I struggled trying to find a thorn proof or at least very very thorn resistant bicycle tire tube protector. I have unsuccessfully tried tire tube liners as they seemed to cause more rubbing flats then they fixed though I now realize a step in this instructable could help remedy that. I have also tried a thorn resistant tire but its biggest drawback is the protection area is too small.
I am in a desert like area that is sandy and has lots of prickly tumbleweeds and other thorny vegetation. After a windy day new thorns are strewn all over. I am also not near any stores and supplies are limited so I had to use what was available.
This instructable is pretty simple and it has worked effectively for a couple weeks now(I ride one hour each day) and I have had 2 flats in my rear thorn resistant tire that I purchased since then. I basically use a plastic tube and a old tube to protect the real air pressurized inner tube. The result is a much stiffer and heavier tire that is at least a very very thorn resistant. It seems kinda like what I would imagine one of those airless tires to be but without the hassles of trying to mount it on the rim. I only needed to put in enough air in the tube to make the tire bead stick on the rim which I found was about 10-15 lbs. I use this on the front wheel of a mountain bike with a front shock fork so I still have shock absorbancy because a lot is lost using this plastic tube in the front tire. I have not currently tried it on the back tire because I don't have any more plastic tube available. The plastic tube I did get was found out in the sun in the burn pit/junkyard. The area of protection coverage is much higher than either of the two commercially available solutions mentioned above with the extra weight and tire stiffness being the drawbacks. For me it was a choice of being able to ride or not.
Additional Materials Beyond Normal Bike Tire Setup:
* 1.25" diameter plastic tube; mine has a coil of imbedded stiffener in the plastic itself.
* Old tire inner tube
Step 1: Cut the plastic tube to the proper length. 3.14(pie) times the wheel diameter or just fold the plastic tube around the rim and cut where they meet. Then cut the entire plastic tube lengthwise so it can be split open.
Step 2: Prepare the old inner tube. Cut out the inner tube stem but not all the way through the inner tube. Then cut the entire inner tube lengthwise like the plastic tube was above. Put the old cut inner tube around the good inner tube.
Step 3: Insert the good inner tube with its old inner tube around it, inside of the plastic tube. I had to pre-spread apart my plastic inner tube due to the imbedded coil stiffener.
Step 4: Insert this tube assembly into your regular tire and rim and install as you normally would. It will take a bit more pushing and prodding to insert all of this than normal. You may even have to cut and adjust the length of the plastic tube. Inflate and install on the bicycle and you are done.