Myth 7: Tubeless Tires Roll Faster

When tubeless tires first became popular on mountain bikes, it was their resistance to pinch flats (above) that made them popular. Off-road, there are few nails or broken bottles that can cause punctures (and even those usually will be pushed into the soft ground rather than puncture the tire), but rims can bottom out on sharp rocks and other obstacles. So much so, in fact, that top mountain bike racers used to race on tubular tires – because tubular rims make pinch flats less likely. Eliminating tubes did the same, and while you still could ‘burp’ the tire, in general, tubeless allowed running lower pressures with fewer problems.

Many also believed that tubeless tires were faster. It made sense: an inner tube, even a thin one, added a membrane that flexed and absorbed energy. A tire without a tube had to be faster, even if only by a small amount! One big manufacturer advertised their tubeless tires with the slogan “Nothing is always faster than something.”

This turned out to be another myth. Tubeless tires have real advantages, but speed isn’t one of them. To seal the tire, you have to add sealant. Pouring liquid into your tires inevitably slows them down. Old-timers tell stories of how they put water in the inner tubes of their friends’ bikes as a practical joke. The inertia of the water made the bikes impossibly hard to pedal.

The website Bicycle Rolling Resistance ( measured tires with and without sealant (above). Testing on a steel drum measures only the hysteretic losses, so ignore that the graph shows higher pressures having less resistance. (That isn’t true on real roads.) But for the effects of sealant inside the tires, it’s the hysteretic losses that are important, so the drum test works in this case.

What you can see is that once you add enough sealant (40 ml) to have actual liquid inside the tire (after the tire casing has become saturated), the energy required to turn the wheel increases significantly.

Our own testing confirms this. We tested the very same tires mounted tubeless with as little sealant as possible – a best-case scenario for tubeless. Then we removed the sealant and installed tubes. The tires rolled at almost the same speed. Even with almost no liquid sealant inside, the tubeless setup rolled only marginally faster.

Riding the tires with that little sealant is inviting trouble. I set up another wheelset the same way, and the tires worked themselves loose from the rim walls when the sealant dried up a week into the experiment. (Supple tires always move slightly on the rim, and sealant is necessary to keep tubeless tires sealed on the rims.) Once you add enough sealant for the tire to work reliably, it will be slower than it was with a lightweight inner tube.

How about making the tires themselves airtight? There are tubless tires that you can run without sealant, but to make these tires airtight, they need thick rubber coatings on their casings. And this makes them less supple, so they are in effect slower than a more supple tire with a lightweight inner tube – as shown by the steel drum test of a Schwalbe Tubeless vs. Standard tire (above, from

Most of these differences are small. A tire set up tubeless won’t be faster than a lightweight inner tube, but also not significantly slower. The simple fact is that a tube, especially a lightweight one, is extremely supple and adds very little resistance. The sealant required to run a supple tire tubeless will cancel out the gains from eliminating the tube.

What will be significantly slower on real roads (much more than the drum test above suggest) is an airtight ‘tubeless’ tire, since its stiffer sidewalls don’t absorb vibrations as well, which increases the suspension losses. Better to add a little sealant to a not airtight tire, if you want to run tubeless…

Tubeless tires have their place: They are great for preventing pinch flats, and most of Compass’ wider models, which are intended to be ridden off-pavement, are tubeless-compatible. And yet for most of us, pinch flats aren’t really an issue any longer, even on gravel roads, because we now run wide tires – mostly because they roll faster on rough surfaces, but also because they are less likely to bottom out and pinch-flat.

What about puncture resistance? The sealant inside the tires can seal small punctures. However, in my experience, the hassle of dealing with the setup and maintenance of tubeless tires outweighs the hassle of fixing the occasional flat tire. If you want the simplicity of tubes with the puncture resistance of sealant, simply pour some sealant into your inner tubes – many riders report that this self-seals punctures, too.

In the future, I will run my tires tubeless when I ride across really rough terrain – like our recent passhunting adventure in Japan (above) – but not for my normal riding on paved and gravel roads.

