Remembering Lyli Herse’s Birthday

Today would have been Lyli Herse’s 91st birthday. And last Friday has been a year from her passing…

… and the 111th birthday of her father, René Herse. They continue to inspire us in so many ways. Today, we just want to remember their smiles and their passion for cycling in all its forms.

Lyli was a friend for so long that it’s hard to believe she’s gone. Until the very end, she rode her home trainer, but she told us that she dreamt of cycling in the mountains.

We miss her! She passed on her family’s legacy to us, and she told us that her father would have been happy to see so many people passionate about rides and adventures again. Together, let’s keep their spirit alive!

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Myth 16: Higher Tire Pressure is Faster

This used to be one of the first things you learned as a cyclist: If you want to go fast, make sure your tires are pumped up to the maximum pressure. The harder your tires are inflated, the faster they roll.

We now know that this isn’t true. The realization that tire pressure does not affect performance is the key to the revolution that has swept through the cycling world in recent years. Without this new-found knowledge, all-road bikes and their supple, wide tires would make no sense at all. Here is how it works.

Tire resistance is determined by two factors:

Hysteretic Losses: With each turn of the wheels, the tires flex. You can see that in the photo above: Both tires flatten where they touch the road. Flexing the tires takes energy – imagine squeezing a tennis ball. Energy on a bike can only come from one source: the rider’s power output. Reduce the energy lost to flex, and you’ll go faster.

The easiest way to reduce this energy loss: Inflate the tires more, and they’ll flex less. Less flex means less energy is converted to heat as the tire casing deforms under the weight of bike and rider.

You can also reduce the losses by making the tire casing easier to flex. A supple casing is easier to flex than a stiff one, so it absorbs less energy for the same amount of flex. Imagine squeezing a marshmallow instead of a tennis ball.

So we want a tire that is supple and runs high pressures. That means we have to make it narrow. Why can’t a wide tire be supple and run at high pressures?

Pressure is force per surface area. For example, PSI stands for Pounds per Square Inch. The larger the tire’s circumference (more inches), the more force will act on it (more pounds). Imagine the casing as a chain, with the pressure as an elephant standing on each link. If the chain is ten links long, it has to support the weight of ten elephants. Make the chain twice as long, and you’ll have twenty elephants standing on it. The chain has to be twice as strong. Or you have to reduce the weight of each elephant. Back to tires, this means that a wider tire either needs a stronger (read: stiffer) casing, or you need to reduce the pressure.

Summary: The best way to reduce hysteretic losses is to use supple tires, make them narrow, and inflate them hard. With wider tires, you either can have a supple casing or high pressure, but not both. Either way, wider tires will have more hysteretic losses. If you only look at hysteretic losses, ‘wide high-performance tires’ seems like an oxymoron.

That was the accepted wisdom when we started looking at tire performance way back in 2007. It’s not incorrect, but it overlooks a second factor that also affects how fast a bicycle rolls – and tire pressure works the opposite way there.

Suspension Losses: As the bike vibrates, energy is lost. Most of that energy is absorbed in the rider’s body, as soft tissues rub against each other. Decades ago, the U.S. Army studied tank seats and found that the discomfort we feel from vibrations is caused by friction between our body’s soft tissues. This friction consumes energy that is turned into heat. (Rub your hands against each other to see how friction creates heat.) The more uncomfortable the vibrations, the more energy is lost.

Mountain bikers have known for a long time that bouncing makes your bike slower. The fastest mtb is the one that absorbs shocks best. Road cyclists used to think that we had to ‘tough it out’ to go fast. We endured the discomfort of narrow high-pressure tires because we thought that they rolled faster. We thought that pavement was too smooth for suspension losses to matter.

At Bicycle Quarterly, we started to test the performance of tires on real roads in 2007. At first, we also assumed that higher pressures rolled faster. However, as long-distance cyclists, we suspected that there was a point of diminishing returns. Our thinking was this: In a short race, we may endure all kinds of discomfort if it makes us faster. But we can endure discomfort only for so long before it affects our power output. In a ride as long as the 1200 km (750 miles) of Paris-Brest-Paris, we might give up 5% in rolling resistance if we gain 20% in comfort. What we wanted to know: Where is this point of diminishing returns?

Back then, tire resistance was tested on steel drums that measure only the hysteretic losses. On steel drums, there is no doubt that higher pressures produce better results – as shown by all tires in the table above. Take the Vittoria Rubino Pro (second from bottom): At 60 psi, it requires 40% more energy than at 120 psi. I mention this tire, because later on, you’ll see how it performs under real-world conditions.

