rsbob 

Very helpful..Thank you

Looks like Jan Ulrich just didn’t quite have it right. But he did enjoy some nice ‘juice’.

PeteHski

This reminds me that Jan Ulrich was actually "grinding" at around 90 rpm. Lance was spinning at around 100 rpm. So it's all relative. The pros have always been "spinning" to a large degree, except when limited by their gearing on very steep climbs.

chaadster

Wuuuuttt?!?? Tell that to his Olympic gold medals, TdF win, Vuelta win, numerous other wins AND the pro team he rode in on.

Trakhak

To clarify before people jump on you: you're not saying that he wasn't on the juice, only that his results show that he was spectacularly successful everywhere except against the even more juiced Armstrong, and then only in the Tour de France. Where, let us remember, he won once and podiumed repeatedly.

chaadster

Kinda, yes… Correct, I’m not saying he wasn’t on “the juice,” but rather am pushing back against the statement that Ullrich “didn’t quite have it right” with regards to cadence. He was a top-level pro with some of the most prestigious wins in cycling.

63rickert

Force equals one half mass times velocity squared. Apply that basic physics formula to pedal speed.

Pedal with exponents on your side.

90 or 100rpm is barely beginning to be spinning.

Does anyone here do a warmup? You should, any sport, and emphatically in cycling. Do that warmup at 110 and 120rpm. Easiest way to do that is to have a group that does that. Used to be every cycling club everywhere did exactly that. Those clubs are gone. Doing it on your own is harder. It can be done. It can be done faster.

Last summer I was 70 years old. Last summer I finally got to being able to go downhill smoothly on a fixed gear at 200rpm. Young people can spin much more easily. You believe you can't. Try believing you can.

RChung

That's not force.

63rickert

That is the most common form of the physics equation.

I expected there would be someone picking nits to no purpose. The word force has a variety of English language meanings, the physics meaning is perfectly clear.

No one is ever going to understand the mechanics of pedaling if they don't understand the physics. You can understand the physics intuitively or practically while never knowing the formula. If you can apply the formula you will understand lots. Try. Just try. Or attempt to score points online and know nothing. Suit yourself.

79pmooney

Fix gears! Cadence? I learned long ago if I didn't ride with exactly the cadence of my fix gear, the outcome was very poor! I started riding fix gear because the club vets told me it would smooth out my pedaling style. And, wow, did it! Especially going down hill. The longer, and steeper the hill, the better. Incentive! The smoother I pedaled, the faster I could go and the more fun that descent was.

18 months after I stopped pinning on race numbers, I was rebuilding my life after a big accident. The crazy years. To stay sane, I would ride up Oakland's Jauquim Miller to Skyline, turn around and blast back down; on a 42-17. (Now 42-17 yields 20 mph at 100 rpm.) I never was passed by a car going down. California 4 lane parkway with a park median. So I had to be going what? 45+?

And the true all-the-time gift of that high speed fix gear work - my body learned to relax those muscles not actually providing power. (On Jauquim Miller, that's all of them!) Long hard rides and doing those final miles hammered, fix gear or no, what a gift! And those completely relaxed muscles get to be in recovery mode, if only very briefly, unlike the muscles that haven't been "taught" to relax while you pedal.

And sadly, next summer I'll be 70. Those 250 rpm descents - long gone. 200 is still there and still fun. But I stop and put on tiny cogs now for the big descents to keep the rpms down and fun up. (The sad part is the lost rpm. Hitting 70? Big win! I'm making it!

tomato coupe

Whoa there. Your “most common form of physics” is incorrect. Your equation represents the kinetic energy of an object.

RChung

I'm not sure it's the most common incorrect form, but nonetheless it is incorrect. That you got this basic equation wrong did not bode well for the rest of your post but I read it anyway. Then I decided that it was indicative.

But congratulations on your 70th birthday. That you still enjoy riding is a wonderful thing, and that's far far more important than your lacunae in physics.

rsbob 

Josh knows - almost…

Troul 

force can be a form of torque. I like torque multiplication.

PeteHski

I thought your name rang a bell and then I recalled your last attempt at physics - Gravity:-

Why does one bike climb better than another?

I would stick to your day job if I were you.

PeteHski

As in Torque = Pedal Force x crank length

ofajen

Force is not energy and the internal work of pedaling seems to follow a power law, not an exponent.

However, it is a sharply increasing function of cadence, so you make a great point that spinning is a good warmup.

From Formenti’s data, you can assume about 1.0 W/kg at 110 rpm. It appears to obey a cubic power law in the region (50-110 rpm) that he published.

If that power law continued above 110, you would spend 1.3W/kg at 120 and 1.65W/kg at 130. If it applies out to 150, that would be 2.5W/kg and if it still applies at 200, you are spending 6W/kg (I assume most of it from your rider/bike kinetic energy) to move your legs and the pedals.

