The Ultimate Efficiency
 

Its fairly well established that a bike is one of the most efficient forms of transportation. However, I would like to take that a little further. Bikes come in a huge range of forms, from full suspension mountain bikes (Full sized trucks) to hybrids (compact SUV's) to decent road bikes (fwd basic everyday car) to really good road bikes (diesels) to fixed gears (Insight).

What, a fixed gear? Yes, a fixed gear bicycle is the most efficient form of transportation in my mind, so let me explain why.

One of the best things about a fixed gear is that it is a direct drive. The chain goes from your crank, where your power is generated, straight to the wheel. There is no derailleur interfering, no tension on cables, no alignment issues. It is a straight and pure lever pulling a gear. But does this matter? Oh yes.

On the bike below, I can get up a rather large hill in Seattle riding a 3.0 gear ratio on normal road wheels (48t x 16t). Riding a high-end road bike I would be in one of the lowest gears, usually a 39t x 20-23t, which is a gear ratio under 2.0. I would have to gear down to 2/3 of the fixed gear ratio in order to make it up the hill, due mostly to the derailleur's added stress, the non-straight line of the chain, and slightly more weight of added parts (gears and gear changers). Amazing.

15lb fixed gear

One big problem with fixed gears is that they are often made for "tricks," or made out of older road bikes as a "fun" project, so they don't reach their optimum in efficiency.

For this one we chose to spend a little extra money on the key parts, wheels, crank and fork. The result is that it is extremely fast. By making the bike so light, one gear is not a problem. I can make it up almost any hill that a person on a good high-end bike could (even on a $3000 road bike). I could accelerate to 20mph just as fast if not faster than someone with gears, and I could steadily hold 25mph, with bursts up close to 35mph.

I helped build the bike above for a friend, so it is not my own, but even at 15lbs, it still uses an old Peugeot frame (5lbs). Someday we'll swap that out for some nice 3lb frame so that we can glean an even bigger smile as we effortlessly ride around :)

My bike isn't quite as fast, but hopefully I'll get there:
Leader 735tr

If you ever have a chance to ride a good quality fixed gear, its worth your time as you can immediately feel the efficiency gain. Maybe its not for everyone, but as far as efficiency, I believe it is the purest form of transportation available.

No brakes, only one gear ratio, no cupholders, no cargo space. You're crazy, you know. Those features more than pull their own weight through added safety, comfort, and versatility. Your bike is faster than my 24-speed road/utility bike, but only in a narrow range of speed and loads. I can turn at 100-120RPM at 5mph, up a hill, in traffic, whenever. I feel sorry for your knees.

How much weight do you save by going fixie, anyway?

I would agree, a fixed gear isn't for everyone, just as a Honda Insight isn't either.

You only loose about 2lbs by "converting" to fixed, but its more about the efficiency gained through running your chain through fewer parts.

I wouldn't feel too sorry for my knees. There is a vast difference between a good fixed gear and a cheaply built one, and I think that idea mostly comes from heavier cheaper fixed gears, as a lighter bike with light wheels isn't very harsh. I will get flogged if the fixed gear community sees this statement, but I ride with two brakes too, so I don't have to use my knees to brake if I don't want...

I rode for 2 years on a fixed/singlespeed through Seattle, and I could make it up all the hills just fine, and I carried a change of clothes and shoes with me in a backpack. I also have a singlespeed cyclocross bike that would be considered my utility bike if I don't need to go quite as fast :)

IMHO, a singlespeed bike would suit most people wanting to travel relatively short distance (commuting, in-town transportation). You'd get the advantages of a straight chain line, teh ability to coast, and the safety of having brake(s) when needed. :o

BMWBaorder, is your bike a fixie ? I see you have one speed, and brakes, and I was wondering if it was singlespeed, or fixed.:)

I have a flip/flop hub, so I can run it either way. In the picture it is fixed, but I ride it both ways now and then. A fixed gear doesn't have to have no brakes, that is just the status-quo (unless you are riding on a track.) I like both singlespeed and fixed, though really I just like nice bikes that are super efficient (aka fast!).

I have one bike for more than 10 years. Bought mine from Wall Mart for $90. It was on the back of my car and traveled across the country twice with it. Been trough hurricanes outside my house (it was under water for two week during Katrina) still runs and serves me well.

BTW that site for the bikes is cool, I like it.

