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-   -   road versus fixed::anyone done the math? (https://www.bikeforums.net/singlespeed-fixed-gear/120479-road-versus-fixed-anyone-done-math.html)

eat_raw 07-09-05 07:02 PM

Got up to 32 m.p.h. on the Prospect Park decent today.
Had to be spinning at least 150 rpm.
Of course, that wasn't good enough to stay with the pack of road racers I was racing with.
I'm pedaling like crazy and they're coasting.

Got to thinking about how much harder someone on a fixed gear has to work than a road racer. (No kidding)
Granted, in most cases the road racer is going faster even though he's not putting forth as much effort.

So, let's consider 20 miles (a little bit less than 6 laps in P.P.)

I can fairly easily do 20 miles in just over 63 minutes (or 19 m.p.h ---- broken down roughly: ~15 mph on the hill; ~27 on the decent; and ~18 all others)

Anyone have any suggestions how that effort would compare to a typical 20 mile ride on a road bike; i.e. can anyone quantify it?

53-11_alltheway 07-09-05 07:23 PM

An easy way to figure this out might be to get a heart rate monitor with a calorie burn function on it. Then record calories burned for the ride with the fixie and the road bike.

Other than that, I have no idea.

Terror_in_pink 07-09-05 07:32 PM

I can't help you. but i remember the first time i rode a freewheel after riding fixed for a good while. i thought WTF the pedal isn't coming back up, then i realized, i think fixies might have it easier in that sense. I'm not arguing about the gears or the coasting, sure that makes it easy but when i expect my pedal to come back up it does.

Bikeophile 07-09-05 08:07 PM

You really can't compare the two because you can coast on the road bike, and you can change to easier and harder gears when needed (they are more efficient)

53-11 has the best idea to just use a HRM and compare you calories burned...Thats as close as you're going to get I think...OR just change your gearing so you can go faster at 150RPM and stop getting dropped!! :)

Ceya 07-09-05 08:31 PM

Spin,Spin, Spin. The art of spinning is the vaulable thing in riding a bike. I have a friend who can spin and keep up with the guys in Central Park with his track bike because he can spin . I used to do this well before injuries.

Marinano Friedrick of Team Jellybean could spin with a 45 x 15 and stay with us when I lived in LA in the 90s and he was 16 yrs old. He had spin,power and endurance.

S/F<
CEYA!

eat_raw 07-09-05 08:47 PM

No doubt the idea is to refine one's spin while developing power and endurance.
Always room for improvement.

The road racers have an incredible advantage, however, with the ability to shift gears.

Which takes us back ON TOPIC: any way to quantify that advantage?


On a side note: what gear ratios are those riding Prospect Park using?

Ceya 07-09-05 08:58 PM

You would use a little less than half of you energy if you used a road bike for the same 20 miles since you are not spinning the gears the whole ride. this is the rider stays in the same gear the whole ride. Due to the fact the rider can rest and recover during the ride.


S/F<
CEYA!

pedex 07-09-05 09:00 PM

Based on my caloric intake riding fixed vs freewheel when im working, its about a 25-30% difference, dont know how that translates into speed difference because from what Ive seen it doesnt seem to make much difference in speed, just effort.Ive raced in alleycats with both and done the same each way.Riding fixed makes me have to eat alot more though or I start losing weight pretty quickly.

53-11_alltheway 07-09-05 09:28 PM


Originally Posted by eat_raw
Which takes us back ON TOPIC: any way to quantify that advantage?


I haven't ridden a fixed gear yet, but the other day I tried to ride in one gear only and never coast (yeah I know I don't have drivetrain momentum with this freewheel bike). One thing I noticed was that I coast a lot more than I thought.

pedex 07-09-05 09:55 PM

not only do you coast alot on a freewheel, but brake alot too, on a fixie that is usually done with the legs which takes lots of effort as well

lots of racer type roadies dis fixed gear then find out the hard way that a regular fixie rider is likely to be in very very good shape despite what they may be riding or wearing, kind of ironic really, so many roadies look for any way they can equipment wise to get more speed and reduce the work they have to do to go faster yet the easiest way is just get a better workout and make more power

JavaMan 07-09-05 10:01 PM


Originally Posted by eat_raw
...The road racers have an incredible advantage, however, with the ability to shift gears...Which takes us back ON TOPIC: any way to quantify that advantage?...

