There will be a lot of pressure on a relatively small wheel there, so I wonder what dust or a grain of sand would do there. I would guess making sure the mechanism near the pedals stays operating smoothly takes more maintenance than with normal bicycles. I wonder whether they considered exchanging rotary motion of the pedals for up/down movement so that they could get rid of that complex shape.
Also, given that they sell a “seatpole spare string holder“, those strings don’t seem to last as long as a traditional bicycle chain.
Bike gears wear out pretty fast too, so you'd want to factor that into the equation (different schools of thought on this; some replace the cassette every time the chain is replaced, some replace it every 2-3 chains, some replace chains much much frequently so that they don't have to replace the cassette as often).
I'm curious how often you'd need to replace other moving parts on the stringbike; at a guess since there's much less exposed metal-on-metal there'd be less wear.
As said, there are different schools of thought. The smaller cogs in particular will wear out the fastest; if you're using them a lot, the cog wears, which then causes the chain to wear faster, which will then cause the other cogs to wear faster.
It's sort of the opposite, a worn chain will wear on your cassette. Using a chain checker, or a ruler, you can measure how worn your chain is. If you replace the chain too late, the new chain will not mesh with the cassette, and it will slip. You can usually do this 3-4 times before the cassette will also need to be replaced. How long you will be able to use a chain is dependent on the riding environment, chain material, how well it is cleaned, and how well it is lubricated.
With an 8 speed bike, riding between 300km - 500km a week, I usually get around ~1000km on a chain riding outdoors, or about a month on a chain. Riding indoors on a trainer however, my chain almost never needs to be replaced.
For an 8 speed bike you replace the chain at 0.75 wear.
Depending on the bike you may choose to let both wear, and replace both at the same time. Eventually you will find the shifting sloppy, and the chain slipping however. This observation is from personal experience.
I find the idea of using string interesting, more commonly on the market you would see belt driven designs like the pinion.
Minimum time to failure seems to be 500 in either unit, so it makes sense to move manufacturing (or at least testing) the the region that uses the larger unit.
Ok. Silly quips aside, bike chains do actually last 5000 miles, not 500, if you keep them relatively clean. That's a lot better than 1500 miles or kilometers.
If this rope works well and is easy to replace, and is inexpensive I think I would be fine with changing it every 300 to 1,000 miles or so. They have it listed that you can change colors to match your outfit, so I am expecting it to be that easy.
> Change the strings quickly and easily in 2 minutes, no tool required and no need to remove the wheel. Choose the color to match your outfit or mood.
They say a few minutes, but with a lockring tool and a chain with a masterlink, I bet someone with a bit of experience could change a cassette in under 2 minutes as well. The rest of the mechanism seems a lot less durable and a lot less amenable to off-road riding where one might wish to pedal backward up to a full revolution to reposition their feet without wishing to propel the bike forward. It might be OK for casual / commuter bikes, but belt drives already exist and last a long time. The width of the rear axle required for the dual-sided drive also looks super goofy and probably gives a poor Q factor ( https://www.cyclingnews.com/features/what-is-q-factor-and-do... ). Overall these seem like a lot of compromises for little benefit beyond a chain or belt. Chain-driven bicycles are also incredibly robust and proven to work amazingly well in a very wide range of conditions, and are serviceable worldwide.
My Gates belt probably has >10k miles on it and is also silent. Coupled with a Rohloff, it is an essentially maintenance free drivetrain, save for changing the hub oil once per year.
Too bad that the Rohloff setup alone is like $1600, and the non-electric bikes with them tend to be >$5000. That Santos Cross Lite with the Lauf suspension fork does look pretty trick though. They have a helpful bike finder, though lots are not available in the US https://www.rohloff.de/en/service/search/bike-finder
Any serious cyclist carries a chain link tool for fixing a broken chain, along with a couple of spare inner tubes. Breaking a link doesn't happen often, and you'd typically not let a chain get so old that it happens from age; that will trash the sprockets. I've had breakage happen, though, and was glad to be able to get going again, in minutes.
Since you can't fix a broken string just by removing a link and closing it, the only protection against string breakage is to carry a full spare.
> Any serious cyclist carries a chain link tool for fixing a broken chain
Your definition of "serious cyclist" excludes a lot of serious cyclists. Precisely because it happens so rarely, carrying a bulky tool for a rare problem isn't worth it to everyone.
