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-   -   Shaft driven folding bike (http://www.bikeforums.net/folding-bikes/382282-shaft-driven-folding-bike.html)

geo8rge 01-25-08 09:18 AM

Shaft driven folding bike
 
Flying Pigeon 20" Shaft Drive Folding Bike - 880

http://cgi.ebay.com/Flying-Pigeon-20...QQcmdZViewItem

PolishGuy 01-25-08 10:57 AM

I saw that one too. Take a look at Dynamic Bicycles' website: http://www.dynamicbicycles.com/ I'm not into shaft drive bikes but the U.S company might be a better source than an e-bay vendor. The e-bay store for this person also has the PA-06 bike available that I had an interest in a while back. But, I think I'll continue searching for a Raleigh DL-1 Toursit in good condition to add to my collection. PG.

Mr. Smith 01-25-08 12:20 PM

Quote:

Originally Posted by PolishGuy (Post 6048099)
I saw that one too. Take a look at Dynamic Bicycles' website: http://www.dynamicbicycles.com/ I'm not into shaft drive bikes but the U.S company might be a better source than an e-bay vendor. The e-bay store for this person also has the PA-06 bike available that I had an interest in a while back. But, I think I'll continue searching for a Raleigh DL-1 Toursit in good condition to add to my collection. PG.

While searching for a non-folding commuter, I came across these bikes in an LL Bean catalog. I always preferred shaft drives motorcycles... It's an interesting concept and I doubt the losses are that relevant to those pedaling around leisurely to work or through a park. I found their folder, but couldn't find any info on it from owners.

PolishGuy 01-25-08 12:31 PM

Take a look at Velo Vision magazine issue #10 (I think). It has a review of the Zero Cycles, English maker(?) of a shaft driven cycle, that is similar to the Dynamic Bike and Flying Pigeon. For all I know they're all probably made by the same firm in China. PG.

brakemeister 01-25-08 01:16 PM

Mr Smith
...I doubt the losses are that relevant to those pedaling around leisurely to work or through a park. ....

on what basis would you make a statement like this ?

Mr. Smith 01-25-08 02:34 PM

Quote:

Originally Posted by brakemeister (Post 6049135)
Mr Smith
...I doubt the losses are that relevant to those pedaling around leisurely to work or through a park. ....

on what basis would you make a statement like this ?

I was thinking of my own intent for the bike when I saw it and the minor losses in efficiency that occur in using a drive shaft versus a chain (assuming the chain is well maintained). Someone who is really an advid cycler looking for maximum efficiency over long distances at high speeds might find any power losses no matter how small enough of a problem to not consider a shaft driven bike. Me on my commute to work or my mother for example going out for an afternoon bikeride would not be bothered by these small losses. For that purpose, however, I thought the idea of not worrying about snagging clothing was very appealing and might have considered the folding bike (and still may) if I had found more info on it or could see one. As always, no one nearby has anything remotely unusual in stock.

Mr. Smith 01-25-08 02:56 PM

Quote:

Originally Posted by Mr. Smith (Post 6049678)
I was thinking of my own intent for the bike when I saw it and the minor losses in efficiency that occur in using a drive shaft versus a chain (assuming the chain is well maintained). Someone who is really an advid cycler looking for maximum efficiency over long distances at high speeds might find any power losses no matter how small enough of a problem to not consider a shaft driven bike. Me on my commute to work or my mother for example going out for an afternoon bikeride would not be bothered by these small losses. For that purpose, however, I thought the idea of not worrying about snagging clothing was very appealing and might have considered the folding bike (and still may) if I had found more info on it or could see one. As always, no one nearby has anything remotely unusual in stock.

Here are some efficiency tests run on several bicycle drive systems done in 2001:

http://www.ihpva.org/pubs/HP52.pdf

brakemeister 01-25-08 04:46 PM

Well I do not find any information about drive shaft losses in your link ..... internal gears is something totally different...

