Folding Bikes - it works , I cant believe IT works

I am soooo stoked .... worked on a bike this weekend and IT works ....
I am taking some of my comments back from earlier ...I really like IT :thumb:

feels different ...... I can see why other people like it so much ....

this was a money no object mod....
Now that I like it I need to tie up a few loose ends, pricing availibilty .
Also need to make a couple pics for you to enjoy

what is IT ?:mad:
take a guess .......:)

thor

I am soooo stocked .... worked on a bike this weekend and IT works ....
I am taking some of my comments back from earlier ...I really like IT :thumb:

feels different ...... I can see why other people like it so much ....

this was a money no object mod....
Now that I like it I need to tie up a few loose ends, pricing availibilty .
Also need to make a couple pics for you to enjoy

what is IT ?:mad:
take a guess .......:)

thor

Not 'stocked' but 'stoked' .. old surfer term from way back in the day... my guess is you found a Brooks saddle that you like..

fixed it..lol
No much better than that
took me a little while to get right
thor

An "electric" model Dahon folder?

An "electric" model Dahon folder?

I agree, either that or a gas powered bike.

Okay, here's my last guess.. Thor, did you go belt drive?? do I get a prize if I win??

Okay, here's my last guess.. Thor, did you go belt drive?? do I get a prize if I win??

Nah, he said it's a "money's no object" mod. Belt drive is too cheap.

Maybe it's a ROHLOFF!

have a electric Bionix Mu P 8 with a 500 watt engine here for testrides ....
that wasnt it
it is indeed a Gates Belt drive

I am super busy , will try to make pics tomorrow and have them here for you to see first
Thanks

Rohloff? Nah, both it and Thor are of Teutonic descent, he would not have doubted it works in the first place.

But then, I can't come up with a better guess. Rohloff does fit some of the other remarks. But how would that feel different? Perhaps a NuVinci.

Aww Man! BruceMetras nailed it!!!

That would be Foldable Two. :)

Awesome!

Just this morning I was looking, with disgust, at some chain gunk that got on my new coat, and was thinking how nice a Curve with a beltdrive would be.

What frame did you "fix"? Uno?

Now "marry" the Bionix Mu and the belt-drive. That would make a lot of sense.

That would be Foldable Two. :)

What would (?!?) :twitchy:

Now "marry" the Bionix Mu and the belt-drive. That would make a lot of sense.

the bionix motor has a thread on sprocket .... as far as I know there is no Gates rear sprocket for thread on ... otherwise I would have done that :-)

I used a Mu xl Sport with 8 speed Alfine rear hub

Sounds like a job for a machinist - threaded sprocket can't be that hard.

Jur,

BruceMetras had it right, not me. You have to read Thor's posts very carefully, due to his typing accent...lol

Lou

Ah, I see it now. :)

http://www.thorusa.com/dahon/technical/belt.htm

ok here we go
I havent worked out all the details yet but this is a first raw effort with pics and little explanations
thor

Looks good, Thor. Very clean solution

As with so many good ideas, the question is - why hasn't it been done before?

Well done - Inspiring.
I now want to try and do a Belt conversion on my brompton (already love it on Strida5).
Do you use a 'snubber' bearing and low tension to stop slip, or just good old tension ?
I guess there is a horizontal drop out for this ?
Nice work - I hope you show the bosses at Dahon.

Any idea how much weight this saves, Thor?

weight savings is a little complicated as I used a different ( needed) crankset ..... that one is light but in all reality way to expensive. I need to order a more civilized Crank replacement and weigh that instead. From the feel of it the weight saving is however significant , but that can also be my exurbarance about this project ....
( I can understand the wildly optimistic weight savings/ weights of bikes etc etc if the engineers finally see their plan take shape... I can understand... but I do not agree doing so )
No snubber cam or anything ..I have horizontal dropouts on the Mu xl sport .... down the road I would mind trying a nice quality chaintensioner, but I dont think its really needed

Thor

OH almost forgot ....quote: Bosses at Dahon..... there are friends, business partners, folks I can fall back to with real complicated questions, folks who I do admire, but no Bosses ....
I dont get a paycheck or anything like that from Dahon.
I am what they call an IBD ( Independent Bicycle Dealer)
I dont make much money therefore the I in front of BD is very important to me.
The reason I sell Dahons is all the above, plus I like the bikes, To me they represent the most bang for the buck ....big time. Never anybody is 100% right with everything but they are close and trying.
(Simple SImon : I think you might have meant it the right way, just to make absolutely sure that there is no missunderstanding...... its the "I" thing ...lol )

No probs Thor - I meant this is so good, dahon should do it at the factory, for others to benefit. I think it would be a good option for say the black Mu uno (?) urban single speeder.

Oooooooh. Want.

*checks money levels*

*curses like a sailor*

Recently I hear more and more about belt drive. I wonder if they will eventually displace the metal chains.

Any thought?

