DIY Tank Tracks Give Tons of Traction

If you’re building a robot for off-road or rough terrain, chances are you’ve thought about using a tank-tread style drive. There are a ton of kits available with plastic tread and wheels, but they are typically really expensive or pretty flimsy. Instead of going with an off-the-shelf solution, [Paul B] designed a heavy-duty tank tread made with common bike chain and conduit.

Some DIY tread designs we’ve featured just use a single bike chain on either side of the tread pieces. This gets the job done, but each section of tread is usually bolted through the chain. This means that you can’t use a sprocket to drive the chain since all the bolt heads block where the teeth engage. Instead, these designs typically use drive wheels inside the tread, which are prone to slip under a heavy load. [Paul B]’s design is a bit different: it uses a DIY double-wide chain so he can bolt tread segments to the chain and still use a drive sprocket.

Constructing the double-wide chain took quite a bit of work. [Paul B] completely disassembled a couple of bike chains with a delinker tool and then reassembled the chain in a double-wide configuration with M3 bolts instead of the original chain pins. Each section of tread (made out of cut pieces of plastic conduit) bolts on the outside section of chain, and a sprocket runs on the inside. His DIY chain approach saves him money too, since double-wide chains are pretty expensive. Since his sprockets directly engage the drive train, his design should be able to handle as much torque as his drivetrain can put out.

22 thoughts on “DIY Tank Tracks Give Tons of Traction

  1. Rather than put bolts through the track (and so require the super-wide chain), as he’s re-bolting the chain, I’m surprised there wasn’t a simpler solution where a link isn’t replaced with something more tooth-like (a bit like a chainsaw chain).
    I do like the re-use of both the bike chain and using the sprockets (could probably make a more elaborate set-up with bike bits and a modified chain)

    1. How about grinding the gears so that the bolt wouldn’t be in the way? That way you could bolt directly to the chain. Ofcourse the toothing has to be even and in the correct ratio.

      1. If properly done, I think the welded pins could be pushed out through two links just as well as they can be pushed out of one (though maybe you’ll need a custom chain tool).

    1. If welding, why not just weld the head of the bolt to the link. You could use a single strand that way. The only problem might be that the threads now protrude through the conduit and down to the ground where they could get damaged and make tread replacement more difficult.

  2. There are industrial roller chains with conveyor attachments.
    08 chains have same pitch as bicycle – half inch (12,7mm) and for smaller projects you could get smaller chains than bicycle one. Plus you could get tons of different sprockets (double or triple row even) witch are not hardened. Typically bicycle sprockets are hardened more-less as hard as they get 55HRC to reduce wear so its not easy to modify them to your suit.

    1. [Koit] I think the point was to actually build one ourselves. But if we are talking about saving time versus money then might not be a bad thing.

      One last thing, Can you give a price break down on that time of chain?

      We have to actually copy the link location from your post…Then remove the image and upload extension…Then find out we have to fill out a form to RFQ.

      1. [Big_Up], Mcmaster-Carr sells these as “ANSI Roller Chain Attachment Links.” Their pricing is a bit steep ($2.00 for a single #35 link), but if you only need a few they may be a viable option.

      2. Well, I get the point of making things yourself, but as you can read from the original post, he only knew about engine timing chains and sprockets (expensive) so the idea behind my post was to let him and other people to know there are some cheap alternatives. Witch are way better option than bolting bicycle chains together with small bolt after dismantling them. You see him using standard ball bearings, one could argue he could of made them himself or make DC motors himself or even the M3 bolts he is using , but the outcome would’t be any better nor cheaper than using standard off the self parts.
        Even using the bicycle parts in projects sometimes doesn’t make sense, cause if you only need a sprocket you most likely have to buy them as a part of some assembly (hub assembly etc.) and they might even cost more than standard industrial part.

  3. If you’re going to fully de-link a chain, save money and weight by attaching a bunch of angle brackets when you bolt the links back together. Or use smooth pins and snap rings.

  4. I was going to do this once, but I realized that the amount of de/re linking was stupid.
    I later saw a battlebot called scuicidal tendences, that used hinges bolted togethor.

    But now I have a 3d printer.
    — end of story —

  5. We did something like this but it was on a half ton underwater crawler. We had great traction going straight but had issues turning on surfaces such as sand or gravel. On a smooth hard surface there was no problem. The channels would dig-in and resist skid steering

    1. That’s when you have a separate motor for each tread. When you want to turn right, you engage the right tread backwards and the left tread forwards. And there’s a turn right. Do opposite for turn left.

      I did a bot the same way, but with heavy rubber. And it had problems with drag turning as well.

      1. this doesn’t solve the problem of excessive lateral and footprint torsional traction, which is the problem. and it sounes like [O_E] already had a skidsteer drive train. the simplest way would be a less-aggresive tread, but that can be troublesome.

  6. A much better solution would be to start with Hollow Pin Roller Chain. It’s made in a similar way to regular chain except the rivets are hollow so you can pass bolts through them. That way you avoid having to disassemble the entire length first.

    http://www.mcmaster.com/#hollow-pin-roller-chain

    And yes, I understand the point of hacking is doing it yourself and making something work in a way it wasn’t designed, but it seems like an aweful lot of work for not much savings.

  7. Great build. but reading the OP’s problem in his post on his site it would be easier to invest in a decent set of winter tyres for his rear wheel drive car. That is the real problem with RWD (read BMW drivers in the UK) in winter is the use of summer tyres on the snow which then they bitch and moan about! go and get your self a set of these http://www.tyrereviews.co.uk/Tyre/Continental/WinterContact-TS-850.htm for your winter traction problems and leave the awesome tracks to the robot….

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