Twenty Nine Inches first published this series concerning tubeless tires, sealants, rims, and what you need to know to get your mountain bike set up with tubeless tires. We'll discuss the "why" of tubeless mountain bike tires. We will also get into the different systems, sealants, and tires being used sucessfully- or not- out in the field.

Why Tubeless?

The tubeless tire discussion really can not begin until we cover the "why" of the tubeless tire choice for cycling. While it may seem obvious to some, this may enlighten a few first timers and there may be a few surprises along the way.

First of all, the cyclists worst enemy is a flat tire. Nothing ruins a rides flow like a flat tire. Tubeless tires can puncture, rip, and leak, of course- so does a tubeless tire help in regards to the flat tire problem? Is it worth setting up your tires tubeless for this reason?

The short answer? Yes! Tubeless tires, while vulnerable to flatting, are <em>far less likely to flat</em>, and if you use sealant in them, they are even less likely to lose all the air in your tires. Here is why: A tube in a conventional tire is not part of the tire casing, obviously. Because of this, the tire casing can pinch the tube between it and your rim edge, or "bead". This can happen when you strike an object hard enough that the force applied overcomes the pressure in the tube to withstand that force, allowing the tire carcass to pinch the tube against the rim. This is commonly referred to as a "snake bite" due to the usual pattern of two punctures on each rim bead directly across from each other which reminded someone of a snake's bite, thus the name.

Geax TNT Saguaros: Tubed or Tubeless!

A tubeless tire has no tube, so nothing to pinch against the rim means no pinch flats......usually! One still can pinch the sidewall against the rim beads, but this is very unusual.

But what about punctures? Well, this is where sealant comes in. Sealant- some substance that seals punctures and seals up non-UST tire carcasses so they can be air tight, is a product that comes in many forms. Usually some form of latex sealant is most popular, however glycol based sealants are also somewhat popular for cycling. At any rate, the sealant seals up punctures, small tears, and holes....sometimes...and allows you to finish out the ride.

So, sealant combined with a tubeless tire greatly reduces the chances for flat tires. This is perhaps the single most popular reason for average mountain bikers to run tubeless tires, but there are other benefits.

Tubeless tires, since they do not pinch flat very easily, can be run at slightly lower pressures, enhancing traction. Also, since there is no tube to cause rolling resistance, this makes lower pressures even more attractive. A tubeless tire run at a slightly lower pressure than a tubed tire can get better grip, ride smoother, and have similar or less rolling resistance than the tubed tire. Reduce the pressure on the tubed tire to match and generally you will increase the likely hood of a pinch flat and greatly increase the rolling resistance.

Weight was an early reasoning for going tubeless, but this is not necessarily the number one priority of off road cyclists. Tubed tires, if the tire is a very lightweight folding type, can weigh less by far than a similar model that is tubeless. The extra butyl rubber necessary to make the casing air tight is the culprit. Now days though, there are a vast number of cyclists who convert standard tires to tubeless use by way of sealant. This has met with varying degrees of success and should be approached with caution. We'll cover a few of the techniques used to do this in a later post. At any rate, tubed tire to tubeless tire weights are very similar these days, especially with conversions to tubeless type set ups.

To recap- Tubeless tires are a great way to avoid flat tires, get better performance characteristics, and may save some weight over a standard tube and tire set up. Now that you know why, we'll delve in to the "how" of tubeless tires next time. Stay tuned!

“How To”

After getting to know why you would want to go tubeless, we now will delve into the "how" of going tubeless with your "wagon wheels". There are a couple of standardized systems out which I will cover first. Then I will touch briefly on the typical ways folks are turning components meant to be used with tubes into their own tubeless systems.

But before that, we need to understand a couple of key things that must be done by any company or individual that attempts to attain a state of perfect "tubelessness". Without making sure these things are secured, disaster, possible injury, and even death may result. Really!

First, a way to seal the rim well must be found, and usually this means sealing off a bunch of spoke holes drilled into the rim. Of course, if you can find a way around drilling all those holes, it makes this job a lot easier, and in fact, that is why a UST standard rim is so appealing. Unfortunately, only pre-built wheel sets are available with this sort of rim, so unless you buy into a complete system, the UST rim isn't an option. Other ways to seal a traditionally drilled rim have been done, and usually in conjunction with a specific rim extrusion.

Bontrager TLR rim strip, tubeless valve stems, and bonus skewer image!

Stan's NoTube system consists of a specially extruded rim that features a "bead socket" for the tire and a rim well designed to assist in making a tubeless tire air up without much effort. The spoke holes are covered with a specially developed rim tape, thus sealing off the holes in an effective manner. Bontrager does something similar with its Tubeless Ready System, but instead of a tape, they developed a rim well and plastic strip that mate together. The rim can be built on any hub, then the plastic rim strip is snapped into place, sealing off the spoke drilling. In fact, a tubeless tire set up on this system actually seals against the strip, and not the rim.

