Well, I'm impressed (here we go again)
Ronnie said:
Recently on a night ride a girl that I sometimes ride with hit a rock she didn't see, causing her to crash, at quite a slow speed. In fact she was going too slow. A little more momentum and it probably wouldn't have thrown her of the bike. I was riding directly behind her. Anyway, she had pulled the front tire off the bead with the impact as her wheel twisted sidewards. She has non-tubeless wheels and rims treated with Stan's No-tubes kits. There were bits of grass caught between the rim and tire bead. The tire pumped up fine though. This is not the first time I have read/seen this type of thing happening. I think the sealent is fine for use with UST rims and tires to seal punctures but I think the whole No Tubes system is unsafe.
Ronnie.
Yes, there are conventional tires that are absolutely not good candidates for running Stan's tubeless system. Some of them are too small, or have too flimsy a sidewall, or don't have a sufficient bead for sealing to the rim no matter what one does. Stan does make some recommendations and warns against some tires, but I guess no one has actually tested every conventional tire and rim combo to qualify everything--an impossible feat anyway. I agree that Stan should warn a little more strongly about this factor. I think the bottom line is that there are many conventional tires under the 2.2--2.3 size range that should not be run in a tubeless manner. People not very, very familiar with their bikes or the Stan's tubeless system should probably not run conventional tires in this size range...period. With the wide range of affordable and quality UST tires available now, why should they--even the weight has come down. Riders running bigger conventional tires from 2.3 on up can usually do this without problems as long as they run the strip system. As indicated by some of these posts, it's most always the front tire that tries to burp or separate in an extreme situation. I run a strip in the front even with a 2.5 conventional tire on a UST rim. This setup has been totally bombproof. We've been using and experimenting with tubeless at our shop for nearly 3 years now--even from the days of the "roll-your-own" tape and mold builder systems. Todays system run within reasonable parameters is safe and reliable. One of the other caveats about this system is user error which is very hard to identify over the internet. We've had riders come back in the shop with a tubeless bead problem, and upon checking the air pressure on the other tubeless tire that was still on the bike, we found extremely low pressure--like maybe 20 psi. When asked when the last time they checked their air pressure...they would respond a week or two ago. Many riders try to treat their bikes like they do their cars. In other words, only when there's a problem. Now I'm not saying that everyone who has had a problem with their tubeless system is a mechanical idiot. Working at a shop, I can say there are many out there who have no business with any slightly more technical system or hardware on their bikes. They are clueless when it comes to working on or maintaining some of the aspects of their bikes. And heaven help them when they've tried to install something like a Stan's system.
For Stan's tubeless use, I'd recommend these guidelines for realiability and safety:
1. Unless you really know what you're doing and are willing to experiment, stay away from conventional tires smaller than 2.3--even if using UST rims.
2. Using 2.3 and bigger conventional tires will "usually" produce total reliability on either type of rim.
3. Using 2.1 and bigger UST tires on any rim will just about guarantee bombproof reliability.
4. Using 2.5 and bigger conventional tires on any rim will just about guarantee bombproof reliability.
5. Using UST tires on UST rims will be bombproof (if system installation and decent air pressure are correct).
6. There is more latitude from the above comments on the rear wheel vs. the front wheel. The front wheel is usually the most challenge tire/rim issue in extreme conditions.
7. Service the Stan's fluid occassionally--depending on temperature, at least every 2-3 months.
Tubeless setups properly executed are one of the best things that has happened to mountainbiking--better traction and just about flatproof. Tubed tires still work...so do hardtail bicycles. I want something better.
