8" Pnumatic Wheels @ Andymark soldout
 

With the pnumatic wheels at Andymark sold out, and giving a couple week lead time does anybody else know of a supplier of a decent replacement?

Re: 8" Pnumatic Wheels @ Andymark soldout
 

But ... they came back in stock this morning.

Edit: Apparently I can't see big red blocks of text.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

From the AndyMark website:

"AVAILABILITY NOTE (UPDATED 1/11/16):
Currently, this wheel is in high demand. We had many in stock and we are receiving another supply of tires within two weeks. We are accepting orders for these tires although we may run out of stock soon. Therefore, even though you can purchase this product, it may not ship until 1/22 or 1/25. We apologize for the delay. Please check here for the latest availability info before calling our office. "

It sounds like they have either run out or are going to run out very soon. They are still allowing people to place orders, but are saying there's a chance your order won't ship until 1/22 or 1/25.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

What do you mean by 'decent replacement'? There are plenty of suppliers if you can create your own hub.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

The Andymark 8" Cheng Shin tire is commonly used on mobility scooters and should be available from many sources. The hubs sold as part of the wheel assembly are single source, from Andymark.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

You didn't catch the 10" pneumatic wheels on sale at Harbor freight this weekend? I picked up six of them, $4 each. They require hub work, as mentioned. But they might only be needed at the front of the robot, so we need to get busy prototyping and see what we can come up with.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

what are you planning on doing with those steel hubs?
How much do each of them weigh?

Re: 8" Pnumatic Wheels @ Andymark soldout
 

They're heavy. The steel hubs have a tube on one side, I think it's 1-3/8" id. I was pondering whether we could weld a small steel hub onto the tube, and bolt a common robot sprocket to the hub. Or maybe press a longer tube into the existing tube. Or see how they work as unpowered wheels, going over the defenses. It's all conjecture at this early stage.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

I know this is an AndyMark thread, but we have these available:

http://www.wcproducts.net/pneumatic-wheels

We will have pictures of hubs up today along with a full wheels assembled. Also we currently are 1/6 of our total "inventory" sold and have a decent amount of diamond tread available & zigzag tread available.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

those look like a viable option as well
Got any idea what the durometer rating of the tread is?

Re: 8" Pnumatic Wheels @ Andymark soldout
 

Off hand I do not, If I'd have to guess somewhere around 60-75 ish. I'll email our supplier and find out and post the info here/to our site.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

looking on the web for tires there seems to be lots of choices.
It's the hubs that will get you.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

If any team looking for these AndyMark tires are near these locations:

Atlanta/Greater Marietta
Northest Ohio/Mayfield Heights

Those 2 Microcenters each claim to have a box containing 2 of these.
Please put them on 18 minute pickup before you try to pick them up to be sure they really are in inventory.
They will likely be on clearance.

Ahem - there were more of them - :yikes: SOMEONE:yikes: - put the rest in my barn.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

I was looking at these yesterday for our team, but decided to go with the Andymark wheels for two reasons.
1. I knew they had stock
2. They were easier for sprocket mounting

I suggest you update your website to show these as in stock. I would also confirm whether these could be used with your wheels:

http://www.andymark.com/product-p/am-2469.htm

Re: 8" Pnumatic Wheels @ Andymark soldout
 

Hi Derek,

We will show these in stock once they are kitted & ready to go. We also updated the site with lead times so customers can see when they will be shipping. Let me double check today, I have an AndyMark hub handy and will get back to you. I believe that those hubs work with our Tires + Tubes for customers who want dead axle, those will be an excellent choice.

The hubs we sell are specially designed for VersaChassis like setups and/or live axle drivetrains.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

Back in the olden days we purchased from Colson. Might not have the size you want, but remember them as a backup.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

I just ordered 4 of the AM 0970 this morning and there wasn't any note on a delay.

Maybe they just found a few boxes in the back? I hope so, because I would like to get them in soon!

Re: 8" Pnumatic Wheels @ Andymark soldout
 

We used them in 2012. I think 6 of them weighed about 20lbs. A bit of over kill in my opinion

Re: 8" Pnumatic Wheels @ Andymark soldout
 

Missed this ... errr ... if we wind up with live axles, I'll probably return the ones I just ordered from elsewhere so we save a lot of heartache and time.

When inflated are they exactly 6", slightly under or slightly over?