Drum tests also suggest that high pressure is more important than a supple casing: In the table above, the slowest tire at 120 psi has less resistance (13.4 W) than the second-fastest tire at 60 psi (13.9 W). That is why tire makers used to make their wide tires with stiff casings, so they could withstand high pressures. A wide, supple tire – limited to a low pressure rating of, say, 60 psi – would perform poorly on the steel drum. That is why they didn’t exist – who would want to make a slow ‘high-performance’ tire? It all made sense – if you test tires on steel drums.

Imagine our surprise when we found that in the real world – on real roads – tires perform very differently. We tested numerous tires, with two different methods (roll-down and power-meter), and always found the same: Higher pressures don’t make tires faster. And the advantages of supple casings are much larger than the steel drum tests suggest.

Why? Because the suspension losses are significant even on very smooth roads. And both lower pressures and supple casings reduce the vibrations of the bike and thus the suspension losses. But you cannot measure suspension losses unless you have a rider on the bike. That is why earlier studies (and many since) failed to give meaningful results…

Above are the real-road results for three Vittoria 700C x 25 mm tires, including the Rubino Pro. We tested on brand-new, ultra-smooth asphalt. For the Rubino, there is no difference in speed between 80 and 11o psi. It’s clear for all tires: Higher pressures don’t make them faster.

(Note that the Watts are for the entire bike and rider, not just for one tire. That is why the power measurements is so much higher than in the drum tests.)

What happens is this: As tire pressure increases, the tire flexes less, and the hysteretic losses go down. However, the tire also vibrates more, and the suspension losses increase. The two roughly cancel each other, and that is why there is no clear trend in the table above.

Before we continue, it’s important to mention that we made sure these results are statistically significant. This means that we are seeing real differences in performance, not just ‘noise’ in the data.

The graph shows a few more things:

  • Really low pressures make a tire slow, because it flexes way too much: the hysteretic losses are huge. The extreme is a totally flat tire – very slow. At some point, the tire has enough air to avoid excessive flex. Above this ‘break point,’ hysteretic and suspension losses start to balance each other.
  • Hysteretic and suspension losses are non-linear, so they balance differently for different tires and different pressures.
  • CX Tubular: A tubular tire sits on top of the rim, so it can flex around its entire circumference. It can run at very low pressures without excessive flex. The break point is low (80 psi).
  • CX Clincher: A clincher rim constrains the tire around about 1/3 of its circumference, so higher pressure is needed to avoid excessive flex. The break point is a bit higher (87 psi).
  • Rubino Clincher: The Rubino’s stiffer casing is harder to flex: The hysteretic losses for the same amount of flex are higher. The stiffer casing also transmits more vibrations, so low pressure doesn’t reduce the suspension losses to the same amount. This means that the break point is higher than for the more supple CX (95 psi).
  • All three tires roll slowest at moderately high pressure: The tire is already too hard to absorb vibrations, so suspension losses are high. However, the casing still flexes, so hysteretic losses are also high. It’s better to run low or very high pressures, at least on the very smooth asphalt of our test track.

Summary: On real roads, even smooth ones, higher pressures don’t roll faster.

We tested many tires – above from our first tests in 2007 that measured the time for a roll-down on a carefully chosen test hill – and we always found the same: Above the break point, increasing the tire pressure doesn’t make you faster. The break point is higher for stiffer tires. For the tubulars, the break point is lower than the pressures we tested.

I wish we had done this testing when I was still racing. Back then, I ran 21.5 mm Clement Criteriums at a bone-rattling 130 psi. I would have been faster – much faster – on 28 mm Campione Del Mondos at much lower pressures.

The above results were on ultra-smooth pavement (Vittoria) and relatively rough, but not bumpy, pavement (others). Does the road surface affect a tire’s break point?

To test the extreme, we ran various tires on rumble strips, which are a good stand-in for cobblestones. (Unlike real cobblestones, rumble strips are very regular, so we could obtain repeatable results.) We also tested each tire on the smooth pavement right next to the rumble strips.

On the smooth pavement (left), the Compass 26 mm tires roll as fast at 75 psi as they do at 95 psi. This confirms what we’d found before: Even on smooth roads, tire pressure makes no difference.

On the rumble strips (right), higher pressure was slower: The 26 mm Compass tires used 20% more energy at 95 psi than they did at 75 psi.

