Avoid tubeless disasters

There is high demand among mountain bikers for tubeless tires on their bikes, and for good reason! Anyone who has ever ridden a bicycle has experienced a mid-ride flat tire. Since these are relatively rare on pavement with a good quality tire and proper installation, I will leave road tubeless alone for now. I want to focus today on tubeless tire for off-road applications where riders are concerned with thorns punctures and pinch flats.

The beauty of a tubeless system on a mountain bike is that the latex-based sealants available will seal up most punctures caused by the local vegetation, and eliminating the tube means there is no tube to pinch in a hard impact. This means riders can ride worry-free through over-grown trails and run much lower pressures to increase traction on the trail. Many who are used to pumping their tires to 35-40 psi to avoid pinch flats can enjoy a grippier, softer ride at pressures below 25. The feeling is liberating and many bike shop customers will ask their local shop if a) the new bike they are eyeing is "tubeless ready" or b) if the shop can convert their existing wheels and tires to tubeless.

As I have seen, many bicycle mechanics are all to eager to please and are willing to "convert" a rim and tire combination to a tubeless kludge. Consider the results of a badly done tubeless conversion: your customer happily starts riding after you return the freshly converted bike. He or she drops the tire pressure to 24 PSI and decides to test the system on the local trails. As the rider gains some confidence and rails a tight turn, the tire slips off the rim. If the rider (and the mechanic responsible) is lucky, the tire merely "burps" some air and the rider has to top off the pressure at the next stop. Otherwise, the rider could crash, causing bodily harm and damage to the bike. The shop that did the work could get negative reviews or face a lawsuit. This is a lose-lose for mechanics and customers.

The other reason to refuse to do questionable conversions is productivity. Anyone who as attempted more than a few conversions knows that some take longer than others. A conversion should take no longer than the time it takes to wrap the rim in tape, install a valve, mount a tire, squirt some sealant, and inflate the tire. You should not have to struggle to get a tire to inflate and seal. Inflating the tire should take no more than one minute- if it takes longer, the tire and rim combination is somehow sub-optimal and will likely not stay sealed and inflated.

Basically, inflating a tubeless tire needs to result in a tight fit on the "shelf" of the rim. If the rim is not designed to form a tight enough seal or the rim is fitted with a strip that sufficiently seals it, the movement that results tire failure what could be catastrophic. Stan's has an excellent article on the topic here.

To minimize the chances of a tire failure, let's first lay out what NOT to use in a tubeless conversion:

• "Cheap" tires- in a professional setting, I would not attempt a tubeless conversion on any tire that has a wire bead, or any tire that is not somehow identified by the manufacturer as "sealant compatible" or "tubeless ready," or at least otherwise known to be a good quality tire with strong casing. Some tires are known to break down chemically with some sealants, which is why Kenda identifies some of their tires at SCT.
• Rims that are not designated as "tubeless ready" by the manufacturer, unless used with an appropriately chosen and installed tubeless rims strip, such as Stan's strips.
• Tire/ rim combinations that are known to be problematic. You will need to do some research on this, but if the mounted tire is impossibly tight or incredibly loose, the end result will be bad.

Manufacturers have developed several options and "standards" for tubeless tires and rims, and not all of them are compatible with one another. I will not go into very disputed merits of each system, as I am primarily concerned with compatibility. The most common tubeless interfaces you will find are:

• UST- Universal System for Tubeless. This system requires rims and tire casing and bead to be manufactured with narrow specifications to be considered UST.
• BST is Stan's NoTubes design is intended to allow riders to use "regular" tires in a tubeless system. It is found on their ZTR rims, and on a few licensed products, notably Sun-Ringle (click "Features"). Stan's rim strips can also create a BST-type interface when done correctly.
• "Tubeless ready" is a bit murkier. Most "tubeless ready" tires have a bead similar to UST specifications but without the airtight casing and therefore require sealant to work. Wilderness Trail Bikes' TCS and Bontrager TLR designs might fit under this category.
• "Ghetto tubeless" is a DIY kludge involving the use of a split inner tube, various tapes, home-brewed latex sealant, and other methods. Some of these methods work wonderfully for riders, but should never be done in a bicycle shop.

The final but equally important issue to consider is how well any particular tubeless-specific tire will fit and seal on any particular tubeless-specific or converted rim. I have found that BST rims and Stan's rim strip conversions do not play well with UST, TCS, or several other "tubeless ready" bead tires. I witnessed the anguish of a friend trying to fit some WTB TCS tires on his Stan's rims recently, breaking several tire levers and very nearly breaking some fingers in the process. The bead on most rims with a bead based on the UST design is simply too tight to fit reasonably on BST rims (Stan's agrees with me here), so I don't recommend trying those.

If you are ever uncertain about what kind of materials are needed to successfully convert a rim to tubeless, ask the manufacturer directly. If it causes your customer to wait an extra day to get wheels back, it will be worth it to both parties to do it right rather tan compromising in the name of expediency. For example, I just noticed that Alex manufactures several rims (MD21, for example) with their Tubeless Ready System or TRS, which they describe as "Tubeless Ready System = Universal Valve + Rim Tape + Sealant," but they fail to specify what tape and valves are to be used. That kind of specificity may seem absurdly fastidious to some, but a good bicycle mechanic makes or breaks a career on that fastidiousness. [I will follow up with Alex on this topic.]

