Hi,

Does anybody know how much leverage this has in how far the universal joints pivot for steering and how far up the wishbones pivot for suspention (with no wheels or springs attached to it) with this hub (this hub isn't in LDD) attached to it.

I want to know how well the new wishbones work with the 3L universal joints, the prior wishbones won't work at all unless you have a 5L gap between the upper and lower wishbone but those can be quite big for some MOC's and the design of this wishbone should be better due to the thin part at the front.

This is the setup I'm talking about . there'd be a wheel axle that connects the hub to the universal joint and note that there is no parts that go through the wishbone holes as this will probably block the universal joints.

Edited September 19, 201212 yr by SNIPE

22.75 degree. I don't know, build it and find out.

22.75 degree. I don't know, build it and find out.

I Would if I could get the parts from bricklink or whatever easily.

I'm afraid that construction won't work. It will be to far between the pivot point of the steered wheel and the first joint on the axle. The axle will need to expand (or it will pull itself out of the wheel, creating trouble when you try to center it again), and the only part that can help you with that is the CV-joint with the joint axle. There will still be a lot of force playing on the axle, so I would not recommend it. The only viable option would be to use this king pin, or to create one for your self... I have made several such "hubs" if you are interested. One has integrated gearing, and gives you realistic KPI angle as well (I believe I've seen Efferman make something similar). Another one gives you "realistic" caster angle, while still placing the whole hub inside the rim. And I have one very simple that is easy to make, and easy to implement.

that wishbone alone means nothing to turning radius.

the radius depends both on the maximum steering angle and the wheelbase (and marginally could depend on axle track, if you do not build a ackermann steering

to calculate the turning point, you intersect the front wheel axis with the rear wheel axis as shown in figure:

(the 4 axes intersect only in the case of ackermann steering)

isn't it the hub that is stopped because of the wishbones being in the way? it normally is I've seen on official models

how big are these hubs that you made?

I might have one idea ill try but id need to try to buy the parts first, ill take the middle bit out of the king pin and put the uv joint inside of the large hole but leave the pivot of the uv joint clear.

If it can help you :

It uses portal axle so it's big. Also, if you want to use portal axle, I advice you to use 8110 parts, more efficient, as I use on my new hub.

how big are these hubs that you made?

See for your self. Link to LXF file

You will need to space the upper and lower wishbones further apart. I recommend putting the lower wishbones at an slight angle (it will make the whole setup tighter), 4 studs from each other at the inner end and 5 at the outer end.

The blue parts are possible connections for the steering arms.

The best thing about this is that the towballs will allow the wheels to turn at a much greater angle then the traditional Lego hubs.

-ED-

Does it have a pivot so the wheel stays flat on the road surface?

I need a lot of pivot as the spring im using is a coiled tortion spring that connects the wishbone to the body

Edited September 20, 201212 yr by SNIPE

Does it have a pivot so the wheel stays flat on the road surface?

I need a lot of pivot as the spring im using is a coiled tortion spring that connects the wishbone to the body

All of these will have that if you angle the lower wishbone slightly (i.e. 5 studs between the outer points, and 4 between the inner points). This will give you a slight negative camber that will help make the true camper of the wheel zero degrees when you put a load on it. At the same time it will give you a progressive change of camber angle as the wheel is pushed up. If you don't want this, but want a slight positive camber that increases you can use a longer lower wishbone (It's half a stud longer than this).

I'll post some pictures with an example this weekend if you can wait.

-ED-

If it can help you :

...

It uses portal axle so it's big. Also, if you want to use portal axle, I advice you to use 8110 parts, more efficient, as I use on my new hub.

That's pretty nice.

I'm building something very similar. Do the wishbones pop out of the ball-pins since they are not connected vertically? Or putting the lower one upside down (ball-hole points down)is enough to make it strong?

It is strong enough thanks to the vehicle weight. It can only pop out when the car is not on their wheels.

Hi,

After about half an hour in the shed I came up with this double wishbone suspension, using the hubs I described earlier. It is of course possible to make an simpler version, but that should be easy to modify for anyone who needs it. This version is very realistic, and fits with both the "normal driven hub", and the "geared hub".

I also spent some time drawing them in LDD. Below follows some pics from LDD and an explanation of the setup.

The hubs I ended up using, and the complete setup:

The red line in this pic shows the toe angle. As you can see it has a slight toe in. This is easy to change by moving the whole steering rack to the other side of the diff. For a front/all wheel drive vehicle (as this hubs are indicating it is) a slight toe out would be preferable. It also archives an Ackermann steering geometry, but because you have an outward angle on the steering rods you might get trouble with the steering becoming unstable at larges steering angles. This is a problem you will have to solve by yourself, as it has nothing to do with the double wishbones and will add a lot of complexity.