If you’ve been curious about running your tires tubeless, check out the illustrated how-to guide on setting up tires tubeless in the Spring 2018 Bicycle Quarterly. With the right technique, it’s possible to seat the tire even without an air compressor. This makes it easy to set up tubeless tires at home or even when traveling.

Further reading:

Photo credits: Ryan Hamilton (Photo 1), Westside Bicycle (Photo 2), Natsuko Hirose (Photos 6 and 7).

Posted in Testing and Tech, Tires | 63 Comments Reviews the Compass Barlow Pass

“A supremely grippy, comfortable, fast tubeless tyre with no downsides” is the verdict of the popular British web site Tester Mike Stead goes on to explain how he used the Barlow Pass tires: “After months of trying, I smashed a 1km Strava sprint segment, knocking five seconds off my previous best and setting a KOM benchmark that the previous holder is going to be hurting to regain.”

Of course, Compass tires aren’t just known for their speed, and Mike enthuses about the “supreme comfort” and “prodigious amounts of grip for cornering and braking.” Reading this, you might think that he’s a friend or relative, or that we paid him to review these tires. But no, all our British distributor Sven Cycles did was send a set of tires.

When Mike went “properly off-road into rooted and rocky singletrack,” he found that “the super-supple casing deformed around and gripped to trail irregularities with amazing ease.” When I read this, I really wanted to join Mike Steed on his rides. It sounds like he was having a lot of fun on his Compass tyres! But instead of telling you more about the review, why don’t you read it yourself?

Further reading:

Posted in Uncategorized | 5 Comments

Spring 2018 Bicycle Quarterly

The Spring 2018 Bicycle Quarterly celebrates how past, present and future have come together to enrich our cycling enjoyment. As we venture off the beaten path into amazing landscapes and toward memorable adventures, we take inspiration from the past, benefit from current technical developments, and shape the future of cycling.

Take the Torino-Nice Rally, which straddles the crest of the Alps all the way from Northern Italy to the Mediterranean Sea: Thomas Hassler describes the landscapes and emotions of this incredible ride. His stunning photos will make you dream of putting some wide tires on your bike, packing a lightweight bag or two, and heading into the mountains yourself!

It was for this terrain that Jo Routens designed his bikes. We bring you the full story of this inspirational randonneur and builder, whose skill with the torch was matched by his riding prowess. Studio photos of three wonderful classics complement evocative images from the Routens family archives.

With Lyli Herse we have lost one of the greats of French cycling. To celebrate her life, we take a very personal look at Lyli beyond her role as eight-time French champion and daughter of the ‘magician of Levallois.’ Discover the real Lyli through stories and anecdotes, many told in her own words.

Perhaps you’ve already seen the video of our passhunting adventure in the Japanese Alps. It was the perfect ride that played to the strengths of our test bike, a beautiful titanium Caletti Monstercross.

We didn’t just hunt passes in Japan, we also took the Caletti on some of our favorite rides in the Cascades, where we compared it to my Firefly allroad bike. Both bikes are equipped with titanium frames, wide tires and drop handlebars, and yet they couldn’t be more different. Where does the Caletti’s high-trail geometry shine, and where does the Firefly’s low-trail setup bring advantages? We took both bikes to the limit to find out. The result surprised us, and it adds to our growing understanding of bicycle geometry and handling.

It was on the roads and trails of the Cascades that the idea of the ‘allroad’ bike was first conceived more than a decade ago. When we realized that wide tires could roll as fast as narrow ones, our riding was liberated: No longer did we need to seek out smooth pavement to enjoy the sensation of effortless gliding. Looking back over 15 years of Bicycle Quarterly (and beyond), we chronicle the development of wide high-performance tires, including anecdotes like Peter Weigle (above) shaving the tread off prototype tires for our testing. This is the story behind the trend that is now sweeping the bike industry.