Summary: On really rough surfaces, higher pressures roll slower. Wider tires roll faster on rough surfaces because they can handle lower pressures.

So now we know that higher pressures don’t make your bike faster – whether on ultra-smooth asphalt, on rough surfaces like cobblestones, or anywhere in between. For supple tires, the break point – even on smooth surfaces – is close to the point where the tire becomes unrideable, because the sidewalls collapse under hard cornering. On rough surfaces, it’s hard to reach the break point – the tire pinch-flats before its performance deteriorates.

Conclusion: If you want to go fast, you need supple tires. That is all. Pumping them up harder won’t make you faster. On rough surfaces, it actually makes you slower.

When we saw these results, we realized that this could revolutionize bicycles: If we didn’t need to high pressure to go fast, we could make wide tires with supple casings, run them at low pressure, and still roll as fast as we did on narrow ‘racing’ tires. With these wide, supple tires, we could go on roads and trails that wouldn’t be much fun on a traditional, narrow-tire racing bike.

We envisioned a new breed of bike – racing bikes with ultra-wide, supple tires – and we called them ‘Allroad Bikes’ (still without a hyphen). That was way back, in 2007.

The first step was to make the tires needed for these all-road bikes. First we worked with other manufacturers, but in order to get exactly the tires we wanted, we introduced our own Compass tires in truly wide widths (above). It’s taken the bike industry a little while to get on board, but now our ideas are generally accepted: all-road bikes are the most important segment in the performance bicycle market.

All-road bikes are more than a passing fad, because they finally correct one of the shortcomings of traditional performance bikes: the need to trade comfort for speed. Now we know that discomfort not only is unpleasant, it actually slows you down. Put more simply:

Comfort = Speed

Cycling has become much more fun on all-road bikes that combine the fun of riding a performance bike with the comfort and go-anywhere ability of wide tires. They are the bikes of the future, and they are here to stay.

As Compass becomes Rene Herse Cycles this year, we will continue to push the envelope beyond what most people think possible. The latest development are our dual-purpose knobbies that roll as well on pavement as many racing tires and offer great traction in mud and snow. It’s going to be a fun ride!

Further reading:

Posted in Testing and Tech, Tires | 35 Comments

Happy New Year

We are looking forward to another great year! We wish all our readers joy, happiness and many great rides in 2019. See you on the road!
—The BQ and Compass/Rene Herse team

Photo credit: Ryan Francesconi

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What Makes a Good Winter Tire?

Winter riding is fun. The crisp air, the clear skies and the beautiful views. Getting out and breathing fresh air. There are many reasons to enjoy it.

Winter riding requires preparation. The most obvious is clothing – which we’ll leave for another post. Today, let’s talk about what makes a good winter tire.

Cold temperatures make rubber less grippy. There is no way around this. In theory, it should be possible to formulate rubber compounds specially for optimum grip in cold conditions. In practice, many ‘Winter Compound’ bicycle tires offer less grip in cold conditions, rather than more.

With all tires, you need to consider the reduced grip when it’s cold. Especially on familiar routes, it can come as a surprise when the grip suddenly bleeds away, at speeds that are well within the limits when the temperatures are warmer.

Having ridden many tires in cold conditions, I can say with confidence that the rubber compound of our Compass tires is among the most grippy you’ll find anywhere, cold or warm, wet or dry.

The chevron tread of Compass road tires helps to improve traction by interlocking with the road surface – which works regardless of the temperature. Even so, take it easy during cold days!

What about snow? Snow is surprisingly grippy. How much tread you need depends on the temperature: Cold snow requires only a chevron tread, like that of our road tires, to hook up. (You’ll see an imprint of the tire tread on the snow surface.) But when the temperatures are around freezing, the slushy snow is slippery, and you really need knobs to get good grip. (The knobs don’t hurt when it’s colder, either.)

Should a snow tire be wide – to float over the snowpack? Or narrow – to cut through the snow and try to find grip on the ground underneath?

Rally cars use narrow tires in snow. They are heavy and powerful, which allows their tires to dig down to a firm surface underneath the snow.

Snow cats use the opposite approach: Their wide tracks allow them to travel on top of deep snow without sinking in.

For bicycles, wide tires seem to be a better choice. Compressing the snow takes energy, and the less you sink in, the easier you roll. And cyclists don’t have enough weight and power to dig through the snow into the firm ground below.

