Chassis and suspension building techniques and approaches discussion thread

[tomek9210]

2 hours ago, nicjasno said:

My future plans:

I hope you will document the development on YT :) Do you plan to use your own turntable hubs?

[sirslayer]

I have a question about Ackerman steering and chassis design ... Is this an example of a Ackerman steering with the chassis design where the pivot points angled to the center of the rear differential??  I believe is so... can anyone correct me!! adding or removing the yellow bushings can adjust the steering length ..   

 

 

Edited September 26, 2019 by sirslayer

[nicjasno]

32 minutes ago, sirslayer said:

I have a question about Ackerman steering and chassis design ... Is this an example of a Ackerman steering with the chassis design where the pivot points angled to the center of the rear differential??  I believe is so... can anyone correct me!! adding or removing the yellow bushings can adjust the steering length ..   

 

 

No amount of ackerman can save this. Pivots too far away from wheels, negative caster..

[nicjasno]

1 hour ago, tomek9210 said:

I hope you will document the development on YT :) Do you plan to use your own turntable hubs?

Youtube, yes, I will try to use what lego uses, to enable people to build everything themselves. Only 2 moded parts if all goes well, 2 gears in the gearbox.

[tomek9210]

Awesome. I can't wait to see first results. I hope for caster, kingpin and nice turning radius :)

[nicjasno]

Turning radious might be tough. I was hoping for wheel hubs with the new cv joints, but lego cheaped out. Those old cv joints are pretty useless.

[sirslayer]

I appreciate your time @nicjasno and your advice is much needed on this website!! thank you for your evaluation of my MOC..   do you have a solution for the steering pivot to be closer on any 11 wide or smaller length for the front suspension and steering with drive??  the negative castor I can fix !!!   Can it be done?? I'll have to do my own homework!!  Great videos on youtube by @nicjasnoon all types of suspension solutions!!  

https://www.youtube.com/user/nicjasno/videos

 

Edited September 27, 2019 by sirslayer

[tomek9210]

What about 42099 joints and hubs? I know that upper ball joint is fixed, but sides can be used for building a custom one hub over the existing one.

[nicjasno]

5 hours ago, sirslayer said:

I appreciate your time @nicjasno and your advice is much needed on this website!! thank you for your evaluation of my MOC..   do you have a solution for the steering pivot to be closer on any 11 wide or smaller length for the front suspension and steering with drive??  the negative castor I can fix !!!   Can it be done?? I'll have to do my own homework!!  Great videos on youtube by @nicjasnoon all types of suspension solutions!!  

https://www.youtube.com/user/nicjasno/videos

 

I would use the new CV joints. Will try to devise something in the afternoon.

 

18 minutes ago, tomek9210 said:

What about 42099 joints and hubs? I know that upper ball joint is fixed, but sides can be used for building a custom one hub over the existing one.

The new hubs are useless because they are reduction hubs. I wish lego would make a version without reduction. I was hoping for one in the Discovery, but we got shafted again and have to live with a mere suggestion of steering.

 

[MangaNOID]

 

19 hours ago, grego18f said:

Some time ago, I tried to add the McPherson Strut on the 42056 set. This is what I obtained:

how was the looseness of the hub assembly with this setup @grego18f

I believe McPherson struts in Lego to be close to complete disaster with the small spring (I haven't really tried the long spring). only on a shelf model that will not get much use would they be any good and definitely not on a motorised set.

I have stuffed around for hours and hours the last few days trying to minimise steering looseness but there is a lateral twist in the small spring that shows itself (especially with large fat tyres with poor scrub radius from the strut build) add to that the normal steering link looseness and loose lego tolerances its all a bit disapointing in a way.

 

[grego18f]

@MangaNOID, the hub assembly was stiff. The only problem is this black section of the shock absorber which is bending under pressure... I have tried this setup with an axle and it worked fine. The spring taken from the hard shock absorber is not stiff enough sadly for this configuration. 

[Gray Gear]

5 minutes ago, grego18f said:

@MangaNOID, the hub assembly was stiff. The only problem is this black section of the shock absorber which is bending under pressure... I have tried this setup with an axle and it worked fine. The spring taken from the hard shock absorber is not stiff enough sadly for this configuration. 

You could replace the inside Part of the shock with a normal Technic axle...that inside part is made of pretty soft plastic, a normal axle is way more stiff.

[MangaNOID]

I think actually most of the looseness is from the ball links. If I hold everything else tight there is still play in those. There is plenty of sets with these links so I’ll have to build an axle from one, to see, to compare.

[nicjasno]

18 hours ago, nicjasno said:

No amount of ackerman can save this. Pivots too far away from wheels, negative caster..

