torque cyclist

i'm looking to increase my power output. Both HP (or watts) and Torque. So what i'm interested in noting is how much most cyclist are concerned about each factor; Power, RPM and Torque.

My bike has a 21 speed Shimano EF40, 48 tooth front (highest) and as low as 14 tooth rear. 26 inch rim

Personal stats
195 lbs, 5 foot 5
bike 45lbs (about)

Now, I personally like to cruise in the final gear (48x14) and turn about 50-60 rpm. according to bike calc, that plots me at 12.5-15 mph cruise speed. ranging 120 watts- 170 watts. Torque being around 17 lb/ft and 20lb/ft. I hope to be able to cruise 20mph in the future, and that's calculated for 305 watts, @ around 80 rpm 27lb/ft torque.
(MTB tires, and normal handlebars etc.)

I feel most comfortable at those lower RPM, but I can feel alright at about 80 in a lower gear. I was wondering if anyone else prefers a lower cadence as well. My legs are generally strong, but spinning faster is a bit more difficult.

gsa103

Once you're above about 5 mph, torque doesn't matter. To a large extent cadence doesn't really matter. Power is basically the only thing that matters. For the most part, low rpm mashing feels like you're doing a lot of work, which you are per pedal stroke, but you're generating much less power than someone at a higher rpm.

With a little bit of practice, most people are more comfortable spinning at 80-90 rpm. Clipless pedals make it a bit more comfortable at high cadence. The advantage of spinning is that you gain a much larger usable range.

In your case, the simplest way to increase power is probably to ride more.

torque cyclist

yeah, HP/watts is the only true measure. was just thinking of the possibility of raising the TQ value in order to raise the power output. currently at 50-60 rpm in high gear my legs push that with relative ease on a flat. Once I get comfortable I should be able to hit 80-90rpm, and the force on the legs shouldn't be the limiting factor, rather my crap cardio.

hamster

Estimating your power based on your speed on a flat road is a very tricky proposition. It depends a lot on your aerodynamics and even more on wind speed and direction (2 mph wind is virtually unnoticeable when you're standing still, but it can seriously mess your power calculations.)

You mention 45 lbs bike and MTB tires, which further convinces me that your config is way off compared to what bike calculators assume. One of the determining factors of your aerodynamics is the angle between your torso and horizontal. A well-fitted road bike allows you to go very low (at least 45 degrees off vertical, possibly as low as 60 degrees) while keeping things relatively comfy. A 45 lb bike is most likely going to be set up for upright posture, which means bad aerodynamics.

If you want a good power estimate, find the steepest hill you find. Steep hill minimizes the effect of aerodynamics. Make sure to get your tires fully inflated (MTB tires are going to be a handicap anyway, but having them at proper pressure should minimize the handicap.)

torque cyclist

yeah, it's hard to be accurate without proper sensors. i'm relying on a friend watching pedals and a guestimation from a online calculator for everything. My tires are slightly above recommended pressure. the only thing i'm sure on is the gear speeds at cadence.

What is the major limiting factor for all you guys and gals, force/torque or cardio and endurance? For me at higher speeds my legs cope just fine but going faster makes me overwork the cardio aspect.

rpenmanparker 

You will be a better cyclist if you can comfortably get your cruising cadence into the 90-00 rpm range. It takes some practice.

hamster

The limiting factor is always cardio. My legs are strong enough to put out as much as 800 W for short periods of time, but, since my cardio system can't supply oxygen to the legs nearly as fast, if I try to go at 800 W, I get exhausted in 30 seconds. My cardio can supply oxygen for 200..220 W and I can go for an hour nonstop at that power level.

Comfortable cadence will increase with practice. Weight training (squats/leg presses) may help too.

You are probably not going to get to 300 W sustainable (cyclists often talk about max 1-hour sustainable power, or FTP). You can get to 200, you _might_ get to 250, 300 is very unlikely. You can exceed FTP for shorter periods - e.g. if your FTP is 200, you can go at 250 for 10 minutes with enough motivation.

