Pneumatic Wheels vs Treads
 

The Robot in 3 Days Team Indiana tested a six wheel drive with pneumatic wheels and the rhino treads. In the videos below. The treads look like a much better option than the wheels. Is your team going with treads or wheels? Why?

6 Wheel Drive
https://www.youtube.com/watch?v=j3ZP...utu.be&t=32384

Treads
https://www.youtube.com/watch?v=j3ZP....be&t=8h15m26s

Re: Pneumatic Wheels vs Treads
 

My team is going with pneumatic wheels simply because we did not want to deal with the long lead time on treads.

Re: Pneumatic Wheels vs Treads
 

Also, I don't think pneumatic wheels on the kitbot frame are representative of their full capabilities, because the kitbot does not have much ground clearance, which contributed to it getting stuck in the moat.

Re: Pneumatic Wheels vs Treads
 

My concern with tread is that the current offerings are essentially untested on the field. The long lead time is also a deal breaker. The last time I can recall seeing tank treads on an FRC field was in 2006 with Karthik's triplets (perhaps I've missed a robot or two). But for the most part, most teams do not have experience with using them or maintaining them or dealing with their failure modes. Couple that with the long lead time of the Rhino treads, I know most teams aren't going to be able to practice driving with them. It's a scary situation all around.

Re: Pneumatic Wheels vs Treads
 

1251 TechTigers did it in 2010 and 2012 and i know there have been a few more

Re: Pneumatic Wheels vs Treads
 

It actually got stuck in the moat because the far side of the frame fell off the side of the field element! That's why Charles picks it up and moves it to the middle.

There will be some lovely footage of it flying over the moat Dukes of Hazzard-style in the reveal video or uploaded afterwards!

Here's the testing video of the moat

Re: Pneumatic Wheels vs Treads
 

Same reason, but we're looking at COTS semi-pneumatics and making our own wheels more than pneumatic. Our goal is to have a drive platform crossing half of the defenses before the tread would be available so we can spend time on manipulators. An hour of web searches renewed our previous understanding that there aren't any other COTS treads out there that looked both tough enough for FRC and affordable.

Re: Pneumatic Wheels vs Treads
 

If I was looking to make my own treads, I would look at conveyor belting. Available at Mcmaster Carr or your local conveyor supply company.

Re: Pneumatic Wheels vs Treads
 

Team 1619 has some nice resources on tank treads and they have used them for a while.

http://www.team1619.org/robots/desig...hts/tank-drive

Re: Pneumatic Wheels vs Treads
 

where do you source your belts?

Re: Pneumatic Wheels vs Treads
 

Aside from ground clearance, does the Ri3D Indiana team say if those are 6" or 8" wheels? My very un-calibrated eye seems to think those are 6" wheels in the video. If that's the case, consider that the 8" variety may provide better performance.

Re: Pneumatic Wheels vs Treads
 

From what I see on their twitter their wheels see to be the 8" variety because of the oranges... but if you look at the holes along the side you can see that the wheels go across about 7.5 holes of length so 7.5 inches and the pneumatic wheels are just under 8" from my measurments.

Re: Pneumatic Wheels vs Treads
 

I am not on Techtigers I would recommend messaging, David Guzman or David Ellich

Re: Pneumatic Wheels vs Treads
 

Those are the 8" AM pneumatic wheels though that 8" is a nominal dimension and they measure out between 7.5" and 7.75" in the real world.

Another thing to note is that AM assembled that chassis with the wheels in the "long 8" wheel configuration" using the belts included in their 8" pneumatic wheel kit.

You can use the belts included in the 14u3 kit for the 6" wheel square configuration, put the wheels in those holes for a shorter wheelbase.

I believe that is what Snow Problem did and that is what we did at Team [Redacted]. That shorter wheel base causes the front of the robot to be higher when the front wheel has cleared the ramp and is hanging out in space. That helps get the front bottom corner on the frame over the rock wall. We did find that it hitting it at speed works better than trying to crawl over it.

Re: Pneumatic Wheels vs Treads
 

any idea what these treads from brecoflex cost?

Re: Pneumatic Wheels vs Treads
 

Expensive... I've heard $200-300 a piece is average.

Re: Pneumatic Wheels vs Treads
 

Remember that if you use treads, an opponent can T-bone you and you won't be able to move or turn. And it technically isn't pinning because you aren't trapped against a game element.

Re: Pneumatic Wheels vs Treads
 

They also have this playlist of all the terrain obstacles. Some are tested with wheels and treads others are just treads.

https://www.youtube.com/watch?v=s04B...ozlzd6&index=1

Re: Pneumatic Wheels vs Treads
 

Why wouldn't you be able to move?

Re: Pneumatic Wheels vs Treads
 

We have always purchased them from Brecoflex. They can get expensive, between 130-200 but this was a few years ago.