Yeah "serious cyclist" feels so impossible to define that it's meaningless. If I ride to work every day but go to a shop for maintenance instead of buying my own tools am I not serious?
Go to a shop to fix the problem, but have the basic tools and knowledge to make the temporary repairs needed to be able to ride the bike home or the shop.
Not really; a serious cyclist is someone who depends on and is invested in cycling as a mode of transport, who is not able to meet commitments if their bike breaks down without an real-time remedy.
So... no one within range of being able to catch a bus is a serious cyclist because they have an out? No one who can call a friend for a ride can be serious about cycling? I don't think this is typically what people would mean by that phrase.
Yes; if you go out thinking, "I don't have to care about the condition of my bike or what to do if it breaks down because there are bus routes along the way, or I can call a friend," then you're not a serious cyclist.
Using your logic, I must not be a serious driver because I don't drive with the equipment necessary to repair my car. Or my bike, when I am riding. Or my e-bike when I am riding that.
Folks who are serious about any hobby or activity are also often relentlessly practical. I used to ride 100km from the city I lived in, out to my brothers farm. It was not a particularly long or challenging ride, and it had cell service most of the way, even 20 years ago. I always did a gear check, and carried spare tires, but in 4 years of doing that 20-30 times per year, I replaced tires, but never a chain on that ride. I also never carried the tools to do that work because it fell into the category of unnecessary gear. If there was a problem, I was only about a 30 minute wait for help from either side if I needed to be picked up.
I also used to do a fair bit of trail riding, and for a much longer period of time, and for significantly technical trails. Again, a gear check ahead of time, and proper maintenance meant I took tubes, but not the chain repair tools (and one time I regretted not taking 4 tubes, because it was a long and hot 14km hike back carrying my bike on a July afternoon).
I am not going to gatekeep your ability to gatekeep, but you should at least understand that your perspective on what constitutes a "serious" cyclist is completely subjective and not rooted in anything meaningful.
Pretend instead of “serious” they said “frobnozz”. You’re not a frobnozz cyclist unless you can do a handstand on your handlebars! How absolutely un-frobnozz can you get??
There’s a tendency to ascribe value to words like “serious” but it’s a temptation, nothing more. Who cares that some bozo thinks “serious” drivers drive manual transmission cars, or ride bikes in a particular way.
I imagine serious cyclists also carry spare spokes, spare brake pads, spare derailleur hangers, spare bearings, spare cables, spare tyres, lubricant, assembly grease, spare batteries, spanner for truing bent components, hydraulic fluid (if using disc brakes), spare helmet in event of crash, etc.
The worst mechanical I ever had was a rear derailleur which deformed under load and pulled into wheel. I have never heard of anyone carrying a complete spare derailleur unless on a round the world trip.
That's cool. My multitool doesn't have one and my home tool is much, much larger[1] (160 x 100 x 22mm, 242g). I guess if I were buying a new multitool today, I'd try to get one with a chain tool included, but I also don't feel a pressing need to carry one. I've never broken a chain while riding, nor do I know anyone who has broken a chain, and I ride with a lot of cyclists putting out 600-1000W in sprints.
I'm not a "serious cyclist", I just cycle on bike trails - but a chain link tool and a couple of spare links is just miniscule. If I need to make that fix when I'm in the countryside 15 miles away from my car then not having that option just isn't sensible.
My chain tool weighs 28 grams, and can fit 3 chain tools in a box for a deck of cards. It is the most common form factor for this tool. I wouldn't consider it bulky- are you very small?
Right; I've never met anyone who carries an entire spare chain. It would not even slightly make sense.
If you put a new chain on old sprockets, it will likely skip, particularly on the rear cassette. This will go double if you're someone who allowed the chain to wear for so long that it just broke. That chain will only work with the sprockets that it is on and vice versa.
If you damaged a newer chain due to some freak accident (like cross chaining while shifting under load or something: shouldn't happen on a quality, well adjusted drive train) you probably don't want to replace it; aside from the bent/broken link, it is good. Splice the damaged link out and get moving.
Swapping in a new chain could be extra work. It likely has excess links which you have to remove and set aside, and may have stuck links that have to be identified and massaged into releasing.