@sirslayer i couldn't resist the urge to add a kingpin inclination :) It's not perfect, but it's a starting point for your axle. You need to add some positive caster and you will suddenly have controll over your wheels.

[sirslayer]

Right on!!!  @nicjasno.. Thank you very much!!!  I'll build it asap!!!  You are the oh mighty one!!!   

[sirslayer]

Here is a few pictures of LPE power steering solution I end up changing the design a bit since I didn't have the newer cv-joints .. i used an u-joint and shorten the width to 11 wide.. What I do like about this design is how the axle spring back to the stationary position after you bend it back .. I got a video to share ..Im surprised how plastics can spring back and forth without breaking it!!!  

 

[nicjasno]

If you noticed, the 3 black conectors on the top in my version are designed to prevent this springing back effect. They add a second pivot, so the steering works smoothly.

[platinum831]

sorry to bump an old thread but i would really like to know how the full front suspension was made on the e30 knuckles and all i am trying  to build a macpherson front suspension and multi link rear moc on pneumatic air and would like some pointers@nicjasno

[nicjasno]

Download these pics from my dropbox and you should be able to figure it out. There are springs inside the pneumatic cylinders.

https://www.dropbox.com/sh/hh0ngow9nnhcrn4/AABOmptf2rL35RM2sRpQFwIwa?dl=0

https://www.dropbox.com/sh/ia7rz2po2eszs6k/AAAZBgL5ThZ8heLo7lkG3lpoa?dl=0

Edited September 5, 2020 by nicjasno

[amorti]

On 9/26/2019 at 10:49 PM, nicjasno said:

Youtube, yes, I will try to use what lego uses, to enable people to build everything themselves. Only 2 moded parts if all goes well, 2 gears in the gearbox.

Just watched the whole 3 hour stream on this.

The whole way through I was rooting for you and hoping for a modern day unimog fix.

Also the whole time thinking how the ball joints for the 4 links were 7x11 apart and how much gearbox you'd fit right there between the suspension in a 7x11 frame and with all that extra engine bay.

Rough luck with the CV joints, this has to be one to revisit if Lego ever gives us non reduction hubs on the new joints.

I like how you build. "Let's see", "let's try", "we don't know yet". Refreshingly old school in a world of LDD.

You give me a lot of inspiration to make better suspensions. Nothing useful done yet but I'll be working at it 

Edited September 5, 2020 by amorti

[nicjasno]

You have to try weird stuff, even if it makes no initial sense or even if you don't like it. Because what you learn there might give you ideas for what works.

[MinusAndy]

16 hours ago, nicjasno said:

You have to try weird stuff, even if it makes no initial sense or even if you don't like it. Because what you learn there might give you ideas for what works.

Absolutely! Lego is 100% the best way to try weird stuff. 
 

Here’s a couple of rear suspension designs I’ve been messing about with using wishbones on their side so I can run the driveshaft through the pivot points and also keep it reasonably stiff whilst allowing some camber under compression. The drive shafts are also captive so a lot of stress is removed from the cv/uj’s
 

One using 42099 hubs can  have the shock absorbers integrated and driven directly from the bottom knuckle of the hub. The top arm is simple and wide and you can dick about with wishbone length and position easily enough.

These are wip and based on the ones I used in my last MOC to allow plenty of ground clearance under the diff and still be able to mount the shocks low on the bottom arm without the ball joints popping apart.

 

 

 

[Gray Gear]

Some poeple told me to  try using the Land Rover wheels+tires for a 1:8 car because  it allows for more complex front suspension. So I got myself a set from BL and this is what I came up with:

As you can see this design is fwd/AWD capable,

has Ackermann steering geometry 

and a quite serious caster angle.

 

The shock absorbers are located on the back to make everything nice and compact.

 

The possible steering angle is quite good compared to the posche wheels, the limiting factor here is the maximum  pivot angle of the cv-joint. In a RWD setup the steering angle is even better 

This suspension setup was originally developed for a drift car, but I might try to use it elsewhere as well.

Only problem is that the Land Rover wheels look quite small in 1:8 Scale. A 1:8 scale car that looks cool with these will have to be 1995 or earlier, where smaller wheels like this were "period-correct"

 

[nicjasno]

Use the wheels as the scale. Then it'll be fine.

[Gray Gear]

2 minutes ago, nicjasno said:

Use the wheels as the scale. Then it'll be fine.

I cannot do that I have already built 3 cars in ~1:8 scale and they should fit together nicely. A 1:10 car would look very out of place, and I doubt I could still fit my transmission design inside