Of course, it’s not all clear that we should assume that function continues at those higher cadences.

Otto

livedarklions

I'm fast mashing at 50.

Iride01 

Well many of us don't have strong enough legs to push a 85 tooth chain ring at 50 rpm in the 11 cog. <grin>

I find a 52F/11R at 80 - 90 rpm a little easier to deal with. Though I'm winded soon after getting there. But for downhills 110 to 120 rpm in the 11 cog can be easy and sustained longer.

skidder

I still find a lower cadence (in the 75-80 RPM range) to be more comfortable on a long ride. If I try pedaling into the 90s RPM range and I just start breathing faster and get exhausted. If I'm running out of gas I just shift down a gear or two and keep the same slower cadence, seems to work for me. YMMV.

PeteHski

Well it is definitely more comfortable to ride at a relatively low cadence with a relatively low pedal force. Where it becomes more efficient to increase cadence is when you are riding at tempo and above power, otherwise the required increase in pedal force soon becomes your limitation (Power is proportional to pedal force x cadence). But it requires a degree of cardio conditioning and muscular coordination to achieve. Interval training plans typically focus on both of these performance aspects.

ofajen

That makes sense. You’ll be using about 0.3W/kg more at 90 rpm than at 70 rpm at a given speed. If you read the article I linked earlier in this thread, you’ll see that as part of the discussion on the four big buckets of cadence situations. One typical situation would be you use higher rpm to accelerate and then shift to allow a slightly lower cadence for speed maintenance, since the cardio load is a bit less at a given speed.

Otto

63rickert

Six watts per kilo would mean putting out close to 600 watts. I can still do that, I think, but I would be winded. Instead it is just relaxing downhill. Once smoothness is achieved it is no more work than coasting and then at bottom of hill you are ready to do something.

The way you are thinking is how people think when they have never learned to spin. Or never even tried.

The pedal and leg moving fast puts out a lot of force even when only floating the pedal. The whole game is to create force while not leaning a lot of pressure on the pedal. Stop using pedal pressure and you also stop burning your muscles, making lactic, getting stiff and sore. Speed changes are easy and low stress. Your calves will get smaller and then you don't have to lift that weight.

I have been at this a long time. The guys I learned from were my age now when they taught me 50 years ago. Some instruction even earlier than that. We used to look at the new kids who had built big thumping calves and laugh and say "pedal pressure".

Peter Post set the course record time at Paris-Roubaix in 1964. His speed only surpassed in 2017 and 2022. Post had much worse weather. Post had no 11 tooth cog. He had no 12 either. And no 13, although those did exist. No one spins anymore. Because they never spin and never learn anything they imagine knowledge they just don't have.

tomato coupe

Your physics is still all mixed up. If you’re not putting any pressure on the pedal, you’re also not putting any force into the drivetrain.

ofajen

I’m not suggesting you are necessarily doing the work of pedaling at 200 rpm. On a fixed gear going downhill, the bike will do whatever work you don’t to move feet, pedals and legs at the relevant speed and will extract that from the kinetic energy of you and the bike.

Otto

63rickert

Do you understand how n+1 works? Mechanic secures a quick release normally, customer can't force that thing open at all. The mechanic has big strong hands and did nothing unusual. Customer can't even imagine that level of force.

Yes, I float the pedals. The weight of legs, pedals, cranks is moving. Move that weight faster it puts out power as a square. Lift the pedal and let gravity take it down. And no forcing the pedal on upstroke either. But your leg isn't going up by itself and defying gravity. You either lift that leg or you are forcing it up with power on the downstroke of other crank. You absolutely are pushing down on both pedals if you haven't trained not to. It will be easier if you spin.

I was taught and taught and taught to float the pedals. Teachers who had names would be Othon Ochsner, Sr. and Jimmy Walthour. Othon won the 1919 Swiss Pursuit Championship riding a gear of 23x8, which was thought huge at the time. Pursuit was a 10,000 meter event back then but Swiss Timing and his 4000 split was 5:04 so we can compare with modern. That was with a roll off the line start because 10,000. Figure out what Othon's rpm was. First American to beat Othon's time was John VandeVelde 1968. Who was coached by Othon. And I rode with both those guys. Telling them weight on the pedals is required wouldn't get you far.

Back then cycling in US was largely a sport for immigrants. Who showed up for the club rides were guys from everywhere. It did not matter if they had just arrived from Bogota or Buenos Aires or Bologna or Belgrade. Everyone was on the same program, everyone rode smooth and with pedal speed. We knew what we were doing. Now every single person has a theory and every theory is right. Which is why group rides fall apart if they ever get going at all. Spinning is not natural, you have to learn it. If your head is filled with ideas you will never try. Worked so much better when the guy who won 14 six day races (Walthour) told you what to do and you did it.