Banebots innovative wheels

[mrnoble]

I promised a while ago I would post more details of the Colson wheels and hubs we purchased from Banebots. Even at this point in the season some teams might want to consider these as a quick and significant upgrade for their drivetrain.

The great advantage of Colsons has been their low price, incredible durability, and relatively sticky CoF. The disadvantages are weight, width, and the somewhat awkward and heavy hubs that must be press-fit. We stumbled upon the innovative upgrade that deals with some of these issues, and we won't be looking back. The 1.25" wheels have a smaller bore than the 1.5" or 2" wheels. Banebots has created a new lightweight hub with a pressed barb that fits these smaller and lighter wheels. The dead axles have an Igus bearing, which is maintenance free, lighter than steel ball bearings, and has less friction. All in all, a major upgrade for us. We also opted for the ground off crown finish, which flattened the wheel and gave it a nubby texture. The wheel ended up at 3.8", and the texture (which we hoped might increase the CoF) wore off within 1/2 hour of drive time on carpet. Overall, we cut the weight of each wheel by more than 50%, gained some much appreciated space on our drive train, and got a bit closer to the ground, for a price that is barely more than the low cost Colsons are famous for. Look closely on the Banebots website for these wheels and hubs. They are a hidden gem and I can't think of any reasons (barring a water game) we will be switching back.

[geomapguy]

Could you post pictures please

BB hasn't added any

Thanks

[mrnoble]

http://m.flickr.com/#/photos/118863723@N07/12807341285/

http://m.flickr.com/#/photos/118863723@N07/12807434803/

[Chris is me]

Originally Posted by mrnoble

The dead axles have an Igus bearing, which is maintenance free, lighter than steel ball bearings, and has less friction. All in all, a major upgrade for us.

There's absolutely no way that a plastic bushing has less friction than a solid ball bearing.

Have you compared these to other off the shelf options for Colsons?

[geomapguy]

Originally Posted by mrnoble

http://m.flickr.com/#/photos/118863723@N07/12807341285/

http://m.flickr.com/#/photos/118863723@N07/12807434803/

Wow these looks beautiful!

[geomapguy]

Originally Posted by Chris is me

There's absolutely no way that a plastic bushing has less friction than a solid ball bearing.

Have you compared these to other off the shelf options for Colsons?

http://www.igus.com/wpck/6131/The_5_...astic_Bearings

[mrnoble]

Originally Posted by Chris is me

There's absolutely no way that a plastic bushing has less friction than a solid ball bearing.

Have you compared these to other off the shelf options for Colsons?

We've used the WCP dead and live hubs before. They are fine, but heavier. Free spin on the Igus with a grade 8 axle is smooth as compared to a steel ball bearing, and we have greater drivetrain efficiency than we had using the WCP w/bearings.

[geomapguy]

What's the length from the edge of the hub to the other side of the wheel for the 1.25 wheels

[mrnoble]

Originally Posted by geomapguy

What's the length from the edge of the hub to the other side of the wheel for the 1.25 wheels

Just under 1.5".

[Adamz_]

compared to a traction wheel with nitrile tread, how do these colsons hold up in overall performance (speed, pushing ability, overall grip)?

[Chris is me]

Originally Posted by mrnoble

We've used the WCP dead and live hubs before. They are fine, but heavier. Free spin on the Igus with a grade 8 axle is smooth as compared to a steel ball bearing, and we have greater drivetrain efficiency than we had using the WCP w/bearings.

You must have had bad bearings. There's simply no way a properly made, sealed ball bearing would produce more friction than a plastic bushing. The Igus stuff is great and has a lot of useful applications, but for drivetrains ball bearings are still the clear obvious choice.

How are the Banebots hubs otherwise lighter? Is it just the smaller wheels reducing hub diameter?

Originally Posted by Adamz_

compared to a traction wheel with nitrile tread, how do these colsons hold up in overall performance (speed, pushing ability, overall grip)?