Which by the way is a little outdated anyhow . there has been a lot of good engineering going on to improove in the last 7 years.... todays cans are much better ( at least the more expensive ones )

But back to driveshaft driven cycles

It might make no difference to YOU to losse efficiency .. however you should clarify where YOUR threshold of powerloss is , if you make general statements , people easily can missunderstand that it is very personal how much pedal efficiency is lost...

So again my question, what you think you are ok loosing forward momentum ?
Obviously you do have an idea what you call minor .....

lets hear percentages

Thor

Mr. Smith 01-25-08 05:34 PM

Quote:

Originally Posted by brakemeister (Post 6050739)
Well I do not find any information about drive shaft losses in your link ..... internal gears is something totally different...

Which by the way is a little outdated anyhow . there has been a lot of good engineering going on to improove in the last 7 years.... todays cans are much better ( at least the more expensive ones )

But back to driveshaft driven cycles

It might make no difference to YOU to losse efficiency .. however you should clarify where YOUR threshold of powerloss is , if you make general statements , people easily can missunderstand that it is very personal how much pedal efficiency is lost...

So again my question, what you think you are ok loosing forward momentum ?
Obviously you do have an idea what you call minor .....

lets hear percentages

Thor

Yes and no. To date, I have not seen (doesn't mean it's not out there) a shaft drive system that was not paired with a hub of some kind, so the article is relevant to the point. The article also discuses the efficiencies a chain is capable of. Some earlier sports cars used to use chain drives to try and capitalize on that. Older 4WD casings also used all chains. The only reason they are not used now is shafts are much more reliable, which most consumers value. To say a chain is a more efficient mechanical system than a drive shaft is just an engineering truth, like saying the accelleration of gravity is 9.8 m/s^2 on earth, or the maximum efficiency of a Diesel thermodynamic cycle is around 70%. There have no been no significant breakthroughs in engineering mechanics in the past 7 years to disprove this. Hubs, which are essentially wonderfully complicated planetary gear systems have far too many moving parts to avoid losses. I'm certainly not complaining because they are still pretty darn good, and I think in many ways hubs are superior for primarily maintanance issues, though Lance would have fallen behind with one.

Pedal efficiency and the efficiency of the mechanical system are very different things. The article makes the point that lab tests with cyclers and oxygen use, and whatever else has been used in the past to measure bike efficiencies are not very scientific and do not isolate the test within the mechanical system, which is what I'm talking about. The motors they used to apply torque were constant torques, wherease a human could never replicate that. Put the same rider with the same form on a bike with a chain and a bike with a shaft, and they should theoretically make better time with the chain because of its superior mechanical efficiency. Notice also that efficiency changes between loads and gears based primarily upon friction (as the normal force increases, so does the resistance), also outlined in the article. Each gear in a hub (or sproket) has a different mechanical efficiency. It's the mechanical system limiting the overall performance, not the rider. Pedal efficiency is how well the rider translates work into the system, and that's as individual as swimming or running form since no one can sit upon a bike and say, "Today I believe I will translate 100kW into the system."

I'm not sure what your last paragraph is asking. There seem to be just enough words missing to skew the meaning. In any case, momentum is also a different phenomenon. Typically a shaft system (depending on the gear ratios, size, shaft size, angular/torsional deflection) would be somewhere in the neighborhood of 90%-96% with 96% being a very very good system. Many cars only maintain around 80%. Add that efficiency to a particularly inefficient gearing (say 7th in the Rohloft tested) and that's fairly substantial if you're used to achieving 98% or even 99%. Is it clearer what I am trying to convey, or am I still missing what you're asking me?

