Thursday, July 20, 2017

Non-circular Chainrings: Paradise or Placebo?

Introduction

Several of my riding companions have recently experimented with non-circular chainrings. As an anecdotal observation, most of them report a performance improvement and none have reverted to their original circular rings.  There have been several well-publicized results on non-circular chainrings in the last few years, most notably the Tour de France wins by both Bradley Wiggins and Chris Froome. Interestingly, however, Tim Kerrison, head coach at Team Sky, claims that credible research that has been undertaken is inconclusive. The question then arises: are these scientifically proven benefits or a placebo effect?  This article attempts to summarize current thinking with the disclaimer that I have not yet tried non-circular rings myself.

Concept

The idea is very simple: design and orient chainrings that allow the rider to spend less time in the least powerful parts of the pedal stroke, when the cranks are vertical, and more time in the most powerful parts of the pedal stroke, when the cranks are horizontal to the ground. That is, minimize the negative effect of the so-called “dead spot” which is the point at which the cranks are vertical and neither leg is generating any significant power. 

The single parameter that captures this idea is known as “crank angular velocity” which remains relatively constant throughout the pedal cycle with circular chainrings.  A non-circular chainring varies the crank angular velocity within the pedal cycle which, in turn, alters the time spent in each segment of the pedal cycle. To translate this into practical terms, the chainring should have a larger radius at the stronger segment of the pedal stroke and a lower radius at the weaker segment.

Bicycle engineers have been aware of the dead spot for over a century; non-circular chainrings were first tried back in the 1890s. The most notorious experiment in recent years was with Shimano’s Biopace rings (1983 to 1993). Recent studies claim that the downfall of Biopace was caused not by the shape of the rings but by their orientation.

There are several parameters that are relevant in non-circular ring design: the number of teeth, the “eccentricity” of the rings (the ratio of the major axis to the minor axis) and their orientation relative to the crank arms (including adjustability that allows rings to be “dialed-in” to the specific rider and bicycle set-up).  The various manufacturers of non-circular rings, for example Rotor, OSymetric, Bionicon and Absolute Black, all put their own particular spin (is there a joke there?) on the different variables.

  
Research

There have been a myriad of papers written on the subject, not all of them independent and unbiased.  Researchers have examined the physiological and performance differences between non-circular and round cranks on numerous occasions. Though there are some that report improvements of up to 6% with non-circular chainrings, a majority have concluded that, for efforts longer than one kilometer, there’s not much difference between round and non-circular chainrings. None reported a decreased performance. Additionally, not all authors are even agreed on the appropriate output parameters to be measured:  speed, power output, lactate threshold, heart-rate etc. 

In support of the use of non-circular rings for high-intensity events, an IJSSE study based their conclusions on a 1 km time trial study over a six-week period, using eight competitive male cyclists and triathletes using Rotor Q-Rings. Performance measures during the time trial were based on time to completion, speed and power output. In addition, physiological measures (oxygen consumption, heart rate, blood lactate were also monitored over the time span of the study.  The authors concluded that the Rotor Q-Rings provided a positive effect in the time trial and speculated that they could also prove beneficial in criterium-style racing events or at the end of a road race in which bicycle racers typically pedal at similar intensities and durations as the 1 km test. (“Effects of Chainring Type (Circular vs. Rotor Q-Ring) on 1 km Time Trial Performance”. Christiane R. O’Hara et al. International Journal of Sports Science and Engineering. September, 2011).

However, more recently, The Journal of Sports Science and Medicine published an article which documented extensive testing for blood lactate, power output and oxygen consumption but concluded that non-circular chainrings did not produce statistically significant differences over round ones. (“Physiological Responses during Cycling with Non-circular Chainrings and Circular Chainrings”. Alfredo Cordova et al. Journal of Sports Science & Medicine. May, 2014)

Studies at the University of Utah, while not challenging the fundamental premise behind the use of non-circular chainrings, addressed the issue from the perspective of joint-specific kinematics. The author concluded that use of non-circular chainrings did not either enhance or compromise joint-specific (collectively, the hip, knee and ankle) performance in trained cyclists. (“The Influence of Non-circular Chainrings on Maximal and Submaximal Cycling Performance”. Chee Hoi Leong. Department of Exercise and Sport Science, The University of Utah. December 2014).

