Our team wants to try and use the Colson Performa wheels as the center drive wheel on the AM14U4 KoP chassis. Is there anyone that has been able to convert the wheels for use as the primary center drop wheel on this chassis? Specifically while using the belt driven system.
This hub has the same pattern as the 42t pulley: http://www.banebots.com/product/HC2-P1-BS3-F1.html
But I haven’t done what you are asking about, so maybe someone has a better solution.
Vex sells a more purpose-built product: https://www.vexrobotics.com/colsonhubs-g.html
No reason these shouldn’t work with some design modifications to the setup. Most notably you won’t be bolting the pulleys to the center wheel anymore, you’d instead want to give each pulley its own hex hub. Haven’t specifically tried it though.
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We’ve done this the past two seasons. It takes some clever spacing and a lathe, but you can reuse all the spacers from the two outboard wheels and have a center wheel that doesnt need replacing. I’ll try to remember to post pictures next time I’m in the lab.
Edit: we used the colson press in hubs and turned them down for spacing the used hex hubs also turned down for spacing. It doesn’t take long, we did it in the pits at worlds using withholding for the hubs in 2018.
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But 254 said colson bad…
Jokes aside, why do you want to use Colsons as your center wheels?
If it’s for the traction, Andymark sells a kit to use the 6 inch performance wheels, to which you can attach nitrile tread, which would provide a similar amount of traction, while also saving you the effort of figuring out a custom solution.
That being said, I know Team 1318 uses colsons for their center wheels, so you probably could email them for info about that.
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The main reason is that we are looking for a wheel that can provide a good amount of traction with a solid hub. The traction and plaction wheels with the nitrile band seems more risky to us due to the fact that that band can potentially come off during competition. Game permitting, we are hoping to use the AM14U4 again this year with corner 6” omni’s and test performance over our upcoming WCD off season project. We tried to get a WCD up during our offseason this year but just didn’t make it. Last year we used a 6” regular wheel and corner omni’s with the KoP chassis and had great success minus some issues with the drive wheel wearing away and needing replacement. We feel that the Colson Performa can provide us with an upgrade in that regard and give us another rep on the AM14U4 so we have some baseline info prior to the switch.
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Survey says…this probably won’t happen. I’ve never heard of that being an issue, even on custom wheels without flanges for the tread.
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We used it purely for wear resistance. Have you ever tried to swap wheels on the KOP chassis between matches? Less painful during lunch, but even that makes me nervous about losing parts and loose bolts while rushing back to queue without bumpers on. A set of Colsons last all season, AM wheels are great but didn’t make it through all our practice and matches for our two district events let alone MSC or Detroit.
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Um - you do know there’s no bag this year? You can swap wheels between events now.
I’m aware, the lack of bag this year doesn’t help much with problems we had in 2018 and 2019 though.
I do happen to have a wheel problem and our collection is depressingly extensive, but I’m still not a fan of taking our chassis apart unless it is absolutely necessary. Anytime we can avoid removing structural members at competition will be taken care of at home for sure. I’m still not sure how I feel about the loss of the bag, but our whole teams knuckles and finger tips are grateful we wont have to align wheel spacers under pressure this season.
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We had this issue at Houston Champs this year and were only saved by the field delay issues caused by FMS. The stress of having to change the center drive wheel that had completely worn down by match 4 was super stressful. We are looking to avoid changing out drive wheels at comp, not between events. Bag or no bag doesn’t help with that issue in particular.
This is absolutely a possible failure mode of tread that has happened before. Not necessarily likely, when properly applied, and not necessarily a design dealbreaker, but it’s not like no team has ever lost wheel tread before. I can think of several examples, good teams included.
Colsons are a traction upgrade over HiGrips, and also a strength upgrade. They are a totally valid wheel solution, and it was only the weird dynamics of the 2019 game’s precise long distance autonomous modes that revealed a particular edge case that frankly is not the kind of thing that should be driving the design decisions of anyone using the kit frame.
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[Not related to the wheel but the wheel diameter]
I’ve personally tried looking for 6" Colsons. Didn’t get too far. Vex has a max of 4" and BB 5". We gave up looking and will be looking forwards to Blue Nitrile.
Top result is colson, next three…
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6x1.5 is a standard colson size. We used them this year. You’ll just have to get them from a caster distributor (or Amazon), rather than through Vex, and you’ll need to push in one of Vex’s colson hubs linked upthread
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If you’re willing to pay a premium, you can even get Colsons of any arbitrary size and shape on McMaster:
(80% sure this is right)
Just make sure the inner bore diameter is the same as the press in plug. Get whatever bearing option is cheapest - you’ll be pressing that out and tossing it anyway.
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Here are the pictures of what our install has looked like the last two years. The belts on both sides of the wheel worked much nicer and was obviously thought out better. The one where the belts are together was cobbled together in the pits in Detroit in 2018. There are some questionable decisions that were made in 2018, but the wheels worked well. Not so sure on how strong that frame was anymore…
https://imgur.com/gallery/NPjWVy6
We used the press in hubs from Vex, but then started making our own after some shipping lead times made us nervous. Takes about an hour on the lathe to make a knurled hub. If you look close you can just barely see the AM hex hubs that are attached to the pulleys from the KOP Chassis.
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Note a “6 inch” colson is closer to 5-7/8" where most “6 inch” omnis are actually 6", so your center drop might not be what you expect. Test, test, test!
(Side note: We’ve used both custom lathed/broached and Vex colson hubs, and prefer the Vex colson hubs for the traction pattern; our smooth sided custom press-fit hub (6" colsons) started slipping during our second off-season demonstration after just two comps, so it probably would have started giving out partway through Worlds had we made a run.)
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