With a bit of trigonometry and some observation we can estimate a theoretical limit to the maximum length.
I assume you are looking for the maximum length that would run on the sharpest possible curve, which appears to be one made with flexible track. By observing this photo of 52 flex track pieces arranged in a circle, we can estimate that each piece can ...
Likely you'll have the differential gears oriented wrong in the front or back section.
The differential gear is this piece:
Please check the instructions carefully and see if the orientation of this piece in the instruction book matches your build.
I think the smallest one in diameter is the tire 3641
with the bush 4265c.
Alternatively, you can use the tire 3139
which has a smooth surface and also compatible (but a little bit loosely) with the same bush.
This seems pretty much bordering on the impossible, given the current state of (LEGO) engineering capabilities. What you are describing is a Von Neumann Machine and as far as I know nobody succeeded in creating one, not just in LEGO but in general.
The problems you'd have to overcome:
The robot must be capable to exert sufficient force to overcome the ...
I went to Brickcon 2012. I asked Joe Meno about his red Monorail and he was most helpful. He flipped it over to expose the undercarridge and he was able to show me LEGO tires with fifteen hours of running time. The tread does indeed wear off and the tires actualy begin to split. The rubber doesn't cling to the rails themselves, but residue does begin to ...
You can always brick-build a wheel. The curved slope pieces can closely approximate a circle.
For example, 12 4x1 curved slopes gives a circle with a radius of 160 LDUs (8 studs).
For more information on brick-built wheels, I suggest you refer to the "Brick Built LEGO Wheels Book":
I can't speak to "best". But as a point of reference, many many of my lego tires are many years old and they are usually stored on rims. The older tires were often not removable from the rims. As I rarely build cars, I take no special care of the tires, and I've found that there doesn't seem to be any particular problems. The rubber ages over time, but this ...
The main trick is to simultaneously push all three pins of the hub:
If you have another hub, and the wheel allows for this, take it and push carefully from the other side. If both hubs are half-way in, you should be able to pull out both.
Otherwise, take two wedge belt wheels, align them on top of each other, insert a pin into every second hole and repeat ...
LEGO and others sometimes calls those pieces a "bearing element". This term however is not limited to just that axle.
LEGO's replacement parts service calls the holes they go into "HOLE Ø11" (possibly read "Hole Diameter 11"):
The width of the axle is roughly equivalent to the width of a "bar", like the 30374 piece used for Lightsabers as such.
None of ...
What you have there is a 6118 Wheel Hard Plastic Small (22mm D. x 24mm), and this wheel is pretty common, it features in 39 sets, but luckily for you only in 4 sets in the color White. These sets are:
1704-1 Ice Planet Satellite Plow - this set has 6 of these wheels.
6983-1 Ice Station Odyssey - this set has 10 of these wheels.
6814-1 Ice Tunnelator - ...
Should they be stored with or without rims inside?
I cannot say for sure whether storing tyres with or without the rims connected affects the lifespan. In my experience it hasn't made any noticeable difference.
There are four practical reasons I can think of not to remove the tyres.
It can take a lot of effort to remove tyres and put them back on again, ...
It looks like LEGO sells chain and sprockets, don't know if you'd have them lying around though.
You could also try using pulleys instead. If you don't have any of the actual pulleys, take the tread off of two wheels and stretch a rubber band across, that should work too.
The Technic Riding Cycle theme features several bikes that may be of inspiration. One particular set Moto Cross Bike (42007) uses several 3711: Technic, Link Chain parts to make a chain.
Based on Bricklink prices for the last six months, 39 chain pieces (the amount shown in the set above) would cost £4.29 (Aprox. $6.91 or €1.26).
Pulleys and rubber bands ...
The math you're suggesting may work for going straight forward or backward where slipping is limited. For a turn, it will not come close. Even getting the center of rotation of the turning robot will be difficult. The tracks will have to slip. A tracked robot can not turn without those tracks slipping. Differences in friction will alter the turn. More ...
Hey, there Happy Dog! These train pieces?
Part #BB37 - Train Brick 2 x 4 x 1 1/3 Sliding Block with Wheels
Part #Wheel2A - Wheel Spoked for Motor.
Together they appear in these LEGO sets.
While it is technically not a rubber wheel, you can use an axle with a half-bush and with an additional rubber band to provide grip. Tensioning the band between two such axles will form a short conveyor belt with a rubbery surface, which could be used for transporting balls when surrounded by appropriate elements to form a channel:
(the black lines are ...
I really expected someone with chemistry leanings to explain to us what was "migrating" out of the rubber with time or temperature, to make them "greasy"...much like cocoa butter will migrate outside of M&M's that have gotten too hot in their package.
The question "chicks" linked to gives some good answers though, and it's encouraging that no one has ...
I was able to find a few elements that are able to make this connection possible. I'm guessing the designer used some type of bar-sized element which is made from a different material that is able to compress slightly more than regular ABS. For example, the softer plastic used on some minifig weapons seems to work nicely:
Another option could be flexible ...
A 360 degree turn takes: (width of robot/circumference of wheel) turns, neglecting track thickness, assuming the tracks are at sides if the robot.
The length of track doesn't matter. Your robots non-slipping part of the track is traversing a circle of diameter=width of robot. The other parts of the track are sliding across the surface. A longer robot / ...
Answer to this question is no longer entirely accurate, the power puller wheel
has been superseded in diameter by the tractor wheel
by an entire mm :) (resp. 106-107 mm)
The instructions show and Brickset lists 4496197: Rim Wide W.Cross 30/20 as the wheel rim of choice, which fits with the release year of the Fire Truck (2006) and the manufacturing dates of the rims (2006-2013).
BrickLink's "preferred" rim was only manufactured up to 2006, which might explain why it lists the pictured rim as an Alternative part - as that ...
Just wanted to elaborate on the answer by Wrzlprmft. The first thing that went through my mind was, "What is this configuration where the Hub is snapped into a wheel but not into the Portal Axle Housing?" A curious MOC perhaps? Because normally the wheel easily pulls off of the hub, when it's attached to the housing.
My first advice for anyone messing ...
LEGO’s Pick-a-Brick service has only a limited amount of the total range of pieces ever produced. It contains a subset of the pieces available in current sets.
The Bricks and Pieces service (on the LEGO website under Customer Service) has a slightly larger range of pieces, but still limited to those that are currently produced by LEGO. This service is ...
The M-motor is directly compatible with almost all the wheels that LEGO has produced, and, with a little building, compatible with every wheel imaginable, even brick-built wheels.
If your problem is that the wheel is smaller than the diameter of the M motor, perhaps you want to attach the wheels to an axle, and then drive the axle with the motor. There are ...
Normally when wheels are powered using an axle they have an axle hole, whereas your wheels have a pin hole, and a 3mm mini pin hole.
So you should probably buy some wheels with axle holes anyhow, for future building.
However, in the meantime, there are tricks to driving parts which use a pin hole, for example, a lego 55981.
You simply use either this, or ...