Now you're almost there. You will need a special tubeless valve stem to finish off the job. Bontrager, Stan's, Mavic, and others make these, and home made ones will also work. The valve- usually a Presta, but not always- is made to have an inner seal of some sort. Either an "o" ring seal or a rubber type collar around the valve on the inside is employed with a nut that threads on to the outside which pulls the inner seal against the rim strip, sealing off the valve hole in the rim.

Mavic's Cr29ssmaxx were the first UST rims available for 29"ers.

Okay, now the final piece of the puzzle is the tire. A typical folding bead tire isn't made to keep air inside its carcass- that is the job of the inner tube. So tire manufacturers either do one of two things- they make a true, air tight casing and bead, or they make an airtight bead with a casing that requires sealant to become air tight. A standard developed by Mavic and other tire manufacturers called "UST" is one way this can be done, but most manufacturers have eschewed this avenue for their own systems which all are of the "tubeless ready" type requiring sealant to become air tight. The common denominator of all of these though is a tighter rim bead diameter standard and special bead construction. Without holding the rim bead dimensions to tight tolerances and reinforcing this critical area of the tire, blow offs and other failures would result and cause possibly catastrophic results for riders.

Special beads are part of a tubeless ready tire and make them safe to use tubeless.

Sealant is the last bit needed before most systems will operate safely and effectively. Usually some sort of latex based sealant is introduced into the tire carcass which seals off the carcasses porous inner walls making it air tight without using an extra layer of rubber as UST tires do. This results in a lighter, more supple casing, and a heightened level of performance in most cases. Sealants come in many forms, some being glycol based, and even home brews are popular with many riders.

Most sealants are latex based such as this Geax product.

DIY Tubeless Set Ups: Note: Twenty Nine Inches does not endorse any of the following. It may be dangerous and cause a crash leading to personal injury and even death. Taking any of these measures to set your bike tires and wheels up tubeless is done at your own risk</em>:

Many riders have been doing their own conversions of standard tubed wheels and tires using home made sealants and rim strips for years. Most of these systems use some sort of combination of reinforced packing tape, a foam backed tape of some sort to fill in deeper rim wells, and home made valve stems. Some folks use split open tubes as rim strips as well. Sealants based on mixtures of commercially available sealants, or mold building latex mixed with an ammonia based substance like windshield washer solvents are common. The tires used are typical tubed tires resulting in various levels of success ranging from bulletproof reliability to hit and miss successes resulting in occasional failures, crashes, and injuries.

Mixed Systems:Some riders will try "mixing and matching" systems or components with each other, and may even do this while introducing their own "home brew" solutions as sealants. Generally I have found that some things work, and some things don't. Here is a short list of my personal findings in messing around with tubeless systems. Your results may vary.

-Bontrager TLR tires: Works with decent reliability on Stan's rims and I have heard enough about failures with Mavic/UST rims that I will not use TLR tires on those types of rims.

-Bontrager TLR Rim Strips/Wheels: Works really well with Specialized's "2Blis" tires. Geax tires are waaay too tight and will not work at all with the plastic strip installed. A Stan's strip in a TLR rim will work with a Geax tire, however. Continental tires work well on TLR rim strips. TLR rim strips have also been used by myself in Velocity Blunt rims with Rampage tires with good results.

-Stans ZTR Rims and Strips: Works great with Specialized, Bontrager, Continental, and some non-tubeless tires. GEAX tires are just too tight to be field serviceable. I won't use a Geax tire on a Stan's rim for that reason. Stan's strips: I have used these only on ZTR rims with the exception of some DT Swiss TK 7.1 disc rims and that works flawlessly.

CaffeLatex valve stems for tubeless tires and the injector for their sealant. This is the best sealant and system available on the market.

Sealants: I have used Bontrager's Super Juice which seals a tire casing really well but is very poor at sealing punctures. Slime Tubeless Sealant works very well, staying wet for well beyond six months. Stan's sealant works well initially, but dries out in a span of three to four months, still keeping the carcass air tight, but the puncture protection falls off dramatically, as you can imagine. Hutchinson Fast Air- Seals up casings really well, but does not stay liquid very long at all and does not provide very good long term puncture protection. Geax Pit Stop works almost exactly as the Hutchinson product. (Note: To be fair, the Hutchinson and Geax products are for inflation/quick repairs. Both companies have a product that claims long term puncture protection.) CaffeLatex: This has been the best available solution I have used so far. It is easily introduced through valve stems and seals punctures very well. It claims the sealant foams up while riding to provide better sidewall protection. While I can not vouch for that yet, it does foam out of my valve stem when I open it. In my still ongoing tests, the CaffeLatex product remains wet going on month five now. Homebrew- I have a home brew that I will not divulge here, but has outperformed everything else on the market I have tried so far with the possible exception of this new CaffeLatex solution.