Thanks Discovery :)

Bikes that last are definitely a good thing. Sounds like your bike has seen more of the country than my bike has too.

I wanted to go penny-farthing for ultimate efficiency but the wheel can't get big enough. :(

I think the weight difference in fixie vs multi-speed is inconsequential; emptying out your colon before departing would have a larger effect.

I wonder about the drivetrain efficiency difference. I've seen derailleur systems credited with 92.5-98.5% efficiency, depending on gearset and tension. Fixed ratio couldn't be 100% and assuming there's no reason it wouldn't be worse than the best derailleur scenario means we'd be comparing 98.5% to 99% or 99.5%? Either way I wouldn't think that's detectable to the rider.

I bought my 27" framed Fuji in 1983 and for quite a long while put 25+ miles on it daily. Sure wish it had an odometer- am curious how many miles are on it! :eek:

I would disagree with the bike weight importance. 2lbs is huge when you are talking about a bike that only weighs 18lbs. I'm not sure why, but it makes a bigger difference then losing two pounds of weight off the body. (I would absolutely trade 2lbs off my bike and put in a backpack on my back anytime!). I can't say why this is scientifically, but I can definitely feel it.

Do you know which derailleurs these super efficient ones might be? I had a bike with top of the line full Dura-ace, which is the bike I used for comparing to the fixed gear.

Either way, if you can get a bike with derailleurs like those, you will be putting much less effort into moving than the vast majority of cyclists.

I have a mountain of bikes to choose from. Which one have I been riding almost exclusively the last two years? A 50 lb behemoth with dual suspension- just on the street. Were two pounds to be subtracted or added, I wouldn't even know. The weight of it definitely is a lesser factor than the comfort and utility of it.

That would be, any ordinary old derailleurs.

2 lbs is not huge when compared to 200 lbs of rider and bike and crap, it is 1%. Having gears so you can pedal at whatever pace is comfortable for you is huge by comparison.

The extra drag of derailleurs is not a big deal, any transmission is going to introduce some of that, and the chain derailleur is particularly efficient since you do not leave every gear meshed at once and spinning, just a couple idlers.

I always prefer my old le-tour for the tall high pressure tires seem to roll the easiest on pavement. Even in the snow, I have to plow less snow with the skinny tires, they just cut through to the pavement.

I had a suspension bike, didn't like how pedaling compressed the suspension and soaked up energy, but I did like how you didn't even have to hop to clear a curb, that's a more delicate maneuver on a le tour.

A side note is that a very nice fixed gear can cost well under $1000, while a very nice geared road bike, will cost more than that. For me personally, a fixed gear is a good choice for max efficiency, especially when also considering the effect on my wallet.

It does seem to be a trade off, comfort comes at the cost of efficiency, maybe even more so on a bike than in a car.

I'm not sure how you determined it was "max efficiency", that sounds a bit misleading to me.

I have no comment on $1000+ bicycles.

Even the worlds record distance in 24hrs guys use a derailleur, if ever efficiency was a concern
http://www.adventuresofgreg.com/images/gears.jpg

I think maybe the thread title should be changed to the ultimate fun:). The bike is only one part of the equation. Unless you live in a vacuum in a flat area a single speed is not the most efficient bike. Simplest but not most efficient.

Every rider will have a self regulated cadence that is their most efficient. Most competitive riders it's around 90-110 rpms. You'll pick your gearing on the SS to match you optimum cadence for normal cruising speed. Throw in winds or hills and the efficiency has gone out the window. Grinding along at 40 rpm or spinning at 130 rpm is not efficient. That why they put gears on bikes so that you can stay in you optimum rpm range for the entire ride.

And that's a purpose-built bike that's going to be operated indoors, on a level track, at constant speed for many hours. If there ever was an application for a single-speed, this was it.

That is pretty interesting. The 1hr record has historically been set on a singlespeed or fixed gear: File:EddyMerckxHourRecordBike.jpg - Wikipedia, the free encyclopedia

And earlier landspeed records used bikes like this:
land speed record bike | Flickr - Photo Sharing!
I would assume in the 24hrs the riders legs can't sustain the same power output for so long, and thus need gears. I don't think that negates the fact that derailleurs do have some drag, even if it is minimal for good ones.

