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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."
Internal gearing in bicycles is not, new, it just never catches on.
How about shaft drive?
this entire standard is designed for the freeride/downhill segment of MTB owners that require a *lot* of travel out of a full suspension rig without the detractions that come with using a standard shifting system (shimano style derailleurs tend to get ripped off at 60mph when they come in contact with a rock) also having the bike shift itself when the suspension compresses would be considered a downfall.. trust me.. i used to race DH.
Alex 'Psycho' P.
I believe those were introduced by Shimano as the "Biospace" (or at least Bio-something) brand chainrings. Didn't catch on much because most people found the pedalling to feel jerky, or so I heard. I've also heard that they're still sold.
In the great CONS chain of life, you can either be the CAR or be in the CDR.
Benefits
Limitations
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You're thinking of Shimano BioPace chainrings. I still have a set on an old mountain/messenger bike and they rock for high RPM grinding on the pedals up the steeps, but you do notice them on the street. But then they weren't designed for street AFAIK.
"They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety" - BF
Biopace. Some people liked it, others didn't. These days everyone's using clipless pedals anyway, making for much smoother power transmission all the way around and elliptical chainrings yet less sensible.
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
1) Tires that don't go flat! Or, rather, I should say... tires that don't go flat and only cost two or three minimum wage units. $15 US. Yes there are Kevlar tires that are as thin as your thumb and cost $200, hold 100 PSI air pressure, and rarely go flat, but they don't count.
Firstly, those $200 tires go flat just as easily as cheap tires on pavement (i.e. a piece of glass or nail). They are $200 because they're light (by way of having a high thread per inch count) and they're grippy (fancy rubbers and compounds). NOT because they're anymore flat resistant than a cheapo knobby or slick. In fact, I'd argue there more flat resistant for punctures (maybe less for snakebites).
Secondly, if you want a tire that definitely won't go flat, buy a solid rubber tire like your bike had when you were seven. Light, Cheap, Strong - pick two.
Thirdly, tire choice pretty much never affects regular flats (assuming the tire is adequately inflated to begin with). It's the inner tube that goes. Here's a tip, throw a bunch of baby powder in the tire before putting in the inner tube. You're probably flatting because your tire is spinning in the rim and cutting the valve stem.
2) Something to keep the rain and road dirt from putting a big skunk stripe up our backs when riding in wet climates. There are fenders, but they don't work well.
Actually fenders work incredibly well. Just get a set of grandma fenders that cover about half the wheel (less in front) and are really close to the tire. Yeah they look dumb, and your cool seat mounted stick is waay cooler on campus, but you said you want something that works.
3) The ability to fold the frame so that it can fit in the back of a small car or on the bus.
These exist in abundance.
4) Brakes that work in the rain.
Yeah. This one would be nice. Discs work well here ($$$), and so do Magura's with salmon pads (haven't tried the froggies), but most mechanicals suck. (Except when you pair old canti levers and v-brake arms... that'll stop anything).
5) Tires that don't go flat. So important, I'm saying it twice.
See above.
In fact, I HATE bicycle helmets. Their sole purpose is to show all the people driving around that the person on the bike is middle class, has a car at home, can afford a $100 helmet, and is seriously concerned about saving the environment to the point of actually going out into the public on a bicycle.
At this point I think I'm being trolled, but I'll continue.
There are plenty of ANSI and SNELL certified helmets for significantly less than $100. Hot damn, I even found you one using Canadian Dollars. The Adrenaline 2 is on sale for $20 and is plenty safe. Hardly seems to justify the yuppie status trophy you want to place on it.
Sure helmets aren't cool looking. BFD, neither are life jackets and designated drivers.
I'll leave the skiing one for the next time, but in the meantime, think about what you'd rather land on if dropped from the sky, fresh powder or a lamp-post/ford pickup/car door/concrete curb and when you're done there, remember that traffic (on streets, trails, and parks) move both ways and don't expect to see you there.
Jeff
2) Something to keep the rain and road dirt from putting a big skunk stripe up our backs when riding in wet climates. There are fenders, but they don't work well.
I don't know what you're talking about. A full set of wrap-around fenders is a solid barrier between the wheel and you, and the bike. They protect your back and butt from the rain thrown up by the wheels, and protect the bike quite a bit as well. I bike year round and know this from experience. I'm partial to the SKS fenders myself, but other brands work. Those 'back scratcher' fenders that clamp onto your seatpost are pretty worthless though.
