Tuesday, June 19, 2012

Making Sense of Handling Characteristics

Test Riding the Soma Smoothie
"Hey, so how does it ride?"

It seems like such a simple question. But the more I learn about bikes, the less certain I am how to answer it. As cyclists, our experience expands as we ride more, and as we try different bikes. And our vocabulary expands as we talk to other cyclists, bike mechanics, salespersons; as we read cycling literature, including myriads of bicycle reviews in magazines and blogs. One thing I notice is that while there are default terms used to describe bicycle handling characteristics, these terms are weakly defined - with different persons using them in different contexts. In particular, it fascinates me to navigate descriptions of bicycle stability versus twitchiness.

In reviews I will often read that a stable bicycle "tracks well" or "rides like it's on rails." As I understand this notion, it means that the bike holds its line of travel on its own accord, without the rider having to constantly micro-correct the steering. This is generally considered to be a good thing. But can it be too good? For me, when experienced at high speeds the feeling of the bike being on rails can also make it resistant to turning. And what about going around sudden obstacles? If the bike tracks so well that it resists changing course, would this not present a problem when encountering an unexpected pothole, or when the rider in front of us swerves?

The concept of twitchiness is not so simple either. There seem to be different kinds, and I can think of at least three: There is the "squirrely" twitchiness of a racing bike that makes it hard to control at slow speeds. This is not to be confused with the twitchiness of low trail - a very different kind of feeling, that gives the rider a more active role in the bicycle's line of travel. There is also the twitchiness associated with a "light front end," regardless of geometry.

Stability can vary with speed. On some bikes there seems to be a linear relationship: The bike will start out twitchy when slow, stabilise at moderate speeds, and "ride like it's on rails" when going especially fast. The faster you go, the more stable it is. Other bikes will be stable at slow speeds and track exceptionally well at moderate speeds, but then level out or even ease up at fast speeds. Other bikes still will handle more or less the same regardless of how fast you ride them.

Whether a bike is described as stable or twitchy, it is hard to know what that means without additional detail, which is not always available. What I wonder is, have there been efforts to maybe create a guideline for both reading and providing descriptions of how a bicycle rides? Without context and well defined terminology, it seems that anything goes and we can easily misunderstand each other's impressions of handling characteristics.

46 comments:

  1. High end bikes , like hi performance snow skis, suit certain riders and not others.You can define the terminology all you like but the only real answer to the question :"how does it ride?" is
    "Get on it and try it yourself."

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  2. Of course.

    The terms you quote have been around for a long time, not coincidentally corresponding to the decline of the use of English in a classical sense.

    It's guy-speak to make it comprehensible to other guys, which in the right hands makes sense, for instance if it's a guy at velonews or cyclingnews who has ridden a ton of bikes and refined their language database.

    Otherwise to a bunch of newbs, it's all greek. As it should be; newbs skills are developing. There is no baseline descriptor that makes sense for this demo.

    As before, descriptors, as with ride quality, are totally subjective out of context.

    Talking about how it rides or handles? It's like dancing to jazz. Subject to the interpretive ability of the participant.

    Yeah, often times the bike doesn't even fit the rider or the rider doesn't re-wire himself to work with the bike.

    That's why the majority of bike reviews are just mind candy, albeit an overly-sweetened one.

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    1. i found the same thing with the magazine sponsored ski tests that come out each year on all the latest skis. they are fun to read but the testers were never of one accord on any particular ski and neither were all my ski buddies. The ONLY way to decide which ski would be best for me was to go to the demo days, get a ski and put it thru its paces in as many conditions as I could find on that mountain, on that day, at that temperature and hope for the best. and the number of variables on a bicycle and rider on so many surfaces becomes an even greater mish mash of permutations. but we all love to over analyze and theorize and appear knowledgable and the circus continues.

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  3. I agree with you that bicycle handling can be hard to describe. General statements like "This bike is stable" and "That bike is twitchy" aren't of much use. It all depends on the situation. For example, a high-trail bike can be too stable in mid-corner, making it hard to adjust the radius, but the same bike is very unstable when hit by a sidewind gust.

