There aren’t many things I hate about cycling, but topping up sealant when valve cores are sticky has to be up there. Now I hear what you’re saying–shouldn’t you be checking your sealant often enough that your valve cores don’t get sticky and tough to remove? Well, yes, but my laziness is not under scrutiny here; rather, we’re testing whether Muc-Off’s Big Bore Tubeless Valves live up to the hype. My laziness has, on the other hand, never failed to live up to the hype.
Moving on, Muc-Off’s Big Bore Tubeless Valves weren’t necessarily engineered to avoid sticky valve core disease, but instead to let you seat a tubeless tire without an air compressor or a booster pump. And, yes, they definitely deliver on that promise.
I’ve been using the 45mm Big Bore Lite in blue for the last several months on my gravel wheels, which were designed by Muc-Off for Presta valve rim and inflation compatibility. These feature a 3.3mm internal diameter valve head and offer up to 230% greater airflow than a standard Presta valve, according to Muc-Off’s marketing team. I don’t doubt their claims about airflow are true as you’ll see later on in my review. Further, according to Muc-Off, “The new valve’s straight through internal bore design means no more sealant clogging or removing valve cores during sealant filling, making tubeless repair and maintenance simpler and easier than ever before.”
These are made with 7075 aircraft grade, CNC-machined aluminum with a stainless steel coreless ball valve and integrated lever. You just open and close the valve as little or as much as you’d like for airflow control, as well as fine tuning tire pressures when the terrain calls for it.
In addition to the Big Bores, I’ve also tested the Hey Dipstick! sealant-level checker, an aluminum and stainless steel dipstick that promises to check your sealant levels and remove clogs at the same time. It’s a surprising piece of machinery, and it’s definitely more elegant than my usual method of flattening a bobby pin. But are these products worth their respective $50 and $15 price tags?
Big Bore Lite Tests
The Big Bore Lite is the Presta version of Muc-Off’s new range, and the key difference in the design is that instead of a valve core that you have to carefully unscrew to open or remove all together using a special tool, the Big Bore has no core at all. Instead, it uses a shut-off lever that you simply turn one way to open and back to close. Muc-Off includes a bespoke tool that is specially built to turn the handle, but I found that I didn’t need it at all to operate the valve. Since my other set of wheels has my favorite tubeless valve stems installed, the Lezyne TLR Valve Stems with a core removal tool built into the cap, I was happy to see that I didn’t really need to add anything else to my on-bike carry in order to properly use these new stems.
For those of us who don’t have a fancy air compressor at home that will inflate and properly seat tubeless tires, the Big Bore Lite remains fully open when you’re filling up your tires with air–meaning that you can get a good deal more airflow in without the valve core getting in the way. Generally, I use a booster pump to seat my tires (a pump with a tank that holds the air while you pump and allows you to release it all at once just by throwing a lever). And these Big Bore Lites seated the tires first shot with absolutely no problems. In order to fully test them, I also seated a tire without the help of the booster, and these made seating a tire with just a regular pump completely doable. Despite a little extra sweat equity, they worked perfectly well to fill and seat the tire–add to this the fact that I didn’t need to mess with pulling the valve core to add sealant, and I was pretty much a convert.
Install of the stems was pretty straightforward, and Muc-Off includes multiple gaskets that match the profile of your rim to ensure you get a good seal. But this is where you’ll want to ensure you get a long enough stem for the profile of your rims. These stems screw together at the base of the cut-off valve, so you’ll need to check with Muc-Off on the recommended length for a proper interface with your rim. Definitely do not go based on the measurement of your current stem length as these don’t follow the same install process or fitment at all.
Downsides
While these stems address a problem with seating tubeless tires, I did find some minor annoyances with them. If you’re not paying close enough attention, and you’re used to being able to just open your Presta valve and add air to your tire, you will learn the hard way that these will eject sealant everywhere! Make certain that before you open the valve, you’ve connected your pump or you have the wheel rotated until the stem is at the 12-o’clock position. If not, the blast of air that ensues will spray sealant all over your rims, clothes, walls, shoes, artwork, sofa, anything in its path. While this is definitely user error–force of habit for myself–it’s a mistake that teaches you exactly how patient of a person you really are. And when you finish cleaning up the mess from the first wheel only to proceed to do exactly the same thing with the second wheel, you’ll find out how patient your spouse is as well.
So if you’re looking to top off sealant, these Big Bore Lite’s are pretty fantastic and quick. But be careful to close the valve before you remove the pump, or you’ll repeat the same problem. In my use, I found that I could control the flow of air when deflating the tire to avoid the sealant fountain and before using the Dipstick to check my sealant levels. Just pay special attention to the orientation of the valve and the effects of gravity.
Hey Dipstick!
Which brings me to the other product here that I honestly did not think I’d be so jazzed about. But this little metal stick is kind of genius. Priced at $15, this makes a great gift for the cyclist in your life. It’s very high quality machining, and the ridges on the bottom of the stick give you a good idea of how much sealant you have left in the tire–or whether you have no sealant left in the tire. Where this tool really shines, though, is the ability to clear any clogs that keep you from properly inflating the tire or adding sealant. You don’t have to use it with Muc-Off stems, and it worked great with every brand stem I tried it on across all of my family’s bikes. I can’t say enough about this product–especially since I was so skeptical of it to begin with. This one will stay in my kit for a long, long time.
The Verdict
If you’ve been struggling with valve cores, and you’re looking for new tubeless valve stems, I do recommend the Big Bores. The color range is surprisingly cool, and I really liked the little bling of matching the anodized blue with my blue Supacaz bar tape. These valves make seating tubeless tires much easier if you don’t have an air compressor, and they are very well made. I had no trouble with install, leaking, or operation, and I feel like the leaps the industry is making these days towards better stem technology make for major sunny days ahead. At $50 for a pair, the cost is a little steep compared to simpler stems that do the job just fine, but, if you’re feeling like a splurge that is actually functional, these might be for you.
Get more info on Muc-Off’s Big Bore Lite at their official website.
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