4) Brakes that work in the rain.
Disk brakes. Hub brakes.
5) Tires that don't go flat. So important, I'm saying it twice.
Skinny high pressure tires (700x23 in my case) need to be pumped up two or three times a week, otherwise you'll get pinch flats. But any bike that uses such small tires is high maintance (and expensive) anyway. For wider tires (26x1.9 in my other case), what flats? Sure, if you ride over broken glass you'll probably get a flat, but there's an easy way to avoid that. If you're unwilling to learn how to change a tire, you can get solid tires (though they are heavy, have high rolling resistance, and are harsh to ride on), but it's really not that hard.
Comeon. Let's be serious.
Bikes with drailleurs have the most efficient transmission possible. Because a chain, unlike gears, has no inherent inefficiency caused by the gear teeth engaging and disengaging themselves. With a pair of gears, the distance of point of contact between teeth and the axis varies as each gear teerh engage and disengages the opposing gear teeth.
The result: non-constant velocity at the output of the geartrain. This induces vibration and is a source of drag.
On a chain, the distance of the point of contact of the chain link with the teeth remains constant WHERE THE POWER IS APPLIED TO THE CHAIN. Of course, the distance varies when the link engages the teeth, but as it happens for a very small percentage of the time the links are around the wheel, the gear teeth can be cut in a shape that does not allow any teeth to contact the chain until it is firmly seated against the gear.
A chain transmission will therefore offer the most efficient power transmission possible.
This is why race bicycles have chain drives. They cannot afford to lose the slightest erg of effort!!! This is why many motorcycles have chain drives, too. And the drailleur offers the best solution: variable diameter sprocket gears! The number of intermediate points between the cyclist leg and the pavement is kept to a minimum. How many inner gears and clutches does that 14-speed planetary gearcase have???
And a planetary gear change is not the most efficient design around. Ford-Ts had planetary gear transmissions. Cars have evolved a little bit since then, in case you haven't noticed.
Uh, no. Unless you prefer looking at the scenery through your ass. You'd be going backwards.
The derailleur is on the bottom because that's the direction the chain travels. Clockwise, viewed from the right side. The derailleur is the chain tensioner, and it also moves the chain from one sprocket to another to change ratios. If it was on the top, the action of pedaling would stretch it out, lose the tension of the chain and provide no motive power. And the chain would fall off the sprockets through the lack of tension.
Nope, it belongs on the bottom because that's how it works.
You can't take the sky from me!
Motorcycles uses chains because they're (1) inexpensive, (2) lightweight, (3) lowest unsprung weight, (4) compact and narrow, (5) immune to the 'shaft jacking' (rear end rises and falls due to torque on the rear hub), (5) able to handle lots of power (ZX-12 anyone?), (6) directly compatable with transverse engine layout and finally (7) they're highly efficient when properly cared for.
Some motorcycles use shafts because (1) they're somewhat lower maintenance than chains. That's the sole reason. Yes, there have been some performance improvements in shafties (Paralever for example) but they still find use primarily on models targeted to riders who aren't so concerned about weight and cost and put a premium on maintenance (yes, that'd be you propeller-heads and Gold Wingers.)
And even then I'd argue the maintenance point: an O-ring chain sprayed every 600-1000 miles with a good lube like Maxima Chain Wax will give trouble-free service for a long time. My literbike's chain and sprockets lasted 30,000 miles with this sort of care. Cost of a new chain and sprocket set? About $185, and a half hour to change them out.
Oh yeah, there's belt drive too. S'ok if you don't mind the extra half-inch or so it adds to the width of the drivetrain, not to mention the limited power that realistic belt widths can handle. Also, don't get gravel in one, it'll mess up the sprockets if not damage the belt (I haven't priced belts and sprockets but I bet they're a lot more than a chain set.) However, they don't tend to stretch and need only a little shot of silicone once in a while.
- dvd_tude
That was my thought immediatly upon seeing a picture of one of the bikes. Looks like it adds a ton of weight. The only thing I could see this being used in is a downhill bike, because weight isn't as much of an issue. But no one riding on the road or riding cross country will ride one of those things.