A good road bike is very efficient, and a fixed/singlespeed does away with some of the few parts that do cause drag on such a bike. How is that not max efficiency? It is certainly not suitable for all situations, similar to how I wouldn't take a prius 4-wheeling, but that doesn't negate the prius's efficiency.

when making a human use a single speed, that human cannot maintain their most efficient rpm and load. In and of itself the derailleur ads a tiny bit of drag, but on the road the gears allow the human to remain more efficient, which probably falls off exponentially vs a constant slight drag from the idlers. That is how it is not max efficient.

Besides you are looking at a restricted class of one hour racing, on a bike from 1972. Which is only running on a track at a constant speed, yadda yadda.

DCB, fair enough, I agree with you on that. :)

For me personally, my 9 mile commute to work kept me in that efficiency zone the vast majority of the time, so it worked well for me.

Anyways, if anyone reading this hasn't tried a fixed gear, see if you can find one just to try. It is fun to discover the efficiency gain, even if it is a trade-off of efficiency at other times by not having gears.

I ride a Rans Vivo, a full suspension recumbent with 20" wheels at 110 psi. Yes, it's more weight, but I'm not all bent out of shape when I arrive and my wrists enjoy not having to support my weight. I'm thinking about trying some summer commuting with it, in which case I am going to look into an electric hub motor and a lithium battery.

http://www.siskiyoucyclery.com/images/rans/vivo.jpg

That would be sweet! Definitely post how that goes.

How many teeth do you recommend on the fixed gear?

Do you think that this is a good bike?

I would probably want a freewheel, because I am a pedal and coast kind of guy.

Looks like a fine bike. It wouldn't be the lightest around with all steel parts, but it would be fun still. Gearing depends a lot on the person and how many hills or wind you'll encounter. I would start with a lower gear ratio and move higher if you feel comfortable. With that bike, the 46x16 seems high, but maybe you are pretty strong already?? A 17t freewheel would lower it if you wanted.

If you're looking for a cheap single-speed simulator, shift your bike into a certain gear and leave it there for a week. Let us know how you like it.

Are you against singlespeeds for any particular reason?

This won't give you the foggiest idea of riding a singlespeed because it will only give you the negatives of riding one without any of the positives.

Not busting your chops but what are the positives??

Haha ok. The benefits are a more direct drivetrain that do away with inefficiencies. If you put 200 calories into a fixed/singlespeed that is properly geared, you will travel further than if you put that energy into a similarly equipped geared bike. If you don't believe me, try it. I would think this would be the type of forum that would enjoy this concept.

I'm not convinced. I just don't think that unless you are on flat ground with no wind you would use less energy over a given course compared to a geared bike. Maybe Bicycle Bob will chime in.

I will say that I think racing or riding (not quite so much) a SS is one great learning tool that can really help a ecodriver to maximize their efforts. It's all about momentum. Any acceleration takes a big hit on energy required to get back up to optimum cadence. So you learn to read the terrain, not scrub speed in turns and ride with load up hills. So much of it transfers to the car.

This page is written by a fairly well-known bike guru:
Singlespeed Bicycle Conversions by Sheldon Brown

He does say a multi-speed bike may be better for going the furthest with the least amount of effort. I would say perceived effort isn't necessarily the same as power output... but it probably doesn't matter.

He does say:
"You can really feel the difference! A singlespeed is noticeably quicker and easier to pedal than a multispeed bike in the same gain ratio."

Anyways, this has been a fun discussion. A good bike is a great way to get around. Any bike that allows you to not use a car is a good one in my opinion :)

The 3.0 ratio seems about right and I have tried it on a internal gear 3 spd. Try to reduce rotating mass first. Aluminum rims and lighter tires, crank and gears etc. The trick is to find the bike and fit that works best with your body, riding skills, and terrain. Every bike will benefit immensely from reduced wind drag through a light weight fairing system.

Why not carry this ultimate efficiency quest to its logical extreme? Remove one wheel, and the associated weight & friction. Then you can get rid of the chain, and large parts of the frame, and wind up with this: Unicycle - Wikipedia, the free encyclopedia

Ditch the frame too Rollerblade - Wikipedia, the free encyclopedia

Or ditch it all Streaking - Wikipedia, the free encyclopedia

Just don`t get too carried away with "deletes" for aero purposes :D.
Might be a good idea to go easy on the gap sealing, too.

Not much of a win: you're trading less frame for a lot more (typically 7) sets of friction-inducing wheels & bearings.

Rollie Free presents a better way:

http://upload.wikimedia.org/wikipedi...record_run.jpg