Re: 8" Pnumatic Wheels @ Andymark soldout
 

We measured a few and they are about 5.96", so ~6". They'll vary depending on the pressure so teams can tune their drop via filling or deflating their tire.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

It says they're currently on backorder. Is there or a chance they would ship sooner or are you guys completely cleaned out?

Re: 8" Pnumatic Wheels @ Andymark soldout
 

There is now a note at the top of the page about that:

Re: 8" Pnumatic Wheels @ Andymark soldout
 

We are not cleaned out nor have shipped any hubs out, we are currently putting them into stock. We just allowed people to que in line/pre purchase them.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

The coefficient of friction for these wheels is listed as TBD. Do you have an qualitative opinion on the difference between the tread types especially as they might apply to this year's game?

Re: 8" Pnumatic Wheels @ Andymark soldout
 

I told him to order these, but nooooooo :rolleyes:

Gonna go to harbor freight then. Or see what Mark make for tread in his garage...

Re: 8" Pnumatic Wheels @ Andymark soldout
 

The 8" Andymark tires (tires, without hubs/wheel) are used in the mobility scooter business. I was able to secure what we need with a medical supply warehouse, but I took all they had. They called the manufacturer (Cheng-Shin/Maxxis) and the manufacturer is apparently out of stock.

Finding them at a medical supply store may be more expensive, but if they have them on hand, it might be worth your trouble if you desperately need them.

Here's some search terms for the tires to save you some time:
200x50mm tires
8"x2" tire
8" Scooter tire
T021 tire
8X2″ KNOBBY TIRE
GRAY PNEUMATIC WHEELCHAIR OR SCOOTER TIRE

Good Luck!

Re: 8" Pnumatic Wheels @ Andymark soldout
 

The steel hubs on the wheels from Harbor Freight are pretty heavy and are probably hard to use with the hubs and shafts we are all accustomed to using. Currently, AndyMark has the 8" plastic hubs in stock. You may want to verify that the tires from the Harbor Freight wheels will fit the AndyMark hubs.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

R.C., did you confirm that the AM hubs, am-2469, will fit your 6" pneumatic tires?

Re: 8" Pnumatic Wheels @ Andymark soldout
 

HI Terry

I totally forgot about replying to this thread. But our diamond tread tire will work with the AM hub, the zigzag tread will not. I would advise teams that use the am hub to buy a low profile tire fill gauge as ours did not fit.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

Skywaywheels.com they are the direct supplier. They will send you an order form for the wheels. They have approximately 10 different wheels to choose from for FIRST teams.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

They don't fit. Harbor freight sells mostly 10" tires but they do have an 8 inch non marring tire that is red in color. However, the andymark tire isn't really 8 inches as it is a metric tire. The HF tire is a 4x2 hub, so a totally different standard of measurement.

In the past we mounted hubs and sprockets to the steel wheels, but they are heavy heavy heavy. We are currently printing hubs for our 8" non-marring tires and tubes.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

Well, the hubs for the 8 inch wheels are out of stock at AndyMark making this moot now.

I did pick up one of the red wheels from HF the other day and had a student take it apart yesterday. We also found one half of one of the AndyMark hubs and tried to fit in the red tire. It looks a bit small, probably due to it being made to a similar but different sizing standard so it is not clear if the AndyMark hubs would grip the tires properly. The red HF tire is also a bit wider (along the axis of the axle) so people who use it should beware if they are using the AndyMark wheel in their CAD. We are looking at alternatives now. Please let us know how the printed hubs work out for you, especially how they take abuse.

I know AndyMark running out of these wheels is a great inconvenience to many teams but I feel that if FRC is to be an introduction to the world of engineering, this supply issue is not a bad thing at all. A significant portion of my work supporting existing products in my day job consists of finding alternatives for components that we are having a hard time getting enough of or the supplier cannot deliver on time or the component has gone obsolete. Not finding a replacement part usually means that the production line stops and the money stops coming in.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

You might be able to get away with adding airing up the tire a lot to increase the grip on the hub, but I would have concentricity concerns using the AM hub on the Harbor Freight red tire. We're 3d printing hubs, but I wouldn't have huge concerns with wrapping the hubs in something to make it a bigger diameter (duct tape?). Due to the nature of how those wheels and tires work, the tube should help to center it a little. I would still have concerns about large impacts due to the smaller bead retainer in the bigger tire.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

I took the CAD of the hub off of Andymark and modified it to be a bit more 3D printer friendly.
If anyone is feeling brave enough to try running a printed hub, I posted it to Thingiverse.

