Thursday, March 11, 2010

solobreak has left a new comment on your post "Hey, Tough guy"

Fixed gear riding is not a canard as derided by its detractors, nor a panacea as glorified by its proponents. Some fixed gear training is good, and if you have some designs on actually competing in the discipline a bit more is better. Solo left a comment on my last post that was so full of misinformation that I felt the need to address them in a separate post.

> Lemond and Ray have it correct.

No they don't.

> All else being equal, going slower requires less power.

Thank you, captain obvious

> In this case "equal" means rider, weight, tires, not the gearing.

Wrong. When I'm the only fixed gear in a group of ten riders on geared bikes, nothing is equal. The gear restriction is _THE_ critical factor. If I want to go faster, I have to pedal faster, end of story. When you're coasting down hill at 30 mph, I have to spin a cadence of 150 just to keep up. Even in the situation where my 'power' is being derived from gravity, the very act of spinning a cadence that high for more than 60 seconds is a lot of work. If I want to keep up on the flats when you're cruising at 25 MPH in your 53x16 at a cadence of 100, I'm spinning _and_ pushing power at 125 rpm. I'm working a lot harder, weight is of no consideration here.

Now let's consider climbing - forcing my 42x16 over hills that you've dropped into your 39x19 takes significantly more effort on my part, and this is demonstrable in terms of basic physics: W=Fd. With out getting too heavily into the math, it takes more work to complete one rotation of the crankarms using ratio of 42/16 than it does to complete one rotation with a ratio of 39x19. Factor in the exponential increase of the vector force of gravity (proportional to gradient) and you can see where it leads: You're spinning a comfortable cadence in your efficient zone, I'm power lifting. This brings us to biomechanical efficiency:

> If fixed is "harder" it's because it's a less efficient way of producing the same result. In other words, you are wasting energy.

This is partially right. There are two things to consider here; Mechanical efficiency and biomechanical efficiency.

Biomechanical efficiency - We know that we have a 'sweet spot' where producing a certain amount of power at a certain cadence is the most comfortable, and you could extrapolate that to be the most efficient in terms of biomechanics. You could also consider it in terms of a efficient balance between fast twitch and slow twitch muscle fiber usage. Spinning too fast forces you to use more energy on the fast twitch, grinding too slow uses too much slow twitch, i.e. you can't keep up a speed of 20 mph spinning a cadence of 150 or 50 for as long as you can with a cadence of 100 . From that perspective, excessively high or low cadences are in fact inefficient. (I'll go into the training aspects of this later)

Mechanical efficiency - from a strict mechanical perspective, fixed drive trains are more efficient, and anyone who does not understand and agree with that statement is wrong through either ignorance or arrogance. It's provable in terms of physics, both in theory and practice. In any _given_ ratio, a fixed gear _will_ be more efficient than a freewheel. To encapsulate the concept, a fixed drive train has considerable less loss than a freewheel. On a fixed gear, pedaling efficiency is enhanced by the forward momentum of the bicycle, sometimes referred to as a 'return'. Some detractors misconstrue this as 'getting something for nothing'. They're morons.

You can somewhat emulate this (i.e. minimize drivetrain loss) with a freewheel and a super-efficient pedal stroke, but your stroke would have to be pushing the realm of 90%+ efficiency (even more with a derailleur). Not likely. Most riders who say they can get the same effect as a fixed gear by riding one-gear are full of shit, letting their bloviated egos claim they have a super efficient pedal stroke. These people are asshats that any serious rider could drop over a speed bump.

Here are two easy experiments that will prove out the concepts -

Find a steep hill of reasonable length (big blue would work for Solo). Set up a fixed-gear in a gear that you would be comfortable riding mostly flat roads with. Ride the hill. Next, take your heaviest geared bike and ride the hill with gear you feel comfortable in. You will notice that riding the fixie up that beast was not only harder, but also took more time than the heavy geared bike. This will disprove the statement "equal means rider, weight, tires, not the gearing".

Next, find a flat/predominantly uphill course. Take your geared bike, ride the course and pick _ONE_ comfortable gear, so that you are attempting somewhat of a TT, concentrate on riding a smooth cadence in the _ONE_ gear. Next, set up the fixed gear with the same gear you rode the hill on the geared bike. Your effort will be less given the same cadence. Why? drivetrain efficiency. This proves why riding a fixed gear is more efficient than riding a freewheeled bike with the same gearing.

That isn't to say you will _always_ be faster in a fixed gear, there will come a point where your biomechanical inefficiency will significantly affect your ability to ride faster. This is where gears come in handy.

> It is quite a stretch to think that wasting energy by propelling the bike forward in an inefficient manner would be better training than simply being as efficient as possible, and ultimately going faster.