Conclusions

The anecdotal evidence in support of non-circular chainrings, though not compelling, is certainly intriguing. Perhaps they are at the same stage of development and general acceptance as clipless pedals, integrated shifters and mountain bike suspension were in their early days …. innovations that are now regarded as de rigueur.

Nevertheless, it would appear that objective scientific experimentation in support of the use of non-circular chainrings is somewhat lacking and there is unquestionably no measure of consensus among the various researchers.  At the end of the day perhaps we need to just accept that even a placebo has the potential to offer a significant performance gain.

Some challenges

If you decide to give non-circular chainrings a try, be aware that:

·       Not all of the various manufacturers’ non-circular rings fit all cranks. Be sure you understand your crankset’s spider pattern, bolt circle diameter etc.
·       All front derailleurs are optimized to work with round chainrings and some degradation of mechanical performance might result with non-circular rings. In this regard, front derailleur fine-tuning might a tad more finicky.
·       The risk of dropping a chain appears higher with non-circular rings so consider installing a chain catcher on the front derailleur.
·       Because non-circular chainrings change the angular velocity of the crankarms and thus the power transmitted to any power-meter strain gauges that yu might use, any historical power data from your prior use of circular rings cannot be compared to the data set from the new rings. 


Tuesday, September 6, 2016

Left Turns – Let’s Do Better


 Of all the cycling maneuvers that I watch in our group rides, one of those that we consistently perform poorly and often dangerously, is making a left-hand turn.  Ideally, in a group, these are best lead from the rear but first let’s look at the basics.  To start with, watch this short video.  https://www.youtube.com/watch?v=p8caeR4j_GM

Here is a diagram that summarizes the points in the video.


 Note these important points:
  • When making a left turn on a two-lane road, you will first need to move safely to the left of your lane. On a four-lane road, you will have to move across more than one lane.
  • Never attempt to make an abrupt left turn directly from either the right-hand side of a two-lane road or from the right-hand lane of a four-lane road.
  • Before you change your lane position, you must first look back for traffic. Turn your head to look even if you have a rear-view mirror. No mirror will show cars at your side and physically looking back alerts traffic approaching from the rear.
  • Extend your left arm to signal that you want to move to the left. Wait a couple of seconds, then look back again to check that the drivers have slowed down or moved aside to make room.
  • Assuming that the drivers behind you have time to react to your signal, they should let you into line, allowing you to proceed with the turn.  Do not change your lane position until you're sure that the driver has made room for you.
  • Your signal alone doesn't make it safe to change lane position. Only a driver’s affirmative response to your signal ensures your safety.
  • In high-speed traffic, drivers coming up from behind may not have time to react to you. In that situation you must wait for a gap in the traffic before you move to the left.
  • Traffic typically comes in waves, if you find yourself in a gap a block or two before your left turn, merge left and use the left lane for a few blocks. This is perfectly legal and much easier than trying to negotiate through a wave of traffic.
  • Maintaining your left-turn hand signal, position yourself in the middle of the intersection as necessary and continue to make the left turn when there is an adequate gap in oncoming traffic or when it has been stopped by a stop-sign or traffic light.
  • Make sure you turn first into the right-hand lane of the new route and then into the shoulder or bike lane if one exists.
  • If you cannot safely maneuver yourself in the left-turn position by the time you reach the intersection, don't force the situation. Continue straight through the intersection and make your left turn at the next intersection.
  • It's also perfectly okay to make a left turn as a pedestrian. Stop at the far right corner of the intersection and, when clear, walk across the road to where you can safely re-enter the traffic flow.

 As mentioned above, in a group setting, changing lanes in preparation for a left turn is best orchestrated from the rear though I acknowledge that this requires training, practice and knowledge of the route.  Watch this video to get an idea of this concept:  https://vimeo.com/album/1881848/video/52474720   

Saturday, June 11, 2016

No-drop bicycle ride descriptors

Note:   Typical speeds below are for a flat ride with little or no wind. Actual averages may vary and will often depend on which riders are in the group.  To maintain average speeds, certain stretches will usually be somewhat faster.

E – Social rides for anybody wanting a very relaxed pace. Suitable for recreational riders, beginners and families. Ideally has more than one ride leader. Typical average speeds less than 11 mph. 

D - Advanced-beginner riders who still feel the need for some mentoring/support or for more experienced riders wanting a leisurely outing.  Typical average speeds in the 11-13 mph range.