    You also have the factor of the rider. Traditional geometries usually work best with a light touch on the handlebars, so a rider who firmly grips the handlebars will have a different experience.

    Finally, there are way too many reviews where people are guided by their expectations. That is we at Bicycle Quarterly never look at the specs of our test bikes, and only measure them after we are done testing. Only then can you form an unbiased opinion, and sometimes, there are real surprises in the process. Those surprises help us fine-tune our understanding of bicycle handling.

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    1. and in the end, your opinion of the handling really only applies to the type of rider you are.

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  4. This may be a tough problem. It seems to me that what's needed is quantification, not more careful qualification. About the only entity with sufficient resources and neutrality to create and carry out valid tests that I can think of would be Consumers' Union, and they might well test bikes you're not interested in. In their pursuit of fairness, they would likely disdain the romance and whimsy that some of us relish in bicycle writing.

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  5. I agree, but I guess there are too many other variables that will affect handling unlike for instance a car which perhaps has a more defined vocabulary in this respect. If our bodies were all of the same weight and dimensions and proportions, we could draw some definite conclusions on handling characteristic. So until we're comfortable with cloning, I guess we just have to live with bike handling being described as twitchy or stable. It's when I hear bikes being described as "fast" that I really start to wonder...

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  6. I guess it is a bit like the Supreme Court's definition of pornography, "You know it when you see it", but in this case you "Know it when you feel it".

    I totally agree about the confusion.

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  7. I have never encountered a bike I had trouble dodging potholes with. It is not necessary to change course to do so.

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  8. This is where the little details make themselves noticeable. I think that tire volume and pressure are the number one most noticeable factor when you compare one bike to another handling wise. Then you have head tube angle, weight distribution/center of balance which is affected by bottom bracket height, chain-stay length and seat tube angle/saddle offset. That's not even mentioning loaded bicycles. It's no wonder that sales people don't want to get into those kinds of discussions. Sometimes it's better to just ride the thing.

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  9. When I describe a bike as twitchy, I mean that it gets a slight wobble or an over response to any of my hand movements (as this is a front end thing), the "wobble" is just small, not pronounced enough to really be described as a wobble or else that is what I would call it. It is, to me, a matter of degree, but then, as you say, are we all talking the same language?

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  10. This is one of the better discussions I've encountered of high and low trail and what they mean through the stable/twitchy lens: http://bikebuilding.blogspot.com/2006/08/yet-more-on-trail.html

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    1. Thanks, that is a very useful compilation.

      This certainly rings true:

      "Higher trail makes the bike more responsive
      to rider lean and subtle body movements and small weight shifts, and less responsive to arm handlebar movements. This is more true the faster you go."

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    2. But might it be important to consider the amount of weight on the front end when describing the feeling of a high trail bike versus a low trail bike?

      "Higher trail makes the bike more responsive
      to rider lean and subtle body movements and small weight shifts, and less responsive to arm handlebar movements. This is more true the faster you go."


      I wonder if same might be described of a low trail bike when enough weight is placed on the front end.

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    3. So far I have ridden 3 low trail bikes for significant periods of time with and without weight on the front. My impression is that the weight not so much changes the handling characteristics, as doesn't change them, and that is the point. With a heavily loaded bag on the front of my Brompton, it still feels like a low trail bike on turns and never attains that "on rails" feeling. I remember the same about test riding the Royal H randonneur last summer. I must have had 15lb of books in the handlebar bag at some point and this did not make it ride like a mid/high trail bike.

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  11. The one confusion for me in the bike building discussion is that it describes the high-trail bikes as more responsive to body inputs. What I find, once I have trained myself to ride a "twitchy" bike no-hands, is that the stable bikes "ignore" my inputs. So either I'm confused, or it's not just body inputs. The Surly docs for my bike pointed me here:

    http://www.dclxvi.org/chunk/tech/trail/

    Frame shimmy I don't think has much to do with "twitchy" or not.

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    1. My beater ride-to-work-bike was very high trail (the fork had been bent back a bit in a crash) and it was soooo easy to ride no-hamds - around corners, in side winds, off curbs even, and subtle direction changes were easy.

      I changed the fork, because I wanted V-brake mounts, and now the bike seems to over-react to my inputs and I have to concentrate just to keep it going straight. And contrary to what Janheine said above, side winds just make it worse.

