How Wide is Right for Me?

open_corner

Our ideas of what is a performance bike have changed a lot in recent years! One of the most exciting bikes of the moment is the Open U.P. – a carbon race bike that accepts 50 mm-wide tires!

Not too long ago, every performance road bike had 700C x 23 mm tires. Now you have to choose not just how wide you want your tires to be, but – thanks to disc brakes – even which wheel size you want to use! For the Bicycle Quarterly test, we rode the Open with 650B x 48 mm tires, but our second tester, Nate King, raced his Open with 700C x 44 mm tires. Which is better? Or should you get several wheelsets for different courses? Is there a reason to switch tires and wheels on the same bike?

tire_test

Let’s first talk about some fundamentals: Wider tires don’t roll slower than narrow ones. Bicycle Quarterly‘s latest tire tests, published in the Winter 2016 issue (BQ 58), have shown this once again: In a real-road scenario, even 54 mm tires don’t roll slower than 32 mm – or any size in between. Before this, we already tested tires between 20 and 32 mm tires and found that the 20 mm and 23 mm were slowest, and all the others offered the same performance.

By the way, we tested at 22 mph, so this factors in the greater air resistance of the wider tires. It appears that wider tires have slightly lower rolling resistance, which cancels out the small increase in wind resistance. This means that at lower speeds, wider tires probably are faster than narrower ones. We tested on very smooth asphalt. On rougher roads, wider tires also are faster.

Yes, I know it’s not what we used to believe – we were quite surprised when we saw the results of our testing, but we’ve confirmed this time and again. And so have others in recent years.

To summarize all this research: Narrow tires (<25 mm) are slow. Above 25 mm, the width of your tires are won’t change your speed (at least up to 54 mm wide tires).

That doesn’t mean you can just slap any wide tires on your bike and expect it to go fast. What will change your speed is how supple your tires are: Tires with high-performance casings are faster, more comfortable and offer better traction, regardless of their width. If you choose heavy, reinforced ‘touring’ models when you switch to wider tires, you’ll likely to be disappointed – they’ll roll slower than racing tires because of their sturdy casings, not because of the extra width.

So we know that supple casings are key, and that width doesn’t matter. What size tires should we run then? Is wider always better? And what about wheel size?

open_paved_corner

Wider tires offer more cornering grip. This is true for racing cars and motorbikes as well as bicycles. On bicycles, there are two reasons for this: More rubber on the road gives you more traction. And wider tires are inflated to lower pressures, which means that they stay in contact with the road. If your tires don’t bounce over small irregularities in the pavement, they have even more traction than their width alone would suggest.

If you like to corner fast, you want the widest tires possible. Even on smooth pavement, the difference between 38 mm and 48 mm-wide tires is noticeable, and on rough surfaces or even gravel, it’s no contest.

WheelTest

Wheel size is another important consideration. The photo above shows three Bicycle Quarterly test bikes with identical geometries (head angle, trail, BB height, etc.), but different wheel sizes. What we found in that test: Wheel size greatly influence the handling of your bike. Larger wheels make the bike more stable, and so do heavier wheels – it’s the rotational inertia that matters, not the outer diameter.

Since wider tires are (slightly) heavier, you’ll want to decrease the wheel size to keep the rotational inertia – and thus the handling – the same. That means that your wheel size should be chosen based on your tire width and tire weight. That way, you can enjoy the nimble handling of a great racing bike even with wide tires.

Let’s a look at a few tire sizes that I enjoy riding, with their pluses and minuses:

ritchey_swissx

38 mm wide

  • To me, tires narrower than 38 mm don’t really make sense any longer. 38 mm tires still give you the “connected to the pavement” sensation that makes a racing bike feel so fast. Below 38 mm, all you gain is harshness. The bike doesn’t feel any better, just more jiggly.
  • 38 mm tires are great for pavement and occasional gravel riding.
  • To go with 38 mm tires, you have a choice of wheel sizes:
  • If you like the nimble handling of a racing bike, then choose 650B wheels for 38 mm tires.
  • If you prefer a bike that locks onto a cornering radius and won’t be deflected even if tense up in mid-corner, then use 700C wheels for 38 mm-wide tires.

hahn_shiretoko

42 – 44 mm wide

  • Adding 4 mm to the width of your tires gives you some added plushness – compared to 38 mm, you’ve increased the air volume by 22%.
  • In exchange for that added cush, you lose a little bit of connection to the road. To me, that isn’t a big loss, and I enjoy the greater traction and go-almost-anywhere capabilities of the wider tires.
  • For tires this wide, 650B is the optimal wheel size.
  • 42-44 mm tires are fine for most gravel riding. They have the advantage that good rim brakes (like our Compass centerpulls) fit over them – even with fenders. In fact, fender mounting becomes a compromise with tires wider than 44 mm (see below).