It should fit any 200x50mm tire and inner tube which can be found all over the place.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

Be sure that the outer diameter is thick enough, I had trouble with it not having the thickness to get three full layers in so I ended up with two layers and a hollow gap between them.

Did you remove all of the fillets? Doing that cut supports in half after I took the draft off and made my own spokes so it would be prettier.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

What diameter nozzle are you using? I have not printed it myself but Repetier says it can get 7 shells of thickness on the outer edge using a 0.4mm nozzle.

I removed the indexing holes that align the two halves so the part can lie flat on the bed. I also chamfered the outer lips (that retain the tire). Otherwise I made no visual changes.

I am not sure how removing the fillets would change anything. Do you mean the on the outside (where the inner tube would rest against)? If so, I did reduce those to being a 50deg overhang which my printer has no trouble doing without support. The outer rim that holds the tire on is the real concern with support for me.

EDIT:
I think I understand what you meant. I was intending for the one I made to be printed upside down compared to the way I believe you were printing it. Reason I chose the way I did was so that the hex pattern would come out right but to each their own.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

IMO the pneumatic tires are not any better than solid ones.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

That's fantastic! Perhaps you could provide some insight as to why instead of just making an empty statement?

Re: 8" Pnumatic Wheels @ Andymark soldout
 

There is a reason that every car on the road has air* filled tires, and it is not for better traction.

*or nitrogen

Re: 8" Pnumatic Wheels @ Andymark soldout
 

gwiw, the steel hub and 10" tire on it, from Harbor Freight, weigh 3 lbs. each.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

I'm printing on a Stratasys machine with soluble support.
As I don't have the freedom you do to change parts, I'm stuck at a .010" nozzle. Also, the radii in the fillets required support material to print, thus the savings in material. I always forget that not all printers work like that...

However, I did start printing 8 sets of hubs yesterday and then left school. Went back to check on them today and I only have until 10:00 and they'll be done. The saving grace of an expensive machine like a Stratasys is that it is like an appliance rather than a hobby printer. The ability to print overnight without having to babysit sure is nice when you print a 33 hour long print job...

Re: 8" Pnumatic Wheels @ Andymark soldout
 

I'm hoping that these wheels end up back in stock within a couple of weeks, since we still need to order another set. I saw the new tires (other brands) pop up on andymark and thought we could try them, but they're all sold out already as well.

Goodness, these things sure are fun to play with though.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

I would not try to suggest that the pneumatic wheels are worse than solid ones, simply that they are not better. I was actually hoping someone would explain to me why everyone seems so convinced that pneumatic wheels are necessary for this game. I do not understand why so many people are going out of their way to try to find ways to get these wheels.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

The wheels are just awesome!

Re: 8" Pnumatic Wheels @ Andymark soldout
 

If you'll check what he posted again, you'll see that he was not asking about the intensity of your dislike for pneumatic wheels, but why you dislike them. For instance, what do they fail to beat solid tires at? Efficient running? Ease of use? Shock absorption? Traction?
There are many aspects to what makes a tire "good" for a certain application, and I believe Dave was trying to get you to dig into that and see what your opinion is based on.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

Those sneaky 4 inch wheels between your tires make me wonder whats going on over there :D

Re: 8" Pnumatic Wheels @ Andymark soldout
 

First, I may say I am a student, not an engineer or professional whatever. I do not have lots of years of industry experience, but physics was my favorite class.
I actually don't have any dislike for the pneumatic tires, and we considered the pros and cons of them plenty. But I'm not bummed that we can't get them, and that was just the easy way to rule them out for our team.

For the sake it, here:
Ease of use: Solid tires are easier to use for two reasons. Dropped center designs are very straightforward with solid wheels, and I have heard that sometimes you need a greater drop with pneumatic ones. I do not have experience with this, nor does anyone on my team, so we would rather not take a chance at having to fuss around with that. The other reason is managing the air pressure of the wheels. This could be related to reason #1.

Shock absorption: Seems to be the greatest benefit of pneumatic wheels. That said, I don't see how the impact of crossing defenses is going to be any more violent than the full court ramming that robots survived in 2014. Therefore I believe that the electrical and mechanical parts of the robot should handle it just fine.

Traction: We are planning on using 2" wide VexPro traction wheels, which I expect to have comparable traction to the pneumatic ones. I would like to see some proper testing of this if anyone could point me to it.

