Hi everyone, im about to order a set of tracks for a japonese sumo bot im building and am concerned with the rubber compund used and the friction thhey will provide for a 3 kg bot. is it somewhat gummy or is it a hard rubber? has anyone used them for a 3kg bot application??
thanks guys.
from what i gather the tracks hjave a shore A hardness of 45, I looked up a chart and the closest contender would be a bycyle inner tube @ 40.
Can anyone confirm that the rubber studs on the tracks are slightly harder than the rubber found on a bike inner tube?
There hard enough! I got a pair and their the most rugged and best tracks (especially the price) for tracks that size on the market. From what I’ve heard Jim said they would have no problem holding a 100lb bot up! 
my robot is only 3 kg! my fear is that they will be too hard to provide adequate traction for a sumo fight.
I would think you would need to coat or attach to the outside of the tracks some type of traction material/compound. Be advised that tracks must slip on the surface to make any type of turn, so there is some trade off of what would be used.
I can’t see how you would have a problem with them even @ 3Kg. My bot is just over 6 lbs and I feel it has too much traction on some surfaces. 
sweet. tats whhat i liike tyo hear!!
Other than “somewhat squishy, yet still quite firm,” I don’t know what to tell you as to the hardness and “grippiness” of the treads. I piled about 2.9 kg of gel cell batteries onto a length of 2" tread (a length of about 5 links), and it was “quite difficult” to move it on the surface of my desktop. As I have never built a true sumo bot, I haven’t ever had a reason to build a “pushometer”, so I really have no way to tell you how hard it actually was to push it. Using five links in flat contact with a flat surface, I had a hard time moving a 2.9 kg weight. I assume that if you were to build a bot using at least five treads per side, and used a base with evenly-distributed weight, which kept the treads in constant flat contact with a surface similar to my desktop, that it would be at least “quite difficult” to push around, or roughly twice that, figuring that you’d be using two such treads.
I’ll leave it as an exercise for you to do the math and figure out just what two times “quite difficult” is, since I lack tools appropriate to the job.
are the links 1" from pin center to pin center?
I measure 1.1 inches, center to center, edge to edge, cleat to cleat, or any other common point between two links.