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48 – 54 mm wide

  • Now we are getting into some seriously wide tires for a road bike! A 54 mm tire holds twice as much air as a 38 mm tire.
  • Tires this wide change their feel depending on the pressure you run:
    • With the tires inflated to 38 psi (2.6 bar), our Open U.P. test bike felt like a road bike. The tires made more noise as they rolled over the pavement, but otherwise, the feel wasn’t all that different from narrower tires.
    • Letting out some air and reducing the pressure to 26 psi (1.8 bar) changed the bike completely. Now it was super-plush. The tires still had enough air so they wouldn’t collapse under hard cornering, but I could feel the ‘suspension’ when riding out of the saddle. At this pressure, the tires were ideal for rough gravel.
  • For tires this wide, I definitely recommend 650B wheels. With 700C rims, your bike will just plow straight ahead like a 29er mountain bike, and you’ll need suspension to absorb the bumps that you cannot steer around. On my Firefly (above), I went with 26″ wheels for a more agile handling. As a result, the bike feels remarkably similar to a good racing bike.
  • Fender mounting is an issue with tires this wide and road cranks: Ideally, a fender should be about 20 mm wider than the tire, but the chain will hit a fender that is wider than 62 mm when riding in the smallest gear! The solution is using a 62 mm fender that doesn’t wrap around the wheel very much and mount it a bit higher above the tire. It works, and we now offer a 650B fender specifically for 47-48 mm wide tires.

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How about tires wider than 54 mm? That might be interesting, but you can’t really fit them between road cranks with narrow Q factor. 54 mm tires already are quite wide: They have the same air volume as 2.3″ mountain bike tires – it’s just that they don’t have knobs on the shoulders, so they measure out a bit narrower. Below is a comparison of the air volume of my three favorite tire sizes (to scale).

38-54-mm-tires

To summarize, if you want your bike to feel connected to the pavement like a good road bike, I recommend 650B x 38 mm tires. Compared to narrower tires, you get added comfort and speed on rough pavement, and more cornering traction, too.

I prefer a little extra rough-road performance and even better cornering traction, so for paved rides, my choice is 650B x 42 mm. You lose a little of the connection to the road, but during hard cornering, you actually get more, not less, feedback of how much traction you have in reserve, because the tires can really key into the pavement.

If my ride includes a lot of gravel, I’ll pick 650B x 48 mm or even 26″ x 54 mm. On pavement, the downside is that you get some tire roar – how much depends on the diameter of your bike’s frame tubes that provide the resonance chamber for the noise – and the tires’ feel is more sensitive to tire pressure. On the plus side, the traction in paved corners will blow your mind.

If you are using lightweight carbon rims and superlight tires, like our Compass Extralights, then it makes sense to go up one wheel size to compensate for the lighter weight. So for 38 – 43 mm tires, I’d recommend 700C wheels, and 44+ mm tires, I’d use 650B. Otherwise, your bike gets that ‘small-wheeled’ feel: The bike doesn’t hold its line on its own, but requires active input from the rider to go straight. It’s not a big deal, but we are talking about optimizing your bike here.

It seems that more and more riders are converging on these tire sizes: BQ‘s second tester for the Open U.P. recently received the latest model from his sponsors (above), and he spec’d it with 650B x 48 mm tires – like our test bike. And he tells us that he loves it!

With these suggestions as a starting point, I recommend test-riding a few bikes with different wheels and choosing the ones you like best.

Resources:

Photo credits: Toru Kanazaki (Photo 8), Natsuko Hirose (Photos 1, 3), Nate King (10).

Posted in Tires | 77 Comments

Compass Photo Contest Winner

The votes are in! Giovanni Calcagno’s photo on the Via del Sale won the Compass Swift Campout photo contest! The Via del Sale criss-crosses the Italian-French border as it connects Limone Piemonte with Ventimiglia via the Maritime Alps.

To me, the photo embodies everything I love about cyclotouring off the beaten path: beautiful scenery, interesting and challenging roads, and the romance of discovering new places beyond the horizon. I can’t wait to hear the full story of Giovanni’s adventure: He’s agreed to share it in a future edition of Bicycle Quarterly.

