9398 - Lego Technic 4x4 Crawler

[DLuders]

Looking at these it seems you could get a higher steering lock on each axle if you would move the whole steering rack half a stud closer to the wheels...

Perhaps The Lego Group anticipated their customers wanting to use LARGER TIRES (Power Puller, Unimog, or 3rd Party). Did TLG design it this way so that larger tires don't touch the chassis?

Edited July 4, 2012 by DLuders

[efferman]

or they want to be sure that the servo has enough power for steering

Edited July 4, 2012 by efferman

[Dannnohhh]

Perhaps The Lego Group anticipated their customers wanting to use LARGER TIRES (Power Puller, Unimog, or 3rd Party). Did TLG design it this way so that larger tires don't touch the chassis?

Good point DLuders, and you prompted my natural, imaginary investigation into the final 9398 model variations that didn't make it to production. The designer no doubt played with the larger tires on each prototype model, but now I wonder if there was a new secret tire that was voted out by the suits because of cost.

[Technic Gearhead]

Good point DLuders, and you prompted my natural, imaginary investigation into the final 9398 model variations that didn't make it to production. The designer no doubt played with the larger tires on each prototype model, but now I wonder if there was a new secret tire that was voted out by the suits because of cost.

Along with them, the remainder of the orange parts needed to make it whole!

[5150 Lego]

Perhaps The Lego Group anticipated their customers wanting to use LARGER TIRES (Power Puller, Unimog, or 3rd Party). Did TLG design it this way so that larger tires don't touch the chassis?

Very possible. I think part of it is also stability. The farther away the steering knuckles are from the hub of the wheels, the easier it is for the wheel to deflect back when it hits an obstacle. Anyone who has the Unimog will know what I'm talking about. By moving the steering rack further back it provides better leverage to keep the wheels straight when hitting an obstacle off angle. This is also probably one of the big reasons they did 4 wheels steering as without it the turning circle would be a good 4 or 5 feet.

[raus]

Guys, the biggest problems is not only the diameter of the tires but the adherence. rubber is very tough, no use putting a tire 125 mm in diameter that besides forcing the whole steering and wheel hubs, will also reduce the torque since it will run faster and will have to make even harder to pass by obstacles. We need a softer rubber as the rc rc crawlers or even the scales. Without adherence with larger diameters and with this set differential really should not leave the house. And yet not try to climb or a pillow!

[daniele]

Should be better without differentials?

Did anyone noticed about pdf version of instructions?

[jacobkristensen]

Should be better without differentials?

Did anyone noticed about pdf version of instructions?

Yeah, I am just done reading them, and the b-model are up too.

[Sariel]

A little video of mine, with Unimog wheels, PP wheels, time lapse build and vanishing torque:

[GuiliuG]

Are you sure your battery were recharged? It seems less performanc from what I have seen at fanabriques. Also, when trying to pass your hand, you need to turn a wheel not to attack the obstacle with two wheels perpendicular to it. Same thing happens when you try to climb over its box. Also, to compare it with your jeep you need to climb the same obstacle ( a step of 5 cm and a staircase of 5 cm is different obstacles).

But it's still clear than a trial truck with a xl motor is more performant. Designers don't put Xl motor simply because its torque can damage parts.Thanks for the vid !

[chorlton]

I'm positive that's Alistair at 15:09 - It doesn't look like me anyway.

[Sariel]

Are you sure your battery were recharged?

Yes.

Also, when trying to pass your hand, you need to turn a wheel not to attack the obstacle with two wheels perpendicular to it. Same thing happens when you try to climb over its box. Also, to compare it with your jeep you need to climb the same obstacle ( a step of 5 cm and a staircase of 5 cm is different obstacles).

XL-powered vehicle would have no problem with my hand or the box, that's my point. If could attack any obstacle if reinforced and geared down enough. As for my Jeep, the comparison is unfair in general, as the Jeep was lighter, with stronger motor and more geared down. But the point is - you can get so much more out of LEGO even without the need for new motors or new IR receiver. Hence my disappointment - LEGO designed some new parts that can be beaten by the old ones.

I'm positive that's Alistair at 15:09 - It doesn't look like me anyway.

Yes, I like to think it was him ;)

Edited July 5, 2012 by Sariel

[daniele]

If anyone searched here's the instructions:

http://technicbricks.blogspot.it/2012/07/building-instructions-for-2h2012-lego.html

[davidmull]

A little video of mine, with Unimog wheels, PP wheels, time lapse build and vanishing torque:

Performance looks quiet bad in ur model,how come it looks better in other videos people made,like in fairness fernandos one was driving up walls with ease,I really think ur problem is battery's because there's no way it performs that bad on other peoples videos,rechargeables only give u 7.2 volts also.

I'll be using lithiums in mine they give great power and torque :).

[Sariel]

I'll be using lithiums in mine they give great power and torque :).

Technically, batteries don't affect torque of a motor, only speed. Torque depends on internal gearing and is therefore constant for a given type of a motor. With more voltage from batteries you can drive faster though, and build a higher momentum, that helps against obstacles.

Anyway, my batteries were fresh. Note that I was driving Crawler head-on against obstacles, in other videos it usually approaches them at angle.

[raus]

Crawler?! Nor is it a truck trial! The name of the set should be 4x4 FAIL! Not a tire rises 2cm?!

