This instructable will show you how to replace a tire on an iRobot Roomba vacuum cleaner, using only household items. It is not meant as an expert's advice on casting, and there are probably many mistakes. The goal of this project was to replace a tire using only items that were available on-hand. If you don't have a house and kids, then you might not have everything you need (although it can all be easily obtained for little money).

For some reason, it appears that iRobot used two different rubber compounds on my Roomba 400 series vacuum. On one side, the tire has held up magnificently. The other side is as bald as [insert funny analogy here]. I'm not sure why.

It seems like the bald wheel has a softer rubber compound that shreds easily, leaving black rubber dust on the floor, mostly right near our one carpet - a small mat near the back door.

On top of that, it had a noticeable list to the left.

// if you're only interested in the process, and not the back-story, skip the rest of this step

Because I'm usually quite busy, I tried to do a quick-fix. I took a piece of bicycle inner-tube, and stretched it over the bald wheel. Then I swapped the drive wheels from either side, and stuck 'em back on the machine. (I thought that perhaps there was more of a frictional load on the left side wheel).

It seemed to work, because the tire wasn't shredding itself any more. Unfortunately, the drawbacks of this fix were brought up with a comment from my wife.

"What are these black marks all over the floor?"

Well, they seem to follow the pattern of some kind of automatic floor-cleaning apparatus with a limp. Yup, room-bot's spare tire was not up to the task.

However, he remained in this state for several months. Then came my wife's requested birthday gift - a stick vacuum that's really light and works pretty well. Also, it doesn't leave black tracks all over the floor.

Step 1: A little light reading to get started...

Now that we had another convenient way of cleaning the floor, I took advantage and took poor old room-bot apart. I knew that this process would take several days (and with several days in between when I had the chance to work on it, it would likely be a few weeks before room-bot had completed his recovery).

http://www.robotshop.com has a good set of pdfs documenting the disassembly/reassembly procedures. They also have reasonable prices on used and new parts, but I'm extremely cheap, so I thought I'd give it a try on my own. I referred to http://www.robotshop.com/PDF/roomba-disassembly-discovery.pdf and http://www.robotshop.com/PDF/roomba-drive-wheel-discovery.pdf through the repair. I also used clear tape to affix screws to parts in order to keep everything organized.

Because the assembly procedure is so well documented, in a much more thorough manner than I could do here, I have skipped the disassembly and reassembly steps. Just be sure to keep yourself organized, and it's fairly straight forward as to what goes where. If you can't keep track of that stuff, this 'ible is probably too advanced for you.

As you're disassembling, it's a good opportunity to get rid of any little hair clumps or dirt that's really jammed in there. With five hairy animals at home (and that doesn't include me), I periodically do this just to keep the machine running in top shape.

The possibility of doing this on my own without spending a bunch of money on specialized equipment was made clear when I read mikey77's 'ible on Oogoo. Turns out, I have everything I need to do this fix, without spending anything!

Finally, a small caveat to this instructable. This was my first time ever making a mold and casting a part. I made some mistakes. I will attempt to describe what I did wrong, and what I believe would improve the process, if you decide to do this. However, if you know better, or have different ideas, please don't take this instructable as direct instruction. It's intended more as a journal of what I did, and what you might want to try, as well.
<p>&quot;Just be sure to keep yourself organized, and it's fairly straightforward as to what goes where. If you can't keep track of that stuff, this 'ible is probably too advanced for you.&quot;</p><p>I object to this statement. It would take me about ten seconds to lose those screws, and about 10 minutes to forget what goes where, but that does not mean I lack the necessary intelligence to understand your Instructable. Though I did nearly fall asleep before I got to the end of it. Which is not a comment on the quality of your writing, just the length. The fact that I made it to the end means that it was at least interesting and entertaining. </p><p>Thanks for the tip about the baby oil and Vaseline. I will add that to my notes as something to try. </p>
How has the recap held up?
It held up better than the poor Roomba which had a glass of wine spilled on it. In fact, it seemed to wear better than the other tire!
Impressive! ... and determined! :)
ATTENTION READERS:<br><br>I tried making a mould with polymer clay (Sculpey) to fill in some gaps. Where the oogoo touched my object it came out perfect, but wherever it touched the clay it left weird pits and also the clay bonded with the oogoo pretty bad.<br><br>I'll definitely heed jptrsn's advice and try some more kid-grade play-doh next time!

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Bio: Teacher in Canada. Complete techno-junkie. Open-sorcerer. I am devoted to learning - teaching just sort of follows... (also, I clearly think I'm quite clever)
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