I'm really quite surprised you made that statement, it's completely wrong. Fitness training for bicycle racing _concentrates_ on working your inefficient zones. Do you get faster by riding in your most efficient gear? Only slightly, and only in terms of endurance. HR Zone training will only get you so far. If you spend all your time riding in your most efficient biomechanical/cardiovascular zone, you will plateau quickly and in fact _not_ get faster. You do interval training to become more efficient at producing more power. This - by definition - requires that you propel the bike forward in an inefficient manner, by both riding excessively high and excessively low cadences - again, by definition, inefficient methods of propelling the bike forward.

Take, for example, this article from the Journal of Strength and Conditioning Research. From the abstract:

"High-resistance interval training produces substantial gains in sprint and endurance performance of cyclists in the competitive phase of a season. Here, we report the effect of changing the cadence of the intervals. We randomized 18 road cyclists to 2 groups for 4 weeks of training. Both groups replaced part of their usual training with 8 30-minute sessions consisting of sets of explosive single-leg jumps alternating with sets of high-intensity cycling sprints performed at either low cadence (60-70 min-1) or high cadence (110-120 min-1) on a training ergometer."

"Low-cadence interval training is probably more effective than high-cadence training in improving performance of well-trained competitive cyclists".

But, to add a caveat to that last line from here:

"higher pedaling rates will preserve more glycogen in the fast-twitch muscle fibers, leading to faster and more powerful finishes at the end of the race."

Or, to paraphrase Thomas Dolby

"if you want my opinion
it doesn't mean a thing,
if you haven't got
the ability to spin"

So here's what we've learned here today:

- Riding a fixed gear in a group with geared/freewheel riders is more work because you're constantly in and out of your most efficient biomechanical/cardiovascular zones.

- riding in and out of your efficient biomechanical/cardiovascular zones are a critical component to becoming a stronger, more efficient cyclist

- Greg Lemond is suffering from lead-poisoning induced dementia

- Solobreak is wrong on this issue.

Any questions?


solobreak said...

Luckily, I already know that when it comes to debating something online, your energy and willingness to put in the effort is endless (as evidenced by the length of this post). So I'll mostly let it go, it's your blog. But I have seen you race, for years. Your m.o. is much the same as your strategy for hanging on to a group with a fixed gear, rarely, if ever going on the offensive, almost always following. Which makes sense, as most everyone ends up racing the same way they train...

I'm looking forward to your podium pictures.


zencycle said...

Your analysis of my m.o. is spot on. It's why I'm much better at team and defense tactics, which incidentally I enjoy more than self-serving opportunism anyways.

If there was ever anything missing out of my lackluster cycling 'career', it's a little negacoaching. I'm glad we finally got that out of the way.

Jonny Bold said...

WOW! Thats all I got. WOW!

zencycle said...

JB, I don't suppose you could elaborate on that....

CB2 said...

Another thing to consider when riding fixed down hill is you are trying to keep ahead of the cranks so your legs don't go all flappy. Yes, you are getting a gravity assist, but it's not really a free ride. Same with the back stroke; your still trying to keep ahead of the pedals.

Jonny Bold said...

Sorry man you dropped me. I dnf'd.
Although I was laughing my ass off as I pictured the two of you madly typing away.

I use to know a lot of guys that rode the fixy in the winter, but no one seems to bother anymore. Except of course the new era hipsters that ride to the coffee shop and then back home to make animated movies. How the hell did the sport of cycling end up inventing a thing called hipsters? I mean think about that shit, it's friggen hilarious. Plus they all blow on race day! So it's cool to laugh at them, I mean they're laughing at themselves which is a good trait, so how 'bout a post in honor of them.

It's been good reading since I found the blogoshpere, but my favorite post was the one about the cat and the cat shit/piss and all the cling ons that seem to fall everywhere. I would never have a cat, but my girlfriend does and you described her situation to a T. I had fucking tears in my eyes. Thanks for that!

zencycle said...

@cb2 - I'm reasonably good at spinning the fixed. I don't usually have a problem hitting 170 RPM down hill, but getting over 175 takes a quite bit more effort. I've hit over 190. Years ago I used to do flying 1K unloaded roller sprints in the winter. We had a PC set up with sensors on two rollers that would show your position, sort of like a 1k matched sprints. If you couldn't hold over 170 RPM for most of the sprint you weren't shit. My PR was about 35 seconds, the winners always were pushing the 30 second mark. fwiw - these competitions provided absolutely no benefit in terms of racing. The only applicable skill was riding a smooth straight line. Other than that training for roller races actually took time away from more effective off season training.

zencycle said...

@jb - Comedic entertainment wasn't what I was going for, but 'art is in the eye of the beholder'.

RE: hipsters - I feel the same way about cyclocross. It used to be hard-core guys getting muddy on home-made bikes. Now there are as many poseurs as legit racers. I'm sure if I lived in a more urban hipster environment than the lily-white suburbs I might feel differently about the hipster-fixie phenomenon, but then I might be living in a loft with a tattooed cigarette smoking girlfriend having pseudo-intellectual debates ala La Vie Bohem.

However, cats would still suck.