Recently I’ve been wanting to gather some opinions from teams about types of wheels. I’ve really enjoyed using the 3.25" wheels because of their ability to have shaft inserts, and the holes that are already available for mounting. If we look at the entire product line, most of the parts are designed for compatibility within both their sub-category, and the entire platform. I think the 3.25" wheels were a great step forward in upgrading the style of the wheels so that they too can easily be attached to gears, sprockets, and metal. I was wondering if VEX would be interested in applying these changes to the other wheels to create a uniform design that allows for simplified building. The 4" wheel (all variants), undoubtedly the most widely used wheel size, could really use the changes that were implemented in the new wheels. Would this be something that you could find useful? Any opinions and further suggestions are welcomed.
I was almost going to do this for the cad challenge and also include the 5in wheel. That would have helped with ratcheting flywheels too much this year. My school only has 3-4 5in wheels left with inserts intact.
All wheels, except the 2.75" ones maybe, should have screw holes to attach to gears and metal. I’m not sure how useful the inserts would be on most robots, since there is not much need to use high-strength axles on a drive (that I have seen, there probably are exceptions), nor free-spinning wheels (I’ve seen a few cases, but axles still seem to be a better option). I do, however, think high strength sprockets should have inserts. Free-spinning sprockets make great tensioners, and high strength axles might make cantilevered sprockets a valid compact design.
You can actually remove the 4 inch omni wheel inserts and use metal or free spinning inserts. I use metal inserts on my wheels to remove slop from damaged plastic inserts
I don’t know if this is still possible with newer 4" Omni wheels. I broke one on our robot a few weeks ago (I’m not sure how, but the wheel cracked all the way through, and it was rounded out.) And it would appear that the insert is welded to the rest of the wheel. We only had 4 wheels, thankfully 1039A was really nice and lent us one of their spares. I hadn’t ordered additional wheels because I thought we could replace the inserts.
While this is semi-manageable, they don’t always come out cleanly and we’ve destroyed omni wheels doing this. Another downside to this method is that it still doesn’t allow for gears and sprockets to mounted directly to the wheel.
It certainly hasn’t been easy to remove them, and it seems like they are firmly secured to the inside walls. Another thing teams use is a lock bar on the omni wheel, but this is difficult to do because the omni wheel supports don’t allow for a standoff to pass through smoothly, and this takes quite a while to get done correctly. All of this difficulty would be relieved by a redesign that incorporates the replaceable insert and mounting holes that the 3.25" wheel uses, resulting in easier building, advanced designs, and removing the need to potentially destroy wheels to place inserts in.
I would like to see smaller mecanum wheels next year. Maybe 3.5 in. The 4" mecanum wheels are too big, too slow and too expensive
I found that the if u give the Omni wheel a soaking bath in acetone for about an hour or so, the plastic inserts soften and the super glue they are secured in with dissolves. However, I have found that only about 70% of the time will this work properly, leaving a 30% chance of failure and ruining that wheel. I would wait to replace the inserts until they actually break, which makes the removal process a lot easier
Also this is illegal for competition.
The chemically treating a Vex part.
Wow, Didn’t know I couldn’t do that. I will replace those wheel with the the unfixed ones Right away!
It was ruled even water was illegal for this purpose. https://vexforum.com/t/answered-boiling-wheels/23048/1
I have always gotten off fine with a hammer and an axle that I use as a square chisel.