Video: In Depth with Bike Transmission

Jun 11, 2013 at 0:00
Jun 11, 2013
by Karl Burkat  
 
You must login to Pinkbike.
Don't have an account? Sign up

Join Pinkbike  Login



It's been around for about 100 years, and many believe there to be a better solution but the humble derailleur is still going strong. We get the lowdown on the why and the how courtesy of SRAM's race coordinator Todd Anderson and the Santa Cruz Syndicate team.
Must Read This Week









84 Comments

  • + 26
 The amount of additional loss from a gear box is substantial, but the net loss from a chain/derailleur for the average joe is pretty big too. You have to figure in the resistance from the chain control devices, the inconsistency in performance in varied conditions, required maintenance, premature wear to the chainrings, and the occasional massive failure.

The derailleur might make sense for racing for a long time, but considering we have all already accepted the efficiency loss from suspension for the trade off in benefits, I really do believe that a gearbox could be done in a way that is more than good enough. Think: straight chain line (long life chains), minimal retention devices, no derailleur repair or replacement, new chain paths influencing linkage for better suspension. The payoff could be pretty big at only a 5-10% loss in efficiency. I know I lose more than that from my tires and suspension.
  • + 18
 After trying Rohloff, it is efficient enough. And quickly becomes more efficient in the mud. And it is a revelation to be able to shift under tension when winching up a climb. It is just heavy, and hub is a wrong place for it. I want Pinion frame, but about 6 gears over a wide range.. to keep weight low. Gazillion gears to keep cadence is for roadies.
  • + 11
 Zerode G2... my work here is done
  • + 5
 Funny how he went from clutching at straws trying to discredit Gearboxes into needing to control the chain slapping about. Much less of an issue with a gearbox. He also neglected to mention with a gearbox it's much easier to select the right gear any time, making it therefore much more efficient, and you don't need to waste as much time pedaling through the gear change, especially with multiple shifts in one hit. No need to slam gearboxes to justify cashing in on fragile derailleurs, and perishable cassettes that eat chains. It's only the most efficient way to pedal a bike in a lab, it's debatable when riding. and add a bent hanger, twisted mech, Stretched cable from forcing the chain into the next sprocket, twisted or worn chain from the same reasons, some mud n shit, worn guide wheels etc etc and there's no way.
  • + 1
 Reposition the derailleur EI where rocks cant hit it and introduce a method for keeping the complete drive chain in closed thus not affected by weather and crashes... this is all
  • + 8
 so make a gearbox then huh?
  • + 2
 he did use the word "thus" in his sentence. he must be knowledgable on the subject.
[Reply]
  • + 21
 "There's no loss here"...

Yes there is! It's considerably less loss than in a gearbox, but to say there is 'no loss' is completely false. It really... grinds my gears Wink
  • + 10
 Exactly. It's entirely incorrect. And to add, the parasitic loss is increased with the addition of a chain guide, or gears not aligned (which is about 9 out of your 10 gears.....), then add some mud and grit in the mix and that's nothing but a blatant lie (or someone is misinformed) because they nearly wash out. Grinds my gears too.
  • + 7
 He ment no loss from the casset to the wheel
  • - 3
 Well there's a loss there as well! (albeit microscopic).
  • + 1
 i think you guys are missing the point. All he is trying to say is the fewer the gears and other what not that is needed to run a gearbox takes away a lot more of your power than a traditional chain and deraileur.
  • + 7
 Actually, I researched this topic about 10 years ago, so it's probably me that gets the 'point' isn't actually backed by much more than marketing claptrap..... There's a few studies available on the web, that actually test the 'power loss' of different drivetrains. To say it's a 'lot more' is, sorry, complete rubbish. It's in the region of maybe 5%, tops, when you start factoring the required guides and chain line deficiencies (92% vs 98% for a perfectly aligned brand new derl drivetrain WITHOUT a chainguide....). And that number shrinks when a standard drivetrain starts getting gunked up. A dirty moto chain dyno tested at a 10% loss over a new one (again, the web is your friend), so factor gunked up pulley wheels and guides that you see in the real world and that 'lot more' is actually not noticeable by you and me. Furthermore, a gearbox varies between types, so not all are planetary systems and as such each system has different efficiencies, but all are encased with clean, fresh synthetic oil protected from the elements. Don't forget what Honda achieved with theirs! The statement you heard was through a guy who gets a paycheque from a company who would love to see the durable gearbox idea go away so we can keep hanging $200 fragile bits of metal and plastic off our bikes.