-=(8)=- 01-25-08 05:49 PM

I actually have a full sized shaft driver.
Its an Incline Newport. Generic Kinesium
Alu frame that is on par with all other
mid level universal Taiwanese bikes.
3 speed Sturmy Archer hub, no suspension, etc...
This bike is a utilitarian commuter bike. You
can feel that something is 'slower' for want of a
better term , but it really doesnt feel any different
than your tires being a few lb's low. The shaft
mechanism would last a few lifetimes if you give it
a modicum of care. It is way overbuilt.
As I said, this is a commuter bike. It would be a
godsend to someone in Vermont or any other place
snow and salt are on the roads for 6 months out of
the year. :)

Mr. Smith 01-25-08 06:07 PM

Quote:

Originally Posted by -=Łem in Pa=- (Post 6051120)
I actually have a full sized shaft driver.
Its an Incline Newport. Generic Kinesium
Alu frame that is on par with all other
mid level universal Taiwanese bikes.
3 speed Sturmy Archer hub, no suspension, etc...
This bike is a utilitarian commuter bike. You
can feel that something is 'slower' for want of a
better term , but it really doesnt feel any different
than your tires being a few lb's low. The shaft
mechanism would last a few lifetimes if you give it
a modicum of care. It is way overbuilt.
As I said, this is a commuter bike. It would be a
godsend to someone in Vermont or any other place
snow and salt are on the roads for 6 months out of
the year. :)

Absolutely. I really very genuinely think its a great concept and would love to try one out. Even in a mountainbike I would think the durability aspect would be wonderful. Then you only have to watch twigs in the spokes. :o If you really stomp on the pedals do you feel any bounce in the system from torsional deflection? That might be hard to determine on a 3 speed...

-=(8)=- 01-25-08 06:40 PM

The frame is an old school style MTB even
though the rest bike is fairly new technology, otherwise.
The rims and tires are commensurately huge 2.25's
which Im sure doesnt help efficiency any. I think the
3 speed is a limiting factor in my enjoyment of the bike.
There is too large a gap between second and third gear.
But no, there is no torsional deflection. Nothing feels
different that way. If anything I would assume the
shaft assembly might even add a lot of rigidity to the
frame because it is encased in an aluminum tube.
It is a little harder to wheelie than a chain bike, but
that is no surprise. I was using it as a commuter until
I got my Downtube which I fell in love with and use
now. There is a picture of it in the Utility Bikes Foto
sticky if you want to see it. If you are near me in FL
you are welcome to ride it too....There are threads on
these bikes where they take a lot of beating, coincedentally
form people who dont own them, and I believe it to be
undeserved. Its a very nice commuting unit. The only real
issue I have with it is that changing the back tube is time
consuming because of the shaft/SA-3 combo. I can pull and
patch a tube without removing the rim so normal flats are
not an issue, but if you get the dreaded tube shredder variety
you will be sidelined for about 10 minutes longer than a QR
equiped bike. :)

sherbornpeddler 01-25-08 07:04 PM

I gotta believe the shaft drive folder is a heavy (solid) commuter for a train or bus. Love the cleanliness of the chain, tires still can gundge clothes so for me the small Denon like size is only good for occassionaly in-town/city rides and I'd rather walk.

brakemeister 01-25-08 07:16 PM

you are saying somewhere in all that writing that :

CLIPP
would be somewhere in the neighborhood of 90%-96% with 96% being a very very good system
CLIPP

You have told us all that you are an engineer .......SO you telling me that a bicycle shaft drive works between 90 - 96 percent......

I am not an engineer, and I havent slept in a Holiday Express lately either ...

go ahead buy a shaft driven bicycle ... but please be a little more considerate with your general statements which are wrong or misleading .....I might remind you that you made a statement about BF which was wrong as well ( I think it was your 10th or so post here )

slow down, take a breath , please do not post about things you have very little knowledge about


thor

Mr. Smith 01-25-08 08:00 PM

Quote:

Originally Posted by brakemeister (Post 6051544)
you are saying somewhere in all that writing that :

You have told us all that you are an engineer .......SO you telling me that a bicycle shaft drive works between 90 - 96 percent......