Yeah, it's about 50 to 60 IQ points! :rolleyes:

phidauex 07-09-05 10:17 PM

The fixed gear is super efficient in its own element, which is generally a small range of cadences. Fixie riders develop the ability to work efficiently in high and low cadences, but they are still going to have an ideal range.

If you are in the right gear for the speed, and on a flat course, you'll use the same amount of energy as the roady, or slightly less because of drivetrain efficiency. However, on climbs and downhills, the roady can shift to stay in their ideal cadence, and you just have to adapt. That will cost you in the long run...

I don't necessarily buy the ability to 'rest' during coasting as a big benefit. In stop and go traffic coasting is nice because you get up to speed, see a red light, and then realize 'all this pedaling is useless, I'm just gonna lose it all anyway', and then you coast to a stop. However, on open road, coasting will get you nothing. From a physics perspective, there is a fixed quantity of energy required to move your body and bike from point A to point B. Whether your exert this energy in a continuous gentle flow, or a series of rests and sprints, is up to you. But the quantity is the same. On the flat course, in the right gearing, your lighter bike and higher efficiency means you'll expend less total energy, in a continuous flow (which your body prefers over sprints/rests).

Hardcore roadies calculate the power output required to maintain a given speed on a given grade. You could do the same, and then, on a trainer and with an HRM, figure out your calories per hour burn at a given cadence. Mash some, spin some, etc. Collect data points for several cadences, at maybe 20 minutes of exertion. You could make a curve showing that your caloric burn isn't linear with power output.

Then for a given ride, figure out how much time you spend outside your most efficient range. If you spend a lot of time out of it, the roadie has one up on you, if you spend very little time out of it, you have one up on the roadie.

Fun stuff, this math. ;)

peace,
sam

redfooj 07-09-05 11:08 PM

the most relevant answer would be: we dont care. how many people here ride fixed to go faster, or to burn more calories?

phidauex 07-09-05 11:10 PM


Originally Posted by redfooj
the most relevant answer would be: we dont care. how many people here ride fixed to go faster, or to burn more calories?

Mad props. I'm going to rock some calories right now. In beer form. I may or may not end up riding my fixie tonight, depending on how many calories I get from my beer. Its all part of my training schedule I call, "Too drunk to ride?"

Represent.

peace,
sam

53-11_alltheway 07-09-05 11:20 PM


Originally Posted by pedex
kind of ironic really, so many roadies look for any way they can equipment wise to get more speed and reduce the work they have to do to go faster yet the easiest way is just get a better workout and make more power

They will say it never gets easier...you just get faster.

I agree with you though, heck, that's why I want a fixed gear bike. Plus I just think they are cool. No derailleur and cables, etc. to maintain. Just a massive 1/8" chain that takes forever to wear out and costs $10. Fixed gear wheel is also stronger.

filtersweep 07-10-05 06:28 AM


Originally Posted by phidauex

I don't necessarily buy the ability to 'rest' during coasting as a big benefit. In stop and go traffic coasting is nice because you get up to speed, see a red light, and then realize 'all this pedaling is useless, I'm just gonna lose it all anyway', and then you coast to a stop. However, on open road, coasting will get you nothing. From a physics perspective, there is a fixed quantity of energy required to move your body and bike from point A to point B. Whether your exert this energy in a continuous gentle flow, or a series of rests and sprints, is up to you. But the quantity is the same. On the flat course, in the right gearing, your lighter bike and higher efficiency means you'll expend less total energy, in a continuous flow (which your body prefers over sprints/rests).

sam

A lighter bike really means nothing on a flat road- most TT bikes are substantially heavier than climbing bikes, for example (with all the aero equipment and wheels).

The original poster referenced that he was racing... and in a crit setup, coasting gives the body (and heart rate) some room to recover. Typically racers in a crit coast into corners and sprint out of them- the typical accordian effect. The other issue is soft-pedaling- which can be done on a fixed, but not with the same results.

Back to the original poster:


I can fairly easily do 20 miles in just over 63 minutes (or 19 m.p.h ---- broken down roughly: ~15 mph on the hill; ~27 on the decent; and ~18 all others)
That's all fine and good, but if he rides with geared bikes that hit 35 on the decent, losing the draft will have nasty consequences.

*new*guy 07-10-05 07:03 AM


Originally Posted by redfooj
the most relevant answer would be: we dont care. how many people here ride fixed to go faster, or to burn more calories?

more than you might think.