It's much, much easier to cruise at 20 mph on a road bike than on an upright MTB.

gregf83 

I wouldn't worry too much about torque and power until you get some more miles in your legs. Work your way up to riding consistently from 10-15 hrs/wk and your cadence and power and torque will sort itself out. At the moment you likely don't have sufficient fitness to make your legs tired. You need to build up the oxygen transport system within your body which takes time on the bike.

Cruising at low RPM feels comfortable to you now because you're not putting out much power and the force you're applying to the pedals is relatively low. As your fitness and power improves your cadence will just naturally increase.

datlas 

Agree get more comfortable at 90-100 RPM.

Ride more.

torque cyclist

i'm not sure as to what sort of output a typical cyclist makes. from my estimations, at cruise speeds i'm outputting about 20lb/ft @ 50-60 rpm, while the lower rpm are reducing potential power output. From a bit of messing around with calculations and such a road bike and for my cruise speed, my friend on his road bike only needs to output 70 watts, and his cadence is something like 80+. He usually averages about 18mph, but because between bike and me, he slows down for me.
300 watts might be a bit high. right now a 48x14 is the highest gear I have, so in order to get to 300 watts, I need to spin a minimum of something like 80 rpm, meaning I need cardio work. I would be interested in seeing how my legs deal with even higher gears. I can do 5-600lb leg presses and have done as much as 720.

Vicegrip

what are you wanting to do? for fit humans a cadence of 50 to 60 is not in a good range for the way we work best. you can play around with numbers and calculations all you like but I suspect you are similar to any other human of your weight, height and fitness. (unless you look up and see the bottom side of a bridge)

What goals go you have? faster? Longer? Farther? Less hurt after?

Per your post you might want to do a bunch of squats at low rep and high weight. This will up the low rpm power numbers but not for long durations.

This is not the way to increase total power and duration on a bike BTW. Cardio fitness and cycling form will.

achoo

First, 720 lb leg presses are nothing to write home about. Sorry, they're not. At your weight, even doing a 720 lb squat just makes you a merely decent drug-free powerlifter. (A 195-lb drug-free lifter who can squat 700+ is like a decent cat 3 bike racer - likely to crush any random person off the street, but in the right places you'll find literally hundreds of stronger people who can crush a 195-lb lifter who squats 700+. Just like at bike races there are a LOT of riders who can crush a decent cat 3. FWIW, I used to be a competitive powerlifter...)

Second, drop the emphasis on torque. There's a reason why NOBODY who cruises at 20+ mph does that.

Because mashing away at 50 RPM is not going to make you fast. High force means your muscles are burning carbs and not fat. You only have a limited supply of carbs to burn and when you're done, you're done. It's called "bonking".

And it doesn't even work for short distances/times. Track racers don't mash either.

torque cyclist

yeah, I never mentioned that 720 was that much, how much is your leg press? I've never actually heard anyone talking about torque, or leg presses. I mean the basics of power is HP= torque*rpm/5252, from there convert the HP to watts. by increasing torque from 20lb/ft to 30lb/ft @80 rpm the HP jumps from .3046 hp to .4569 hp, a significant increase in power from a 10lb/ft increase.

achoo

Leg press is not an exercise you can compare results in because machines differ.

But I've done over 1200 lbs if you care to know.

I've also squatted over 720 lbs. And that is an exercise that can be compared.

Yeah, in my comparison above to racing categories, as a power lifter I'd have been a cat 2 or maybe a crappy cat 1. Still well under the best amateurs and not in sight of pros, with lots of venues chock full of guys stronger than me even though I'd likely have been the strongest guy by far in any random gym. There were gyms where'd I've have been almost a weakling, though.

And that's all pretty irrelevant to going fast on a bike - except for short sprints. Which is also irrelevant if you've been dropped because you've ran out of gas before it's time to sprint.

Again - there's a reason why no one worries about torque when cycling.

gregf83 

Put down the calculator and go for a ride. Cycling is largely an aerobic sport and doesn't require strong legs. 400W @ 90 RPM results in a peak pedal force of just over 110lbs. Even if you could squat 1000lbs it's not going to help when you want to ride hard for longer than 20 seconds.

mr_pedro

Your kinda asking the wrong questions. At the moment it seems like your muscles are not adapted to cycling, you can produce a high force for a short period of time, but cycling only requires a small force applied over a very long period of time.