We used AT10-K13 Self-Tracking Belts. You have to pick one of the backings available. Lead time has always been around 3 weeks. Cheapest way to go is to buy their regular pulley stock and machine the K13 V-Groove on them for self tracking.

Re: Pneumatic Wheels vs Treads
 

I asked Brecoflex for a quote earlier this week and they sent this guide. I'm not 100% sure on the pitch but I think their largest pulleys are 150mm diameter. Plus-side: they're estimating 2-day lead time!

Re: Pneumatic Wheels vs Treads
 

I've never ordered from them until today, but Superdroidrobotics lists quite a few pneumatics wheels in stock.

the six-inch is about 5 bucks and the ten inch is about 8 bucks.

http://www.superdroidrobots.com/shop...nd-shafts/153/

They also have tread/track sold by the foot for DIY. 4-inch wide is about 10 bucks a foot, 2 inch wide is $6.50.

http://www.superdroidrobots.com/shop...nd-treads/162/

If anyone here has experience with them, I'd be pleased to hear your comments.

Re: Pneumatic Wheels vs Treads
 

Wheels, hard and pneumatic. They're efficient, they're cheap, they're light, they're simple, and offer just as much (or not that much less than, at least) traction as treads.

Re: Pneumatic Wheels vs Treads
 

The tread looks worthless for FRC applications. You need some kind of toothed interface to transmit the type of torque we'd be applying.

Re: Pneumatic Wheels vs Treads
 

Which backing material tread did you go with? PVC White Nub or T-Cover sounds to make the most sense for FRC.

Re: Pneumatic Wheels vs Treads
 

I will be interested to see this robot with legal bumpers.... and then see how it works on the different terrain challenges.

I am not saying that it won't work... I am just interested in seeing how that changes things ... if at all...

Re: Pneumatic Wheels vs Treads
 

I've never actually ordered from them before (we still haven't placed our order), but Team 1619 recommended PVC Herringbone and SuperGrip Green (neither of which are on that PDF).

It probably also depends on your team's budget. If a set of treads doesn't need to last the entire competition season, then I'd go with PVC Blue for the "very high friction on smooth surfaces" or the Supergrip Blue. If the game is rough enough on the treads, though, then they might wear out 1 or more times and you'll need to buy spares (the ones with higher abrasion resistance but lower traction might save you from that, but there's no way to know other than experience).

Re: Pneumatic Wheels vs Treads
 

For what it's worth.... My kids saw the Rhino treads on AndyMark a couple days before the reveal video. (Yes, I have nerds on my team who spend their hours day-dreaming and reading about the newest robot parts as an entertaining way to pass time...) They were speculating that AndyMark had created them specifically for this game and wanted me to purchase them early -before the rush....Not wanting to drop $400 x 2 x 2 robots = $1600 for something we might not lose, I said we had to wait until we knew the game and our strategy and design teams had a chance to weigh in. Besides we had spent much of the training season perfecting our abilities to build a great mecanum system and had already invested in all the parts we might need to build either a 6 wheel tank drive or a mecanum drive - either with varying wheel sizes.

Of course.... Our strategy team passed the recommendation on to the designers that we wanted the Rhinos and the design team agreed... Checking online, it was now a potential 3 week delay. A lot happens on Saturday. We weighed the risks and agreed to pursue our other aspects of the robot first - besides there are quite a few game elements to build. Saturday night, we ordered the Rhinos for both our competition bot and the practice bot....

They arrived today?! It was like a second Christmas.....

Maybe we'll have a mecanum system next year...

Re: Pneumatic Wheels vs Treads
 

Personally, I prefer option 3...

Wheels, Treads, or Wheels that act like Treads :rolleyes:

Re: Pneumatic Wheels vs Treads
 

Certainly beats out treads that act like wheels. *cough* Plantation wheels *cough* ;)

Re: Pneumatic Wheels vs Treads
 

I'm interested to see how people will put legal bumpers on this system.

Re: Pneumatic Wheels vs Treads
 

the last option is actually pretty great for teams that are unfamiliar with treads but want the benefits that treads give :P

Re: Pneumatic Wheels vs Treads
 

It's also a lot more efficient and reliable than treads by a good margin. I'm waiting for the rude awakening many teams (especially newer teams) will have this year when they go to their first competitions without spare treads or extra batteries. :(

Re: Pneumatic Wheels vs Treads
 

997 used to do a mean tread system...then the team realized that spending 300 per tread was not realistic.

Re: Pneumatic Wheels vs Treads
 

I remember some teams use to use belt sander belts for tracks. There are very specific reasons you see the rules in the book that you do.:yikes:

Re: Pneumatic Wheels vs Treads
 

the 2-day lead time is for the base belt only.

"The standard lead time for a base belt with a back cover is one week, with Linatex having a two week lead time due to the curing process. Lead time does not include shipping time."
--from the bottom of the .PDF