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Bicycle Tech Drivetrain Advances Showcased
whoda writes "For many years, bicycles have had very few advancements in drivetrain technology. This is finally changing. The newly formed g-Boxx Standard has been incorporated into the new Nicolai Nucleon TFR bicycle frame. This bike uses an internally
geared 14 speed planetary gear system, mounted in the center of the bicycle, to drive the rear wheel using a conventional chain. The design allows the chain to run inside of the frame. This removes many fragile components from the bicycle, and allows a more rigid frame structure to be made. Evil Bikes have also shown a protoype
Evil 2013i hardtail which also incorporates this new standard - I've found the toy I want for the holidays."
This just means now that if something breaks down, it would be hard as heck to get at it. Parts inside the frame? Kind of hard to do trailside maintainence on that! (Especially since it's not from a well known component manufacturer.
I'll wait until I see it on the World Cup circuit before trying it myself...
How about shaft drive?
Look at that photo carefully. Notice that part of the chain is exposed. Now just were do you think all the road dirt and other muck is going to end up?
Sounds good for mountain bikes that need to protect the chain and sprockets but might add some unnecessary weight to roadbikes.
The Q looks horrific, the weight is high, the chain is still exposed, there's no easy way to clean the frame out when it gets filled with the muck and water that the chain will inevitably drag in, the lanetary gearing is less efficient than a pure chain drive. Yeah, I can really see why you'd want that setup: to look like an idiot with a fat wallet and a small brain. Oh, and prepare to be savaged by rec.bicycles.tech, where the posters actually know a bit about the technical issues.
You could simply ride fifteen pounds of funk.
One gear -> stronger legs, more distributed workout, less to maintain, fewer parts to fail, just mo' fun
Every once in a while someone spends a crapload of money trying to change the fundamentals of the bicycle, but really, other than the derailleur, not much has changed in over 100 years.
Okay, I admit the chain-inside-the-frame thing is cool : less crap on the legs, cleaner, well lubed chain, etc... But somehow, there has been a notion that current bike drivetrains (i.e. chain+derailleur) are inadequats. There are continuously people who dream of making CVTs for bikes, or non-rotating drivetrains or whatever, to replace the "old" chain-and-derailleur. Well here are some facts :
...
- A chain/derailleur system is the only system that offers that many speeds under 2Kg
- Bicyclists don't need Continuously Variable Transmissions : human legs are incredibly efficient over a range of speeds from 0 to 13/140 RPM
- A bicycle is virtually the only vehicle where a chain drive is useful and needed, because the "engine" (you) is slower than the wheel, which is unique amongst all vehicles. This is also why any other kind of transmission will fail miserably compared to a chain drive in terms of efficiency (a chain drive routinely gets over 97% efficiency, and you need that with the 75W-100W power you get out of an average rider).
- A cyclist who's moderately used to shifting well will *not* feel impaired by derailleur actions.
- A chain + derailleur system is maintainable on the road. Just try to service a geared hub on the road
- Geared hubs are great for compacity and easy maintaining. However, their efficiency sucks. For example, a 7-speed Sachs hub can go down to 90% efficiency. That's a lot of power loss with under 100W of input power.
For more bicycling myth debunking, read the rec.bicycles.tech newsgroup and the Bicycle Science list.
I do over 10000Km/year and, apart from chain cleaning and re-lubing, I think the derailleur system is very adequate.
"A door is what a dog is perpetually on the wrong side of" - Ogden Nash
Reading these comments, it looks like 99% of the detractors of this concept fail to understand that the biggest plague of the downhill racer is the rear derailleur - it hangs in a VERY exposed position and is extremely easy to rip off. When you lose your rear derailleur in a DH race, your chances of making the podium are slim. Believe me, it happens a LOT, and it gets expensive and very annoying.
Another thing people fail to realize is that this concept is about DH bikes, not about cross-country bikes. It may weigh a lot, but a 40-pound DH bike is pretty light.
Too many opinions, not enough brain power to go around, if you ask me. If you ride a 23 pound XC-racer, you might as well comment on the suitability of an 8" travel, 12 pound, dual crown suspension fork for your riding style.
I spend a lot of time on high-performance Human Powered Vehicles (HPVs), and efficiency is a big thing among high-speed bikes. The main problem with these internally geared drivetrains is that they are not very efficient at all. They rob you one heck of a lot more power than chains and derailers. The regular chain and derailer design is something in the neighborhood of 97-98% efficient, while these geared drivetrains are about 70% or less.
The main advantage of the internal gears is for downhill mountain bikes. Drivetrain efficiency is not as much of an issue since gravity is doing most of the work, and there is no risk of losing your chain in mid air at 40mph.
Joao "member of far too many HPV and bicycle clubs and associations" de Souza
100W? are you kidding me? I am not a fast cyclist by any stretch of the imagination (I just do triathlons, any cat4 cyclist can kill me easily) and I can do 200W sustained over fairly long (1h+) periods of time, Armstrong IIRC can do 400-500W sustained, and sprinters (Pantani) can generate up to 2000W for short periods of time.
:)
Also the most efficient cadence (in terms of power generation) is more like between 90 and 110rpm (of course you have to train to have a 'round' pedal stroke, 'mashers' tend to pedal around 70rpm) and the range of maximal power generation is not that wide (in terms of rpm), that's why the latest geartrains have 10 cogs at the back (and 2 or sometimes 3 at the front). If human legs were =incredibly= efficient we'd all be riding single speed bikes
Agreed about the rest, internal drivetrains are a fad that doesn't seem to want to go away: the only application where IMHO they make some sense is pure downhill, where hitting your derailleur on a rock can put you out of the race and where pedaling power doesn't really matter that much...
-- the cake is a lie
I've ridden 10s of thousands of miles and I'm here to say that a bicycle helmet is an absolute necessity, period. I've completely destroyed two helmets and scraped several more. I once scraped right through the plastic cover of a helmet and well into the insulation. If I hadn't been wearing it my scalp, hair, and a decent chunk of skull would have been left behind on the road.
Yes, you do. It's a matter of when, not if. Every cyclist wrecks, and some wrecks you land on your head. Why would you not want to protect your head?
On this we agree: the government should stay the fuck out of decisions that affect only my own health. Anyone above the age of consent should be able to ride anything with as much or as little safety equipment as they desire, as long as no one else is at risk of harm. Mandatory helmet laws are like anything else the government does "for your own good:" dangerous.
This isn't as much "normalization" as it is "don't take so many drugs when you're designing tables."
This year, you may (or may not have noticed) that every rider in the Tour de France was wearing a helmet. They're only allowed to take off their helmets for the last 5km or so of a race when the finish is uphill. Why?
Well, earlier in the year, a nice young rider with a 2 month old son went over his handlebars in a low speed crash. He bumped his head on the ground, and never woke up. From all accounts, Andrei Kivilev was a nice guy just trying to make it as a pro.
He was apparently the last straw. Finally, the UCI has instituted mandatory helmet laws for all riders. It's not because it's flashy, it's because they CAN save lives. It's not a guarantee, but neither is a seatbelt.
The bike that you're asking for is constantly being aimed for, not by bike companies, but by people that try to develop cheap bikes for third world countries, where they're actually a fantastically important asset. Hopefully, they'll also make bikes domestically. I think that something like what you're suggesting could bring cycling back to our overly sedentary society. What we need are cheap, effective helmets and cheap effective bikes. In that, you're totally right.