We take you inside Davidson & Kullaway, one of the oldest custom frame shops in the country, and just around the corner from us here in Seattle. Bill Davidson reminisces about the days when the shop made 750 frames a year, and when he traveled to Japan to have the very best lugs custom-made, which allowed Davidson to make bikes efficiently without cutting corners. He tells us why he prefers brass over silver brazing, and why it’s so hard to make the current generation of allroad bikes. Davidson’s partner Max Kullaway provides insights into the origins of titanium bikes and discusses the intricacies of welding frames.

Tubeless tires are useful to avoid pinch flats when riding in rough terrain. Our illustrated step-by-step guide shows you how to set up your tires tubeless with just a floor pump. A few tricks will go a long way toward making your first tubeless installation a success.

It’s exciting to see a BQ-inspired bike at an affordable price point. For $ 1420, the Masi Speciale Randonneur features wide tires, a low-trail geometry, and even metal fenders. How does it ride on the road? We tested it to find out.

Mountain bikes have dropped a bit out of the limelight lately, but they still have their place. Natsuko Hirose talks about her ride on a beautiful custom-made Steve Rex mountain bike, and how it feels different from riding the passhunter she uses to explore the Japanese Alps.

Subscribers will get the Spring 2018 Bicycle Quarterly within the next few weeks. Don’t miss it – subscribe today!

Posted in Bicycle Quarterly Back Issues | 2 Comments

How are Compass Tires Different from Panaracers?

From time to time, a customer will ask us: “How are Compass tires different from Panaracers?” It’s no secret that Panaracer makes our tires – we benefit from the research and technology of one of the best tire makers in the world. Panaracer’s engineers know more about casings and tread rubber than almost anybody, and they translate our ideas into tires that outperform all others in their intended environments.

That also means that it may not be immediately obvious how our tires are different from Panaracer’s own tires, like the Gravelking – or even Panaracer’s budget model, the Pasela. At first sight, with tan sidewalls and black tread rubber, they can look very similar. They are even made in the same factory!

Recently, we had the opportunity to spend some time with Mark Okada from Panaracer Japan (right) and Jeff Zell from Panaracer USA (left). When I mentioned the Pasela, Mark just laughed: “They are completely different tires that have almost nothing in common.” 

I guess it’s the same as asking whether a Bugatti Veyron supercar has the same engine as a base-model Volkswagen Golf, since both engines are made in the same German factory…

What about the Gravelkings, which are available with a tread pattern similar to that of Compass road tires – evidence that the technology transfer between Compass and Panaracer goes in both directions. Jeff said that Panaracer gets the same question, and this is their reply:

“The Gravelkings and the Compass tires are two different types of tires. The reason that Compass tires are so successful is that Jan and Compass have a clear vision for what they want in a tire, and Panaracer has the technology to deliver that. The materials and the construction of the Compass tires vary from the Panaracer line, because of the performance that Compass wants to deliver to the customer. The components that go into the Compass tires, and the processes to make them, cost more, hence the price difference. Both are high-quality tires, but the ride and performance are different. If you’re looking for the most supple tire that incorporates all cutting-edge tire technology, you’ll choose Compass. If you’re willing to sacrifice the ultimate ride quality Compass is known for, to get a little more puncture and sidewall protection, then Panaracer has you covered there.”

Which tire is best for you really depends on your riding style and terrain. Natsuko rides her 30 mm-wide Compass Elk Pass Extralights on really rough gravel with little trouble (above), but if you are somebody who tends to get a lot of flats or destroys tires with rock cuts, we’d recommend the Gravelkings. As the name implies, they are designed for riding on rough gravel, which also means that they can be a bit overbuilt for riding on the road.

The Compass tires (above) are designed for riding on the road, but they also work well – and offer superior performance – on gravel, provided the rider lets the bike move around and doesn’t force it into rocks that could cut the sidewalls. It helps if you ride wide tires. Not only are they faster on rough surfaces, but their lower pressures also make the sidewalls less susceptible to cuts: the tire just deforms when hitting a rock.

Around here, we ride Compass tires – even on our Urban Bikes – because they offer world-class performance while being strong and durable enough for everyday use.

Click here for more information about Compass tires.