Technically, batteries don't affect torque of a motor, only speed. Torque depends on internal gearing and is therefore constant for a given type of a motor. With more voltage from batteries you can drive faster though, and build a higher momentum, that helps against obstacles.

Anyway, my batteries were fresh. Note that I was driving Crawler head-on against obstacles, in other videos it usually approaches them at angle.

Can not climb the front tires of that size? Or these engines are terrible, or the binary is wrong to!

[DLuders]

Technically, batteries don't affect torque of a motor, only speed.

Sariel, I politely disagree. On Philo's "LEGO 9V Technic Motors compared characteristics" webpage, one can see in the graph below that Voltage DOES have a great effect on Load Torque and Mechanical Power. The graph is for a PF M-Motor, but if the new Power Functions L-Motors have ~150% the torque of the PF M-Motor, why wouldn't higher voltage to the L-Motors improve Mechanical Power?

Also, in your posts above, you discuss having fully-recharged batteries. Can you confirm that you have new 1.5V Alkaline batteries (as specified in the Building Instructions) instead of rechargeable 1.2V batteries?

[Badger]

ok, on a slick ascending slope it works till 30°, then the rear axle motor goes into stall, because the frontaxle has no grip.

obstacles, my foot for example, against a single tire, are possible till 5cm height.

overall is grip the problem. with my ansmann tires is much more possible. the vid which was posted by anio shows good the possible performance.

Old comment i know but ....

I have been into rc crawling a while now and a lego MOA (motor on axle ) would be better . Ansmann stuff is poor at best , Try some hot bodies sedona white's :D

[Sariel]

Can you confirm that you have new 1.5V Alkaline batteries (as specified in the Building Instructions) instead of rechargeable 1.2V batteries?

I tried both, actually. This week I will have a chance to take Crawler on a TrTr course to see how it does there. I'll probably film it too.

[DLuders]

legotruck59 posted

(a slightly different perspective of the SeTechnic / Fana'briques indoor "torture test" of the 9398 4x4 Crawler):

[rm8]

Hey guys, dont forget that 9398 is serial toy, which was constructed by lego to play safe and not to destroy gears and ujoints. I'm sure they can use two xl mototrs or make l motor more powerful - but this will be dangerous for plastic details. Tell me please, who builded any truck trial trucks without broken gears and joints? Powerful Truck trial moc - always risk for details, Lego understand it. Underpowered crawler - was their goal. They did it. They dont want to launch exchange program for broken details like with 8043s actuators, or 8110 pneumatic pumps....

You are waiting too much from serial plastic toy.

Edited July 5, 2012 by rm8

[davidmull]

Guys why can ye not use lithium AA batteries like iv done in 8043'the difference in power is huge and most important power is always the same and doesnt die off,also a plus too is the lithiums are very light so save weight too.

Yes there expensive I think Maybe €10 for 6 pack but last longer too.

http://www.google.ie/search?hl=en&tbo=d&biw=1024&bih=672&tbm=isch&sa=1&q=lithium+aa+batteries+6+pack&oq=lithium+aa+batteries+6+pack&gs_l=img.3...26509.30176.0.30510.7.3.0.4.0.0.407.562.0j1j4-1.2.0...0.0.3QzpKQMhSSg#biv=i|5;d|HPTpiglIHMjh_M:

[Paul Boratko]

I am wondering if Lego purposely didn't implement the XL motors into this because they knew that kids would be doing crazy things and breaking parts left and right that in turn would need to be replaced by Lego, where as this new large motor would limit how much punishment the plastic parts can actually take...

I know those guys who build those Trial Trucks break parts pretty often and breaking parts isn't part of TLC's gameplan...

Hey guys, dont forget that 9398 is serial toy, which was constructed by lego to play safe and not to destroy gears and ujoints. I'm sure they can use two xl mototrs or make l motor more powerful - but this will be dangerous for plastic details. Tell me please, who builded any truck trial trucks without broken gears and joints? Powerful Truck trial moc - always risk for details, Lego understand it. Underpowered crawler - was their goal. They did it. They dont want to launch exchange program for broken details like with 8043s actuators, or 8110 pneumatic pumps....

You are waiting too much from serial plastic toy.

LOL.. I was just outside with the dog thinking about this and came back in to give my opinions on it as well before I refreshed the page and seen this...

Edited July 5, 2012 by Paul Boratko

[raus]

Hey guys, dont forget that 9398 is serial toy, which was constructed by lego to play safe and not to destroy gears and ujoints. I'm sure they can use two xl mototrs or make l motor more powerful - but this will be dangerous for plastic details. Tell me please, who builded any truck trial trucks without broken gears and joints? Powerful Truck trial moc - always risk for details, Lego understand it. Underpowered crawler - was their goal. They did it. They dont want to launch exchange program for broken details like with 8043s actuators, or 8110 pneumatic pumps....

You are waiting too much from serial plastic toy.

Really! A toy for children. But it should be named differently, crawler? Trial maybe. The manual stated that it is not advisable to play outside. Sariel the tests at home he barely rises 2 cm obstacle ahead! The value that costs should at least overcome obstacles simple.

[allanp]

Forget your internally geared motors, this beast performs great with a 5f+1r tranny (and is rather heavy!)

It's been dismantled for at least ten years tho, I can do much better now

Edited July 5, 2012 by allanp