Misc. DIY - Replacing my bicycle tire with recycled plastic

[Evanish]

So the rubber on one of my bicycle tires has worn out to the point it needs to be replaced, and I was thinking I'd prefer a solid tire this time. Rather then buying one like a normal person I was thinking if I could make my own out of recycled plastic.

Here is the plan as it currently stands. Get some cardboard and cut a hole for the spokes so the tire can be level with the board. Get some more cardboard to form a ring so I have a crude mold to melt the plastic into. then glue all this together so it won't move around while I'm working. Here is a picture of the crude mold I'm thinking about making to form my plastic wheel.

Next I'd melt little pieces of plastic into the mold with a 14 amp heat gun.

Then I'd remove the newly formed tire from the mold. I assume that it won't be formed well enough at this point to make for a good ride. In order to fix this I though about using a lath, but the tire is too big. Then I though about reattaching it to the bicycle and using lath tools on it there. Here is a picture of the tools in question.

In order for this to work I think I'd need to find some way to use an electric motor to spin the wheel. I have a motor I took form a blender that I'm hoping to use. Here is a picture.

Of course I'll be careful about the exposed wires. I was thinking I could attach a wheel to it, and then put that wheel in contact with the bicycle wheel in order to spin it using friction.

One big issue is this idea is finding some way to secure everything in the correct position while I'm working. I have some clamps, twist ties and other simple restraint for that, but I'm feeling that trying to find something to attach everything to and getting everything lined up would be very frustrating.

Frankly I'm not really feeling confident about the project as a whole so I thought I'd post it here and see what people think. Any suggestion on the project would be appreciated.

 

[jedishrfu]

Why not just fill the tire tube with solid material?

 

[Evanish]

Why not just fill the tire tube with solid material?

I actually attempted filling the tire tube with something. After considering various options I decided to try filling the tire with cement. I purchased some masonry cement and put it through a strainer to get out the bigger rocks. Then I cut short the bicycle tire air valve so that I would have an unimpeded hole to squirt the concrete into it. Then I bought one of the bellow from dollar tree to use as a pump to get the cement into the tube.

I cut of the upper end so that the plunger could be removed, and the cement funneled in. Unfortunately at some point before I could get started someone mistook my pump for trash, and threw it away. Feeling frustrated I decided to use a bit of scrap PVC pipe and wooden doweling in it's place. This turned out to be a mistake as sand from the cement got jammed between the wooden doweling and the PVC pipe leading to the plan's failure. The only thing I succeed in was clogging the air valve with cement leading me to need to switch to this new plan. Perhaps it would have failed anyways as I had added quite a bit of water to the cement to get it flow smoothly so it was really weak when it dried and so I may have ended up with lumpy tires as result.

 

[anorlunda]

Selection of the recycled plastic would be critical. It needs to be not brittle, yet durable, and with a melting point compatible with your heart gun. How are you selecting the plastic?

Could you use another tire to make a mold, then use something like lost wax casting?

 

[Evanish]

Selection of the recycled plastic would be critical. It needs to be not brittle, yet durable, and with a melting point compatible with your heart gun. How are you selecting the plastic?

Could you use another tire to make a mold, then use something like lost wax casting?

I was thinking of using LDPE. The melting point is pretty low at 180-240 centigrade. I tried melting plastic bags with the heat gun, and it seems to work well enough so LDPE should be good. It's also not brittle. As for durability it will hopefully be good enough. Also, I picked up a big LDPE kids sand box someone was getting ride of so I should have enough material. I'm guessing they put something in it to protect against UV light which is also a plus.

As for using another tire to make a mold I'll have to think about that a bit. I can't use a big mold where the plastic enters in from a single point because melted plastic doesn't flow very well. From what I've read in the plastic industry they use high pressures injected into steel molds to get around this, but that isn't an option for me. Maybe I can make a half mold of a good tire with concrete though. That might be more effective then the crude mold I talked about above.

 

[jedishrfu]

In truth, I think this is an effort in futility. You must know you need something as pliable as rubber.

Using cement doesn’t make sense.

Have you researched solid tire construction?

 

[Evanish]

In truth, I think this is an effort in futility. You must know you need something as pliable as rubber.

Using cement doesn’t make sense.

Have you researched solid tire construction?

The cement thing is very likely a bad idea as even if I succeed in getting it in the resulting tire would likely be less than ideal. My hope was that the tuber tube, and old tire would, would encase the cement in such a way that even if it broke into many pieces the tire would still be fairly firm, but I've given up on this idea now. I've also heard about people using construction foam to fill their tires, but from what I've found on it the results weren't that great either as the foams used tend to collapse over time. As for my plastic idea I'm not too confident on it either. If I was a more practical person I'd have long sense given up and just bought a pre made solid bicycle tire of the correct size. Even though I'm low on funds it's bound to be a lot cheaper, easier and more effective then what I can do DIY wise. At any rate perhaps out of stubbornness, or just to see if I can pull it of, I'm incline to preserve a little while longer.

At any rate here is a fun video of a Russian man filling his tire with concrete, and another where he replaces it with a log.

Spoiler

The results are less then ideal.

 

[Spinnor]

I spent 75 dollars for 3 Continetal 700x25mm 120psi tires. They are a good compomise of low weight and good wear characteristics. The low spinning weight helps improve my preformace. Quality tires reduce my risk of of injury.

 

[Spinnor]

I spent 75 dollars for 3 Continetal 700x25mm 120psi tires. They are a good compomise of low weight and good wear characteristics. The low spinning weight helps improve my preformace. Quality tires reduce my risk of of injury.

My memory is bad, checked the order, 3 tires were less then 50 bucks with free shipping.

 

[Evanish]

So here is an update. I decided to make mold the other tire like anorlunda suggested. I decided to make it out of masonry cement since I had some, and I thought would be sturdy enough. To start with I prepared some ground to work on. Here is a picture of the ground I leveled and the whole I made for the spokes.

Next I put down the cement (about 11 pounds dry), put the tire one it, stepped on the tire to make it sink in and then shaped the cement around the tire by hand. Here is a picture of the result.

The next day I made a mistake by trying to remove the tire too soon, and ended up breaking the mold before it hardened. After waiting for things to harden fulled I glued the mold back together with super glue, used some more cement to fill in the missing pieces and then enforced it with even more cement. At any rate, I'm waiting for things to harden now. I'll be back with more updates as things progress.

 

[jedishrfu]

I have to say you have the mind of a classic inventor. There’s a movie you should watch

The Worlds Fastest Indian

Its a story about an eccentric inventor living in Australia who keeps tinkering with his old Indian motorcycle with the hope of someday racing it at the Bonneville Salt Flats.

He had the mind of a classic inventor who attacked engineering problems in ways no engineer ever would. One example was how he made his high speed tires by using a paring knife to remove the tread.

Anthony Hopkins stars as the inventor.

 

[Mark44]

Its a story about an eccentric inventor living in Australia

Bert Munro was a Kiwi (New Zealander). I don't believe he ever lived in Australia. He changed his first name from Bert to Burt after it was mispelled in a motorcycle magazine.