From Dynamic's website: "With a constant 94% efficiency, our shaft drive bikes perform..." (http://www.dynamicbicycles.com/info/top10.php) I'd say my rough guess wasn't exactly a disaster. I would imagine they have done rather extensive testing on their system (probably licensed technology), though getting it might be a challenge. To determine it theoretically would require knowing exactly what the system was and a long calculation. To determine it experimentally would require the bike and the testing equipment, and I don't have either. Back in college I worked on an SAE race car in which we tried and tested shaft drives and chain drive systems.

Quote:

I am not an engineer, and I havent slept in a Holiday Express lately either ...
Then why are you assuming I'm not? The Holiday Express thing I don't get. Are you implying that you pedaling Dahon's (yes, it's a homonym) is somehow a better way to earn a living? Perhaps "to each their own" is in order. I have stayed in a Holiday Inn Express before and find it to be a rather good value, particularly in rural areas. <shrug>

Quote:

go ahead buy a shaft driven bicycle ... but please be a little more considerate with your general statements which are wrong or misleading
What exactly am I wrong about in this case? I fully admitted to miss-stating on the other post. Their website states the limit is 200lbs and the salesperson I spoke with said 230lbs. Only later did I realize that was for stock bikes. It was an honest mistake. Does that mean I am automatically a moron from that point forward?

Quote:

slow down, take a breath , please do not post about things you have very little knowledge about
Only if you promise to stop trying to sell everyone who comments on here a Dahon. A bit biased, don't we think? I suggest you research what I'm telling you with some trusted sources before assuming I'm wrong. You seem like you're reprimanding me for being more informed in this particular area.

brakemeister 01-25-08 08:22 PM

I see that you are basing your knowledge on the add of a company who sells nothing else than shaft driven bicycles. There is not a hint of actual experience there.

I do have a bridge for you to buy ... ..

and yes .....I do sell Dahons because I like them, I am not suggesting anybody to buy a Dahon and only if people are asking about my opinion. Just like you about a week ago, when you started posting here and were asking for help, with very basic questions. Now a week later you are presenting yourself as an expert.

thor

Mr. Smith 01-25-08 08:31 PM

Quote:

Originally Posted by brakemeister (Post 6051909)
I see that you are basing your knowledge on the add of a company who sells nothing else than shaft driven bicycles. There is not a hint of actual experience there.

I do have a bridge for you to buy ... ..

and yes .....I do sell Dahons because I like them, I am not suggesting anybody to buy a Dahon and only if people are asking about my opinion. Just like you about a week ago, when you started posting here and were asking for help, with very basic questions. Now a week later you are presenting yourself as an expert.

thor

Physics for Scientists and Engineers - Serway & Beichner
Vector Mechanics for Engineers: Dynamics - Ferdinand P. Beer & E. Russel Johnston Jr.
Thermodynamics: An Engineering Approach - Ynus A Cengel & Michael A. Boles

Not knowing which folding bike to buy and general knowledge about drive shafts and dynamics are not in any way related. My posts on this thread are related to drive shafts as a less efficient mechanical system than a chain. You are manifesting anything more, and it certainly has nothing to do with folding bikes.