Congratulations, Giovanni! You won a $ 200 gift certificate to Compass Cycles. The nine finalists receive a one-year subscription of Bicycle Quarterly, and their adventures also will be featured in our magazine.

Click here for more information about Bicycle Quarterly.

Posted in Rides | 3 Comments

Road.cc Reviews the Compass Switchback Hill

Road.cc tested another Compass tire. After the Barlow Pass and the Steilacoom dual-purpose knobbies, they had a go with the Switchback Hill 650B x 48 Extralights. This time, they used a different tester, Dave Atkinson. He liked the tires just as much…

His conclusion echoes ours: “At a time when people are doing roll-down tests to see if it’s worth switching to 28mm tyres from 25s, my advice would be to skip a few sizes and fit a pair of these, if you can. They’re great.”

I smiled when I read that in group rides, he had “to remember to point out holes and other imperfections that you can glide over on 48s but might easily pinch-flat a 25.” I remember that from the days before my friends switched to wider tires, too…

His conclusion: “There really is no downside to a big tyre like this.” But rather than retell his story, just read his review for yourself!

Posted in Tires | 12 Comments

Myth 12: Disc Brakes Work Better Than Rim Brakes

To celebrate Bicycle Quarterly‘s 15th anniversary, we are looking at myths in cycling: things we used to believe, but which we’ve since found not to be true.

Disc brakes have become popular on allroad bikes for a variety of reasons. One of them is that they are perceived as offering superior braking. It seems to make sense – after all, disc brakes on cars and motorbikes revolutionized braking performance. Why wouldn’t they do the same on bicycles?

On motorized vehicles, disc brakes replaced drum brakes that enclosed the braking surface inside a drum. The heat generated by braking had to go through the drum before it could reach the cooling air. During vigorous braking, the brakes got hotter and hotter, until they ‘faded’ – braking power was lost as the friction between pad and drum decreased.

Disc brakes solved this problem: The braking surface is exposed and cooled by the passing air as the motorcycle/car moves forward. And disc rotors are lighter than drums, so they can be larger, which increases the braking power further.

Why doesn’t this work for bicycles? If you’ve ever ridden a bike with drum brakes across hilly terrain, you’ll know how dreadful they tend to be: mushy in feel, and on long downhills, the braking power fades away almost completely. That is why they never became popular, especially since the bicycle’s rim provides a convenient brake rotor.

That’s right: Rims brakes are disc brakes. Most bicycles have had disc brakes all along. Using the rim for braking makes a lot of sense: The braking surface that is as large as possible, and since it’s (usually) made from aluminum, it dissipates heat quite well. Using the rim for the dual purposes of supporting the tire and braking saves weight, too.

However, there is a problem with rim brakes: The caliper has to reach around the tire (and fender). The wider the tire gets, the beefier the caliper needs to be in order to avoid flex that robs braking power.

For that reason, rim brakes work great on racing bikes with narrow tires (above), but many rim brakes for wider tires are poor stoppers. This gets worse in the rain, because the pads need to cut through the layer of water coating the rim to get any braking power at all. Many rim brakes for wide tires are too weak to do this quickly, so in the rain, you end up with almost no braking power at all.

It’s important to remember that this isn’t a problem with rim brakes in general, but with brake caliper flex. Unfortunately, there are few well-designed rim brakes for wide tires.

There are ways around the flex issue. Instead of beefing up the caliper until it gets so heavy that nobody wants it on their bike, you can use the – very stiff – fork and frame as part of the brake. Cantilever and centerpull brakes do that, and well-designed ones offer plenty of stopping power, even in the wet.

The calipers of disc brakes only reach around a thin brake rotor, so they can be made stiff with relatively little effort. This means that even inexpensive disc brakes usually offer adequate stopping power. Because the rotors are smaller than bicycle rims, disc brakes have less leverage over the wheel and need to clamp the rotor much harder than a rim brake. This has the positive side effect of wiping water off the braking surface quicker than many rim brakes.

Due to the small rotor and thin pads, disc brakes tend to bite earlier, offering more braking power during the initial application of the brake. As a result, many riders believe they have more power.

So what’s not to like on disc brakes?

