the way, and a good amount of mostly highway driving.
 Cheers