Whatever you do, make certain that you understand how tubeless systems work, what combinations and techniques work the best. Set standards for your shop so that everyone on staff is on-board with using the same techniques so there is continuity from the sales floor to the service writer to the mechanic and back to the customer. Your shop and your customers will be happy.

addendum 5 July, 2018: I recently had my Schwalbe mountain bike tires leaking a lot of air in spite of a proper tubeless rim, tape, valves, and sealant. I sprayed soapy water on the tire and rim to locate the leaks and noticed fine bubbles all around the sidewalls of the tires. I pulled the tires off the rim and discovered that the Truckerco sealant I have been using had not reached the inside of the tires' sidewall at all, but had concentrated on the middle of the tire tread.

Suffice it to say that the "tubeless dance" you're supposed to do it important! when installing new tires, turn the wheel sideways in your hand so the rim is parallel to the ground. Roll, swish, shake, dance a little gig to slosh the sealant all over the inside of the tire. Schwalbe sidewalls are notoriously thin, so really coating the inside of tires like this is especially important. I have not tried "painting" the inside of the tire with sealant, but I might try that with an actual paintbrush in the future.

The other bit of advice is to avoid tires with very thin sidewalls. As nice as lightweight tires feel, tires that hold air consistently are preferable.

cyclocross on singletrack

Much has been said lately of riding mountain bike trails on bikes designed with racing through muddy grass and hopping over barriers in mind, but not carving a ribbon of hard-packed dirt and rocky ledges. The allure of beating yourself up on such terrain caught my attention too, so I tried it a few months ago.

Unfortunately, my Salsa Vaya was fitted with 42mm knobby Continental Speed Ride tires at the time and it did not take long before the rocky crust of central Texas claimed one inner tube. By that, I mean I was on the trail for less than 15 minutes before a rock killed my tube. I patched it and kept riding, but the experience was somehow stilted from that point forward. I became paranoid that another misstep was going to bring my fun to a grinding halt. I put roadie tires back on that bike after that and kept it on the pavement, leaving my mountain bike for those off-road adventures.

Vaya- great stable bike for long rides on road and gravel

After some more months on that bike, I decided that the Vaya was probably a terrific touring bike, but I was not touring anywhere loaded with camping gear; just zipping around the city and riding as much dirt and gravel as I could find along the way. After a lot of over-analyzing with spreadsheets, in-depth interviews with fellow riders (forums, that is), and the discovery and subsequent obsession over bikegeo.net, I decided to get a Soma Double Cross Disc.

Double Cross Disc- a subtly but noticeably different bike!

This frame would easily accept all the part from my previous build with little drama and featured angles and features I thought would make it better suited for road and trail riding. It does all those things well and Soma makes a great product. For a long time, it served primarily as a commuter and road bike with skinny slick tires, fenders, and sometimes a rear rack. Something in me still wanted to beat myself up on singletrack with it though, but the thought of pinch-flatting myself out of the fun was holding me back.

The impetus for finding a tubeless solution came while riding my mountain bike. I lost all pressure in my air sprung fork and even blew the seal off the fork during a ride. I guess I should have paid closer attention to that service interval schedule.

oops

I did not want to take up precious riding time rebuilding a fork, so I got a hold of some WTB Cross Boss tires. I picked these after hearing a lot of reports of how incredibly tight-fitting the WTB TCS bead tires are on Stan's rim. One rider I know spent several hours and shattered a tire lever or two trying to fit some WTB tires on he Stan's rims, so I knew they would likely be a sufficiently tight fit on my non-tubeless rims (DT Swiss x430). Sure enough, a layer or two of 1" Gorilla Tape, some Velocity tubeless valves, and some home-made latex sealant got these to grab the rim and not let go.

patented skull valve cap

these fit surpisingly well on my rims

just enough tread for singletrack, smooth enough for pavement

On my first ride on these, I could not help myself. I rode about 40 miles of (mostly) singletrack on the local urban trail system, complete with rocks, ledges, and loose gravel. Riding a bike like this on rugged terrain is certainly different! It is not for people with bad backs and poor bike handling skills. You have to pick your lines carefully. A mishandled ledge can buck your off the bike pretty easily. The tires don't grab the dirt like you are used to. Bumps that come faster than you can soak them up with your arms and legs, usually the job of a suspension fork, build up and force you back on the brakes. If the gnar gets too gnarly, you have to get off and walk, which is part of the cyclocross experience.

On the other hand, you can go much, much faster flat sections and non-technical climbs. I went for a second ride with two friends who were on rigid mountain bikes and I smoked them up a non-technical hill, only to realize at the top of the hill that I never bothered to shift out of my big (48 tooth) chainring! If your trail system includes sections of pavement between trail systems, the "boring" slogs feel like less of a drag and more of a go-fast interlude.

Will the 'cross bike replace my mountain bike? certainly not! Certain trails and types of dirty terrain are lots of fun on a bike with drop bars and skinny tires, but you have to know it's limits. There are parts of the trails that I ride that I would never ride on this bike, and this is one of them:

I did that once trail and will probably not do it again for a while, until I get the urge to beat myself up again.

Results? Riding my mountain bike after this ordeal was a bit strange. The handlebar felt very high, the front steering a bit vague, even though it was just above the saddle height. I have since lowered my handlebar a bit and it feels a lot better- closer to the stability of the 'cross bike but with the advantage of fat rubber and a suspended fork.

Logs are there for a reason- trail leads to the left