      I've found that it helps if I lean/shift my weight forward, but that isn't very comfortable, and even then I still can't maneuver with the grace I did before. More work on technique is needed, I guess.

      My short commute is along a low-traffic, quiet street. I used to ride no-hands almost all the way to work, but since I changed forks only about ten percent of my ride is no-hands.

      I'm not taking a stand against low trail bikes here, I like quick handling bikes too. (I ride bmx at the skate park and on the half- pipe in my back yard).

      It's more a case of horses-for-courses. For me, on my commute to work, quicker handling isn't better handling. It's just less relaxing.

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  12. You really got me curious about that SOMA now! ...So hey, how does it ride? ;)

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    1. Nicely! Not twitchy. And doesn't "over-track" at high speeds.

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    2. I figured there has been a shortage of made up words lately. It corners more easily (for me) at high speeds than bikes that track "too" well.

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  13. sorry for a tangent, but an experiential one:), my brompton is twitchy and it's great in some ways (alive, manueverable), but it's an enduring feeling of loss that i'm not able to text (like most respectable drug dealers do in my neck of the woods..) while on it (or just sit back and forget about steering for a while..)

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    1. apples don't have street cred around here..

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  14. If you were to describe the feeling itself, how is the low trail wobble different from a twitchy bike? I recently test rode a Brompton and a Gazelle, and they both wobbled at slow speeds. So does my boyfriends vintage Peugeot road bike, which is why I am terrified to ride it. But you are saying these are all different effects?

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    1. I will have to think about how to describe the subjective sensation; maybe the topic of a future post.

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  15. Christopher FotosJune 20, 2012 at 11:53 AM

    Stability can vary with speed. On some bikes there seems to be a linear relationship: The bike will start out twitchy when slow, stabilise at moderate speeds, and "ride like it's on rails" when going especially fast. The faster you go, the more stable it is. Other bikes will be stable at slow speeds and track exceptionally well at moderate speeds, but then level out or even ease up at fast speeds.

    Well naturally there is a direct relationship between stability and speed, thanks to the wheel. Just think of a Dreidl or a gyroscope. I can't think of any reason bike stability would "ease up" at higher speeds unless there were a mechanical defect not apparent under less stress.

    As Les Grossman says in Tropic Thunder, It's physics

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    1. Right, I am more intrigued by the non-linear relationships. I don't think the bikes that "ease up" at fast speeds have mechanical issues, as I've ridden several now that behave this way. But maybe it's just a gentler, less steep linearity rather than an actual easing up.

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  16. This whole discussion seems in the realm of bike geekdom :) I wonder how many, when deciding to cycle more in their lives, consider these issues....It can be enough to make one just get back in the car!

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    1. That's like saying that car talk is enough to make people want to ride a bike. I only wish!

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    2. That's why I switched to a bike!! Besides, car talk is entertaining ;)

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    3. I think the whole geek concept is overused these days. Some people like to know how objects are made, others prefer not to know. I try to share my interest in how bicycles work without making it over-the-top technical.

      It's interesting, because I get emails from people who are curious about (or frustrated with) their bicycles' handling characteristics, but lack the vocabulary to express themselves. They read articles, they go on bikeforums, and only get more confused. I think there is room for a middle ground between the "I don't even want to know how this works" and the super-technical analysis that puts people off.

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    4. That's the problem when people are raised in a world in which answers a fed to them and experience is discounted.

      Ride. The. Bike.

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    5. I'd say that handling actually has a pretty big impact specifically on newer riders. Us geeks kind of get used to expecting different bikes to ride differently and can adjust and discuss. Newer riders tend to just say "that bike scares me", "that one doesn't". The fact that no one can give them very good advice on why or which bike might be better is a real problem.

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    6. Those easily scared should always ride the less scary bike. Giving advice to someone is often problematic, even with shared vocabulary.

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    7. I'd say approach it like wine, or food - mainly with your senses, work out the logic later, if you care

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    8. Vive le geekdom des bicyclettes!

      If you ever figure out why the old Raleigh in your previous post handled and rode better than others, do post your findings.