Next time I will get into the day to day care and feeding of your tubeless tire set ups. Stay tuned!

“Day To Day”

Now following up on the last post onGoing Tubeless, here is a post dealing with your day to day living with a tubeless tire set up. This assumes you have a set up that is successfully sealed and ready to roll.

The difference between using a dedicated system and a mixed and matched set up is huge in the world of tubeless tires.

Using A System Or A Mixed "Rider's Choice" Set Up The way your tubeless tire set up will work depends upon what components you have chosen to work with to a large degree. A "system", such as Bontrager's, Stan's, or a system using UST type components, will typically be much more successful and safe than a tubeless tire set up that draws from different systems or uses non-tubeless parts. Differences may include the ability to stay sealed, tire bead/rim interface issues, or even poorer tire performance.

Tubeless systems from Bontrager, Stan's, or the UST developed rims and tires are not infallible systems, but they do require less fussing around with. Set ups using parts of other systems, or non-tubeless tires and home made sealing systems have success rates that vary about as much as the different combinations. It seems that a lot of folks have their particular favorites or have learned through trial and error to tweak out the bad and keep the good. However; one must discern whether they are willing to take the risk of possible failure and have the ability to take responsibility for their experimentation. For those who are not willing to take that gamble, then the systems that are offered now are your best bet. The good news is that several wheel manufacturers are working on tubeless rims/rim strips for their 2010 lines, so the list of choices will blossom soon.

Systems such as Bontrager's Tubeless Ready System are very reliable typically.

Tires and Sealants: Tires and sealants are also part of the picture here and once again, we see tubeless ready tires, UST tires, and several sealants available or being concocted for use. Not everything out there is workable in a tubeless situation. Getting non-tubeless tires to seat, seal up, and stay on are probably the number one problems here. It can even run counter to what benefits tubeless tires are supposed to offer in terms of pressure. Non-tubeless ready casings often do not have the support to carry a load without the tube inside resulting in the rider needing to use <em>higher pressures</em> rather than the lower pressures one is supposed to be able to use when going tubeless.

Care And Maintenance:Tubeless tire set ups will require similar maintenance to tubed tire set ups. Pressures will have to be checked, inspection of the tires should be done on a regular basis. The only real difference here is maintaining your sealant. Some sealants will outlast others, but predicting what you will experience is difficult. The climate, the conditions your wheels are stored in, and whether or not you regularly get punctures will all affect how often you will need to replenish your sealant. A good rule of thumb is to check your tires every three months or less. You can shake the wheel, and perhaps hear the sealant sloshing inside. Otherwise a visual inspection will be necessary which will include letting the air out, breaking the bead, and looking inside.

A note on mixing sealants-While I have not dabbled in the mixing of sealants, some readers have asked me to comment on this. It is my opinion that latex type sealant and glycol based sealants should not be mixed together. I do not see any benefit in doing so. Some folks do add glitter, or some other small particles to aid in sealing punctures. There may be some positive benefit to this. (Actually, Slime Tubeless product actually has small bits of rubber in it to do exactly this.) My experience bears out that there isn't anything wrong with using sealants as recommended. Slime, Stan's, CaffeLatex, and others all do what they claim without assistance. Adding anything beyond some glitter to aid in sealing seems to my mind to be a gamble at best.

Next time: I'll wrap up the series with an overview of where tubeless tire technology is now and where it should be headed.

Questions And Answers

One of the readers of Twenty Nine Inches- "Mickey", had some great questions that were posted in the comment section ofthe last article. I thought I would break them out into their own post and share the answers with all of you readers. Here are some day to day issues one might face going tubeless.

What (do) you do with (old) sealant then, throw it away? Probably yes, but how?: This question can be answered in a few ways depending upon which sealant you are using. If you are using a latex based sealant and it dries up, there really isn't any clean up necessary. Usually the sealant dries into "interesting formations" which Stan's users have a rather uncouth name for. (!!) These can simply be discarded. If the sealant isn't dried out though, it can be re-used. Recovery of old sealant from a tire usually is easiest when using a "syringe" type instrument such as the unit available from Stan's or a similar product from CaffeLatex. Draw out the old sealant and mix it in with new sealant, then add it back into a new tire.

An injector/syringe tool aids in sealant recovery as well as injecting sealant into tubeless tires.