BB49 01-26-08 02:18 AM

I rode the Dynamic Sidekick 7 speed shaft drive folder for about 3 weeks. I bought it with a 30 day trial offer. The people at Dynamic are very good to deal with.
I really liked having an internal gear hub, and being totally chain free by having a shaft drive was wonderful.
So, why did I send it back? Mainly, it did not fit my long legs, without going beyond the seatpost min mark. I did not want to do that long term. The new model will have a one inch longer seattube, and so it should fit me, 6ft tall with long legs. I could have added a ButtBuddy to gain 2 inches, but I did not want to invest that in the 7 speed bike. I would only get one with the Nexus 8 speed hub. I needed a lot more low range, without giving up on the high range. The Nexus 8 speed will do that for me, (307% range instead of 244%). They did not have the 8 speed available at the time, and I did not know that the 7 speed would not work that well for me until I tried it.
The bike also did not fold well, did not stay folded, and rarely stood up by itself. I used it as a "lay flat" by only folding the handlebar post, lowering the seat, and rolling it into the backseat of my car. The folding is nothing like a Bromptom or Dahon. Dynamic wanted to have Dahon make frames for them, but Dahon was not interested. Dynamic was receptive to my idea that they add a lighter layflat to their line. This bike was fairly heavy, 32 pounds.
I may buy the Crosstown 8 instead from Dynamic. It is a full size, non folding road bike, but it is only 27 pounds, and has a wide gear inch range since it has 700C wheels. I would opt for the lower range drive, but you can read their gear inches and decide for yourself. If I add folding pedals, and remove the front wheel, I could fit it in my backseat as a layflat. I drive a very small 1991 Civic SI hatchback that I bought new and really like.
I would definitely recommend a Dynamic bike to anyone who wanted a very clean and low maintianance bike. If you get the Sidekick, I would recommend upgrading to the 8 speed. You would have a bike that rode and maneuvered well with its 20" wheels. I did not notice any extra drag or loss of efficency compared to chain drive. It can work well as a layflat, but remember it does not fold well.
For a folder, I am now considering the 2008 Dahon MU XL Sport, it's twin, the Novara Fly-By at REI stores, or the 2008 Dahon Curve SL. All have a Shimano Nexus 8 speed hub and chaindrive.

makeinu 01-27-08 06:39 PM

The problem with internally geared chain drives are that the chains usually still have oil on them.

So a few months ago I cleaned the oil off my chain and haven't put any more on since. I've not been able to detect any loss of efficiency or any increased wear.

I think most of the problems with unoiled and/or worn chains have to do with derailleur shifting anyway. It's hard to imagine why a chain would need oil just to drive a single cog. I guess it's possible there might be some friction between the chain plates, but I would be very surprised if there weren't more friction between my thighs and the saddle.

Simple Simon 01-28-08 04:09 AM

Thor - what have you got against Shaft drives it seems like you are on a mission to rubbish them ? What are your sources ?

Shaft drives, like hub gears, belt drives etc and many other engineered systems have improved in efficiency over the years. Methinks you are just passing on more old school 1930's 'cycling club gossip' :D.... just cos its new or different, doesn't mean its no good ... thank goodness there is choice.

brakemeister 01-28-08 09:21 AM

I have absolutely nothing against new designs and I have nothing whatsoever against shaft drives. I do have rode several ( one of these days you might look up Fendt that was the first shaft drive I ridden besides a parking lot circle on a Duerkopp, but that doesnt count in my books as a testride).
Than several newer ones to many to mention.
If somebody can prove to me that there is any, I mean any new design which is BETTER than a 15 % loss versus a chain driven bike, I will listen. 15 % is huge effort on a human peddled bike, nut lets take 15 % as a benchmark. I certainly do not want to hear a range from 85 to 98 %

I am only perturbed if somebody who hangs on this board for a week comes up with various general statements about this and that and his knowledge is based on the webpages of said manufacturer which are completely bogus. ( or youtube like somebody else suggested earlier)

There is a HUGE amount of wisdome here on this board from people who do not have to tell anybody what they do in the regular life. Hardly ever somebody is asked for references or experiences, still the wisdom is unbelievable deep. But said wisdom doesnt come with one week "getting involved" or who can write the longest winding posts or what profession somebody has. ( or what bike he personnally likes or dislikes )

Thor

Mr. Smith 01-28-08 09:58 AM

Quote:

Originally Posted by brakemeister (Post 6063988)
I have absolutely nothing against new designs and I have nothing whatsoever against shaft drives. I do have rode several ( one of these days you might look up Fendt that was the first shaft drive I ridden besides a parking lot circle on a Duerkopp, but that doesnt count in my books as a testride).
Than several newer ones to many to mention.
If somebody can prove to me that there is any, I mean any new design which is BETTER than a 15 % loss versus a chain driven bike, I will listen. 15 % is huge effort on a human peddled bike, nut lets take 15 % as a benchmark. I certainly do not want to hear a range from 85 to 98 %