  • Disc brakes tend grab: For the same reason that disc brakes bite early, they tend to be grabby at low speeds. Not a huge problem unless you do U-turns.
  • Mechanical discs lack power: Hydraulic discs offer great stopping power, but mechanical discs tend to have a lot of flex in the mechanism that translates the brake cable actuation into a clamping force on the disc rotor. Large rotors can make up for this deficiency, but few bike makers are spec’ing rotors large enough to match a really good rim brake. I have yet to ride a bike with mechanical discs that can lift rear wheel during hard braking (with the rider shifting their weight all the way back).
  • Weight: Rim brakes are an elegant solution, as they make dual use of the rim. Discs use a separate rotor, plus very stiff (and heavy) calipers, which add weight.
  • Loads on fork and spokes: Disc brakes transmit all the braking forces through the wheel and fork legs, so both must be stronger. I don’t have enough miles on my disc brake bike to tell whether the front-wheel spokes fatigue more, but we already know that disc brake forks need to be stiffer, which means they absorb fewer shocks.

 

All these disadvantages aren’t really an issue on many bikes, especially those with wide tires. Compared to cheap rim brakes, inexpensive disc brakes offer more power and better bite. The extra weight of the rotor can be mitigated by using carbon fiber rims, which are lighter. And modern carbon forks are stiff anyhow – carbon delaminates if it flexes too much – so adding disc brakes doesn’t result in a loss of shock absorption.

And yet, on a bike optimized for performance, rim brakes often remain the better choice. The best rim brakes are lighter than discs, while offering plenty of stopping power and more linear modulation. They allow for flexible fork blades that improve comfort and speed by reducing suspension losses. And the (much-thicker) pads tend to last longer, too.

Mountain bikes are a different issue: Hydraulic disc brakes have the added advantage of requiring less hand force during long descents on really rough terrain. And suspension forks combine stiff legs with shock absorption, thus eliminating one of the main disadvantages of discs on allroad bikes.

In conclusion, I think disc brakes are here to stay, at least on bikes with wide tires. (They make little sense on racing bikes with narrow tires.) Rim brakes will continue to have their place on high-end road and allroad bikes. It’s a bit like steel tubing, which you still find on some of the very best bikes, but on mid-range models, carbon now offers better performance.

Originally, we planned 12 articles in our ‘Myths in Cycling’ series, but as we’ve reviewed 15 years of Bicycle Quarterly, we realized that there are more myths than we thought, so we’ll continue this series for a while.

Further reading:

Posted in Brakes | 113 Comments

Compass Photo Contest: Vote for Your Favorite!

The Compass Swift Campout photo contest has been a huge success with almost 500 entries! With so many amazing photos, it was impossible to select just 8 finalists, so we finally settled on 10. We selected photos that show different aspects of the contest theme ‘Cyclotouring off the beaten path.’

Now it’s up to you, our readers, to select the winner among the finalists below. We present the images without context so you can enjoy them for their photographic qualities alone. Then please choose your favorite at the bottom of the post.

▲ Photo 1

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▲ Photo 3

▲ Photo 4

▲ Photo 5

▲ Photo 6

▲ Photo 7

▲ Photo 8

▲ Photo 9

▲ Photo 10

 

The winner will receive a $200 gift certificate from Compass Cycles, and all finalists will enjoy a one-year subscription to Bicycle Quarterly.

The polls close on Sunday, July 15, at midnight. Results will be published next week, and all finalists and their stories will be featured in a future issue of Bicycle Quarterly. Also check out the many other great entries in the #swiftcompasscontest.

Posted in Uncategorized | 8 Comments

Supple Trumps Wide

hahn_popocatepetlHigh-performance bicycles have changed tremendously in recent years. As one manufacturer said at last year’s Interbike: “In the past, everybody asked how much your bike weighed. Now all they want to know is how wide a tire it fits.”

Wide tires have revolutionized how we view performance bikes. In the past, you knew a rider was serious about going fast if his or her tires were narrow. Now it’s almost the opposite: The latest performance bikes have wider tires than many utility bikes (below).

utility_vs_enduro_allroad

This change has happened so quickly that the bike industry can hardly keep up. Just a few years ago, ‘gravel’ bikes had clearance for 32 mm tires. Now 48 mm tires are becoming the standard for ‘allroad’ bikes that are intended as much for pavement as for gravel.

As a result of this rapid change, many cyclists are on the fence when it comes to buying a new bike: Bicycle technology seems so much in flux right now that it seems prudent to wait and see how it all shakes out. Why not postpone a new bike purchase for a few years? By then, we should know exactly what a 21st century high-performance bike looks like.

jan_herse_gravel

Or should you just take the plunge and buy the bike of your dreams? After all, there is so much fun to be had. Will a 2018 bike be obsolete in just a few year’s time?