What about ice? Under most conditions, only studded tires grip on ice. They punch holes into the ice that allows them to interlock with the surface. However, studded tires aren’t much fun to ride on dry roads. I suspect that a supple tire with studs wouldn’t work well – you probably need a stiff tire to push the studs into the (hard) ice.

There is one other issue: When it snows, many communities spread fine aggregate on the roads for better traction. Often, that aggregate contains freshly crushed rocks that can be very sharp and cause flat tires. In our area, we’ve found that the crushed rock will puncture worn tires – probably both because they are thinner and because aged rubber is easier to cut. Running relatively new tires has eliminated that concern for us.

If you live in a place that sees snow, but also dry roads, our dual-purpose knobbies are hard to beat as all-round winter tires. They roll as fast on dry roads as most racing tires. They corner as well as most road tires (above). And yet on mud and snow, they offer the grip of the best knobbies. Available in 700C x 38 and 650B x 42 mm, they are a great choice for rides where you may encounter all kinds of conditions.

Click here for more information about our tires.

Posted in Testing and Tech, Tires | 35 Comments

Happy Holidays!

All of us at Compass Cycles and Bicycle Quarterly wish you Happy Holidays!

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Rides to Remember

As 2018 comes to a close, it’s fun to look back on the great rides we’ve done. For me, it’s been a wonderful year full of exciting adventures. It started with the annual New Year’s Cycling of Tokyo’s Yama Saiken (Mountain Cycling Club), the famous passhunters. Jikkoku Pass is a great destination at any time, but climbing it in the snow was doubly fun, especially with such a great crew. It was also a great test of the Caletti Monstercross bike and of our Pumpkin Ridge dual-purpose knobbies.

February saw a return to favorite roads with a chilly ride across the Tahuya Hills. Steve and I enjoyed the ride so much that we decided to make this the venue for the BQ Un-Meeting.

March was even colder that February, but Mark and I were on a mission: We wanted to compare a high-trail monstercross bike with a low-trail all-road bike. We thought that the trail to Jack Pass might provide new insights, and so we headed out during a rainy day on fender-less bikes, all in the name of science. The results proved even more instructive than we thought, as we finally figured out why mountain bikes should have high-trail geometries, but all-road bikes are best with low-trail ones. And despite being chilled to the bone when it started to snow, we honestly enjoyed that ride!

April saw another trip to Japan. With the Yama Saiken, we headed to Ueno village at the foot of Jikkoku Pass to help with maintaining the old road that we had cycled a few months earlier. A campfire by the river, but also the great lunch with the villagers were highlights of this trip.

In May, during a short break from my busy schedule, I headed to Yabitsu Pass near Tokyo. The forecast was occasional showers, but it turned out to be a day of torrential downpours. And yet I was having so much fun that I headed up two additional climbs on closed roads for a full day of exploring. (My bike had fenders this time!)

The summer solstice was a great excuse for an ambitious plan: Ride around Mount Hood in Oregon almost entirely on gravel roads. It was a great day of challening climbs, super-fast descents, and breathtaking views. Our ride was too big to fit even into the longest day, and we returned to Portland at 1 a.m. – giddy with the joy of spending a day on our bikes with great friends.

In July, Natsuko and I headed to the Sawtooth Range. Would a new route finally make it possible to traverse these beautiful mountains? Just in case we’d have to portage our bikes, we carried our gear in backpacks loaded into the Farfarer trailer. The roads started out smooth enough, but soon, we were deep into a real passhunting adventure.

In August, we were reunited with our favorite tandem. We took the 1947 Rene Herse on a ride along the Mediterranean Coast, traversing miniature mountain passes and discovering small fishing villages almost untouched by the passage of time. It was a short trip, but no less memorable for it.

The Bicycle Quarterly Un-Meeting in September brought together a great crew of old and new friends. About 60 riders took the ferry from Seattle to enjoy two days of riding on backroads along the Hood Canal. A great camp at Scenic Beach State Park was filled with socializing and meeting like-minded cyclists. To be repeated…

October provided the last chance to enjoy the high passes of the Cascade Mountains. Ryan Francesconi and I charted a course around Mount Rainier on paved and gravel roads, riding through the (very cold) night to see the the giant volcano in the moonlight, before welcoming the warmth of the new day with a beautiful sunrise on the snow-covered peak. Our ambitious ride allowed for a comparison of two approaches to all-road bikes: Ryan’s Smeltzer set up as a backpacking rig, and ‘my’ MAP as a randonneur bike with a large handlebar bag.

