The case for motorcycles. Why not use one?

[brucepick]

True that you could get superb FE on a bike.
But this Volvo driver here wouldn't travel that way.
Just too scary for me. I like that nice steel cage around me.
It helps keep you warm in the winter, too.

I'd seriously consider a Civic HX for my next car. But I think that's as far as I'd go towards lighter weight and less protection. One really nasty accident can ruin your whole day.

[CoyoteX]

I rode to work yesterday

So far I have rode in 28 degrees F and 35F with freezing rain. I guess a dualsport is far more flexible and forgiving in bad weather than a cruiser or sport bike.

If you are worried about safety here is the gear I ride with

Olympia AST jacket
Olympia Airglide 2 pants
Cortech Scarab gloves
Acerbis X-tight boots
Dayton Modular helmet

That combo is good from ~25F to 100F I just swap from those cortech gloves to Alpinestars Alloy gloves when it gets warm.

[Mighty Mira]

Originally Posted by SD26

Crosswinds are pretty rough on bikes. In road racing they were outlawed from the international bodies in the 50's/60's as they led to some deaths on track. Yes, they did allow better acceleration and higher top speeds for those that worked on such designs, but they never really moved much into the main stream production market.

What exactly was outlawed in the 50s/60s? You omitted to say, and I'm curious as to what was outlawed.

Note the hayabusa has a token attempt at a front fairing for the wheel, and that has the best CdA of any of Suzuki's sport bikes.



The drag coefficient of the hayabusa is 0.56, or about half that of a barn door.

[mrmad]

Due to the high performance engines that most motorcycles have (anything over 600cc) and their poor aerodynamics, motorcycles do not get that great mileage. A 600cc would probably be around 45mpg and an 1100 would probably be lucky to get 40. A smaller twin cylinder might get you in the 60mpg range but are pretty underpowered at freeway speeds. As funny as it sounds, you can escape some bad situations in traffic by just blasting past it and you couldn't do this on a 250.

The other consideration is tires. A sportbike can go through a rear tire in less then 8000 miles (and much less if you ride aggresively) A rear tire for a sportbike can cost over $200 and $50 to mount it. Fronts last longer, but they aren't cheap either. And on a motorcycle, it is not a good idea to buy cheap tires or run them down on the tread, good traction will save your life. Touring tires last longer (maybe closer to 20000 miles), but they still don't last as long as tires do on a car.

Overall, if you ae getting one to save money, I think you would have a hard time getting a motorcycle to save you alot on long commutes when compared to a small, FE car.

[Mighty Mira]

Originally Posted by mrmad

Due to the high performance engines that most motorcycles have (anything over 600cc) and their poor aerodynamics, motorcycles do not get that great mileage. A 600cc would probably be around 45mpg and an 1100 would probably be lucky to get 40. A smaller twin cylinder might get you in the 60mpg range but are pretty underpowered at freeway speeds. As funny as it sounds, you can escape some bad situations in traffic by just blasting past it and you couldn't do this on a 250.

Is avoiding freeways an option? Plus almost every motorcycle I've seen zips to the front of the lights everytime it is backed up at a red. Then you wouldn't need acceleration at 100kph to save you.

The other advantage is that your combined weight on something like a postie bike is about 200kg or less. My car is about as light as cars get, 760kg for car + driver. If my car was a hybrid, ignoring weight of batteries, they'd need to have > about 75% efficiency with regeneration to be better than the bike. I believe the prius's regenerative braking system is about 30%, someone correct me here.

So you've automatically got more tolerance for more frequent stop/starts.

So, bikes have a tiny engine, which means great idle efficiency for glides. They have a tiny frontal area. With fairings, the drag coefficient can really be cut down, in fact, an hpv like bike can do better than a car because there is no ground effect on most of the vehicle. Rolling resistance is minimal because of low weight. Stop start losses are minimal because of low weight. Acceleration is great because of low weight.

[GasSavers_Dust]

Originally Posted by Mighty Mira

Stop start losses are minimal because of low weight.

