Hi All!
I have actually performed a homegrown tubeless tire conversion on a friend's bike that worked and continues to do so some 7 months later with air loss comparable to or less than that of a conventional tire and innertube setup. While it is not as slick as the commercial rigs, my pal is pleased and sees no need to "pay good money" to get similar results from commercial products.
A DIY effort at going tubeless can be done inexpensively and even successfully, but not without some trial and effort the first go-'round. It gets easier on a second and successive wheel/tire conversions, but is not the relative turnkey effort provided by combining purpose-made components.
Despite this "success", I have decided not to go the (DIY) tubeless route myself for several reasons:
1) By the time the rims were taped and the tires filled to the appropriate/recommended levels with anti-puncture goo (Stan's), there wasn't a lot of weight savings over a conventional innertube and lightweight rim strip, given I tend to prefer fairly light tubes.
2) No matter how little, I don't like the idea of free goo inside the tire cavity or getting on the rim when I demount the tire in the field to fit an emergency tube. I might feel differently if I used disc brakes as on my friend's bike instead of the v-brakes on my Nomad.
3) So far, when traveling in goathead thorn country (i.e. large patches of America's Great Basin desert regions), I've had good luck stopping mid-tour to fit some Mr Tuffy tire liners for the period when I'll be <ahem> amidst thorns instead of just riding one. This has worked well for me and in that relatively brief period of time, I did not suffer from any Mr Tuffy end-caused tube abrasion, though I have seen such punctures happen in long-term use on my late father's bike. When I leave goathead country I stop roadside or in camp, remove and roll up the liners, then remount my tires and go my merry way as before.
4) If the Tuffy liners did not work (so far, so good), I think I would prefer either thicker, "thorn-proof" tubes (which aren't "proof" but are more resistant to puncture), perhaps filled with sealant. However, I am still leery because of the horrible mess caused in the past when a tire sealant was used on my sister's bike. The task fell to me to try and disassemble the lot when a puncture too big to seal occurred. I swear, the tire casing was glued to the tube which was glued to the rim strip and rim and forever after, the spoke nipples were reluctant to turn. Some sealant remained on the rim sides as a stain forever. Thank goodness it was a coaster-brake bike. What a dreadful mess.
5) Based on the homegrown tubeless conversion I made, I think it was potentially more trouble than it was worth. If you reduce the air pressure too much, the results can be (were for me) unpredictable in terms of air loss.
For those interested in a DIY conversion, I'll include some links below, but here is the basic procedure I used:
1) Demount your tires and tubes and rim strips and clean the rims so the surface is smooth and clean of any debris or goo.
2) Using Gorilla Tape (a sort of duct tape with more tenacious adhesive), cut a *roll* to width. By "Cut to width" I mean a width that allows the tape to cover from crochet (rim bead hook base at the inner sidewall to rim bead hook base at the inner sidewall *including* the extra length needed to drop fully into the rim well. It is very easy to go wrong with the registration of the tape on the rim between the bead seats, and Gorilla Tape can be difficult to re-seat.
3) This taping is the most critical part, because it not only helps seat the tire to allow inflation without a compressor, it prevents leaks and aids tire retention. It can also make it *very* difficult to dis/mount a tire. The procedure here is to start the wrap and go all the way 'round, overlapping the ends and covering the valve hole. What is Unknown until you try it several times (because actual tires vary in bead-seat diameter as a result of production tolerances, age, and de/mounting/stretch) is how many wraps are needed. I ended up redoing the rear rim twice (so 3x total) and the front was good the first time.
I'll make the point again, because it may not be obvious to a first-timer: The layers of tape are intended to overlap the rim at the tire's bead-seating area, unlike many conventional rim tapes. This makes the rim effectively larger at the bead seat and a better seal against the tire bead. Get it right and you can (re)inflate the tire with a hand pump and it will retain air for a long time. Get it too small in diameter, and the tire will leak air and might not even seat well enough with a compressor to retain air. Get it too large and you can fold a tire lever trying to get the bead seated or removed from the rim. This is why the redos on the friend's rear rim -- the rim was either a wee bit small or the tire was a wee big big, or both. Once I got it right, it worked perfectly, but it took me trial and error to get there and I would expect to adjust the wraps of Gorilla Tape if the tire is replaced with another example.
This all works better if your tire has not been cast in a radial-sectional mold, which leaved little ribs across the bead that can cause small air leaks. With care, those bits of rubber flash can be trimmed using the scissors from a small (Classic) Victorinox Swiss Army Knife, but it is far better if circumferential molds have been used; they leave a smooth bead.
4) Cut a hole in the tape over the valve hole and install a proper, commercial valve intended for tubeless installations. Homemade versions will not work well here, and in any case you will need a two-piece valve that can be disassembled to pour in the sealant.
5) It takes some bouncing of the barely inflated tired to seat the beads and some roll-out to finish the job, then some fairly frantic pumping to finally seat the beads. I don't really know how better to describe the process, but assuming you've laid down the correct number of tape layers for your tire and rim combination, it goes pretty smoothly and would allow for field installation of an innertube in case of punctures too large or too numerous for the sealant to plug or if you want to get going quickly without applying a patch to the inner tire casing. All that said, I had some trouble with the first (rear) rim getting the tire bead to seat evenly, so that alone required several tries in addition to the re-wraps of (fresh) Gorilla Tape. The front rim again presented no trouble and all went fine in one go.
6) Assuming you got everything right, you now have a workable DIY tubeless tire setup.
I expect that with time and temperature, the Gorilla Tape will become very difficult to remove cleanly even with a heat gun and considerable effort with solvent. It makes it impossible to get to the spoke nipples, but with great care (and a good deal of frustration), a spoke can still be replaced while the tape is intact by reusing the original nipple, though getting it out far enough to catch threads can require considerable patience because the nipple top wants to stick to the sticky underside of the Gorilla Tape above it.
Further, I expect the tape's adhesive could become less effective with time and water entry through the spoke nipples onto the adhesive layer, causing air leaks and the need for a redo.
Now, the promised links:
A custom Google search for DIY tubeless, in case you wish to give it a try:
https://www.google.com/#q=make+your+own+tubeless+bike+tiresA guide that hews closely to what I did:
https://www.ridemorebikes.com/mtb-tubeless-conversion-guide/A video showing a Stan's No Tubes kit...other methods will show in the sidebar on the right side of your screen:
https://www.youtube.com/watch?v=mH1O2W7E_wQHope this helps. The DIY approach is inexpensive and can make for an interesting afternoon's project. Short-term results depend mostly on patience and devotion to task, while long-term results are unknown.
Best,
Dan.