Lego 8258 Crane Truck

[TechnicJuan]

I just finished building this set and it is simply huge! It was a fun build with Tons of great new parts and more gears than you can imagine. My only complaint is that it feels flimsy in some parts and in the base of the Crane there are 2 Red Friction Pins that hold the bottom of the Linear Actuator into place, but when they are pushed all the way in, they rub the universal joint. Sure, you can pull them out some, but that is defeating the point of having them there. Something else could have been used in that place.

This was a VERY fun set to build. I worked on it for 3 nights off and on. There are 4 instruction books. I easily give this Model a 9/10 and it was well worth the money.

[Milan]

Why dont you write more detailed description, if not review of it, based on your opinion?

It would be great!

[Smithy]

There's a video of the model on youtube

The crane arm does appear to be rather flimsy, same goes for the stabaliser legs. In previous models the legs normally raise the model. These just look like they hit the ground and no more. The crane arm also doesn't look like it extends much beyond the body of the model.

[Anio]

There's a video of the model on youtube

The crane arm does appear to be rather flimsy, same goes for the stabaliser legs. In previous models the legs normally raise the model. These just look like they hit the ground and no more. The crane arm also doesn't look like it extends much beyond the body of the model.

You are totally right !

The fourth and last default is with the steering wheels. Actually, because of 12t/20t, the parallelism of the wheels is not perfect.

But it is still a great model !!!

[Meatman]

My New Crane Truck and Front Loader are on the way.

I am very excited.

[5150 Lego]

The outriggers defenatly seem to be week. In the video them seem to just flop on the ground. Thats not going to do any good. Thats one aspect that defenatly need to be worked on. I'm curious to see just how much the crane arm can lift.

[Anio]

The outriggers defenatly seem to be week.

That is true for the rear outriggers.

The front outriggers are as strong as those of the 8289. So, they work quite well, even if they don't raise up the truck.

[fasterthanlight]

You are totally right !

The fourth and last default is with the steering wheels. Actually, because of 12t/20t, the parallelism of the wheels is not perfect.

But it is still a great model !!!

Assuming I know what you are referring to, which would be the fact that the front wheels turn at a larger degree than the second set of wheels, then I can also assume you haven\'t built a multiple steered axle model before.

Read through the \"Steering\" section of this page for a good explanation.

http://www.jenniferclarkbass.com/lego/hooklift.htm

http://www.jenniferclarkbass.com/lego/imag...ng_trig_lrg.gif

Edited July 31, 2009 by fasterthanlight

[Anio]

Assuming I know what you are referring to, which would be the fact that the front wheels turn at a larger degree than the second set of wheels, then I can also assume you haven\'t built a multiple steered axle model before.

Read through the \"Steering\" section of this page for a good explanation.

http://www.jenniferclarkbass.com/lego/hooklift.htm

http://www.jenniferclarkbass.com/lego/imag...ng_trig_lrg.gif

No, that's not what I mean.

The first axle turn more than the second one. That's ok, it is normal on a truck.

What I say is that the second axle turn more on the left than on the right.

That is due to the fact that there is only 12t/20t, which make a gap equivalent to a half tooth. On the contrary, on the 8421 there is 20t/12t, AND THEN 16t/16t on the first axle. So, there ins't this gap.

PS : sorry for the mistakes. But these explanations are technical, so it is quite hard for me to write right sentences.

[cybergibbons]

I just posted my review at Brickset.com - it's quite similar to what people are saying on here!

[Milan]

Good reviews there.

It seems that no one likes its non-rigidness and weak outriggers.

[Blakbird]

Good reviews there.

It seems that no one likes its non-rigidness and weak outriggers.

I'm almost done building this set. I was going to post a review here, but I see in the "Reviewer's Academy" that Starstreak is already working on one, so I guess I'll let him finish it. I may throw in a few thoughts of my own though.

[Front]

I'm almost done building this set. I was going to post a review here, but I see in the "Reviewer's Academy" that Starstreak is already working on one, so I guess I'll let him finish it. I may throw in a few thoughts of my own though.

I would like to see a different kind of review of the set, in a few weeks time. Please consider that, and I'll let it up to you, what different means :-)

[Blakbird]

What I say is that the second axle turn more on the left than on the right.

That is due to the fact that there is only 12t/20t, which make a gap equivalent to a half tooth. On the contrary, on the 8421 there is 20t/12t, AND THEN 16t/16t on the first axle. So, there ins't this gap.

PS : sorry for the mistakes. But these explanations are technical, so it is quite hard for me to write right sentences.

