Perhaps I should have written "accumulation of the bad effects which accrue from muscles experiencing high tension". Whether that's lactic acid or not is too much detail for my simple brain.

djconnel wrote: to reduce accumulation of lactic acid.

I think you were going pretty good until you got to this chestnut. It's a myth. Review your exercise physiology.

True enough.

But at high power there may be a small hit in drivetrain efficiency: the chain is at higher tension, and bends more when it hits both when it leaves the cassette and when it hits the chainring, with a smaller chainring and cog than with a bigger chainring and cog. The chain moves slower, but this will only offset one of the two other factors, not both, I suspect.

The smaller chainring and cog is likely better at low powers since then chain speed is more important: the chain moving slower through the pulleys is an advantage. But at high tension the tensioned (upper) part of the drivetrain may be the most important part.

Still, I like compact because I like access to the smaller gears.

Dan, I'm sure you're also well aware of the fact that a 50-34, 11-23 setup is lighter than a 53-39, 12-27 by several grams :D

Nonsense. 42-19 or die. You just need to master the "Merckx head bob".

With a compact crank you can still climb at 60, 70, or 80 rpm if you like. It's just nice to have the option of spinning at 90 or 100 rpm. :D

Back when men were men, and they pedaled uphill at below 60 rpm:

1974 Giro d'Italia

Lay on your back with your legs in the air. Spin them slowly. HR goes up. Now spin them faster. HR goes up more. Zero power.

So of course higher cadence is going to have a metabolic cost. The motivation for low cadence isn't HR -- it's to reduce peak force on the muscles, to spare fast-twitch muscles, and to reduce accumulation of lactic acid.

If energy efficiency is your goal, use as low a cadence as possible.

But I'm not talking about becoming a spinning fiend. A lot of folks have issues cracking even 70 rpm on climbs.

Careful with numbers, too much focus and you lose the dynamic aspect of racing.

The body is an amazing thing, and you can learn to adapt by trying different styles of riding. The numbers might tell you to run little gears in order to climb. But, if you are sloppy while trying to spin up a hill you are leaving power on the table. Sometimes a slower smooth pedal stroke can turn out to be more efficient.

Consider this:
If a rider reduces the cadence from 95 to 85 by turning a bigger gear the resistance is increased, but if the rider is able to clean up his pedal stroke, and drop his heart rate the power is being produced more efficiently.
There is a calculation on the Computrainer called "Pulse Power". It is a calculated using HR, Watts, and Cadence. A higher Pulse Power number means you are producing more watts per heart beat. A higher HR that produces a lower Pulse Power for the same watts is an indication that the cadence is inefficiently too high.

I tested a rider that was convinced that he needed to TT at nearly 100 RPM. We did a Pulse Power test using 300 watts for 3 minutes. 1 test at 95 RPM, a second at 100 RPM, and a 3rd at 83-86 RPM.
Same watts, same speed, different cadence. The Pulse Power was substantially higher at the lower cadence. Meaning, he was going just as fast, producing the same speed, and doing it a lower HR.

There is also an aspect to consider as it applies to the muscle contraction itself. A slower cadence allowing a rider to focus on good pedaling form can also allow muscles to relax while not under load. At least this is my experience. This may also be the reason for a lowered HR at the same power output.

Note: Turning a big gear requires the ability to produce a deeper muscle contraction and more muscle fiber recruitment. It's not for everyone, and I would encourage anyone think they will climb in a big gear to develop leg speed for the flats as well. You need different gears in the legs. There is a time to spin, and a time to turn the big gear.

As it applies to climbing, there is no one right way, there is no one cadence fits all, and being able to do both is always nice.

Ron

A top Euro pro can sustain around 6.7 W/kg at "threshold" (according to Dan Coyle's Lance Armstrong's War). Let's suppose he uses a 39/23 for steep climbs.

Take the 6.7 W/kg, divide by W/kg, multiply my 36, divide by 39. See what you get.

If it's less than 21, the compact's probably too small for you.

For example: climbing 5.1 W/kg: I get a 36/28.

A similar calculation can be done with sprinting speed. Tom Boonen reports sprinting at around 70 kph at the end of stages. Similar calculation.

Built my own 11-27 Dura-Ace cogset out of the 12-27. Removed the 14+shim and added the 11. keeps the 16. Dropping from 15 to 13 is no big deal for me. Works the same to build an 11-25.

The draw back is building the chain long enough to cross chain 53/27. Tension wants to pull chain off of top pulley. Kinda have to stay out of that gear. May not be a problem with 50/36-27

I rode a compact for a few weeks last summer and was not the biggest fan. I am more of a power rider and only spin quickly on the hills and even then a 39/27 was more than enough to survive races like the Gila.

As power meters become more common, it is fun to see the guys switching over to compacts after a few months of a PM. I can recall four guys within the last 6 months that told me how they thought they made more power grinding out a climb, until they downloaded data and did some testing.

I have had a compact since 2004 and love it. I used to get a ration of crap about my 34/27 on training rides and such, now people don't say a word (similar to my 42mm deep carbon wheels I raced at Patterson in '04). I am a 98-102RPM type guy, so 80RPM efforts really kill me.

I built a new bike last year and put on an 11/26, and I wish I would have done the 11/28 for training and hilly races. As Kevin stated, it sucks not having a 16T, but spinning for me is the only way I can maintain power.

4 years ago when I was using a coach, he never stopped bugging me about switching to Compact since I live in the foothills and all of the riding is hilly. He wanted me to be able to do a 3 hour ride in zone 1, which is pretty hard if there is going to be 5k of climbing. So i finally gave in and love it! I love that 27 tooth cog going up the hills when I am trying to take it easy.
I have always switched to the 11x23 for racing but after reading this I think I will keep the 12 x27 on!