November is cyclocross time. Riding around in circles is quite a change from our usual adventures that stretch beyond the horizon, but it’s great fun, too. With each lap, I get to hone my lines and technique until, by the end of the race, I feel I’ve learned the course and wish for more laps! I can’t wait for next year’s cyclocross season.

December brings us up to the present and another trip to Japan. Last weekend, the Alps Cycle Friends celebrated their 60th anniversary. It was an honor to join them for a weekend of riding in the mountains on beautiful bikes. The story and portraits of the innovative bikes from Alps and others will be in the next Bicycle Quarterly.

It’s been a fun year, and it’s been great to share these rides. Click on the images above for more about these rides.

As I plan next year’s adventures, I’m inspired by these rides and those of other cyclists. What has been your favorite ride this year? Post it in the comments. We all look forward to being inspired!

Photo credits: David Wilcox (Photo 6), Natsuko Hirose (Photos 7, 8, 11).

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Our Holiday Gift Guide

What to give a cyclist? And as a cyclist, what to answer when somebody asks you to make a wish? Here are a few gift ideas that are certain to bring a cyclist joy for a long time.

You can’t go wrong with Bicycle Quarterly. Each edition covers a variety of topics and perspective, with well-written articles that are illustrated with beautiful photos and original artwork. Give a gift subscription ($36), and we’ll send a postcard announcing the gift. And when each magazine arrives, it’ll provide hours of reading enjoyment.

Just as popular are our past editions, whether it’s the 15th anniversary year (above) or our 4-packs on specific topics ($34). They provide a great opportunity to read up on specific topics or simply enjoy more of Bicycle Quarterly without having to wait for the next edition.

Our books also make great gifts. The Golden Age of Handbuilt Bicycles ($35) is one of the most influential cycling books of the last decade. In print for more than a decade, it’s a true classic that has been translated into four languages. Cyclists who haven’t read it and marveled at the studio photos of these amazing bikes are in for a treat!

René Herse ($86) tells the fascinating story of the builder whose legacy we continue today, illustrated with hundreds of historic photos from the Herse family archives. We’ve even a very small number (about 10) of the Limited Edition, which comes with a beautiful slip case and four ready-to-frame art prints of unpublished photos ($185; above).

Third in our trilogy is The Competition Bicycle ($50), which tells the technical evolution of performance bikes through the actual bikes of great champions and amateurs.  Marvel at the bikes that won the Tour and Giro, were ridden to world championships and hour records, but also to first places in Paris-Brest-Paris and in the races of the Paris newspaper couriers, and learn how bikes evolved from highwheelers to modern machines with carbon disc wheels.

Our small Gilles Berthoud bags also make nice gifts. The Bottle Cage/Saddle Tool Bag ($79) fits into most bottle cages or under the saddle. It’s a neat way to carry a spare tube, a few tools, an energy or chocolate bar and a small wallet.

The Small Universal Bag ($98) is even more versatile. It fits under the saddle or on a rack. Mount it on top or hang it from the platform like a mini-pannier. Under the flap is a zippered compartment to carry your essential.

Previously unannounced, we’re offering the ultralight handlebar bag from the Concours de Machines ($375) in a limited edition. By removing everything that isn’t absolutely needed, Gilles Berthoud has created what must be the world’s lightest handlebar bag – without giving up durability or functionality. We’re taking pre-orders until January 15, and the bags will be delivered in March 2019.

Every cyclist can use a nice bottle cage or two. Choose among three Nitto models, from the versatile T cage ($70) to the superlight R ($95) – all work really well.

Our water bottles ($10) make great gifts, too. Designed by a Japanese artist, they celebrate our two brands and add a quote that sums up our approach to bicycles. They are based on Specialized’s popular Purist design, so they function matches their appearance.

Gilles Berthoud leather saddle is a great addition to any bike. Most riders find them extremely comfortable, but saddles preferences are very personal – check before giving a saddle! Choose between different models, with stainless steel or titanium rails ($228 – 295).

The Nitto Bike Stand ($99) is a great way to display a favorite bike. Made like Nitto’s beautiful racks, it holds your bike securely.

Still undecided? How about one of our Rene Herse Posters ($20) with favorite images from our book?

Holiday Shipping: We usually ship your order the same day it’s received, from our Seattle, WA, base. Select an appropriate shipping method if you want your order to arrive in time for the holidays.

Click on the links above to see each product, or click here to browse our entire program.

Photo credit: Isabel Uriarte (Photo 1)

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