I just have a couple powerlinks in my bag when riding, which take very little space. It is also unlikely to have a chain break while riding, however having a chain breaker tool and spare links comes in handy if your rear derailleur gives up the ghost (due to a fall etc), as in that case you can bypass it entirely with a shortened chain.
Mountain biker chiming in: have broken chains, friends have broken chains. It’s not a common occurrence, but basically ever has a chain breaker and spare links in their bags. MTB also admittedly puts a lot of components under far more wear and tear than other disciplines.
For MTB especially, it’s not the fact that there’s probably better drivetrain options, but the fact that the current options will happily take a beating, and still let you ride back out. I’m sure the string is real nice and quiet, and has a nice internal hub, but my chain, mech and cassette will get whipped into trees and rocks, will have sand, water, grit ground through it for ~20kms, sustain impacts from going off drops and jumps and they’ll continue to work. I’ve bent mechs, hangers, dinged cassettes, ground chainrings, and they’ll put up with an astounding amount and still get you home.
Once home the ease of access make maintenance a lot simpler, everything gets a clean and lube and it’s happy to go again.
I've been cycling for 50 years. When I got a job where I could start riding to work, I carried an inordinate amount of stuff, including full rain gear, all the time. Gradually, I started leaving most of it behind. The reason was that I developed a better sense of the actual risks of breakdown, and the resources at my disposal should something happen, based strictly on my own circumstances. This is also kind of how I live my life.
The people I know who've had breakdowns tend to be physically a lot stronger than me, and more "adventuresome" in their choice of riding conditions. For instance I expect my mountain biking friend to have a new story of destruction every few weeks. In some cases, I suspect that neglect or lack of maintenance skills played a role.
I bring more spares and stuff when I go on really long rides, or if my family travels to some remote place with the bikes.
"Serious" cyclists are often using newer chains like those from SRAM. Many of these newer ones don't use spare links, you'd carry a quick link and remove a portion of the chain to get yourself riding again.
Small distinction I agree, but you come off a little arrogant with such a strongly worded statement.
Cycling is essentially the only mode of transportation that I use but I never carry any spare parts or tools with me. Not even a pump. The only tool I carry is some cash and a credit card.
There's a spare string provided in the seatpost; claims to take 10 minutes to replace and no tools required.
But as with all riding, it depends on use-case. For remote cycling, you'll be carrying more spares than commuting, where worst-case you can walk the bike home.
With this string design the end of the string is fixed to the freewheel. So they don't have wear related issues that regular chains have like skipping gears, dropping a chain
Aka, "wax." I use these products[1][2], but plain paraffin (the main ingredient) works fine. There are also drip-on wax products[3] that can be applied to a clean or previously waxed chain, without removing the chain again.
Totally agree that waxed bicycle drivetrains work very well, are quiet, and avoid the mess of oil-based lubricants.
I use carnauba wax for finishing metal and have heard about using it on chains.
right now about every two weeks I clean the chain with a light mineral oil, then a day later I clean again and put down heavier oil. keeps the mud away.
would be I happier if I just cleaned the chain and dropped it in a pot of hot wax? is there anything to look out for?
> would be I happier if I just cleaned the chain and dropped it in a pot of hot wax?
Quite possibly. Chains stay clean and efficient for longer without intervention. And can be handled without dirtying your hands. It's nice. Other drivetrain components wear slower because there's less grit and the chain stretches more slowly.
> is there anything to look out for?
Main downsides:
* For bicycles, a lot of chains (Shimano, KMC) come in some kind of factory oil/grease. Stripping that off takes time and working with solvents. Fine if you have time and a garage, less great for busy people in apartments. I think some manufacturers sell dry chains (I've heard YBN does).
* Heating wax up is slow. I use a $12 crockpot and it takes a couple hours. Obviously, it's not like it takes any effort on your part, but there's some built in latency. ("Low" heat is about right in the steady state, but it melts faster if you use "high.")
* Again for bicycles, some kinds of quick link / master link wear quite quickly and can only be reused a handful of times (e.g., Shimano 11 speed). So one surprising expense in repeatedly removing chains to hot wax is the consumption of quick links. Can be mitigated with different brands of quick link, and/or using drip-on wax a few times between hot waxes.