Speed has very little to do with wheel choice. In terms of pushing ability they are a step below nitrile tread, but compare favorably to AM and Vex kit wheels and are pretty close to gum rubber rough top / AndyMark tread. If blue nitrile has a CoF of 1.4 and other rough top has a COF of 1.3, I would put Colsons at about 1.2, before factoring in tread patterns.

[JamesCH95]

Originally Posted by geomapguy

http://www.igus.com/wpck/6131/The_5_...astic_Bearings

This says nothing about the CoF of plain vs ball bearings. It seems as if they were writing about plastic vs metallic plain bearings. The word "ball" doesn't appear on the page...

Originally Posted by mrnoble

We've used the WCP dead and live hubs before. They are fine, but heavier. Free spin on the Igus with a grade 8 axle is smooth as compared to a steel ball bearing, and we have greater drivetrain efficiency than we had using the WCP w/bearings.

Free spin being smooth is nice, but basically irrelevant to any real operation.

How did you determine that you have greater drivetrain efficiency? What experiments and/or calculations did you do?

[mc153]

We did not buy our wheels, however we did get the opportunity for them to be cut by Brooks Associates. You can check them out here...

Water cut wheels

[mrnoble]

Wow, I didn't mean to start a controversy. However, the questions are valid and I will address them as best I can. Some of the data is with students, so I will ask them about their numbers after school today. I would love to hear from engineers with expertise in bearings and loads as to what might be happening within both the ball bearings and the Igus. Perhaps there is already a thread in the archives about bearing loads experienced in a typical FRC competition? I will search for one, but if anyone reading this is aware of one, please post the link. My own expertise is woodshop...

The weight is less because there is less material in the hub itself, as well as in the wheel. We weighed both the complete 1.5 x 4 wheel assembly and the 1.25 x 4 assembly about 3 weeks ago. The difference was about 1/2, but we didn't write it down, I don't remember the exact number, and all our new wheels are either on the competition bot or the practice bot currently, while we gave our other wheels to another team. Sorry!

Lacking the two flanged bearings also removes about 40g per wheel. The hubs are spoked as opposed to the solid hubs that WCP/VexPro produces. Please click on the links to the two pictures I posted to see how these hubs differ from the WCP hubs. They are also about .1" thinner on the flange, which might not be clear from the photographs.

We initially built the practice bot with the 4x1.5's and were planning on using the same wheels on the competition bot. We purchased the assemblies from Banebots on a whim and, as I said, loved that they were lighter and gave us more space in the drive train. My efficiency statement was based on the current draw of the two robots. The two robots were constructed using the same types of parts (ball shifters, CIMs, pneumatics, etc.) but (obviously) have differences too, many of which are specific to the individual parts and systems, and would compound. You are right that I ought not to attribute too much of our results just to the wheels, but we did have a notable increase in battery life, along with fewer problems with the wheels. Again, I'll ask the kids after school what their numbers were. We have since switched out the larger Colsons on the practice bot and replaced them with a second set of the smaller wheels to make the driving experience as close as possible to the competition bot.

Without having the background to address the theory on this problem well, I will venture to guess that there are several factors that might make the Igus bearings work well. First, the axle bolts tend to have some warping (though we bought the straightest ones we could find). Second, the ball bearing/hub assembly could potentially have some misalignment. Third, the types of loads applied to a bot in competition might include some that would impact the performance of the bearings. Again, I'd love to hear from someone who knows more about this subject.

Returning to my original point: I really only wanted to say that we like these wheels, and your team might like them too. I understand that I threw out some statements that deserve scrutiny, and that no wheels (including these) are miracle workers. Thanks for your time and patience.

[JamesCH95]

Originally Posted by mrnoble

Returning to my original point: I really only wanted to say that we like these wheels, and your team might like them too. I understand that I threw out some statements that deserve scrutiny, and that no wheels (including these) are miracle workers. Thanks for your time and patience.

Welcome to ChiefDelphi. We serve scrutiny and advice with a side of curiosity and humor. This build season's specials include lawyer-ing the manual and BALLS.



Thanks for the reply. I'm looking forward to the details!