Posted in Testing and Tech, Tires | 37 Comments

Preview of BQ 63: Passhunting in Japan

To put our Caletti Monstercross test bike through its paces, we took it passhunting in the middle of winter. Watch the video for a sneak preview, and enjoy the full adventure and bike test in the Spring 2018 Bicycle Quarterly. Make sure to view in ‘full-screen’ mode!

Subscribe today to get your copy of the Spring Bicycle Quarterly without delay!

Posted in Bicycle Quarterly Back Issues, Rides | 2 Comments

SKF Bottom Brackets Back in Stock

Bottom brackets are almost invisible, and you only notice them when something goes wrong. When the bottom bracket in my Firefly started to bind after just a few hundred miles, I put in an SKF, and that was the last I thought about it. When the bike was overhauled, the BB was spinning as smoothly as ever. That is how it should be!

How does the SKF last so much longer than other bottom brackets? SKF is a world leader in bearings, and they’ve applied all their technology to these bottom brackets. The two biggest advantages are larger bearings and better seals.

Let’s look at the bearing size first. SKF runs the bearings directly on the spindle and on the shell of the cartridge (above). That way, there is enough room for large ball bearings that can handle the high torque and low rpm of a rider’s pedaling, which is really tough on bearings. On the driveside (left side above), the SKF bottom bracket uses even stronger roller bearings to handle the extra force of the chain.

Most other bottom brackets use premade bearings (also called ‘cartridge bearings’ or ‘sealed bearings’), usually the 6903 size shown above. Using a premade bearing is much easier, as you don’t have to grind and polish the bearing seats. Instead, you simply press the bearing’s inner race onto the spindle and the outer race into the shell. The problem is that the extra bearing races waste space, and then you no longer have room for properly-sized ball bearings.

Bottom bracket shells were originally designed for cup-and-cone BBs that run the bearings straight on the spindle and the cups. They started with 1/4″ balls (6.35 mm) and sized everything up from there, without wasting a single millimeter. Most bottom bracket shells still are that size, even though cup-and-cone BBs now are rare.

When you use premade bearings, you lose about 1.5 mm on each side, plus a little bit more because the sleeve needs some room inside the BB shell. As a result, the largest balls you can fit are 2.8 mm in diameter, less than half the ‘normal’ size. These small balls have a much lower load rating, and they’ll also wear out faster.

The other big issue is that the premade bearings don’t have good seals. They are sometimes called ‘sealed bearings,’ but those black or red rubber seals are intended only as dust shields for indoor applications. They aren’t waterproof at all. You’ll never see a bearing like that exposed on a car, and yet even high-end bottom brackets put nothing but a rubber shield between your bearings and the gritty outside world.

The SKF bottom brackets have labyrinth seals that really do keep moisture out. Once, I cut open an SKF cartridge that I had used on my Urban Bike for a full year of rainy Seattle commutes, and the grease inside was fresh and clean. These seals are truly high tech, and SKF even patented them, because they were designed specifically for this application.

As a result of all this quality, we can offer these bottom brackets with a 10-year warranty that includes the bearings. (Actually, we limit the warranty to 10 years or 100,000 km, whichever comes first.) For most riders, one of these SKFs will be the last bottom bracket they install in their bike, and it’s certainly been that way for me.

SKF had stopped making these bottom brackets, and for a while they were unavailable. We are glad that we now can offer them again in all sizes, with British, Italian and even French threading, as well as in an ISIS version, as a world-wide exclusive from Compass Cycles. Click here for more information about SKF bottom brackets.

Posted in Bottom brackets | 49 Comments

Myth 6: Tread Patterns Don’t Matter on the Road

To celebrate 15 years of Bicycle Quarterly, we are examining 12 myths in cycling – things that we (and most others) used to believe, but which we have found to be not true. Today, let’s look at tire tread.

“Bicycles don’t hydroplane,” declared some experts many years ago. “Hence, tire tread patterns don’t matter on the road.” The first part is true – even wide bicycle tires are too narrow to lose traction due to hydroplaning – but the conclusion assumes that tread pattern only serves to evacuate water from the tire/road interface.