C – Intermediate level of intensity for newer riders wanting to complete more challenging rides or for stronger riders wanting a relaxed pace.   Average speeds probably in the 13-15 mph range.

B – Moderately intense. “Upper intermediate” level for fit riders with a few years in the saddle.  Typical average speeds in the 15-17 mph range.

A – Intense. Brisk pace for experienced, self-confident riders.  Might be hilly and/or could involve skilled pace-line riding. Typical average speeds in the 17-19 mph range.

AA – Very intense; fast and/or very hilly rides for fit, experienced riders. Might sometimes involve skilled pace-line riding. Typical average speeds in excess of 19 mph. 

Ride Category
Average Speed (mph)
AA












Þ
A













B













C













D













E
Ü













9
10
11
12
13
14
15
16
17
18
19
20
21

Thursday, January 14, 2016

Defeat the Thieves !!!!!!

Do you want a near thief-proof security chain for your precious bicycle?  Are you willing to pay a little extra and, perhaps more importantly, are you indifferent as to its weight?


 Then proceed as follows.  Buy 3 or 4 feet of Pewag 3/8" square security chain (about $12 per foot excl. tax/shipping, Westech Rigging is one supplier), one Abus 82/70 keyed padlock (about $20 excl. tax/shipping from Zoro or similar) and some heavy duty canvas.  Wrap the chain with the canvas and secure at each end with vinyl electrical tape or similar. 


When locking your bike, if at all possible, run the chain through the rear wheel as well as the frame.  If you are using this for your auto bike rack, get enough chain to go through frame + both wheels.  If you are using it for hanging out at SXSW on your mountain or city bike, you might have to take your chances with the front wheel.


BE WARNED: my 3-ft version with lock weighs about 6½ pounds !!!!   

Thursday, November 5, 2015

Dogs and bicycles usually do not mix too well

Most dogs are normally friendly but seem to go nuts when exposed to a moving bicycle. After all, they are descendants of predators who chased down prey for a living. Some are just being naturally playful but others are, at best, protecting their territory or at worst, out for the kill.   The negative consequences for cyclists can vary.  You may collide with the dog, which could bring you down or you might lose control and fall trying to evade the creature. It’s possible (though less likely in my opinion) that the dog is trying to bite you and, if it successful, the bite could also have serious consequences.

In terms of evasive action, there are many choices but it’s important to realize that there is probably no “one size fits all”. The dog’s intentions and behavior, the road, the traffic conditions and others things make every situation different and will require split-second evaluation and judgment on your part.  So, what are your options?  In all instances, slow down.  By doing so, you increase your control of the situation. In the case of oncoming dogs, it’s even more important that you slow down and be prepared to stop as there is a very real risk the dog may misjudge your speed and turn in front of you into your path.  Ignoring the dog or dogs might be the best thing if you are absolutely sure they are either going to stay where they are or at least remain on the side of the road. 

The average dog can sprint about 19mph and some manage considerably faster speeds.  Out-running them is rarely the right thing to do. Not only is it unlikely that you'll always be able to outrun the dog but panic sprinting means you will probably not be paying close attention to the road, traffic and your fellow riders.  Some people believe that yelling loudly works but many dogs are unlikely to respond to commands and it might aggravate them further.  In fact, one rider I know is a dog whisperer; he uses a very calm voice with any dogs and it seems to be quite effective.  Spraying with water bottles is of limited use; most dogs quickly realize that the water is of no danger to them. They might even find it refreshing.  

Trying to hit them with the pump might be effective but is fraught with risk. It’s probably not a good idea to be gesticulating wildly while at the same time trying to control your bike. Similarly, unclipping and trying to kick the dog is risky and the dog might just see your leg as an easy target.  Stopping and putting your bike between you and the dog or dogs is probably effective. You then feel more in control. In most instances, the dogs will simply continue to bark and then hopefully give up and go home unless you're actually on their land.

There are various devices on the market such as the Ultrasonic Dazer which emits high frequency sounds that supposedly makes dogs very uncomfortable. www.kiienterprises.com/dazer/  They might work under some situations but not always. Let’s hope the dog is not old and deaf.  Similarly, some people recommend air horns that come in small can-sized versions and deliver a very loud burst of sound that hopefully shocks most dogs. http://www.airhornusa.com/product_info.php?products_id=82

Pepper Sprays have a lot of appeal to many riders. Various versions are available; the most popular one is www.halt.com/halt.html but www.foxlabs.com/products/pepper-spray.html is supposedly more powerful. You have to get the dog directly in the face for it to be effective so use the spray variety, rather than the “cloud”. Be sure not to spray yourself.