The next picture shows the caster angle. It can be moved in half stud increases depending on what parts you use, but I would prefer this angle for normal cars. To make the whole setup more complex it is also possible to move one of the wishbones forwards or back to increase or decrease the angle (this will also give you a different "tow radius?", and is often referred to as a combination angle).

Here you can see the KPI angle, resulting in the pivot point being at the inside of the tire. For the ungeared hub it will be almost center with a tire of this size.

The last pic shows you the camber angle. The red line showing a slight negative camber equals the wheels normal position, and a negative angle here is preferable as the play in the parts will make it a slight positive when weight is applied. As the wheel moves up the camber angle will increase, as the blue line shows (as the wheel extends down from the normal position, the angle will decrease, giving it more negative camber angle). This guarantees that the wheel has optimum surface contact in turns.

This model is a proof of concept, and should be seen as such. If anyone wants to include this in a actual model I would recommend using 3 stud liftarms (or similar solution) to make the wishbones more resilient to angular momentum, and using more than one point to connect it to the frame. And you need to give it the correct toe in/out according to what drive setup you have. By playing with the position of the wishbones you can give the setup more or less Caster, and at the same time changes the "tow radius" (I don't know if this is the correct description of it, it's directly translated from Norwegian, but it is decided by the relative position of the wheel center compered to the center of the two wishbones) and thus make the steering more precise and help center the wheels. The steering rack is also placed a bit high compared to the attachment of the steering rod, and this is sure to give bump steer. While this is something to strive for in a rear suspension, it's not at all wanted in the front. It is a problem easily solved how ever...

The full LDD file can be found here...

Good luck!

-ED-

Edited September 25, 201212 yr by Nazgarot

Thanks alot naz,

I was wondering if it works having a 3L gap on the inner side abd having both wishbones sticking out the same amount?

If not can I have a 4L gap but instead of having the lower wishbone angled down by 1 stud from the flat position, have them both moved in by 0.5 studs ( 5 - 0.5 - 0.5=4)

I'm using a lego spring box used jn the lego sports series through the cross hole of the top wishbone the box then links to the chassis,

This box has maximum rotation of -\+ 90 degrees so the wishbones will need to rotate close to that.

im using your hub that dosnt have the gears.

Are you sure about the caster angle?

It's not the orientation of the Lego pieces that matter but the angle of the rotating axle. Since on your setup, the pivot points still appear vertical on the side view, the caster angle is still zero.

Are you sure about the caster angle?

It's not the orientation of the Lego pieces that matter but the angle of the rotating axle. Since on your setup, the pivot points still appear vertical on the side view, the caster angle is still zero.

Yea, I think it's wrong too. Now it only moves the axle slightly behind the steering pivot. That helps with bump steering.

The upper wishbone should be moved back a bit to get a proper caster angle.

Yea, I think it's wrong too. Now it only moves the axle slightly behind the steering pivot. That helps with bump steering.

The upper wishbone should be moved back a bit to get a proper caster angle.

As I said in the explanation below the pictures it's only a proof of concept, and it is possible to adjust the caster angle by adjusting the wishbones (I did not how ever have the time to do so...):

By playing with the position of the wishbones you can give the setup more or less Caster, and at the same time changes the "tow radius" (I don't know if this is the correct description of it, it's directly translated from Norwegian, but it is decided by the relative position of the wheel center compered to the center of the two wishbones) and thus make the steering more precise and help center the wheels.

It might very well be that I have a mix up between caster angle and "tow radius", as the Norwegian definitions differ from English... Anyway, you should strive to have an slight angle/offset on both. And it is possible by a slight alteration of this build.

Thanks alot naz,

I was wondering if it works having a 3L gap on the inner side abd having both wishbones sticking out the same amount?

If not can I have a 4L gap but instead of having the lower wishbone angled down by 1 stud from the flat position, have them both moved in by 0.5 studs ( 5 - 0.5 - 0.5=4)

I'm using a lego spring box used jn the lego sports series through the cross hole of the top wishbone the box then links to the chassis,

This box has maximum rotation of -\+ 90 degrees so the wishbones will need to rotate close to that.

im using your hub that dosnt have the gears.

You will just have to try. It's a question of clearances, and I can't say what will work without trying. But this should be a good starting point for you...

-ED-

As I said in the explanation below the pictures it's only a proof of concept, and it is possible to adjust the caster angle by adjusting the wishbones (I did not how ever have the time to do so...):

It might very well be that I have a mix up between caster angle and "tow radius", as the Norwegian definitions differ from English... Anyway, you should strive to have an slight angle/offset on both. And it is possible by a slight alteration of this build.

You will just have to try. It's a question of clearances, and I can't say what will work without trying. But this should be a good starting point for you...

-ED-

Sorry I didn't read your post well enough

But still the caster angle line in 6th image isn't correct as far as I know.