The reality is more complex. I once cycled on the polished stone that surrounded a college library, and I was surprised by the lack of grip: I crashed. Even though I was unhurt, I learned the hard way that the coefficient of friction between our tires and the rocks that make up the road surface isn’t very high.

If our grip came only from pure friction, the size of the contact patch wouldn’t matter. Physics tells us that if you double a tire’s width, it will be pushed into the road surface with half as much force – the two cancel each other. Yet race cars run ultra-wide tires because they provide more grip. What is going on?

Tires interlock with the road surface. Imagine each little surface irregularity like a spike that pushes into the tire. The wider the tire, the more surface irregularities it touches; hence it has more grip. A softer tire also has more grip because the road surfaces pushes deeper into the tire. That is why the tires of race cars use very soft rubber, and why wider bicycle tires at lower pressures offer more grip than narrow ‘racing’ rubber at higher pressures.

There is another way to increase the interlocking between tire and road: provide edges on the tire that ‘hook up’ with the road surface irregularities. Each edge provides a point where a road irregularity can hook up. The more edges you have, the better the tire hooks up.

This isn’t a new idea – back in the days when rubber compounds were less grippy, all racing tires used treads that were similar to the Compass tire above. I often wondered about these ubiquitous tread patterns, until I found the answer in Bike Tech, a long-defunct newsletter about bicycle technology. Under the headline “The Importance of Real-World Results,” a Michelin engineer described the interlocking mechanism, and explained that, especially in the wet, interlocking is what gives a tire much of its grip.(1) If the surface is ‘greasy’ when it first rains after a long period of  dry weather, friction is even less, and the interlocking is even more important.

That matches my experience. In theory, the friction between road and tire should be less than half when it’s lubricated with water, and yet we can corner at about 2/3 of the ‘dry’ speed in the wet – at least on good tires (and when the road is just wet, rather than greasy).

This doesn’t mean that the rubber compound of the tire tread doesn’t matter – it’s a crucial element in making the tire grip on dry and wet roads. At Compass, we are excited to have access to some of the grippiest, yet long-wearing, rubber in the tire business. That way, we can optimize the grip of our tires in every way.

The result speaks for itself: The photo shows me cornering hard on a streaming wet road, yet I wasn’t taking any risks during that descent. There aren’t many tires I’d lean over that far in those conditions!

Why don’t cars or motorcycles use ribs to interlock with the road? They have too much power. A drifting Moto GP rider (above) would just shred those ribs. Motorbikes and cars also are heavy enough to push their tires into the road surface, where bicycles tend to skitter across the surface.

On a bicycle tire, distinct parts of the tread serve different purposes.

The center tread doesn’t matter much – you are going straight when it touches the road. This is also the only part that wears significantly, so we put some fine ribs on our Compass tires that act as wear indicators: When they become completely smooth, then your tire is at about half of its life expectancy.

Furthermore, some tests have found evidence that a very fine tread pattern can make the tire faster, because it conforms more easily to micro-irregularities of the road surface and reduces the vibrations of the bike. So it makes sense to have a fine tread in the center.

The shoulders of the tires are important for cornering traction. This is where we put our ‘file’ or ‘chevron’ tread pattern for optimum grip. There is no magic to this, and these ribs aren’t directional – the point is just to have as many as possible to hook up with the road surface, but keep them large enough that they don’t just squirm out of the way.

Finally, you have the edges of the tire, which usually don’t touch the road – bicycles simply can’t lean over as far as a Moto GP racer. Here, the tread only serves to protect the tire’s casing from rocks and other obstacles. This tread can be smooth.

It’s all quite logical, and easy to experience on the road. Then why don’t all tires have a tread pattern that is optimized for grip? I suspect it’s hard to replicate the interlocking effect in the lab. But when you ride on real roads, you’ll notice the difference!

Further reading:

Notes: (1) Aaron, M., 1988: Importance of Real-World Results. Bike Tech, October 1988, p. 5.

Posted in Testing and Tech, Tires | 89 Comments