8" Pnumatic Wheels @ Andymark soldout

FIRST General Forum
#49

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.

#50

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

#51

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.

#52

Now that’s what I call “Drive it like you stole it”!

#53

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

#54

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.

#55

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.)

#56

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

#57

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.

#58

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!

#59

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/detail/2-80-x-2-50-4-wheel-assembly/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.

#60

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

#61

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.

#62

Hereis 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.

#63

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.

#64

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.

#65

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

#66

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

#67

Curious about this as well.

#68

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.