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big gear small gear thing..(9 posts)

big gear small gear thing..bisiklet
Aug 6, 2002 1:43 PM
Well for starters I am a tall guy. (6'2" and 167lbs with 10% of body fat). Everytime I see the magazines and everything all they say "instead of shifting a big gear, increase your cadence" I dont think it applies to flats with very light or no wind. It seems like it works on the flats IF there is a huge headwind or on the climbs. However even you spin like crazy on the small gear, big gear would kill small gear on the flats.
It worked for me. I dont know what you guys think. I am always open to suggestions and ideas. What do you think of this gear thing??
re: big gear small gear thing..shirt
Aug 6, 2002 3:40 PM
When you're on the flats with no headwind or even a tailwind, you're not working as hard as you are in the scenarios you described where a high cadence is desirable. I know if I'm on a slight downhill, have a tailwind, or am resting in somebody's draft I always kick it up a gear or two. I tend to spin between 60-80 rpms in these conditions. If I'm on the front of a group attempting to distribute demoralization, I spin at 96 rpms. Yep, 96 exactly. I don't try to hit that, but every time I'm in that position and I happen to take my cadence that's where I'm at: 96.

Regarding climbing at a higher cadence, I know it's all the rage now for obvious reasons (Lance) and has been discussed ad nauseum on this board. For me, my climbing limiter has always been my cardio-endurance, so I tend to favor getting more power out of my legs. I sit most hills and 'spin' at 60-80 (depending on pitch.)

/shirt
Check the record booksKerry
Aug 6, 2002 5:17 PM
You'll find that every hour or distance speed record has been set at a cadence of 95-105 rpm. What do you suppose these guys know that you don't?
Interesting fact.allervite
Aug 6, 2002 9:36 PM
I read in one of Burke's books that although most records have been set with a cadence of 95 to 105, most of the riders that have been tested are most efficient at a cadence of 80.
Check the record booksbisiklet
Aug 7, 2002 6:01 AM
May be there is a little difference between the record holders and me. I only shift down (easier) when there is a hill or a huge wind. I take it easy on the climbs and wind (not easy easy but a little easier) i improved my average speed and max speed at the same distance and terrain. If I go higher cadence I just get tired after a while and have to reduce my speed. Well.. maybe its just me.
Another difference between the pros and youKerry
Aug 9, 2002 5:27 PM
They have trained themselves to pedal at a high cadence, because they belive that it is better for overall performance. They believe this because of their own personal experience, lots of demonstrated results, and the behavior of virtually all experienced cyclists. If one doesn't believe this and therefore doesn't train for a higher cadence, one will never experience the benefits. Simple as that.
Another difference between the pros and youbisiklet
Aug 13, 2002 8:08 AM
I think everybody on this discussion decided their own cadence issue and i believe alot of questions were answered. High cadence is for specific things as i and others mentioned. And what is a high cadence anyway sometimes 130 is high 100 is low 95 is even lower. and sometimes even 90 is very high. So like everybody says it depends. it depends on headwind, tailwind, time trial, hills, crits.. I dont think pros do same high cadence on everything. Well lets say one did not experienced the world record benefits because of high cadence or low cadence.. life still goes on, and Britney Spears makes alot more money than pros..
cheers..
bisiklet
Tend to agreePing_Pong
Aug 7, 2002 4:33 AM
On a mainly flat time trial I would tend to use a bigger gear, nothing massive, but keeping my rev's 85-90. In the latter parts of the ride I move up further through the gears gradually bringing the cadence down. Once I have done a final couple of minutes at say 70 rpm I am spent for a few days !

This strategy has always produced my best results.

Does this mean that my cardiovascular fitness is my limiting factor ? If I try and hold 95rpm throughout my bpm goes through the roof !
torque and powerDougSloan
Aug 7, 2002 6:24 AM
I think the analogy of a car motor is apt.

Car motors tend to make more torque at lower rpms than peak power. They also tend to be more fuel efficient at lower rpms, unless the rpms are so low the motor "lugs".

High rpms are necessary to make peak power, but again up to a point.

Keep in mind the torque is twisting force. It will accellerate the vehicle. Power is how quickly can work be done with that twisting force. Power (horsepower or watts) determines top speed, or how fast you can get up a hill.

Heavier vehicles need more torque to twist the crank to accellerate. On a bike, high torque is usually acheived by standing and pulling hard with the handlebars. You can't do this at 120 rpms effectively. Similarly, high torque in a car is acheived with longer piston rods and crank throws. Again, the trade off is less ability to spin quickly. A semi-truck might have 2,000 foot pounds of torque and 400 horsepower. A formula race car might have 200 foot pounds of torque and 800 horsepower. Each is designed to be optimized for a special job, and efficiency is designed in, too.

Riding at record pace will require lots of power. That's what it is all about. Lots of power requires burning lots of fuel and oxygen. We tend to make more power at higher rpms, limited by our ability to supply oxygen. We make more power because the legs muscles are contracting at a higher rate, more times per minute. Even if each contraction might be a little weaker than at lower rpms, the higher rate of contractions makes up for it.

Each person, like various car motors, will have different power/torque curves and ability to supply oxygen. Some of us are diesel trucks, some of are formula cars, with all sorts in between. Lance Armstrong is sort of a formula car with a very efficient intake/exhaust system, allowing high rpms and thus more power. That's why he does well at power-dependent modes -- hills and timetrials. I haven't seen him win many sprints, though.

Ideally, you'd put yourself on a dyno and determine your power curves and oxygen utilization at various rpms. Then, you'd race at the highest rpms you can sustain for the duration of the event while making the most power. Ya, right.

Think of a continuum of rpms. No doubt you'd not want to ride 10 rpms in a huge gear. Your legs would turn over so slowly you'd not make any power. You'd not want to spin 180 rpms for long, either, as too much work goes into internal friction, just moving your legs around, and you'd lose efficiency, gasping for air despite not doing a proportional amount of work. Every spin on rollers, doing almost no work? You can get out of breath with almost no external load.

So, max efficiency might well be around 80 rpms or so. If you are riding RAAM that's important. If you are setting the 1 hr record, efficiency can be compromized for more power for that limited time period.

Muscle fatigue throws a wrench into all this mess, too. Some muscles get tired, then we might well make more power temporarily by switching from sitting to standing mode, for example, or simply changing rpms.

Doug