Kam

no Kam wont happen
if its done right its expensive WAY expensive and no way to make it cheap ....
there will be more of them around and cheaper ones I will bet in the future....
but than the real cheap ones will show up and destroy it for all of them ....
and everybody goes back to the chain .....

Why is it so expensive? I'd have thought it'd be cheaper, but I know nothing about the materials used.

let me see a stamped steel rear sprocket is probably around 5 dlr ..a working chain can be had for about the same . A cheap alloy front Chainwheel maybe aniother 15 bucks ......

you replace this with Carbon timiming chain ..... cnc alloy parts with Carbon bits and pieces for leightweigt and and and you get the idea
Thor

Why is it so expensive? I'd have thought it'd be cheaper, but I know nothing about the materials used.

Here's a couple of pictures of the components .. aluminum sprockets with hard anodizing at the wear surfaces.. add to that the special reinforced belt and you have a pricey drivetrain.


http://farm5.static.flickr.com/4012/4388176726_f7dd910b98.jpg

http://farm5.static.flickr.com/4043/4387414697_43d167e6e9_o.jpg

Thor,

Your photo link is gone - How did you get belt inside rear triangle (seat and chain stays & seat post)?

Lou

Thor,

Your photo link is gone - How did you get belt inside rear triangle (seat and chain stays & seat post)?

Lou

He was using a Mu frame.. no chainstay.. easy mod if the frame is stiff enough .. also the XL has horizontal drops so that he can adjust the belt tension .. the Mu Uno would be another Dahon that could be used.

Wikipedia articles on belt and shaft drives:

http://en.wikipedia.org/wiki/Belt-driven_bicycle

http://en.wikipedia.org/wiki/Shaft-driven_bicycle

Strida folding bike with belt drive:

http://en.wikipedia.org/wiki/Strida

http://www.thorusa.com/dahon/technical/belt.htm

http://www.thorusa.com/dahon/technical/belt7.jpg

here we go
thor

Beautiful. I would like to see the primitive chain evolve into something better. What are the pros and cons so far? Is it possible to snap the belt by standing on the pedals? Can they become stiff and brittle in cold weather? Can sharp road grit damage it? Will it stretch much?

More questions, can you get them in any length (since the length cannot adjusted)? Can they be made in any color (e.g. pink)? They do not work with derail lures, right? Are they more quite than metal chain?

Thor,

Your photo link is gone - How did you get belt inside rear triangle (seat and chain stays & seat post)?

Lou

This is how it can be used with chain stays

http://www.carbondrivesystems.com/images_us/install_big.jpg

Edit: more technical info here http://www.carbondrivesystems.com/images/uploads/forbikemaker_1251480796.pdf

lots of questions I dont have no answers for ..... some answers will actually be a couple years off....

this is like a car timing belt, which should be replaced after 60000 miles but seldom are and are usually running tripple or more miles. Or when is it the last time you heard that a timing belt has ripped ( Carefull I said TIMING belt not alternator cheap stuff )

Colors: all colors possible as long as it is black

grid dirt and stuff.... like everything in life its need a cleaning same as chain .... they wear but very slow ....

absolutely no noise whatsoever ... thats really a cool feature .... I treid to wet them and see whats happen but the same NO noise....
wet and road grime I havent tried.they MIGHT make a little noise.... Not at the Demo day in the dessert last year. but I havent tried long term yet .. but than they are easy to clean
superlight compared to chain


thor

Only a couple lengths of belts .... available

Expensove ones like the gates one will not stretch
They donlike to be kinked sideways for the lack of better expression
no derailleur model available

On a Harley with hard on the throttle and off again continually no problems, and you know Harley riders are tough on them. Friends have thousands of miles on in rain, grit and to 0 degrees you name it, know slippage. They do tend to have a low level whine at speed(i like the sound),which i doubt would happen on bicycle though. Ok motorcycle ones are wider but way more HP and torque being put to road. I wouldnt hesitate to use one on bicycle with the right dropouts.. Just sayin my 02 worth.

As an owner of Strida 5 (ride it frequently—not just a collector) I can attest to belt drive's quietness, durability, and low maintenance. You may have heard some bad things about belt drive system on those old Birdy Green or Strida 1. Today's system is much better than what it used to be. It's a real deal. I hope soon there will be more folders with belt drive to choose from. Strida and Abios are great bikes but it'd be great to have more varieties.

A few additional note: The front and rear sprockets can be made of plastic instead of aluminum to keep the cost down. Good belts sometimes contain Kevlar fiber. Kevlar is stronger—and expands slightly—when the temperature is lower. I know at least one Japanese company manufactures blue-orange two tone belts (link below). If/When the belt drive becomes much more popular in the bike world, I believe more manufacturers will produce colorful belts for the consumer market.

http://tsubakimoto.com/product/timing-belts-pulleys/timing-belt/ultra-px-belt-hc-type/detail/60/1/1/1/8/

Or when is it the last time you heard that a timing belt has ripped

It actually occurs pretty often, sometimes with catastrophic and expensive side effects (damaged valves, valve guides, cylinder head). These failures are usually because the owners failed to stick to the recommended replacement schedule though.