Glycol based sealants are usually still wet after several months, but may be dried up to a thicker, gooey consistency. If you are switching out tires, it generally will be easier to wipe up the old sealant with an old rag or sponge. After getting the majority of the sealant out, you can wash with a soapy water solution and rinse with water to get any left over residue out. Your rag or sponge could be washed, or discarded with other hazardous waste.

How do you clean tires inside when changing to another (pair)?: Again, in a similar way to what I describe above. Just remember to discard the old rags or sponge with your other hazardous waste.

How do you put the tube (in) when the puncture is too big and you are on the (trail) ? Once you have determined the sealant isn't going to seal the puncture, you should release all the air in the tire, break down the beads from the rim, and remove the tubeless valve stem. All rather simple things to do, but the whole process is complicated by the mess of sealant you will encounter within your tubeless tire. I have experienced this a couple of times. My advice is to carefully install a slightly inflated tube and push the bead of the tire over the rim without removing the sealant out on the trail. (Of course, making sure you do not have a foreign object in the tire yet, or a tear that requires a tire boot.) Keeping sealant off the trail and off you is the best way, if at all possible.

In the case of Bontrager's TLR rim strip, you will also want to make sure you have a long stemmed presta valve to allow good purchase with your pump or CO2 unit after installing the tube. I have also found that carrying a multi-tool with a pliers type tool helps in loosening the tubeless valve stem nut, which is generally too tight to remove by hand. (Make sure you pick up your valve stem and stow it before you ride away!)

<strong>How (do) all those sealants work during a winter time?</strong> Sealants that are water/latex solutions will freeze up. Sealants that are glycol based are much less likely to freeze up, but may become too thick to really seal any punctures depending upon how cold it is out and the particular sealant in question. Some home brew sealants use windshield washer solvent, which aids in keeping the solution from freezing. In my experience, tubeless tires will still work in winter, but you may not see the puncture protection benefits that you do in summer, or during warmer weather.

Okay, that's a wrap on Mickey's questions. Thanks Mickey for writing those in the comments section. Remember, if you have any questions, just put them in the comments. I try to answer all of them and I may use one of yours in a future post.

“The Future”

Here in my final installment on tubeless mountain bike technology and specifically tubeless tire technology for 29 inch wheels, I want to address some areas of concern and where I think the tubeless tire and wheel products of the future can help to make big wheel mountain biking even better.

Why Not Go Tubeless From The Start?The modern mountain bike rider is pretty information savvy. Tubeless benefits and performance are pretty well known and accepted by more and more mountain bikers everyday. To my mind it makes absolutely no sense to not have your product be ready to go tubeless out of the gate these days. Why not enhance the value and appeal of your wheels and tires by offering this as an option? Yes, tubes should be supported, and I still use tubes in many applications today, but if you are a serious mountain biker, you probably will be more tempted to buy a product that supports tubeless use than one that doesn't.

I certainly can also see why manufacturers won't be too thrilled with doing this. The technology to develop your own system, or get UST certification is expensive and time consuming. That said, a non-tubeless rim or tire is quickly being viewed as being "off the back" by mountain bikers. I agree that tubeless tires and rims that are reliable, easy to use and live with, and reasonably priced are the future of 29"er tires and rims.

Information Please: While this series of articles is hopefully shining a little light on this subject, it is by no means an exhaustive study of all products on the market and which are compatible with each other. Getting everybody on the same page might be asking too much, but would it be unthinkable for a rim manufacturer, lets say, to recommend tires for use as tubeless on their product? (Stan's does this already). Or how about a tire manufacturer giving us some idea of how their product works tubeless on other tubeless designed rims? The conversation is pretty one sided on this score and the user group is the only one making any real noise here. I think that is a shame. The UST standard should be either opened to all manufacturers, or another system equivalent to it, so as it is with BB30 bottom brackets, users can all be assured that "this" tire can go on "that" rim without being a living, riding guinea pig. Oh yeah, and let's not forget about sealants in this conversation either.

More Choices : With an "open standard" we could all expect more choices. That would be a good thing, since the way things are now, a tire manufacturer, let's say, doesn't have a clue what tubeless system the end user will try to match their product up with. Yes, as I suggested, they could test on all available systems, but as we march forward, and more rim manufacturers start offering tubeless compatible rims, this situation will need to be settled. With everyone on the same page as far as a standard, the tire and rim manufacturers would be encouraged to make product that supported tubeless use. The way things are currently, the manufacturers are not going to know which way to go in this regard, unless a UST standard becomes the accepted way to do things. (As it is for the most part with 26 inch wheels and tires)

The Bottom Line In the end, how ever things shake out, we as mountain bikers ask only a few things: That the tires be reliable, the rim/tire interface be safe, and that the tires, sealants, and rims be compatible with each other and easy to use. If this starts to become a reality, the days of tubeless tires and rims for 29"ers will finally become like that of the 26 inch world.