I finally figured out what you mean!! Basically, it is impossible to have both steering racks centered at the same time. An axle has 90 degree symmetry (4 points). Since 20 teeth and 12 teeth are divisible by 4, these two gears also have 90 degree symmetry. This means that there is a gear tooth lined up with each point of the axle. If you center both steering racks and try to mesh the gear trains with a 20 and a 12 tooth gear, the gear teeth will line up and therefore interfere. One or the other gear train must be rotated half a tooth to get them to mesh, resulting in either the fwd or rear steering rack being off center. It's only half a tooth and hardly noticeable, but if we can't pick on tiny technical details then why bother messing with Technic?

(In the picture, note that the tan and green gear teeth interfere because they are aligned)

In this case, 1/2 tooth would be 15 degrees of rotation on the drive axle. A 1x4 rack gear has 10 teeth, so this implies that a single gear tooth is approximately 0.4 studs in length. 1/2 tooth is therefore 0.2 studs. On this set, this part is used as a steering arm and has a length of 2 studs between pins. Using some trigonometry, moving the steering rack 0.2 studs will result in a steering angle of ~5.74 degrees.

Therefore the rear axle steering is off center by 5.74 degrees when the forward axle is straight.

Does that make perfect sense?

Of course, all of this assumes that LEGO parts are a perfect fit (zero clearance) which they are not. Therefore in actuality you can get them to line up pretty closely. Or you can just twist an axle 15 degrees!

[CP5670]

Good explanation of this. However, as you said there will always be a little bit of slack in the gears, and in practice you can in fact get the wheels to line up perfectly on most 4+ wheel steering setups.

This set uses 12 tooth gears on the steering racks though, as opposed to the smaller 8 tooth gears used on most sets in the past. That area is usually the main source of the slack, so it may be harder to get the wheels perfectly straight on this set.

[Anio]

Very good explantion. That's exacly what I meaned.

Using some trigonometry, moving the steering rack 0.2 studs will result in a steering angle of ~5.74 degrees.

Can you explain your calculation ?

Therefore the rear axle steering is off center by 5.74 degrees when the forward axle is straight.

On my 8258, it is a bit different. I may have put the gears in a position a little different.

Actually, when the first axle is straight, the second is straight too.

But my second axle turns more on the left than on the right.

[Front]

Very good explantion. That's exacly what I meaned.

Can you explain your calculation ?

If the rack is offset 0.2 modules (stud distance), and the height of the steering parallelogram is 2 modules, the angle is:

angle = arcsin (0.2/2) = 5.74

arcsin also often written as sin ^-1. A function that returns an angle.

[Blakbird]

By popular demand, I am posting a few pictures from my build of 8258. I didn't really do a review so the photos aren't "polished", but you get the idea.

Here are many shots of the multitude of parts:

Here are a couple of shots of the completed model along with a few other large sets for scale (all use the same wheels and tires):

This set is practically perfect, but I still made a couple of minor "improvements". Firstly, as pointed out by another poster, a couple of long pins interfere slightly with the vertical u-joint. I replaced them with 3/4 pins as shown and eliminated the problem. I can understand why TLG did this though, because the build sequence is much more complex with 3/4 pins. Parts have to be put on in an order that makes it somewhat difficult to assemble, while the long pins were easy.

Before:

After:

The second change is a bit more subtle. The fenders over the front wheels are cantilevered out a long way with no support at the front end. This makes them quite wobbly. As you can see in the first picture, there is a nice top of a long red pin with bushing just sitting there with nothing to do, so I used it. The second picture shows the bracket I made. It is shaped like it is to prevent interference with the cab when it closes. The final picture shows the change in place.

Before:

Bracket:

After:

Edited June 6, 2012 by Blakbird

[5150 Lego]

Ahh, the mighty Scania! Such a beautifull rig! I'm preety partail to American trucks, but i have to admit, the Scania isone sexy rig!

Thank you for the teaser pics. I'll have to keep those improvements in mind whenever i get mine.

[CP5670]

Nice pre-build setup. I do the same thing with my builds, although not as neatly and thoroughly as you.

[paul_delahaye]

Thats one serious sticker sheet!

[jovel]

I find out a solution for the steering.

link.

Both axles are still not 100% perfect inline but it's at least an inprovement I think.

You might think that the 16 tooth gears might hit the gear rack but that's not the case. Because 16z are smaller in the center there is just enough room.

Edited August 8, 2009 by jovel

[Anio]

I find out a solution for the steering.

link.

Both axles are still not 100% perfect inline but it's at least an inprovement I think.

You might think that the 16 tooth gears might hit the gear rack but that's not the case. Because 16z are smaller in the center there is just enough room.

Well done !

[Milan]

It looks mighty next to the 8436 crane truck!