* A freshly waxed chain will be stiff from the hardened wax. So a pre-install step is going through every link in the chain (on bicycles, typically ~110-120 links) and making sure each one rotates freely around the pin. This takes a few minutes.
> Heating wax up is slow. I use a $12 crockpot and it takes a couple hours. Obviously, it's not like it takes any effort on your part, but there's some built in latency. ("Low" heat is about right in the steady state, but it melts faster if you use "high.")
It's a bit silly, but I've used a simple ESP8266 board with a relay and a DS18B20 temperature sensor controlled by some Arduino code to make a simple temperature controller. It runs a Telegram Bot so I can start/stop the Crockpot and it notifies me when it reaches the desired temperature and when when lubrication is done.
Over the top, but it was interesting to implement. I might release it one day.
> Again for bicycles, some kinds of quick link / master link wear quite quickly and can only be reused a handful of times (e.g., Shimano 11 speed). So one surprising expense in repeatedly removing chains to hot wax is the consumption of quick links. Can be mitigated with different brands of quick link, and/or using drip-on wax a few times between hot waxes.
Whipperman makes the Connex Link. It does not require tools and can be reused as many time as you'd like. No 12 speed version yet, for some reason, though.
I'm that guy... who chimes in whenever someone mentions a temperature controller. I've learned the hard way that some kinds of controls such as solid state relays can fail or get stuck in the "on" state, leaving you with thermal runaway. Also, software and firmware have to be considered as points of failure.
to soften the carnauba wax in my shop I just took a heating element from an old stove and put a diode on one of the AC legs to halve the power. wax gets semi-solid so that it can be applied easily, but doesn't drip. I'm sure you could use an inductive hob to the same effect.
I wonder if that wouldn't solve the master link wear issue if you could wipe soft gobs of it on the chain instead of taking it out and submersing it completely.
> I wonder if that wouldn't solve the master link wear issue if you could wipe soft gobs of it on the chain instead of taking it out and submersing it completely.
It wouldn't penetrate as well, and you might end up wasting a lot of it / making a mess. The goal is to get wax inside, and you prefer it to be a liquid for that.
Just note that there are two ways to install it. Follow the instructions exactly as described.
Edit:
Specifically, connect the link at the bottom of the chain, put the link on the front of the right hand side link and the back of the left hand side link.
Otherwise, shifting to the lowest gear will not be smooth.
> A freshly waxed chain will be stiff from the hardened wax.
Oh, I always forget about this.
It's not necessary when you only ever ride singlespeed bikes... just wrap your chain around the rings and let the first few cranks do all the hard work!
But if you have a derailleur and whatnot... yeah, don't skip this step!
Yeah. It doesn’t need to be completely smooth when you install it on a geared bike, but you need to be able to thread it through the derailleur pulleys. Then you just ride it to remove the remaining excess wax, like a singlespeed.
On some derailleurs, you can remove a pulley to get the chain off as a closed loop. Still a pain, but in my case would save a $5 master link that isn’t supposed to be reused at all (sram 12 speed).
You’d also need a hole in your seatstay to remove the chain unbroken. (Some frames designed for belts have the ability to remove part of the seatstay, but it’s not common.)
With the wheel out and the bike upside down, you could put a cooking plate and pot on a stool next to the bike and immerse your chain while still wrapped around a stay. (You'd have to do it in two phases, of course, unless you have a really big pot and immerse half the bike...)
Probably; you wouldn't have to do so much maintenance.
Wax fills in all of the voids between the bushings, roller pins, etc - so it physically prevents dirt from getting into your chain. And since there's no oil to cause the dirt to stick to your drivetrain, your gears don't wear down as quickly (as oil / grease + dust is abrasive; each rotation wears the chain and rings down ever so slightly).
Casual! If you aren’t submerging your chain in molten wax while in an ultrasonic agitation chamber then you may as well just throw your whole bike in the trash.
Almost any dry lube will achieve the supposed benefits of this product. Even dumonde tech lube dries so much that you can barely tell the chain is lubed.
We've also had belt driven (with pinion) systems for years, both of which would seem to solve this in a much more straightforward approach. This seems like a technological dead end to me.