The ability to produce a high power output for a long time is related to being able to use the aerobic system efficiently and being able to get rid of the lactic acid that starts to accumulate as you try increasing power output. Also it is about things like efficient pedaling (in circles not in squares), being comfortable on the bike for longer distances and being able to do the higher cadences of 90-100 RPM.
All of this takes time on the bike. First ride a lot (5-10 hours per week), concentrating on increasing the RPM and at a pace where you can only say a few words between breaths.

LMaster

Cruising upright on a MTB at 20mph would require some serious fitness, like you said probably in excess of 300W would be needed. That's some pretty solid power, even if you are a big guy. 20 mph on a road bike in good position still requires decent fitness, but not something on the order of the 5w/kg needed to cruise around at 300W (probably need somewhere in this ballpark to be able to cruise at 300W as no one really "cruises" at FTP).

I'm not going to say 5 w/kg is unattainable, but not on a short timeframe, and it's significantly better than your average hobbyist cyclist is capable of.

bbattle

Anyone who comes into this forum and spouts lb/ft and horsepower is a troll. Pure and simple. Quit feeding the troll.

If he's not a troll, he's already received all the info. he needs: pedal faster.

"torquecyclist"???? come on, people. has to be a troll

achoo

More like about 5 seconds if you're going all out. Then the fade starts....

But you make a good point - absolute max strength is not a limiter in cycling, except for maybe during standing starts in some track events.

And I'll respond to the torque-based power numbers anyway. Yeah, going from 20 ft-lbs of torque to 30 ft-lbs, while holding a constant 80 rpm does increase power from .30 HP to .45 HP.

BFD.

Going from 80 rpm to 160 rpm increases power from .30 HP to .60 HP without having to increase torque at all, and quite likely uses less glycogen to boot.

hamster

Last time I did a round of weight training, I got to 6 x 200 lb squats and 9 x 450 lb 45 degree leg presses (full range of motion). My FTP is 220 ish and I recently managed a 5 km time trial (out & back along the same road, finishing where I started) just under 8 min on a road bike (that's average speed 23.5 mph). Of course, serious racers can do much better than that, a pro cyclist on a time trial bike can probably average 28 mph over the same distance.

bikepro

Power is a function of torque and RPM. Trying to push big gears is a common beginner mistake. You want to work to build a smooth cadence around 80 - 90 RPM or so, using lower gears. A higher cadence with lower gears gives you more of an aerobic workout, and works your legs less. Keep in mind, on a longer ride if your heart rate goes too high you can slow down and recover. However, if you push big gears and tire your legs, you're pretty much done. Spinning a lower gear is difficult at first, but is worth the effort.

bikepro

Or a beginner??

torque cyclist

honestly, if the character limit allowed me to use powerstroke instead, I would have done it. the basic units of power is HP (i'm most familiar with it, and I know the formula very well). the factors of that are torque and rpm. i'm asking if anyone trains their legs strength and torque. while increasing rpm increases power, but I don't know about cruising at a rpm of over 100. The human body operates similar to a very unbalanced diesel engine. if i'm lucky I can hit 100+ rpm, and torque is what makes up for that low rpm (in comparison to a internal combustion engine). think about it 300 watts @100rpm is 21lb/ft , it's incredibly high in comparison to the total output HP or watts.

I was wondering what cyclists tend to train. In order to produce more watts at a set rpm, raw force needs to increase. Everyone has a normal operating range while cycling. everyone recommends about 90-100 rpm. while that is nice and all, if I want to go a bit faster I can either use a higher gear, using more torque or increase my average rpm. after a certain point, there is a redline effect with pedaling, at which point you need a higher gear.

CharlyAlfaRomeo

You need to stop comparing the human body to internal combustion engines and try and take people's advice.

torque cyclist

I am listening. internal combustion engines and legs both output power to a wheel driving you forward. Watt output is a result of RPM and torque. my statement is, there is just levels of spin that aren't going to be comfortable to sustain. for many miles I couldn't see maintaining over 120rpm.