Trailer suspension vs truck suspension

[aminnich]

Is there a difference? 

My next MOC is a trailer and I have been trying to get an idea for suspension. I tried a normal truck suspension, but the spring stick up too high.  I would also imagine that trailer suspension is stiffer than truck suspension? Right? 

The trailer I am building has 3 axles, the rear-most is steerable. I am going to keep trying different possiblities (you could give examples, but I am not necessarily looking for help building them, for now) 

EDIT

Just to give you an example of what I originally built.  This picture is similar to what I built but not the same.  The idea was a low profile stiff suspension that did not need much ground clearance.  It would have worked out fine, but it was too wide.  I am going to try modifying it so that the springs are completely on top laying flat, I think that will make less wide.  

Edited September 27, 2017 by aminnich

[Leonardo da Bricki]

I believe that most trailers don't have independent suspension, so I would advise you to make either pendular or leaf sprung axles, as they are simpler and easier for small spaces, especially when they don't need to be driven.

[Qukie]

If you use the L shape beam 5x3 as the mounting point by the frame (instead of the 4x2) with the shorter part turned up and inward you could use them for effectively mounting the springs two studs further inside thus narrow the total width by 4 studs.

Or you could use the current 4x2 beams mounted up side down and narrow the width by 2 studs.

[aminnich]

I did think about that, but with the example I showed, the "arms" connecting the main frame and hub would be much shorter, so I would have to figure out a way to get the travel from the suspension through the axle. I hope that makes sense 

[M5Technic]

most trailers have solid axle leaf sprung suspension

[aminnich]

Well we do not have Lego leaf springs yet, so I do not think that will be an option. It's either unconventional suspension for a trailer or no suspension at all 

[AndyCW]

Torsion bar

It's easy to implement with lego and prevalent on trailers.

[aminnich]

I think that if it comes to using torsion bar suspension, I will skip suspension all together.  It will make a lot of other things much easier

 

[brickless_kiwi]

First off what scale are you building in as there is a lot of setups that work well without using Springs 

[aminnich]

Scale has no been officially determined, somewhere around 1/18 scale, but not exact.  The width of the axle is around 5.5" (9397 logging truck width)  

[dr_spock]

You could try making a rubber suspension with the rubber technic pieces.   Maybe an "air ride" suspension using pneumatic cylinders?

 

[aminnich]

I think I am going to skip suspension for now and come back to it once the rest of the chassis is built, that way I know how much room I have to add suspension.  I am afraid I will not have room for everything.  Sorry I keep what I build a secret all the time, but I do not want to share what I am building without some kind of progress on building.  It will be a WIP topic and hopefully posted sooner than later. 

[mocbuild101]

11 hours ago, aminnich said:

we do not have Lego leaf springs yet

...or do we?  

https://rebrickable.com/mocs/MOC-2427/Epic_Technic/small-tatra-leaf-spring-suspension/#comments

And:

 

[ThatOneBuilder]

Just now, mocbuild101 said:

...or do we?  

https://rebrickable.com/mocs/MOC-2427/Epic_Technic/small-tatra-leaf-spring-suspension/#comments

And:

<vid>

The rebrickable one is very common in leaf springs and the one nicjasno made isn't really official.... 

So I guess the best bet is the flex axle one... I guess @aminnich was referring to an official part made by Lego for use in leaf spring suspensions.

I think a live axle could work, like in the Arocs, although i do not know how to implement it...

[aminnich]

3 hours ago, mocbuild101 said:

Ok, now you got me thinking. A 2x16 plate used as the leaf spring... hmmm the spring would have to be shorter, but I think that might work. Hopefully progress and a WIP topic started tonight. 

[mocbuild101]

Just now, aminnich said:

hmmm the spring would have to be shorter

If you only support the plate (or maybe tile) from one end, it would be just as springy as a longer plate supported from both ends. (although it won't be a realistic...)

Don't forget, Lego is much more flexible than you might think...

[aminnich]

@mocbuild101 thank you for the idea, I will for sure try it out

[aminnich]

I have tried numerous axles with suspension.  I have trouble with all of them.  The problem is the width constraint.  I increased it to 6" just to give me a little bit more room.  Nothing with suspension is working.  I tried the leaf spring idea, it only works with a longer 2xwhatever plate, which makes sense.  The longer the plate, the more it is willing to bend.  I have not given up on suspension for this build, but I want to move onto bigger and better things.  So for the time being, no suspension, I do not have the experience for me just to through a good axle with suspension together.  I am to have some time to work on the chassis this weekend and have a WIP topic posted by Sunday at the latest.  I am excited for this project, I am going to take my time and try and get it as good as I possibly can.  

 

Thanks for everyones suggestions, it was greatly appreciated!

[suffocation]

There's always pendular suspension if you want. It's the least sophisticated but it beats solid axles and probably takes up the least space of all.

Or, if you're willing to go a more complex but highly rewarding route, you could replicate Pipasseyoyo's brilliant springless multilink suspension. There's an LDD file out there somewhere; if you can't find it I can send it to you as soon as I find it on my hard drive.

[aminnich]

4 hours ago, suffocation said:

There's always pendular suspension if you want. It's the least sophisticated but it beats solid axles and probably takes up the least space of all.

Or, if you're willing to go a more complex but highly rewarding route, you could replicate Pipasseyoyo's brilliant springless multilink suspension. There's an LDD file out there somewhere; if you can't find it I can send it to you as soon as I find it on my hard drive.

Yes, I know there are different say of approaching suspension, but I do not know how much room I'm going to have. I would rather have a bunch of other functions in the space instead of suspension. Sure, once the main frame is built, I may end up doing some kind of suspension once I know how much room I have left. As for now, no suspension, by hopefully that should change later on. 

Thanks again for our help everyone 

[Ivan_M]

Use rubber 2L connector, this is very usefull part:

trailer suspension by Ivan Moc, on Flickr

It is live axle for smaller scale trucks, works like a charm. The rubber connectors are fixed to the frame and axle is only resting on it. Side links are there to limit the movement left/right. Since it is for trailer you can make it more compact, this is just for showing how it works.