In my neck of the woods, the main enemy during winter is road salt. I find that a thick heavy lube is the only protection, and a chain guard to keep it off my pants. Half of the secret of the chain case on the traditional Dutch bike is that the chain can be smeared in really thick evil grease with an exceptional maintenance interval.
> Degrease your bicycle chain with kerosene or some other solvent, and submerge it in molten paraffin for 20 minutes.
Clean it with isopropyl alcohol after degreasing it and before submerging in the paraffin.
After a few hundred kilometers you'll need to submerge it again. Boil a kettle of water and use it to clean the chain before submerging it in the paraffin.
Some people suggest adding PTFE to the paraffin, but I have no idea whether it has any benefit.
I used to use the paraffin wax method, but I added micronized graphite rather than PTFE. It works well, but does make the wax look dirty. Nowadays, I find it too much faff to bother with the hot wax soaking and I just use commercial wax/dry lubes as I was ending up "topping up" the soaked wax chain with that anyway. I found that wax needed re-applying every 100-150km.
This looks weird and interesting and the price of the single speed version is actually not bad. The string is just simple dyneema cord with crimped ends, so you could probably even make them yourself from bulk and carry a dozen spares for basically no extra weight.
The prices on their different lines seem way out of whack though. Carbon and Aluminum cost basically the same? Aren't carbon bikes usually much more expensive than others?
Single speed is _way_ cheaper than the rest. Like unexpectedly so. Are they saying their adjustable gear mechanism accounts for $2000 of the price?
Wow that is a big difference on Aluminum. I was looking at the US prices myself, and my first thought was I bet I could add shifter levers on that single speed myself and save 2 grand. The EU prices make much more sense.
Esoteric gearing/hubs are really expensive. I have an internally-geared bike, and the rear wheel/hub is already 1/2 the cost of the entire bike... and that's more or less using tech that was originally developed in 1957.
Are they saying their adjustable gear mechanism accounts for $2000 of the price?
Look again: the "single speed" includes the gearing:
"The gear shifter was removed however gears can be changed manually pulling or pushing the pulley up or down when the bike is stationary."
You're paying $2000 to not have to stop and change gears manually, or saving $2K by doing without the gear shifter, which ever way you wish to look at it. I almost think the price is a typo.
You can definitely find two fairly priced frames, where the better/pricier one is made of aluminium and the cheaper one is carbon. It helps carbon fiber prices have gone down substantially in the last decade.
It's weird they don't have an embedded video or at least a prominent link to their YouTube channel. Here it is below.
Wish there was audio, I'm personally a little doubtful of the silence of the bike given the sorta clunky front gear system, but I'm sure it's quieter than a chain. It's odd that they muted it.
A bicycle is in my opinion one of mans greatest inventions. It empowers almost everybody to transport themselves five times more energy efficiently than walking. For two hundred years the bicycle has been improved by countless ingenious inventions. Cities where the majority commute by bicycle, are much better to live in.
Fully agreed! A dedicated bike lane that separates riders from car traffic could make riding experience very enjoyable.
I was born in China during the 80s, when biking was the most common way of transportation. The term "Kingdom of Bicycles" [1] was used as a tag line for China in that era. Most roads had bike lanes which could be just as wide as car lanes. Between the lanes are physical separators: 3-4 ft high, made of metal, reliable and heavy-duty [2].
Now I live in the US, and still enjoy biking cause there're nice bike trails near my place. However, most city roads seem not safe for biking. Biking becomes a recreational activity, and no longer a transportation method for me. I appreciate the nicely maintained bike trails, but I hope the city build more physical bike lane separators, not only painted lines on the ground, that can actually stop some reckless drivers entering bike lanes.
Bicycles are indeed the most efficient mode of transportation, but shouldn’t we be taking into account the energy cost of the entire paved system of roads needed to facilitate that rolling efficiency in the first place? Paving a road with asphalt is pretty resource intensive.
Bicycles don’t need that, and it wasn’t made for them, so I don’t know why you’d charge “road cost” to the bicycle ledger when they’re such a distant second (at best) citizen on most roadways anyway.
Maybe some roads somewhere were built for bicyclists, but I don't think you can generally say that when there are literally 6000 year old paved roads leading to Ur. Horse drawn carriages and wagons would benefit from roads and were probably much more common and important to business/transport than bicycles until the 20th century.
