bobotech

I read occasionally how professional bike racers will put out so much power that they can pretzel a bike frame easily. I can buy that but just how much of a difference is there between pros and everyday riders?

And to throw another monkey wrench, what about riders like me who are casual but extremely heavy. I know that I have to be careful because I can kill wheels. Am I putting out significantly more torque per pedal stroke at my 380 pounds when climbing a hill compared to a rider at 175 pounds of weight? My son who used to be a highschool linebacker is about 300 pounds and has killed 4 rear wheels now. He has a tendency to power his way though things instead of gearing down including starting. He will even start pedaling from a stop with the chain on large front/small rear.

I'm just really curious to know how much power is involved compared to the various types of riders.

fietsbob

You mean like a single pedal stroke ,
how much weight can you press with one leg as a gym machine press?

just to offer a base line for comparison..
or alternating one leg after the other, for 5 hours of reps
like the average pro's work day on a grand tour?

contango 

Pro rider to everyday rider, the difference is so huge it's almost indescribable.

When I'm out cycling near my home I'd say of the other cyclists I encounter I'm appreciably faster than about 80%, then 10% are about the same speed as me (maybe a little slower or a little faster) and 10% drop me like a superheated brick.

On a sprint on the flats I can take my cross bike to 27-28mph and can hold that kind of speed for maybe 4-5 minutes. The guys who win the Tour de France stages average that speed for 4-5 hours. I can't get my bike over 30mph on the flats at all as of yet, but in his most recent TdF time trial Bradley Wiggins averaged north of 30mph for the entire course.

I'm far from being an elite athlete, but despite being faster than the majority of other cyclists I encounter can't even scratch the surface of what the professionals can do.

Being heavy doesn't help where breaking stuff is concerned. I'm about 230 now, was closer to 290 when I started cycling, and at first I used to just use brute force to solve everything. Having weight to throw behind something and a total lack of finesse generally doesn't work all that well long term and stuff breaks. Put simply, all else being equal the torque you put through the pedals at 380 is going to be more than double what someone who weighs 175 puts through it, assuming you're standing on the pedals and putting all your weight on them - that's based on a simple calculation of force x distance.

As a heavy rider what you'll probably find is that on the flats and down hills your weight is an advantage, and when it comes to climbing it's a crushing disadvantage. That said if you can build the muscles to get your 380 pounds up hills now, once you've started to lose weight you'll fly up the hills.

bobotech

I really don't know. I'm thinking probably overall max torque for a single pedal stroke. Get an idea of that say the average casual rider is around 200 pounds, the amateur/hard core rider is around 400, and the pro racer is around 600. I have NO idea whatsoever if those numbers are even remotely close, I'm just throwing that out there.

Maybe use a single incline of a 6 degree hill for 200 feet. How much force on average is exerted by the various types of riders at maximum effort for that duration per pedal stroke?

chasm54

I can't answer your question about torque. Power output for cyclists is usually measured in watts. The top track sprinters such as Chris Hoy can put out 2200 watts for short periods. Mark Cavendish will hit about 1600 watts in the sprint at the end of a 100-mile TdF stage, a figure he has been known to describe as pathetic. I recall seeing Chris Froome's data from a climb on last year's Vuelta, a stage he won. Here it is. As you'll see, he maintained over 486 watts for one period of six minutes during a much longer strenuous effort.

This is impressive given the fact that he weighs only 68 kilos. So for that six minutes he was generating close to 8w/kg. A frequent measure used to determine a cyclists power to weight ratio is functional threshold power (FTP) which is the maximum wattage they can maintain for an hour. If you have 6 w/kg you have chances of winning the Tour de France. Froome's FTp is about 410, or 6.1w/kg. My own FTP is around 250, a rather pathetic 2.8 w/kg, though to be fair, it would look better were I to lose the six kilos I need to lose. 3w/kg is around the entry level for Cat3/4 bike racing, though obviously a highly proficient rider will frequently beat a more powerful one. An unfit/untrained rider isn't likely to have more than 2w/kg.

Which brings me back to the power generated by heavy riders. This may be very considerable. Every extra pound we are carrying requires a couple of extra watts to get up a hill, so a rider who is 100 lbs overweight is going to need an additional 200 watts to keep up with his lighter companion. So big riders may be very strong, but still hopelessly outclassed because it simply isn't possible for them to have the same power/weight ratio.

None of this answers your specific question. But it's interesting, at least to me.

fietsbob

Above was a better power quantity answer so I edited out some..

so your kid broke wheels..

FWIW dish in rear wheels to fit in the gear cluster is inherently weaker
than an Un dished wheel , even before you start adding in quality of parts
and the attention to details of hand built well maintained wheels
and those out of the box built by a wheel-building machine.
and having let spokes go too loose , and such..

then there is sideways force on the wheel, heavy weight
out of the saddle climbing, I can see where wheels go Pringles then.

Notso_fastLane

Not sure how accurate they are, but the stationary recumbent I use when I can't ride usually runs only in the 160-180 range for my typical 30 minute session. I feel like I do a lot better on the road, though. I'm usually pushing harder/faster and the hills really make me work.

bikepro

It's watts/kg, not just total watts. Also, just as important, its watts for a given period of time. Thus, 400 watts for 1 second is inconsequential. What matters is the amount of power for 10 minutes, 20 minutes, 90 minutes, etc.

If you want to learn more about this, get a copy of "Training and Racing with a Power Meter" by Allen and Coggan.

zaqwert6

I dont think the Pros are exceptionally powerful overall but what it is , is their sustainable power to weight ratio being where some of the biggest differences are.

I don't recall specifics off the top of my head but I kinda remember hearing a strong pro capable of like 6.7 watts per kilo as a minimum sustainable for 30-60 minutes during the more difficult climbs of the TDF or something like that. Wheras a strong amateur might be capable of near that, near say 6-ish at best and for only a few minutes at a time.

All the factors like converting O2 and VO2max is the areas where they blow the rest of us out of the water.

Something like that anwyay.

caloso

Jens Voigt tweeted that his average power in Tuesday's stage was 314W for 4:45. When I first read that I thought, hey that's not so impressive. I do 5 minute intervals at 320 all the time.

Yeah, it wasn't 4 minutes, 45 seconds. It was 4 HOURS, 45 MINUTES. Which is just insane.

chasm54

He is insane. Nobody races like that unless they're as mad as a box of frogs.

Homebrew01

Summary: road pros are not stronger than many of us, but they can maintain a high output for MUCH longer.

Killerbrewer

OT
Hey Homebrew, good to see another biking brewer on here!

Homebrew01

Hops mmmmmm

bobotech

Wow, this thread is VERY interesting to me. I don't know crap about pro racers but now I want to really read up about it and learn about them.

I was initially looking for power output figures comparable to say gasoline/diesel powered engines. You know, 290hp@2400rpm/345 pounds of torque@1900rpm, that kind of figure but I understand that is totally irrelevant.

Sustained power output is apparently more important with bike engines and that makes sense.

dwatson

It not all about power. There thresholds are much higher in VO2 max and lactate. This is what helps them keep the power higher than us mortals.

contango 

Sustained power output is pretty important with motor engines too. I'll bet you wouldn't be overly impressed with a car that could put out 1500bhp@3000rpm if it could only do it for a couple of seconds.

The obvious difference is that motor engines have a nice ready supply of fuel and an output system that doesn't clog up with lactic acid.