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    9. "Newer riders tend to just say "that bike scares me", "that one doesn't". The fact that no one can give them very good advice on why or which bike might be better is a real problem."

      Exactly. In theory, bike shops should play that role. In practice, that is not always so.

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    10. I respect your experience in this, but must also respectfully disagree. I've been involved with bike shops in four states for three decades and for the most part feel they are trying to lead the way with communication and products.

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    11. How can you disagree with "not always so" - unless you believe that absolutely all bike shops offer good advice?

      There are some great bike shops out there to be sure. But there are also those that are completely out of touch with what customers need.

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  17. Given that the basic physics of why a bike does not immediately just fall over are poorly understood, I suspect it will be difficult to develop a simple, clear, and comprehensive language of description for handling characteristics. There's just so many factors that all interact with each other.

    That said, I think there is definitely room to improve the vocabulary some, especially when comparing bikes with largely similar set up. As GRJ pointed out, there is a fairly meaningful shorthand used for comparing racing bikes. I don't think this is "guy speak" so much as it is the product of people riding large numbers of bikes that are very similar. The ability to pick out (and describe) the differences is a lot better than trying to compare a Brompton to a Cervelo.

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  18. If you write well and take great pictures and have a very thick skin in the face of the peanut gallery it all works out in the end.

    I'm trying to limit my own reviews to "I like it" and "(silence)". I won't get all the way there.

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  19. I have never had any problems with the handling of any bike I have ever ridden (I'm guessing that's over 20). Failing gears , brakes, and one cracking frame, yes, but the bike was always OK. I've recently changed frames (the old one cracked) and the new one makes it easier to ride no hands, but the old one (apart from cracking) handled fine apart from that (wrong size). Have a look at a book by Mike Burrows (formerly of Giant) in which he debunks various bike myths (sorry, too lazy to link). I enjoyed the section on how the human behind is just not sensitive enough to detect the difference between different frame materials, let alone different types of wheels.

    That doesn't stop choosing the right size/type of bike, I'm just saying be careful of voodoo.

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  20. Seems to me that part of the problem is that different people evaluate bikes differently anyhow. For example, if a rider doesn't ride no-hands, then no-hands handling is not an issue. Or, if a rider has an abundance of arm strength, then the difficulty of turning an over-stable bike is not an issue. We bought a bike for my mother (Electra Townie) and though as near as I can tell, it was stable, the steering was so light that my mom thought it was not stable -- she doesn't like it that much, though it took a while to figure this out.

    I've only noticed a difference in handling (beyond weird cargo looniness) when riding no-hands, or when doing long fast descents (e.g., Quimby Road in San Jose). The "stable" bike felt stable; the twitchy bike felt like it needed constant attention.

    I don't mind trying to quantify this stuff, because it can be a PITA figuring out which bikes you'll like and which you will not.

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  21. velouria,
    I really enjoy your blog. I an 60 and started riding in 1984 after watching Alexi Grewal winning the road race. I have never raced, but have ridden with many racers and have enjoyed many club rides that included racers.Also, I have owned a lot of bikes over the past 28 years.
    I have to say that your observations are so right on. I have gone from wanting the latest and greatest to enjoying my Riv Roadeo ( a tank in today's world ). The handling of my Roadeo and my Ram that I sold are more of a benefit to me that saving a few pounds on some of the modern bikes that I couldn't fit anyway.So many riders will never have a chance to ride some of these bikes and probably walk away from cycling after not enjoying the lack of comfort of the poor fit on the many of the race geometry bikes.
    Your conversation about differences in handling will never be discussed when looking at a Trek or Specialized, because they are a compromise.
    Bottom line, if you take the modern hype of advertizing from bicycle sales, most riders would be riding somewhat different bikes and be much happier with their purchase.
    Getting our U.S.A. culture to embrace cycling will not be easy. In the short term, its probably to tell the consumer that he can buy and ride Lance's bike. But in the long run, there will have to be some sport touring bikes.
    Please, just keep bringing these discussions.

    Don C.

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  22. Figuring this out is just about my life's work. It is very tough. But I keep plugging away. I think slowly we are making progress. Jim Papadopoulos, Northeastern University

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