Summary: It is fair to argue that pneumatic tires could be better. If you have them and are planning on using them, it will probably work out well for you. But if you can't get them, don't worry, I don't think it will leave you with a disadvantage on the field, so it is not worth the time and money to go running around trying to find them.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

2014's collisions were bumper-to-bumper impacts. The bumpers allow the kinetic energy to exchange a little bit slower than instantaneously, reducing the impulse experienced by the robot. In addition, the bumpers were usually mounted to the main frame of the robot, which can direct forces throughout the robot in a uniform way.

When crossing defenses, it is your wheels that take the brunt of that force. A pneumatic tire acts like the bumpers do and reduces the impulse delivered to the robot, namely the axle. A hard wheel will shunt the full impacting force all at once into a shear impulse against the axle and its bearings, which could shatter bearings, or shear the whole wheel off.

In our testing, we build a chain driven west coast drive using VexPro versablocks, and due to the specific configuration could only get 2 bolts to hold it clamped to the frame tube. We put VexPro traction wheels on it and sent it at the defenses. After just a few crossings at decent speeds the chains had all fallen off. The impacts of the wheels colliding with namely the Rock Wall had moved each versablock more than 1/8" closer to the center until the chains got too loose. Obviously this was a problem specific to our configuration but I would not expect such a thing to have happened with pneumatic wheels.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

I am confused about the concern about the "shortage." I certainly understand that Vex and AndyMark are the "go-to" retailers for a lot of FRC items, but there are a lot of other folks who sell things such as pneumatic tires... Before responding here, I simply did a search on Google and found four or five different places to purchase such tires.... I glanced at one and it seemed to have all the other hardware needed for them...

Besides, even if there were a world-wide shortage of them, there are other options... Tank treads have been discussed on CD and are certainly viable. And, yes, there are options besides the Rhinos from AndyMark... Even so, could you play with a hard rubber tire (such as 8" traction tires from AndyMark)? Sure.... Okay, the hard rubber would not compress quite as well as pneumatic tires and not "bounce" over some of the surfaces as cleanly, but they could be used to cross all the hazards just fine - though I wouldn't want to go quite as quickly as I would with the pneumatic tires....

If worst came to worst, create a robot with a little different focus... A robot, for instance, operating with mecanum, could go under the low bar; open the portcullis, sally port and drawbridge; and navigate the cheval de frise. Of course, you might have to construct a manipulator or two... A mecanum robot could be fast, agile and have a perfectly good shooter... It could also climb just fine.... So, you could have a short robot with a mecanum drive system that primarily cycles between your secret passage, under the low bar and shoots at the high goal. As secondary functions, focus on opening the more difficult defenses and make sure you can climb. If needed, you could also cycle to the neutral zone to pick up boulders.

Do I think mecanum wheels are ideal? No. In fact, they would be one of my least -preferred wheel options for this game. However, with a little creativity, you could have a very competitive robot with them - or quite a few different drive systems. Heck, it might even force you to find a niche in the game where nobody else really fits and gives your alliances a competitive edge....

I've only been in FRC for five years, so I certainly don't know "everything." However, one thing (of many) I have learned is that you can't afford to get too attached to any one idea. Sometimes, they just don't work out - supply, lack of engineering expertise, too much weight, not enough space, etc.. Sometimes, you just need to take a different course. It's part of the game.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

Just putting in my two cents, our team found them in stock from Amazon.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

I also ordered some 200x50 tires and the tube from Amazon without issue out of curiosity.

I also stopped by the local Tractor Supply and grabbed a 10" knobby tube tire from them: 4.10/3.50-4 which is a tubeless tire. I also grabbed the same size tube.

That 10" tire has just under a 4" opening in the center. 3" PVC couplings have just over a 4" external diameter. I wasn't able to press one into the tire stock even with some petroleum jelly to help. I was able to put the tube around the stock coupling. I put it on my MaxNC lathe, used a dial indicator to check the run out, and then turned it down ever so slightly on the external sides of my centering 3 jaw chuck (minding the internal taper of that coupling). Finished it with some light sanding. It can be made to fit now into the center of that tire and tube around it (minding the air fitting will need an opening). You can put a tube in a tubeless tire. Need a lip on it and something in the middle. Not sure frankly if this tubeless tire really needs that tube in it as it is pretty rigid on it's own and for such a light vehicle as this that might be enough.