If you encounter unrestrained dogs and if the worst happens, these are steps you and/or your riding buddies should take: 
  1.          Seek medical attention for any injuries. Keep good records.
  2.          Take photographs of any injuries or bike damage.
  3.          Gather information, including the location of the dog's residence and the names and addresses of any witnesses.
  4.          Familiarize yourself with any local animal ordinances. There are some in many counties and most cities. Recognise that some are directed more to either preventing dog abuse or rabies control rather than protecting other road users.
  5.          Notify local animal control (usually city or county). This is very important even if no accident happens. If they take no action on the first report, they might on the second …... or third.
  6.          Consult a lawyer if you want to take further action.

 I love dogs and would truly not wish to harm them. In all instances, the problem is not with the animals, it’s with the owners. While there is no statewide law in Texas requiring that dogs be on a leash at all times, many counties and most cities do have laws requiring dogs to be on leash, or prohibiting them from being unrestrained when off the owner’s premises. Unrestrained dog are considered a public nuisance and with few exceptions, courts have ruled that violating such laws can be the basis of liability.


Monday, November 2, 2015

Bicycles, wrecks and solutions

This year has been a bad year for cycling accidents. Of our regular riding companions, a dozen or so have had significant mishaps on the road.  Fortunately, none of the wrecks have resulted in life-threatening or permanent injuries though several did end up with broken bones and periods of rehabilitation that extended to several months.  None involved automobiles, thank goodness, and many did not even involve other bicycles.

In sharing these musings, let me be absolutely clear that I am not in any way pointing fingers. Most of us have wrecked at some point in our cycling lives and, sadly, may well do so again. How can we minimize the probability that this will indeed come to pass? How can we, collectively, improve our safety record?

I have struggled to determine whether there are common threads between the incidents. In my career in the petroleum business, we were taught that all accidents are preventable. Is this true? What, if any, are the lessons learned from the incidents that we have experienced?  I suggest that there are arguably three categories of accident that the group has experienced:

First.  Riding in a way that is too aggressive for the prevailing conditions and misjudging hazards such as pavement on poor repair, obstacles in the road, unanticipated corners etc.  Best practices: always ride defensively and assume the worst.

Second. Sub-par bike handling skills. This could manifest itself as unstable or erratic riding and inability to negotiate hazards when they do appear unexpectedly. Best practices: learn good riding techniques, practice whenever you can and be receptive to mentoring by experienced riders. Remember: “to be aware of one's own opportunities for improvement is the first step towards learning” and thus we need to develop a receptive learning environment.

Third. Poor group etiquette: riding too close to others, failing to announce intentions, losing concentration. Sometimes compounded by momentary lapses of attention. These issues are especially critical when conditions are poor such as roads with lots of cracks in the pavement, ultra-steep hills. Best practices: do not ride in tight groups or pace-lines unless both you and your fellow riders are comfortable with that, always stay super-alert, communicate frequently and back-off (safely) from the group whenever necessary.

Resources are available. The League of American Bicyclists and other organizations do offer classes and or exercises in bike-handling skills and group riding skills. Maybe this would be a start?  Remember that ultimately you have responsibility for your own safety but that does not imply that we do not also have accountability for the safety of the group we are riding with.


Note: this summary excludes two other issues: (a) dogs which will be the subject of another blog post sometime soon and (b) the condition of your bike which could also cause accidents in some instances: frequent servicing by a competent mechanic should be treated as an investment, not as an expense. 

Thursday, October 1, 2015

Guglielmo la Gazzella

Let’s ride Coast to Coast; from the Adriatic to the Mediterranean.  We did just that and thanks to friends Gil Rappaport and Mike Perlmutter, I was invited on the trip, organized by Ciclismo, a high-end Italian bike touring company.



Eight days of riding,  about 400 miles or so and 24000 ft of climbing, give or take. We made it up a "virtual" Annapurna, even if we missed climbing Everest and along the way, I must have consumed three dozen macchiatos and even more glasses of fine Italian wine. Here we start from Pesaro on one of the rare wet days. 