I am only perturbed if somebody who hangs on this board for a week comes up with various general statements about this and that and his knowledge is based on the webpages of said manufacturer which are completely bogus. ( or youtube like somebody else suggested earlier)

There is a HUGE amount of wisdome here on this board from people who do not have to tell anybody what they do in the regular life. Hardly ever somebody is asked for references or experiences, still the wisdom is unbelievable deep. But said wisdom doesnt come with one week "getting involved" or who can write the longest winding posts or what profession somebody has. ( or what bike he personnally likes or dislikes )

Thor

Your mastery of the English language is apparent, so here it is slow:

Shaft: losses between 5 and 20%, the smaller and less complicated, the more efficient. (those are rough numbers since you're so "by the book". I didn't design the damn shaft.)

Hub: depending on the gear losses between 3 and 40%

Shaft + Hub = your 15% benchmark or less. (The hub is a significant loss in spite of your denial.)

Why be ashamed of what you do in real life? What you do for a living weighs heavily in your experience because one spends such a significant portion of one's life at work. With your almighty "retailer" experience and power, why don't you call up the shaft manufacturer and get the test data and post it? Let's see through their lies together.

brakemeister 01-28-08 11:17 AM

ok....last reply to this one

Now its my language which bothers you ?... sorry I can speak a couple different ones, but this is an english speaking board therefore you have to endure my second language skills.



again 5 - 20 % .....and than again a statement which makes absolutely no sense " the smaller the less complicated, the more efficient " ( like 5 % if the shaft is only small enough, versus 20 % if the shaft is really big )

Hub. at no time of this discussion I am remotely interested into hubs, I tried to explain to you earlier that shaft driven is not the same as GEAR driven ( your own words ) Gear driven as you call it.... and you mean internal geared hubs ..... have their merits and are NOT point of this discussion. Even if you continuesly bringing this up again and again...

Again there is NO discusion about hubs, and there is NO DENIAL on my part whatsoever in regards to hubs.

I am not ashamed what I do in real life, same like all the other posters here are not ashamed about their choosen profession. Why should they.
We just do not have to advertise it .....like you obviously think that being an engineer has some benefits in your discussion.

What makes you think that my experince is only based on my retail knowledge ?
I would be careful to say anything about and almighty " retailer " experience. You are insulting all retailers and down the road you actually might need their help....

I for one have the outmost respect for most retailers. People like Harris Cycle come to mind a retailer in the North East..... to call their wisdom and experience almighty comes indeed very close.

Thor

BB49 01-29-08 12:27 AM

Quote:

Originally Posted by makeinu (Post 6061377)
... I cleaned the oil off my chain... I've not been able to detect any loss of efficiency or any increased wear.

I like the idea of going oil free on the chain.
I liked being free of a deraillier by having a hub gear even more than being free of a chain. But I did like the shaftdrive too.
I do not mind replacing the chain more often, so long as it is not excessive.

If anyone has more info on efficiency of chains, lubed vs dry, please let us know.

Also, does anyone know of any chain lubes that are extremely clean and "dry" ?

jur 01-29-08 05:38 AM

Quote:

Originally Posted by BB49 (Post 6069323)
I like the idea of going oil free on the chain.
I liked being free of a deraillier by having a hub gear even more than being free of a chain. But I did like the shaftdrive too.
I do not mind replacing the chain more often, so long as it is not excessive.

If anyone has more info on efficiency of chains, lubed vs dry, please let us know.

Also, does anyone know of any chain lubes that are extremely clean and "dry" ?

In the HPV journal, there is mention that the chain lube had no effect on efficiency. The lube keeps the chain quiet and the dust out, making it last longer.

Personally, I find that while backpedalling, a dry chain feels slightly more drag than a lubed chain.

Dry clean lube: Prolink Gold. Follow instructions carefully. Goes on, wipe excess off, let dry for next day.


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