Can we fill our wheels with water?

[FrankJ]

Realize it is not uncommon to fill off road equipment tires with water so this is as far fetched as is sounds. There is no rule specifically against this so it comes down to a judgement call to decide if it is properly contained. IE not likely to spill on the field. Same class as marbles, sand, BBs, and so on. Do keep in mind that this is coming from a team that never puts a robot on the field without a container full of lead & sulfuric acid.

As for as slime goes. We ran it in our Frisbee shooter flywheel to give it mass & balance. Got a controls award for the accuracy of the shooter at one regional. Good thing nobody ask Q&A is it was legal that year.

[E Dawg]

For the record, I was against this idea from the start. On a related note, 3 years ago we weighed down our robot by filling tube socks with metal bb's and attaching them to the frame. I still can't believe none of them ever tore.

[gblake]

Adding water plus an anti-freeze agent to heavy-equipment (and light-equipment too) tires makes perfect sense. I used a small farm tractor with water-ballasted wheels for many years when I was young.

However, zipping around an FRC field is a different matter.

If you want more mass, I recommend attaching solid weights at spots on the robot that move the robot's center of gravity to a better place, in addition to adding mass.

I also recommend testing to find out whether adding mass helps more than it hurts.

Bottom line: Use the right tool for the right job. Your FRC bot isn't a slow moving tractor or earthmover. Water is very unlikely to be the right tool for this job.

[Michael Hill]

Originally Posted by lethc

If you want to get real heavy I'd recommend pure lead wheels. They're about 12,000 times heavier than air.

Downsides: it's highly toxic and recognized as a carcinogen in CA.
Upsides: Basically everything else

#teamlead

As long as they don't go to a CA regional, it's safe, right?

[IKE]

Originally Posted by E Dawg

We were having a debate tonight on whether or not it is legal to fill pneumatic wheels with water. It would be a good way to add some weight to our robot (yes, I know ), but the catch is that it may violate R9. Do you all, especially current/former robot inspectors, believe "water wheels" to be legal?

While tractors do this all the time, please do not put any fluids that could leak onto the field into your tires. There are easier and better ways to add weight to your robot. Plus, you will want that compressibility as you ram into defense and bounce around.

[MarcD79]

As a Field Supervisor here in New England I would not allow it on the field, whether or not inspection passed it & here is why; All our competitions are done in colleges or high schools on gym/basketball floors. If a tire leaked & caused a wet carpet it could damage the floor below. Not only that, most robots have some type of rubber tire, that when contacting the wet spot probably will slip for the remainder of the match. We don't have the capability to remove the water from the carpet.

[pmangels17]

Originally Posted by sanddrag

What if you pulled the valve stems (the inside part, filled the tubes full of steel ball bearings, and then put the valve step cap back on. Would that work?

5000-ball-bearing-pickup

[bmire3206]

does noone remember R9 hydraulics are forbidden.

[ratdude747]

Originally Posted by pmangels17

5000-ball-bearing-pickup

That happened at Crossroads Regional in 2014, only with lead shot in hidden plastic bags (hence why the RI's missed it). It was a mess both for the head Ref and the field supervisor... Oh the sound of lead shot in a vacuum cleaner...

[PowerfulKitty]

You'd probably be better off filling them with dihydrogen monoxide.

[Jon Stratis]

Guys, this seems like a serious question, and a lot of these answers really aren't helping.

Look at the blue box under R9. The blue box provides "examples of items that will violate R9". In that list is:

G.Hydraulic fluids or hydraulic items

Typing "hydraulic fluid" in google gives, before any links, a paragraph that starts "Common hydraulic fluids are based on waste, mineral oil or water."

Water is a hydraulic fluid. Hydraulic fluids are specifically listed as something that violates R9. R9 is a robot rule that must be followed to pass inspection and play. Thus water is illegal. QED.

[Jon Stratis]

Originally Posted by Tanis

To actually answer your question- In Ultimate Ascent a team in my area came to an event with the wheels on their frisbee shooter filled with water. The inspectors did not allow them to use those wheels due to the risk of the wheels leaking or spectacularly breaking and throwing water everywhere.

While I am not an inspector, I would imagine that this would not be allowed again this year. The defenses cause enough trauma to robots that the risk of the wheels breaking open is too high.

Your best bet would be to ask a Q&A question for an official judgement.

Note that in Ultimate Ascent, there was a similar blue box under R8 (which is the same as R9 this year) which listed hydraulic fluid, and was the basis for the ruling - the description is the justification for calling water a hazardous component, as it doesn't react well with robot control systems. Or, for that matter, the historic 90 year old basketball court we were competing on top of.

[FrankJ]

Originally Posted by Jon Stratis

Note that in Ultimate Ascent, there was a similar blue box under R8 (which is the same as R9 this year) which listed hydraulic fluid, and was the basis for the ruling - the description is the justification for calling water a hazardous component, as it doesn't react well with robot control systems. Or, for that matter, the historic 90 year old basketball court we were competing on top of.

Sort of a definition thing but I don't see water in the wheels as a hydraulic fluid any more than water in the battery is. I am perfectly fine in being told that water is a hazard to the field & you can't use it rather than stretching a definition.

[nakarsten]

Tire beads would be a good way to weight the wheels.
http://www.amazon.com/E-Z-Tire-Beads.../dp/B00VO4ZODE