One for her bike and one for her nose. :wink:

windblocker wrote:where is the jan ullrich of the ncnca, man if you are out there chime in! tell us about you climbing mt figueroa in your 53x39, 12x25, i know you are out there

I've been called out...

52/36 Rotor q-ring combination. Best of both worlds.

Mad Axeman wrote:
Interesting, in contrast one of my best results at Copperopolis was on a single speed with a 46 x 16.

Wait a minute, we just elected someone to vice president who's crazy enough to do Copperopolis on a single speed?
Aye carumba!

slowpoke wrote:Kevin, is the 50/36 a Shimano combination? or another manufacturer?

I think that most compact's come standard with the 34. My SRM compact did. I used that for a while until I got Q-Rings which at the time only had a 36.

Kevin

Mad Axeman wrote:"I use the 12x27 at Copperopolis and absolutely use the 36x27 every lap on the steep climb."

Interesting, in contrast one of my best results at Copperopolis was on a single speed with a 46 x 16.

But it also seems that smaller riders are more comfortable getting in and out of the saddle rather than trying to stay seated.

I don't know how you make that little bitty gear go that fast, but if it where anyone else I would be skeptical.

-R

I just looked at my power file from Copperopolis last year. It looks like I was riding that climb seated at about 80 rpm in my 36x27. 80 rpm is a pretty sedate cadence. What kind of cadence is somebody in a 39x25 using? 60-65 maybe? For me, that kind of effort (low cadence, big gear) kills my legs.

It is also my experience that smaller riders can ride a bigger gear and get out of the saddle with less cost.

For me, using the smaller gear allows me to maximize my strength which is more aerobic engine and pure force from my legs.

Kevin

where is the jan ullrich of the ncnca, man if you are out there chime in! tell us about you climbing mt figueroa in your 53x39, 12x25, i know you are out there

"I use the 12x27 at Copperopolis and absolutely use the 36x27 every lap on the steep climb."

Interesting, in contrast one of my best results at Copperopolis was on a single speed with a 46 x 16.

But it also seems that smaller riders are more comfortable getting in and out of the saddle rather than trying to stay seated.

I don't know how you make that little bitty gear go that fast, but if it where anyone else I would be skeptical.

-R

Kevin, is the 50/36 a Shimano combination? or another manufacturer?

Wall Point wrote:Kevin,

What size cassette do you typically run with your compact crank set? 11-23 or other?

Just curious what you find works best for all around ridding.

Tony

I leave a 12x27 on for general training. For races it depends. For anything flat and TT's I'll use an 11x23. I used the 11 a couple of times last year at the Putah Creek TT, but only with a pretty good tail wind where I was going around 33mph or more. I never came close to spinning it out (low to mid 90's for cadence in that situation). On the other hand for a flat crit I really don't care what is on either end. I could use an 11x23, 12x25 or 12x27 and it wouldn't matter. The only bad cog set would be something like 11x26 or 11x27 because I'd loose my 16 tooth cog. For a crit we'd probably need to average 35+mph for a 50x11 to get uncomfortable.

I use the 12x27 at Copperopolis and absolutely use the 36x27 every lap on the steep climb. I also use it at Patterson Pass. It is nice to be able to climb comfortably in the saddle while everybody else is struggling at 60rpm.

Altamont Pass towards Tracy is the only place where I've missed "man gears". In the P/1/2 race there a couple of years ago it was painful to ride in the pack at around 50mph down Altamont with the tail wind. I was also completely spun out at the Altamont TTT in August. But I was too busy being terrified to worry about wanting to go faster!

I also find that the compact gives me the option of staying in the big ring on crucial laps at Cat's Hill (50x27) or Nevada City (50x23 or 25). I could never do that "back in the day" when I was a young cat 1 with a 53x23, though others could and they sometimes won because of it.

Juniors who use compacts can ride a 48/34 up front with a 13 small cog, or a 45/34 up front with a 12 small cog. The standard 50/34 setup is a disadvantage for them.

George Meilahn
VP Juniors

Kevin,

What size cassette do you typically run with your compact crank set? 11-23 or other?

Just curious what you find works best for all around ridding.

Tony

I have a compact, but use the 50x36. For flat rides/races I have an 11-23 and for climbing a 12-25. The 36-25 is the same as a 39x27..so it's easy on my surgically repaired knees.

And Kevin is right....that 50x11 is plenty of gear!

James

ZebraMan wrote:I just got a compact SRM, but since I don't often climb, I'd rather have gotten a 53/39. I'd rather have the upper end for the power rush than the little tiny gears in case I somehow got lost and had to climb.

50x11 isn't big enough? Seriously? That's bigger than a 53x12...

BTW, I'm sure you know, but just in case you didn't, you can put a 53x39 on the compact SRM.

Kevin Metcalfe

Thought about it, but spinning on a climb is not friendly to my hummingbird heart.
My perceived exertion for the same speed in a larger gear is much lower.

If I had a 50 x 34, I would probably never use the 34.

Ron

I just got a compact SRM, but since I don't often climb, I'd rather have gotten a 53/39. I'd rather have the upper end for the power rush than the little tiny gears in case I somehow got lost and had to climb.

I started racing with a 50-34 and only switched to 53-39 last season because the SL2 Module came that way. I have since ordered a compact spider and 50-34 chainrings so I'll be switching back to 50-34 soon.

I like hills & I like to spin lower gears up the hills.

Compact? Yes.
Sissy? Maybe.