The senior guide did warn us that the trip would be quite intense (his word).  He was right: in addition to the days' rides there were history lessons, Italian lessons, wine tasting and various tours. We are pretty much on the go from about 6 in the morning till 11 at night and by the end of the trip, we understood what he meant. What a hardship!


We had hills-a-plenty but they were usually longish rather than steep.


All the towns we traveled through were "drop-dead" gorgeous with narrow winding streets that must have held many secrets. All our hotels were centrally-located and several were been built in the 13th or 14th centuries. I suppose I can forgive the fact that the décor and furnishings of a few were inevitably rather tired looking.



Over many parts of Central Italy, massive volcanic activity spewed hundreds of feet of ash (tuff), some of which resisted erosion and formed the foundations of many of the medieval hill towns.



Each town square has its Duomo and Town Hall.  Most are huge and impressive though often rather inelegant.
  



And I was constantly being warned what might happen if I do not mend my ways.


On the occasion below, a well-known wine merchant hires a Michelin-star chef to cook for us. Sadly (for him), though the food and wine were delicious, no sales transactions were consummated. I guess most cyclists are just not into $80 bottles of wine.



Here I was trying to blend in with the local bathers at the Saturni thermal springs. More white quivering flesh than you can shake a stick at.


Occasionally, we did allow our achievements to get the better of us ......


But then, we did make it, finishing up at Porto Ercole, yeah ...... !!!!



Wednesday, September 30, 2015

A Yorkshire cycling interlude

The Yorkshire Dales are a series of predominantly east-west rivers in Northern England separated by high fells of dramatic limestone crags and moorland often covered in purple heather.


 The lower levels of the Dales are divided up into arable fields by dry-stone walls, some of which date back to Anglo-Saxon times. 


Gushing springs spew torrents of clear water from the karst limestone. These form becks (streams) that are quickly turned golden brown as they flow through the peat on their way to the rivers below.


Old, old villages, in some instances dating back a thousand years or more, remain clustered on the rivers.


It was the stark beauty of the Dales, and the steep climbs that separate them, that attracted the Tour de France to the area for Le Grand Depart in 2014.


 Some remnants of Yorkshire’s enthusiasm for the tour remain.



A year later, I fulfilled one of my “bucket list” goals and spent a couple of weeks in the northern Dales (primarily Wensleydale, Wharfedale and Swaledale) revisiting Stage One of the tour …. on a bike, of course. Sharon and I rented a house in Middleham, where the Castle, built in 1170, had been the childhood home of Richard III.  


This then, was the base from which my nephew Nick and I set off on our two-wheeled adventures.  


 Of course, cycling up and down the valleys is not too difficult but to cross from one valley to another involved climbs that are not unusually 25% and, on the corners, can be even steeper.  In some instances, these gradients are configured in spectacular hair-pin bends; super-challenging to climb and scary to descend. 


I had rented a bike from a shop near Richmond. It was a reasonable quality carbon Bianchi but alas, equipped with woefully unsuitable gearing. Ideally one would have a 34/32 as the low gear for this terrain but my machine had only a 36/25.  One of my more embarrassing moments of the trip was on one notorious hill when I simply could not turn the pedals. It was a case of get off or fall off. 


 The other awkward incident was on a descent in wet weather when the brakes simply could not bring the bike down to a safe speed. That resulted in an unfortunate encounter with a bridge at the bottom where the turn was just too sharp. The medieval structure won but thankfully only bruised knuckles resulted.


Rural Yorkshire is a very bicycle-friendly part of the world.   Even in years long past, establishments welcomed cyclists as witnessed by this old CTC sign.


Of course, morning coffee with delicious “elevenses” is an essential part of a bike ride and many cafes go the extra mile for customers who arrive on two wheels. For example, Zarina's cafe in Kettlewell has a 10% discount for cyclists, good inventory of maps, several bike racks, floor pump etc. etc.  Most importantly, try their delicious scones with clotted cream and strawberry jam. Five star.


Yorkshire is having to replace a livestock-based economy with tourism though a few remnants of the traditional way of life remain.  This grim manifestation of English rural life was a surprise:  the results of the local mole catcher's efforts. The use of traps had died out with the introduction of poison. However when strychnine was outlawed in 2006, the traditional method of mole-slaughter returned.



 Of course, recreation in the evenings usually centered around one of England's greatest institutions.