Total weight of the tire and tube is: 2.4lbs
Total weight of the turned down coupling is: 0.43lbs
Wouldn't be surprised if the whole thing comes in at 4-5lbs per tire with a hub.

I don't much plan on building this out any further but I had a hard time finding a 10" spoked tire that someone could use for a donor rim. Will try the same trick with the 200x50 tire when it gets here. All the AndyMark tires I had are otherwise occupied.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

Now that's what I call "Drive it like you stole it"!

Re: 8" Pnumatic Wheels @ Andymark soldout
 

The student driving that has a promising career in Hollywood as a stunt driver. Fast and Furious 9 or 10?

Re: 8" Pnumatic Wheels @ Andymark soldout
 

We are trying the HF 8"wheels, we removed the steel hub and used the 4 screw holes to make our 3D printed hub concentric. Probably we will be machining the hubs with some better plastic.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

For what it's worth, the AndyMark 8" pneumatic hubs are back in stock now. We ordered them and then bought the wheels and tubes off Amazon. That should allow us to handle our business with minimal fuss. (Just make sure you buy tubes with right-angle connectors, per AndyMark.)

Re: 8" Pnumatic Wheels @ Andymark soldout
 

ALERT!
The AndyMark 8" hub assembly for the pneumatic wheels appears to be in stock! :yikes:

Re: 8" Pnumatic Wheels @ Andymark soldout
 

We just spent the last week building custom hubs and a drivetrain with these same wheels. Watch out for the bearings. They don't seem... adequate. We're looking for other options still.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

Yes, we removed the steel hub and the original bearings, they can't handle the range of RPM that we use in FRC... Thanks for the hint, anyway!

Re: 8" Pnumatic Wheels @ Andymark soldout
 

These look to be similar to the wheels at Harbor Freight, but at the Canadian Equivalent Princess Auto, for teams that are interested. http://www.princessauto.com/en/detai...ly/A-p8442410e. The unfortunate thing is they don't come with a bolt circle to adapt a hub, and like the Harbor Freight wheels, the tire (2.8 x 2.5-4, whatever that means) does not appear to be compatible with the AndyMark hubs (200x50), but I would love to confirm.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

Would you mind me asking what you replaced them with? Does anything from AM fit these?

Re: 8" Pnumatic Wheels @ Andymark soldout
 

They don't seem compatible. We have these wheels and will be making hubs for them. I wasn't the one to check compatibility but someone on our team said they wouldn't work.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

Here is our solution all mounted up on an 8" non-marring Harbor Freight Tire. Had to do a bit of polishing in the lathe to get everything to sit perfect, but I can adjust some before running the last batch tonight.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

We have printed a hub with the 4 main holes of the wheel's plate, so we can hold it concentric, the hub have space for 2 flanged bearings and the holes for the sproket.
I don't know if i have explained it clearly, if you need more details PM me.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

We've just ordered mountainboard tires from MBS.com once again. We already had their Rockstar Pro Hubs from 2011 and the great folks on the phone there said if we got our order in early enough today, they'd ship today. Note: there are local distributors but none are near us so I didn't bother with that option.

We loved the colors available on their T3 tires but opted to go with the Vine tires because of the increased traction.

Hope this helps other teams out there searching for a hub and wheel option.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

We just ordered a single T3 wheel to try them out. How well do they fit on the AndyMark hubs?

Re: 8" Pnumatic Wheels @ Andymark soldout
 

Thank You. Have some on the way to possibly try out.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

Curious about this as well.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

Just purchased 6 of the T3 in green and tubes. Was on the phone with Tim discussing the available options and all. Great service and provided a small discount.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

We have two Vine's in house (and 16 more coming in tomorrow) they work great on the AndyMark Hubs and we have filled them up to around 70psi. I've heard MBS might be out of stock soon on the Vine's. If you look around you can find a wide variety of 200x50 tires, Razor makes a few scooters that use that size tire as well.

Re: 8" Pnumatic Wheels @ Andymark soldout
 

The same tire as sold by Andymark (except in black) is used on some smaller scooters and lawn equipment. If it is a Cheng Shin brand 200x50 and has the C-968 tread pattern it will be the same rounded profile, diamond treaded knobby many are still looking for. Our set came from a lawn equipment repair shop.

The black ones are NOT non-marking, meaning your robot will leave skid marks on the floor.

http://www.csttires.com/int/lawn-and-garden/c968/