I ride and race a lot of road and x-country, and I for one would not use one of these for either of those.
I think the intention is for downhill though. Stronger frames, less exposed parts, the pictures I saw were of suspended frames (except for that hardtail, which is probably there for suckers.) By the sounds of it, these things would shift a lot better than a derailleur especially when bouncing around. The pedal-less shifting would be beneficial for a downhiller as well.
Someone mentioned maintenance too. Despite the fact that these devices are supposedly low maintenance, you wouldn't be stopping to fix anything in the middle of a downhill race.
-kidlinux.
Sorry to pick on you but the fact that you are chronically destroying helmets may be a good argument for you to wear a helmet but is not enough to prescribe a universal need. People both inside and outside the US (the Europeans sometimes call helmets the "American Obsession") have been riding bicycles to get where they are going for over 100 years and they have not been dropping like flies, regardless of what the fear mongers would have us all believe.
Despite common knowledge to the contrary, cycling properly on the road just isn't that dangerous relative to other ways of getting around.
As anyone who has followed the Helmet Wars in Usenet knows, the rate of fatalities due to head injury while cycling is similar to that of motorists (per hour it is less, per mile it is more) while the motorist FHI numbers are about 50 times that of cyclists - which deflates the 'cost to the system' argument for helmet compulsion quickly. Pedestrians who walk near traffic fare even worse per hour than either of the above groups. Yet nobody even remotely considers wearing a helmet before crossing the street or climbing in the car even though their is a more sound basis for either of those groups than cyclists. Perceived risk is often very different from actual risk and these decisions are often based on emotions rather than logic.
Whole population studies done to compare injury and fatality rates before and after the implementation of Manditory Helmet Laws (Australia being the basis of much of the study) has shown no long term benefit to these laws. One study pointed out that cyclist head injuries had dropped about 35% but failed to mention that the number of cyclists had decreased slightly more which indicated an increased rate of head injury. Such duplicity is the norm - helmet laws are still being lobbied for with the false "85%" figure which even the authors of the 15 year old study have abandoned.
Promotion of bicycle helmets has done two things: First, it has completely and utterly connected Cycling and Head Injury/Death in nearly eveyone's mind (this site being lots of evidence in itself!); parents are afraid to let their children ride anymore even though cycling is statistically safer than it was 20 years ago - rather they let their children safely get fat while being raised by a TV.
The second effect is that helmet manufacturers make oodles of money even though they are shrinking their customer base thorough their vile anti-cycling marketing tactics.
Bicycle helmets are excellent proof that marketing works and that emotional hysteria is the best way to get laws changed.
This mean, among other things, that shifting gets harder when you are putting a grater load through the chain... which is often when you most want to change gear!
Nevertheless, this is how front derailleurs work - they crudely shove a tensioned chain around from one chainring to another. It's not elegant and even with recent improvements in the shape of chainring and sprocket teeth to make it easier to move the chain between them, it sometimes works poorly.
I live in Holland, where everybody and his dog has one and a half bikes and ride the complete one. People laugh at bike helmets for a good reason. we just made sure we don't need them(if your doing 50 km on a small inroad it might be a different matter, most people use bikes in and around the city). We just made sure that there are good bikelanes or bikepaths with clear crossings. on top of that the law was changed to make motirized drivers responsible for all damage if they have an accident with a bike (or pedestrian for that matter) The message is that it is the car driver is the one that causes most damage and should be the one to drive very cautious when bikes can be around. I have been in one majorish accident (drove into the side of a bus when my brakes didn't hold) and a helmet would not have saved me from the concussion anyway.
The thing about fenders and brakes is really nonsense. My bike has fenders and drumbrakes and i usually don't have to ride through mud anyway. My outer-tyres that have a kevlar lining to reduce puncures cost me about 12 euros each.
And to go back to the original article: I have a 3-speed gear hub (sturmey/archer) and have no problems with that. This new gizzmo is nothing but a toy for yuppie boys that don't know what to do with their money and drive a car to work.
This space is intentionally staring blankly at you
I gather you've never been mountain biking then. Try going up a long 30% grade hill sometime, after a full day of riding. Let's say halfway up the hill you fall off the bike. Switching gears at that point (if you're not already in the lowest gear) is near impossible, since you're not able to pedal to start the gears in motion!
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