DLoMatic 07-11-05 07:09 AM

Throw on a set of brakes and let your self coast down the hill too.. ;)

no deraileurs so you at least have some weight advantage.. :p

slvoid 07-11-05 08:55 AM

I always find it funny that a lot of roadies diss fixie riders cause they think they're at a horrible disadvantage. And on the other side, a lot of fixie riders diss roadies cause they think they're lazy. Honestly, if someone rides a fixie and trains 5 days a week and they're at 90% HRM all the time and a roadie with gears trains 5 days a week and they're also at 90% HRM, aside from a slightly better spin for the fixie, the guy on the geared bike (assuming they're both in the same physical condition) would completely blow away the fixie on a rolling course. And on flat ground, well, geared properly, a fixie is a lot more efficient.

It's really all about you, the motor. NYCCommuter has a fixie and he says it's actually easier going up the hill, assuming you're not trying to kill yourself, cause the pedals have a little momentum that actually pushes you.

On a good day, the fast group does about 20 going up the hill, then around 25 coming around, 35 on the downhill, 25 on the flat after that, slowing to 20 again by the zoo. Sometimes they'll up it to 27-28 on the last laps.

noumena9 07-11-05 09:36 AM

Mr Monster Legs and I hit 37mph on the Prospect Park downhill this morning. I'm riding 49x15 and I think He is riding 48x16. My gearing (as some folks who saw me on River Road on Saturday will tell you) makes uphills any steeper than the one in PP a total nightmare. I mashed up the hills coming home from Nyack at 8mph until I cramped my calves.

I think fixed gear gives you a tremendous advantage in traffic where it is all about control and confidence and it gives you an advantage on the flat (if your gear is right) because fixed gear is all about going with what you got and not fussing with the machine, but hills up and down are where you get handicapped for your lifestyle choice! That being said I find that on the hills that don't shut me down I pass roadies all the time... they seem happy to do 100rpm spinning up a hill at 5mph... which I think is odd.

neuron 07-11-05 10:06 AM

yeah -- i'm riding 52x15, and some hills just kill me. i have to stand out of the saddle and mash away. it kinda the fun out of going out on those group rides... and the prospect park races kill me on the uphills. i don't even want to think about riding the central park race until i get a new cog. i'm thinking 42x14.

i just want flat-flat-land to ride on.

also agree with the sentiment noumena9's got about the roadies spinning 5mph up hills... is that just to build CV?

53-11_alltheway 07-11-05 10:21 AM


Originally Posted by neuron

also agree with the sentiment noumena9's got about the roadies spinning 5mph up hills... is that just to build CV?

Yeah....spinning up hills in low gears isn't going to give you monster quads because the resistance is low.

eat_raw 07-11-05 10:51 AM


Originally Posted by noumena9
Mr Monster Legs and I hit 37mph on the Prospect Park downhill this morning. I'm riding 49x15 and I think He is riding 48x16. My gearing (as some folks who saw me on River Road on Saturday will tell you) makes uphills any steeper than the one in PP a total nightmare. I mashed up the hills coming home from Nyack at 8mph until I cramped my calves.

I think fixed gear gives you a tremendous advantage in traffic where it is all about control and confidence and it gives you an advantage on the flat (if your gear is right) because fixed gear is all about going with what you got and not fussing with the machine, but hills up and down are where you get handicapped for your lifestyle choice! That being said I find that on the hills that don't shut me down I pass roadies all the time... they seem happy to do 100rpm spinning up a hill at 5mph... which I think is odd.

49x15 is a bit much for the uphill. It's ideal for the downhill, however.
I started riding 48x16 in the park. On the suggestion of a few of the roadies that also ride track bikes, I dropped to 48x17. This allows me to climb a bit easier but the downhill is a bit more challenging. I can hit 32mph spinning like crazy. I'm going to switch back to 48x16. I really don't need the advantage uphill (I can hit 20mph if need be and let's face it, most of the roadies draft uphill anyway) but I believe the difference is significant downhill and the flat right after it.

Jose R 07-11-05 10:55 AM


Originally Posted by neuron
also agree with the sentiment noumena9's got about the roadies spinning 5mph up hills... is that just to build CV?

Could be many reasons.

They are training within a target HR zone and don't want to go over it.
They are big bodied and are just better on the flats (*rouleurs*).
They like the functionality of their knees and would like to keep that functionality till their old age.
They are not interested in riding at race pace during a recovery ride.
Maybe they are going slower to enjoy the scenery.

fixedfiend 07-11-05 11:16 AM

coming from someone who rides both, there is no advantage to riding fixed if speed is a concern. roadbikes have us beat in that department.


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