The real cost is in the repaving and that's much more a property of weight of the vehicles. Bike infrastructure is significantly cheaper to create and maintain compared to nearly any other vehicle.
Sure we should, but that’s the case for all transport modes. Remember that you can just pave the smaller amount of space needed for cycling down a street and not a full-width road. A cycle track uses less pavement than a roadway thanks to being narrower, and probably lasts longer too due to less damage from heavy vehicles.
It is but it's a lot less comfortable to ride on, and that makes a difference for longer distances. (They also have the unpleasant tendency to become mud when it rains.) But ultimately sure you can usually get around on a dirt path.
Other than that I can't readily find any more reviews from anyone who claims to have ridden one. I wonder why, given that they apparently have been making them for 10 years?
Almost always the downside to a non chain drive is a loss of efficiency. A chain and cog setup is really really good, like 99% efficient with a clean lubed chain. Internal hub gears, drive shafts, strings, almost all of them have losses a bit worse than that, which sucks when you are a 0.5hp motor.
Unless you're commuting in a salty environment destroying your chain (and bike arguably), I fail to see how a conventional chain drive is anything resembling inconvenient for commuting.
Interesting - I was just having a discussion with my son the other day about the term "horsepower". Quick research showed that the average human can generate 1.2 HP in a burst, or 0.1 HP sustained. Is 0.5 HP the accepted measure for sustained output while riding a bike?
Depends on how long to sustain - 0.5 HP is 373 watts, which is more than male pros sustain over a whole race stage but less than some can do for ~10 minute sections.
Seems cool. On the motorcycle side, I enjoy having a bike without a chain. Instead my BMW has a shaft that runs from the transmission to the rear wheel. Maintenance over 75K has been occasionally lubing the rear splines. There's been some attempts at a shaft driven bicycle but the downsides seem to come from the tighter tolerance, harder disassembly and overall heavier frame construction required. still cool from a longevity POV.
Transmission via shafts is also less efficient. It doesn't matter much on a motor bike where there's plenty of power. But on a human powered bike, every watt counts. See for example https://www.cyclingabout.com/chainless-shaft-drive-bicycles/ for more information.
I went down the same path owning a BMW shaft drive motorcycle, doing my own maintenance. I decided i had enough of re-tensioning the chain on my bicycle (Living in Amsterdam) and got a second hand Brik shaft bicycle. Indeed maintenance is harder, but i have far less maintenance. So instead of ~twice a year giving my chain bike some love, i now bring the Brik to the shop once every 2-3 years.
I still ride a normal chain bike regularly, and I can't say i find the Brik heavier to ride. It all seems negligible compared to the watts wasted by the sitting position of a city bike.
I'm no mechanical engineer, but this looks way more complicated than a traditional chain/derailleur drivetrain. Especially the two contraptions, one on each side of the bottom bracket. Instead of a continuous circular motion, the rear hub is constantly having to freewheel, on one side or the other. What's the efficiency loss there? How does the overall weight compare to a traditional drivetrain with the same range of gear ratios? Have they measured the difference in efficiency?
I am a mechanical engineer, and I'm 50/50 on it. The rear hub contraptions aren't too different from the freewheel that's already in a regular bike hub, it just has an extra spring to wind it back up.
The super funky gearbox contraption though? That's a different story altogether. You have a continuously varying normal force on the lever arm throughout the rotation, and I have no idea how long it would last compared to a traditional derailleur setup.
I like how the front pulley acts as a 2X gear ratio. For every distance x the pulley moves, it draws 2x string. That means you don't need a ridiculously small rear sprocket diameter, or make the front lever ridiculously large, to get a conventional high gear (like 52x12).
It's not so much an insistence, more just where the industry is at. Those freewheel hubs are loud because that's generally the lightest, most efficient design - lots of teeth for immediate drive engagement, no extra grease that would lessen said engagement, no extra material for sound dampening.
Clutch mechanisms are available, but these are slightly less efficient and generally more expensive.
Basically... People love spending lots of money for the absolute highest quality components. How will other riders know how fancy your hubs are unless it broadcasts that fact to the world?
I might have missed it but there's no info on efficiency. I can both imagine it's great and terrible. Dyneema doesn't really stretch so that's on the plus side. But surely there's a ton of friction in this system? And that's before you consider the gearbox; these tend to be somewhat less efficient than derailleur systems.