It’s difficult to predict the future, but what I can say is this: The bikes we enjoy most haven’t changed in the last decade. My René Herse (above) is seven years old, and yet, the only thing I’d do differently today is add low-rider racks and make it Rinko-compatible. The basic idea of what makes a great bike for paved and gravel roads hasn’t changed – it’s just that the mainstream bike industry has taken some time to catch up.

 

In practical terms, for normal road riding, 38-42 mm tires will serve you well. If you intend to ride mostly on gravel, look for clearances that allow 48-54 mm tires. It’s unlikely that these recommendations will change much in the future. Wider tires are almost impossible to fit without giving up the character and feel of a road bike: narrow Q factor, nimble handling, and light weight.

 

What if you aren’t ready to take the plunge? Fortunately, you don’t need a new bike to transform your riding. The science is undisputed: The benefits of the ‘wide tire revolution’ lie mostly in the supple casings. The extra width is just an added benefit.

In other words: A supple 28 mm tire will be faster and more comfortable than a 48 mm-wide ‘touring’ tire with a stiff casing. Especially if you ride mostly on pavement, you can experience 80% of the benefits simply by switching to supple high-performance tires in a size that fits your current bike.

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You’ll be amazed by the transformation. Our Specialized Diverge long-term test bike could handle only 32 mm-wide tires (with fenders). That didn’t lessen the fun when I took it on wonderful adventures, like the ride up the abandoned road to Carbon Glacier on Mount Rainier (above).

I also enjoyed its speed and grip on smoother roads. Simply switching your tires buys you time while you decide what you want in your next bike. Only caveat: After riding supple high-performance tires, there is no going back. Once you’ve tried them, you’ll choose great tires for your next bike, too, no matter their width.

More information:

  • Compass tires in widths between 26 and 55 mm (26″, 650B, 700C)
  • Bicycle Quarterly 58 with our latest tire tests, which compare the performance of tires between 32 and 55 mm wide.
Posted in Tires | 22 Comments

Summer 2018 Bicycle Quarterly

The Summer 2018 Bicycle Quarterly is off the press and will be mailed to subscribers soon. To cap our 15th anniversary year, we’ve put together a 112-page edition filled with truly remarkable stories.

In our biggest adventure yet, we traversed the breathtaking Copper Canyons of northern Mexico. It was an amazing ride in every way – if you haven’t seen our video yet, click here to get right into the action.

It’s impossible not to be amazed by the incredible rides of Tokyo’s Yama Sai Ken (Mountain Cycling Club). These pioneering Passhunters explored every mountain pass in Japan, whether it was accessible by road or not. They built their own bikes years before mountain bikes became a thing. Their story is as inspirational as their photos are beautiful.

More than a decade ago, we coined the term Allroad Bike for a new breed of bikes we envisioned: racing bikes with ultra-wide tires, for more grip on pavement and more speed on gravel. Now these bikes are becoming ever-more popular, and we’ve tested two of the most exciting ones. The 3T Exploro (above) is an all-carbon, superlight, aero gravel bike. How does all that technology hold up in the unforgiving terrain of the Copper Canyons? We pushed the bike to the limit to find out.

Bringing the same bike genre down to earth, we rode Surly’s brand-new Midnight Special. Can it offer similar performance and fun as the 3T, at a fraction of the price?

Few bikes have seen as much success in national and international competitions as Harry Havnoonian’s iconic machines. Marvel at this amazing builder’s first and latest bikes in beautiful studio photos, and learn why Havnoonian always mounts the rear brake in front of the seatstays. Mark Hallinger’s article is a beautiful tribute to this American legend.

Going back further into cycling history, we feature the French cartoonist Pellos, who brought the ‘Heroic Age’ of the Tour de France to life. Travel to a time when stages were long, roads were rough, and human drama matched sporting achievements in this incredible race.

For readers with a more technical bent, Aldo Ross explores why dozens of racers switched to bar-end shifters during the 1949 Tour. Why did they use bar-ends only for their front derailleurs, but operated the rears with downtube shifters?

In our ‘Project’ series, we show you how to mount a front rack, with clear instructions and useful hints that will help you with your next bike project.

These are just a few of the many features in this exciting 112-page edition. Subscribe today to receive your own copy!

Posted in Bicycle Quarterly Back Issues | 2 Comments