Flintstones foot start for the win.

[Mighty Mira]

Originally Posted by theclencher

CZ was a Czechoslovakian armament firm (CZ stands for Czech arms) which made mostly 2 cycle bikes. They and Jawa were nationalized in 1945. This is a 4 cycle 125cc racer which has a "dustbin" faring which were popular in the 50's. These fairings were made illegal in the late 50's after riders had the problem of being blown off the track in high winds from the side. CZs were not very competive in the world championship road racing.

Thanks for the link! It's amazing what you can find once you know the correct search terms.

As this link posits, I believe the crosswind argument is a pretext for banning, but not a reason. It is not some magical property of low Cd fairings that causes large force in a crosswind, it is simply area normal to incident airflow multiplied by the drag coefficient at the angle concerned. The drag coefficient from the side could not get any worse than it already is. A fairing can increase that particular area, but it does not have to. My modified postie bike would have maybe an increase of 10-20%, if that, which is neglible (I don't count the wheels because spokes would be as bad as a flat pannel, possibly worse.)

besides the bad aero, most bikes simply aren't engineered for fe. the focus for most bikes (my addidion) is on max power and performance, hence the stratospheric rpms and redlines.

Something like the postie bike is engineered for fuel economy. Australia Post has no interest in their employees looking mean or doing wheelies. It's cheap for Honda to just modify their Cub for that purpose.

as far as glides, bikes don't glide fer crap. low weight + high drag = rapid decel

Again, there is no real reason why that has to be the case. My car coasts very well at 760kg. The drag coefficient is about 0.26.

I don't see why a well modified bike couldn't get near that drag coefficient, and with maybe a third or less frontal area, it would coast almost as well. It would coast great at 80kph or less, which is where you are spending most of your time in the city anyway.

Anyway, thanks for the response! It's amazing how engineers of the past got things mostly right back in the beginning, before Alfred Sloan created the transportainment industry.

[GasSavers_SD26]

Originally Posted by Mighty Mira

It's cheap for Honda to just modify their Cub for that purpose.

I think it's a cost issue with smaller bikes. You've got the actual fairing, then all the mounting bracketry. Mounting a simple fairing/windshield to the handle bars, a cheap, easy way to do it, rather than to the frame at the steering head also transmits any wind buffeting into the steering of the motorcycle.

Adding a fairing also adds weight.

Really, without a fairing, there's not a lot of frontal area on a bike. It's not smooth, but it's very small. I've seen race team test where they have gotten rid of the production full fairings and produced higher top speeds. Again, these aren't "dustbin" fairings to start with.

[brucepick]

I think bikes now are designed heavily towards performance rather than anything else such as FE. I don't really blame the designers/builders; it seems that's what the "market" wants, at least in the U.S.

To remedy that on any given bike - - -
There was a thread re. someone considering or recommending regearing the bike by changing the chain sprockets. I'd think you could drop the rpm's considerably this way, without changing anything else. Might need a correction to the speedo/odo depending on where the sensor is.

[GasSavers_SD26]

A lot of bikes have the speedo pick up coming off the countershaft sprocket. So, yeah, you'd need a "Speedohealer" to correct it after making changes to the overall gearing. The gearing changes are relatively easy to do.

They are becoming more efficient. More electronics on the ECU, fuel injection is common, but not as sophisitated as on cars, Cats on a lot of bikes.

Still, getting 45MPG on a machine that produces 0-60 times in less than three seconds with quarter mile times less than eleven with a cost of less than $10k. That's your common 600cc sport bike.

A bike's best defense is performance often. When I did street ride, it was important to me to make sure that I was going a little faster than traffic as I could manage better what I was coming upon rather than those that were over taking me, read as attempting to run me over...LOL!

The larger portions of the motorcycle market is cruisers. Standard and "metric"...read Harley-Davidson and the Japanese and other manufacturers. Basically large displacement twins from 1000 t0 1500cc's. There are larger displacement models too, up to 2000cc from Kawasaki, if I remember correctly.

But those aren't bikes that people are buying for economy either.