Exposed wheels

There are loads of beetles, particularly in the US, that don’t seem to worry about wheels being chewed off in a weight class overrun with spinners. I wondered if I was missing something and how come more people don’t make an effort to protect them?

Well, depending what sort of spinners you go against it's almost a given they'll do some damage, and I think the reason why the wheels are left exposed is so that side armour isn't there to be bent into the wheels and stop them moving. If you can make the wheels stronger, I suppose you might as well!

At least, that's what I'd assume the reasoning is. A few of the US heavies use a similar idea I recall, it's better to lose a wheel than have an entire side jammed by a bent armour plate (the two that spring to mind are Sewer Snake and Original Sin)

Main reason for that is what in my opinion a rather stupid philosophy. When ive spoke to Americans, the answer i get is that exposed wheels "improves manoeuvrability". i have asked how having your wheels fall off achieves this, so far havnt had a decent answer.

The only real answer i can think of for this is that when your on your side (ie stuck on a wedge) you can drive off it. However the more people i talk to about this the more it sounds like a convention they have gotten into and refuse to change from (such as how they activate robots).

Other answers ive had is that if you cover your wheels, then the armour can get bent and lock the wheel - ignoring the fact the blow which locks the wheels, probably would have torn the wheel clean off aswell. Another one ive heard is that by removing weight around your wheels you can increase the weight of your weapon.

Yeah I dunno just seemed a bit daft. As soon as you see one you think "That'll get chewed off" lol. If you build the robot so that the wheels sit within the body and not just behind a bash plate it's a big help. Rancid took a beating from Will's spinner and was fully functional, but the original design had the wheel sat at the edge with just a piece of angle covering it. Keep thinking how quickly it would have been chewed off.

Just design tendencies. All countries and communities have a distinct look and approach to bots (although in the smaller classes they're beginning to merge). Over here we have dozens of clones of the same HW wedge flipper, which is far more bizarre than having no wheel guards on a robot.

When you're facing a monster spinner, which exist in all classes in North and South America, having a wheel hub get wrecked is often less trouble than getting your weapon ripped out because you had to make it flimsy, just so you could have even more flimsy wheel protection.

Also wheel armour looks like crap on certain designs. Aesthetics matter! :)

Exposed wheels is a risk but it depends whether or not your design requires it, Lynx's wheels are exposed but for that design to be in weight they do have to be. i *could* take enough weight out of the frame or weapon set up to have some very flimsy wheel protection but there wouldn't be much point. i could also make the rear spar wider to incorporate the wheels into the frame but again that would mean taking weight out of other places, at the end of the day with a robot like Lynx if people are going for your wheels they're forgetting about the gigantic bar trying to kill them.

Exposed wheels are a risk, but I’d argue that for some designs it’s absolutely the best option.


If you look at my 1lb bot Algos (http://www.buildersdb.com/botpics/8860.jpg) it’s got one of the more common exposed wheel setups. Large wheels in the rear corners with effectively zero protection. Assuming I was able to shave enough weight to add wheel guards, I still wouldn’t. There are several reasons for this-

-Maneuverability. The current setup keeps wheel contact in almost every orientation, which for a robot that relies on speed and agility to effectively use the weapon is critical.

-Predictable Failure Mode. I know that the weak spot is the wheel itself. It’s a lite flite with a lite hub, nothing particularly durable, and that’s by choice. With the current setup I’ve taken plenty of shots to the wheels and had large chunks of the wheel broken or damaged, but it’s been extremely rare that it’s been enough to disable that side of the drive system. The soft & chewy nature also protects the shaft of the gearbox.

-Quick Turnaround. When the wheels do get damaged (chunks taken out of the tread, cracked hubs, etc) it’s almost no time to put on a fresh set of wheels. I’d rather prep a few extra wheels and swap to a spare set between fights than be stuck with damaged wheels because I didn’t have the time to replace them.


On the other side of things is another 1lb bot in the fleet, Klazo (http://www.buildersdb.com/botpics/8963.jpg) which does have heavily guarded wheels. (0.045” grade 5 ti) Klazo is a bot I wouldn’t run without protected wheels, and again there are several reasons for that-

-Control. The heavy drum and narrow base mean that the bot is prone to gyroscopic instability. The wheel guards keep the bot from turning too quickly and flipping itself over while it’s trying to maneuver.

-Longevity. In this bot I’m using the FingerTech Snap Hubs, which are much more durable than the stock plastic hubs on the lite flites. The extra durability is nice, but it also dramatically increases the chances of a blow to the wheel damaging the shaft on the gearbox. Because of that, keeping the hub itself covered is critical.

The converse of this is the wheel guards do add some risk that the bot might find a stable position without the wheels on the ground. The shape of the guard is meant to minimize the risk, but it’s always a possibility when the wheels are heavily guarded.


I’ll save the wall of text on activation for another time.

I understand about the design not allowing the weight to box wheels in, and that with the open design it's easier to climb off stuff when being lifted / pushed about.

Not convinced about open wheels adding to agility on a flat arena floor. Surely that's a product of drive train, grip and driving style?

i.e - if you boxed in the wheels on Algos would it affect the spin rate etc.?

You're robots are cool and I love your thread. I want to build a 1.5kg version of something like algos, I just can't justify not protecting the wheels and so wanted to learn more about it.

Sitting flat on the floor there isn't a real advantage. What it helps with are things like you said, where someone's underneath it. It's also a perk when the bot gets inverted because it allows for more options for self righting. When the bot's inverted there are a few options for righting-

If the weapon's off, start driving forward to get it spinning and get righted once the weapon gets going, if it is still spun up and not getting the bite to right itself through the hit I can either drive toward a wall to get righted or spin in place to use the gyro to pick it up and put it right side up, which wouldn't be doable with wheel guards.

The other side of it is with how I prefer to drive, I would rather be able to turn faster and not have the wheel guards limit the turning rate.

There is a bit of a trend to all that, they're relatively minor benefits, but often that extra fraction of a second of control or the extra option for how to self right can swing a fight, and really, I've never found the risk of wheel loss to be all that big. Most of the times Algos has lost a wheel completely have been after losing the weapon, so the fight was pretty much over anyway.

On the philosophy side of things, if you have an obvious weak spot, you know where your opponent will try to hit and can better defend it. It's far easier to defend against an attack when you know where they're aiming.

Thanks for explaining. Something I've realised is that by having the wheels exposed it saves an awful lot of body work and makes things a lot more compact.

im currently building a 6 wheel drive beetle and i was going to have guarded wheels till i relised that a) i was getting dangerously heavy and b) that there was a good chance id get beached on my side

Gonna stick with making my new beetle similar to the other with closed in wheels lol.