As for weight savings, it's not fair to compare just the weight of the belt and sprockets versus the equivalent chain and sprockets. You cannot use a belt with a derailleur system. If you switch to a IGH just to get belt drive, you have to take the weight difference between the IGH and derailleur/cassette into consideration.

The expense of a belt system should be comparable to a chain driven system if belts and the required sprockets are mass produced. After all, timing chains in cars have pretty much been universally replaced by timing belts, and not likely because belts cost more.

As for weight savings, it's not fair to compare just the weight of the belt and sprockets versus the equivalent chain and sprockets. You cannot use a belt with a derailleur system. If you switch to a IGH just to get belt drive, you have to take the weight difference between the IGH and derailleur/cassette into consideration.

It's a perfectly fair comparison for those of us looking to make practical vehicles lighter. Not everyone is a playboy seeking impractical toys for a "season" of play with the "club".

Besides, when you account for the rotating weight I'm not so sure the overall inertia of a derailleur system is less than an IGH. After all, with a derailleur you need to weaken the wheel with dishing, which means you need to compensate with a stiffer rim, more spokes, etc.

Question is, where can one get the parts for a conversion?

Hi Thor,

According to the info on your webpage, the bike's range of gearing is 24-74. Do you plan to increase it later? It can be done by using a larger sprocket + longer belt, or fitting a Schlumpf Speed Drive on the front sprocket. I'm sure you know these options, just curious if you'd do a re-mod.

Just found this:

http://www.carbondrivesystems.com/FrameBuilders.pdf

Is Bike Friday secretly developing belt drive models?

This is totally beautiful with the belt drive system! May I ask what is the characteristic like between the belt & the chain? What are the pros and cons you can think of? Thanks Thor!

It actually occurs pretty often, sometimes with catastrophic and expensive side effects (damaged valves, valve guides, cylinder head). These failures are usually because the owners failed to stick to the recommended replacement schedule though.

As for weight savings, it's not fair to compare just the weight of the belt and sprockets versus the equivalent chain and sprockets. You cannot use a belt with a derailleur system. If you switch to a IGH just to get belt drive, you have to take the weight difference between the IGH and derailleur/cassette into consideration.

The expense of a belt system should be comparable to a chain driven system if belts and the required sprockets are mass produced. After all, timing chains in cars have pretty much been universally replaced by timing belts, and not likely because belts cost more.

it doesnt happen very often that a timing belt rips .... as long as you count ALL the cars on the road . The percentage is VERY low

As for weight comparison : The chain and sprockets/chainwheel come of a Nexus bike and the belt is back on a nexus bike . Of course one could compare the weight difference. If that is indeed a major point of exercise .... for me its maybe a small added benefit.

Expense .you make it sound that it would be easy to set all of this up and sell millions just to get the price down .... go ahead do it !
the easiest way to become a millionare in the bike biz is to start with 3 ! LAst time I checked the timing belt wasnt all that cheap either, certainly much more money that a timing chain I replaced a couple years ago ... ! Not everything has been changed due to saving a buck, sometimes it is performance driven as well.


Gearing .. sure a Schlumpf would be nice ( as long as that one is available with a 130 bcd ..... )
to achieve different gearings one would need different size belts as you cannot change the length of the bike ....this is at the moment the ONLY gearing solution which works on A DAhon bike without any frame modification. This is true bolt on and no shadetree mechanic engineering ......

positives : it will stay grease free, is lighter, is different, is cool, is totally without noise ......

negatives : its expensive and doesnt work with every bike or transmission

currently working on prices and availibilty for a kit ......and to have an upgrade for a complete new bike

thor

Just found this:

http://www.carbondrivesystems.com/FrameBuilders.pdf

Is Bike Friday secretly developing belt drive models?

Funny you should ask that. Over on the Yak (Bike Friday) mailing list, we just got an update about a belt drive Tikit that is currently under development. Not sure about other models.

--sam

Glad hearing that a belt drive Tikit is coming. Belt + Alfine 11 speed hub = winning combination. Seems like folder manufacturers are quicker to embrace the belt drive system than other bike makers. It makes sense considering that folders are carried often and typically used for commuting.

Thor: Regarding the cost, there a cheaper alternative to the Carbon Drive System: Delta Cycle Corp's CDRIVE (Cycle Drive Systems). According to the FAQ on its official site, "[it] offers same level of precision engineering and durability, but at a price that is more suited to mass production at popular price points. CDrive may not be appropriate for off-road and extreme." More info here:

http://cycledrive.com

A small Taiwanese company called SEC supplies its own belt drive system (Beltrains) to other bike makers as well, including Abio. Although there's not much info about it online, judging from Abio's price point it's probably an inexpensive solution.

http://tw.myblog.yahoo.com/sec-bike/article?mid=22
http://tw.myblog.yahoo.com/sec-bike/gallery?cfid=5&act=&fid=5