Flex-Grip Wheels

[stramat8]

We recently purchased one of the Flex-Grip wheelse from McMaster Carr after seeing the success they had with bringing in totes. We wanted to start prototyping with them and we noticed that the hub couldn't be easily taken out or it would wreak the wheel and it had a good amount of weight on it. I was wondering if teams managed to take the hub out or machined it in some way?

[wilsonmw04]

We used them last year with success. We made our own insert that then fit into the factory hub.

Edit: the inserts were 3d printed.

[AllenGregoryIV]

We weren't able to remove the hub.

Here is how we made a cheap COTS hub solution for these wheels.
http://blog.spectrum3847.org/2015/07...rr-wheels.html

[Lil' Lavery]

I've been curious about these in the past, but unable to get past the sticker shock. $29+ is a lot for an intake wheel, especially when compared to something like the Banebots wheels. Does anyone know of a cheaper source for these than McMaster?

[IKE]

Looks like you can get a variety including "hubless" version at Fairlane products:
http://www.fairlaneproducts.com/tech...=4-Durasoft-R#

To buy them, they link you to Fixtureworks.net
http://www.fixtureworks.net/Home/Ord...C0%7C0%7C6%7C1


Lots of different variants, volumes, and prices.

We bought some from McMaster last year. Got about 1/2 of the hubs out OK, and half destroyed. This hubless and the 2.5" options might be nice.

Originally we were looking at Bane-bots, but ran out of stock, and the ones that worked well did not have good longevity.

[wilsonmw04]

Originally Posted by Lil' Lavery

I've been curious about these in the past, but unable to get past the sticker shock. $29+ is a lot for an intake wheel, especially when compared to something like the Banebots wheels. Does anyone know of a cheaper source for these than McMaster?

I thought the same thing. However, one pair of wheels lasted for our practice robot and 4 competitions. They are in such good shape we could use them again if we needed.

[nuclearnerd]

Originally Posted by AllenGregoryIV

We weren't able to remove the hub.

Here is how we made a cheap COTS hub solution for these wheels.
http://blog.spectrum3847.org/2015/07...rr-wheels.html

Nice! The close fit with a hex shaft collar looks perfect. Thanks!

[Greg Needel]

Looks like they make one with a 1/2 bore. Perfect for hex broaching. http://www.fixtureworks.net/Home/TechSheet/tabid/57/Default.aspx?catID=DR-9502-35UR-EX500&thumbPath=9|0|4|2|0


The only down side is that those hubs are steel, making them bound to be heavy. I guess it all depends on the application.

[Chris is me]

Sure-grip drive rollers, as they're called on McMaster, come in several different sizes, durometers, and materials that vary in effectiveness depending on the task. The white nitrile wheels were great in 2013 for shooting frisbees, but less so for gripping game pieces in either 2014 or 2015. In 2015 they were good enough for a human load robot, but not good enough to play the landfill well compared to other wheel choices. The polyurethane version of these wheels, while pricier, got the job done a lot better this year.

I think the solid blue polyurethane drive rollers from McMaster are ultimately more useful in FRC, as they have excellent grip on a variety of materials. After extensive testing they were the only wheels that could grip frisbees as well (or slightly better) than the old blue Banebot wheels.

Both wheels are expensive and come with a large-bore steel hub that you'll need to press an aluminum insert into. You can fiddle with / modify certain COTS products (VersaHubs, etc) to fit in certain cases, but the best solution is really to turn down your own hub on a lathe. You could probably print and broach a plastic hub too if you wanted. With an aggressively lightened aluminum hub we got the solid wheels within .25 lbs of a Banebots wheel each, so weight isn't prohibitive.

The price is... a lot, but if you're trying to get the best intake in FRC, you're going to spend a few hundred bucks testing out materials and geometries that will never work, and that's just something you have to accept. Intake prototyping is expensive.