Author Topic: wheel tire rubber durometer  (Read 1758 times)

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Offline frank26080115Topic starter

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wheel tire rubber durometer
« on: September 24, 2008, 11:53:32 AM »
I'm about to buy four banebot wheels, but for some reason, robotshop only stocks 2 of each wheel and i need 4 of the same, to avoid waiting an extra 2 weeks, I think I should buy 4 of the same size but 2 of each durometer (tire rubber hardness) and use one of each durometer on each side of my robot

will this cause traction problems? will the harder rubber prevent the softer rubber to be effective? should i rearrange the wheels in a non-symetrical way (like the left side of the robot uses hard rubber while the right uses soft)?

this is for minisumo, the wheels are http://banebots.com/pc/WHB-HS4-244/T40P-243BG-HS4 and http://banebots.com/pc/WHB-HS4-244/T40P-244BO-HS4

having a working robot quickly is more important at this point than performance so i can order more and replace them later

Offline JonHylands

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Re: wheel tire rubber durometer
« Reply #1 on: September 25, 2008, 06:33:17 AM »
If you have a four wheel robot, I would put the 40 (harder) tires on the front, and the 30 (softer) on the back.

When you're pushing, you want more traction on the back tires, and you want the front tires to spin rather than stall.

One thing that is really essential with these kinds of tires - you have to clean them, constantly. I use rubbing alcohol (70%), and a piece of paper towel. I wipe them as often as I can, and at least between sets, although sometimes there isn't enough time between individual matches.

- Jon

Offline frank26080115Topic starter

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Re: wheel tire rubber durometer
« Reply #2 on: September 25, 2008, 06:52:30 AM »
oh I forgot to mention the robot will be 2 wheel drive, I plan on stacking the wheels, so each wheel is 0.8" thick, or at any time I can remove one from each side to make them 0.4" thick.
like in this picture

Offline JonHylands

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Re: wheel tire rubber durometer
« Reply #3 on: September 26, 2008, 12:05:01 PM »
Well, in that case, I would experiment with putting either the soft tires on the inside or the outside. I wouldn't put them both on one side - your sumo will end up turning in some circumstances where you don't want that to happen.

- Jon

Offline Admin

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Re: wheel tire rubber durometer
« Reply #4 on: September 30, 2008, 04:02:32 AM »
Quote
will the harder rubber prevent the softer rubber to be effective?
Yeap.

Mathematically:

friction_tire1 * normal_force = friction force of softer wheel only

(friction_tire1+friction_tire2)/2 * normal_force = friction force of both wheels

if you put numbers into those equations, you'll see the softer wheel only is better

 


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