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| The business end of a WTB Max-Flow tubeless valve stems. |
The suite of new WTB products I was sent to review, including the Max-Flow valve stems, were introduced HERE in case you missed that. This article will focus on the valve stems only.
Today's riders that use tubeless bicycle tires have different needs and expectations than they did ten years ago, or even five years ago. WTB has responded with a new tubeless valve design which addresses many of these new concerns. The Max-Flow Tubeless Valve Stem's name should give you one hint about this new design.
Things have changed with regard to tubeless tires for bicycles and now the expectation is becoming more and more that a rider should be able to inflate a tubeless tire on a tubeless rim with a floor pump alone. WTB's Max-Flow design has a claimed 84% more airflow than their previous valves. Now, I cannot verify that, but as we will learn here, the valves did work nicely for me.
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| The Max-Flow valve, valve cap with integrated core remover, and the valve nut. |
The Max-Flow also features a valve cap with an integrated core removal tool made in aluminum. This is great as a way to reduce weight and tools in your tool kit, if you aren't one to lose valve caps, that is!
Finally, the valve nut, (Presta valve nut), is designed in a squarish shape with a machined in grip texture which aids in not only tightening the nut against a rim, which also helps seal the rubber stopper of the stem on the inner rim, but also aids in the tooless removal of the stem in case of a catastrophic failure requiring a tube, tire boot, etc.
The length of the valve is a nice, but not overly long, 44mm. Enough to clear most average gravel rims. The core is removable, of course, and the Max-Flow design is also claimed to reduce clogging as well. The stopper is a sensible conical shape which should work in most tubeless rims.
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| I liked the valve nut. |
In Use: The WTB Max-Flow valve was used on my new front wheel for my new King Fabrications Honeman Flyer. The rim is a Velocity Blunt SS which has a 26.6 mm inner rim width.
The tire I was trying to use is a Teravail 42mm wide Rutland model which had already been mounted once and ridden several hundred miles.
The squarish valve nut really was nice for tightening the stem into the rim. I usually have to gently use a pliers to snug up valves good enough to prevent internal sealant seepage.
I was a bit concerned about the way the valve protruded into the inner rim well. The Max-Flow design is intended to work with those new-fangled rim inserts that are designed to help prevent tubeless tires from "burping" or pinch-flatting the tire against the rim when running lower air pressures. To enable the valve to clear these inserts, it sticks into the rim well area more. My thought is that without running an insert, you could hit something hard enough to contact the valve end and potentially break it off or damage it. Admittedly, the chances of it happening are slim, but....there is that chance.
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| While the Max-Flow valve end does flow more air, it does also stick out into the area of the inner tire more. |
When I mounted my used Teravail Rutland, I did so by keeping the Presta valve core in the valve. Obviously, this restricted air flow, so I wasn't enjoying "max" air flow, but regardless, the tire was inflated easily with my old Topeak Joe Blow floor pump. So, I cannot say that the Max-Flow valve did anything there for me, but maybe it did.
I can say that since I have had the valve in that air retention has been excellent and that I have seen no issues with the valve stem at all. My sealant (WTB's own sealant in this case) hasn't caused any clogging either. That said, I am careful to always air up tires with the valve stem at around the 8:00 - 9:00 o'clock position which seems to keep all my valve stems clear of clogging.
Conclusions: The Max-Flow Tubeless Valve Stems have a unique, high airflow design which may come in handy when setting up a tubeless tire or while dealing with a tubeless tire in the field. The valve cap with the core remover is nice, albeit not unique to WTB, and I really liked the square valve nut which has tons of grip and better leverage than a standard Presta valve nut does.
The aluminum construction is well anodized to prevent the valve from corrosion from ammonia which is a common ingredient in sealants. The 44mm length is very good, but if you are running some of the newer aero profile gravel rims you may need to look elsewhere for valve stems.
My concern is for the protruding valve head in the rim area. Yes, if you run a tire insert, this is a good thing, but what if that is not necessary? Hmm.... As I stated, while potential for hitting the stem inside the tire while riding is there, it probably is a low percentage failure mode. That said, that potential does not exist with some other high-flow design valve stems.
So, I like the Max-Flow valves and the idea of the design from an airflow standpoint is sound. I would be reticent to use these without a tire liner in a gravel sized wheel/tire combination. I think anything 29"er sized would be fine. Bikepacking set-ups, and the like, with their larger volume tires are not going to be an issue. However; I would like to see a "low-profile" Max-Flow design which would address my concerns when using tires in narrower widths than two inches wide.
1 comment:
Out of the loop a bit on this topic, but what is the expectation for getting a flat while tubeless, and using a tire liner? Liner goes in your pocket, insert a tube to get home? The liners don't look very compact, but I've never handled one. Thanks!
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