This isn't really a gearbox in the traditional sense, they're just using the word because it makes sense to people. What their "gearbox" does is increase/decrease the lever arm acting on the string. This serves the same function, but the frictional losses would be mostly constant across all the "gears".
There will absolutely be some losses due to rope deformation (squish, not stretch) and heat, but I imagine they would be relatively consistent across the lifetime of the rope - there's not any grease to degrade over time, for example.
Right, but the actual % efficiency does matter. Derailleur and IGH achieve easily 90+% efficiency with low maintenance. Is this in the same ballpark? 80% ? 60% ?
Also the string will definitely pick up grime off the roads, especially when wet, so efficiency will almost certainly drop as a result.
the FAQ says the string is technically more efficient but in practice they are both extremely efficient when properly maintained so the difference is academic. They don't mention losses when the string is wet or dirty so I'm not sure about that.
Huh. Interesting, very interesting. Usually links to bikes here are just nonsensical overcomplicated bullshit IMHO, but this is close to the simplicity of the $300 bike I’m constantly riding around town.
I’m trying to figure out what’s going on with the pull-back motion of the strings. Is there a spring in the hub? Are they stretchy cords that are going to snap someday? How easy are they for a passing asshole having a bad day to cut?
What happens if the string snaps?
It takes 10 minutes to replace, by the rider. No specialist knowledge required, worth watching the tutorial on the website. No tool required, no need to remove the rear wheel, or other parts. Spare string is provided, and neatly stored in the seat pole. The spare comes with instructions to install.
I like this stringbike, if I needed a bike currently I would consider it. However, the durability while minor is an issue. I have never had a chain-link snap. I have frequently had chains derail. So the metric in my mind is, how frequently does this method need maintenance, replacement or derailment.
It looks like they're juuuuuuuuuust the right length so they perfectly match up to pedal stroke.
i.e. - Your push stroke unwinds the string to its max extension length, and then the rotational inertia of the wheel does the job of winding the string
up again.
EDIT: Scratch that, disregard the above. Looks like they're using a spring to wind up one side while it freewheels.
As for assholes? Yeah, they're going to be able to slice those with a pocket knife in a few seconds. Even Dyneema and the like would likely be quickly frayed with a few good knife swipes to the point of being in danger of snapping from a hard pedal push when taking off from a stoplight.
An interesting security feature would be if you could take the string with you whenever you dismount. The site says replacing the string takes "10 minutes" though, which is way too long for that.
I think it’s a neat design but the cost is way to much for the average user to adopt this. It’s certainly not geared towards casual riders like me and my kids. They are way to hard on bikes to justify something like this. So it looks cool and I would like to try it out but never would buy one at anything even close to the price they are offering right now.
Same here, I am intrigued by it, and would plunk down $1k right now for something like this even, but $3k+ is wayyyyyyyyy too much for just a standard bike with a neat drivetrain. Plus, I am sure shipping it to where I live would be another few hundred. I do like the idea of this for low-maintenance though.
They look well suited to road riding. Sounds like mud and grit fouling the string would wear them out quickly. Replacing them seems simple enough, but I do wonder if anybody has tried using a nylon belt instead.
And then there's the bearing surface of the pedal-gear-thingies. I'd bet a little grit in there would sound and feel like nails on a chalkboard.
I wonder what it would be like to independently adjust the leverage ratio on each crank? Maybe if you had one leg stronger than the other? Or you could maintain two gearings for different scenarios — left leg power, right leg torque?
A silly idea, for sure, but fun to think about and a unique feature of a two sided drive.
A stringbike has a completely different feel than a regular bicycle due to the energy storage in the spring. With a stringbike you don't encounter torque spikes going up a hill because the spring smooths them out.
There will be a lot of pressure on a relatively small wheel there, so I wonder what dust or a grain of sand would do there. I would guess making sure the mechanism near the pedals stays operating smoothly takes more maintenance than with normal bicycles. I wonder whether they considered exchanging rotary motion of the pedals for up/down movement so that they could get rid of that complex shape.
Also, given that they sell a “seatpole spare string holder“, those strings don’t seem to last as long as a traditional bicycle chain.