-Sincerely: A guy who has used both standard drivetrains as well as Rohloff and G-boxx ones and currently uses an XTR and Force that constantly need trimming.


Educate yourself (third party studies are out there as well, although the math in this is correct): www.rohloff.de/en/technology/speedhub/efficiency_measurement/index.html
www.rohloff.de/en/technology/efficiency/index.html
  • + 1
 Funny how a joke gets taken seriously and clowns run to neg prop it. hahahah. No one actually thinks there's much loss in your rear hub.
  • + 2
 awesome, didnt know that.
[Reply]
  • + 19
 Pretty sure it's in SRAM's best interest to keep us thinking this way.
  • + 4
 Doesn't mean they're (or Shimano) aren't working on gearboxes. If things go the way of the gearbox I'm pretty sure neither of them will miss the boat.
  • + 3
 For sure. In very dark secret room, they have it all worked out.
[Reply]
  • + 15
 love the kid in the background who nuts himself
[Reply]
  • + 11
 The Redbull video player is, what we here call, a boner killer.
[Reply]
  • + 5
 I like it when Greg says He has no idea what gear He's in, instead He only knows, how many gears up or down He needs to go, to manage a faced section, so now I've learned, I am not the only one unconscious. I just don't understand why they still make shifters with small "TVs" indicating gears with drunk approximation. Who uses that? The only way to be sure about the gear in is to look down between legs Smile which may sound / look funny.

As for my donwhilling I don't really shift so much during. Instead I double click the button down just after few cycles of start. Then it is rare that I need to accelerate by pedalling so shifting only occurs when a track gets "flat".
  • + 2
 I really don't like those windows, they break easily and in my opinion are worthless.
  • + 1
 They're for beginners - they can't really know what gears they're in by just the feel. Which is why higher end shifters don't have it altogether.
  • + 1
 How much beginner should I be not to feel that a gear is too hard or too soft for me at a particular time. This is not for physioteraphy enthusiasts. The screen's appoximation shows only this. Oh it should be somewhere in the middle, or somewhere down. Can't they feel that? It is a big difference. It is like turning right or left. So why don't we have screens "for beginners" indicating "LEFT TURN" or "RIGHT TURN".
  • + 1
 Clearly you've never ridden with beginners - someone who you have to teach what gear they have to be in for what incline. Until you do, you're just speculating.
  • + 1
 American beginner is surely different from European beginner.
[Reply]
  • + 2
 For all those Gear box fanboys, give me a paper (an actual research paper) describing actual experimentation and testing between a derailleur and a gear box and show me quantitatively that the Gear box is better. The major manufacturers have gearboxes (albeit hubdrives) in their lineups, and the equipment to test them against their conventional drive-trains and would offer gboxes if they thought it was better. Don't give me the crap that they just want to produce what is making them money, because that is not gaining them significant market share and hindering growth, if a gearbox were a better option, they would have been in a race to release one by now. It would also probably lead to bikes being designed to only run one company's system due to the inevitable creation of new mounting "standards". Dont get me wrong, a well executed gearbox might work perfectly, but no one has provided any solid evidence as to its superiority.
  • + 7
 I can rip a deraileur off because of where it's placed. A gearbox can be placed safely out of the way. I don't need a research paper to tell me which one of these I would prefer.
  • + 1
 Its the cost that keeps them from using them. In order to make them as comparable, they would have to be using high end bearing and materials, which would negate profits because nobody is going to buy the jeweled gearbox.
  • + 1
 Ride one, get used to it, you'll soon see the benefits. There's too many variables to do a test. The testers interests will easily dictate the results. Own a gearbox bike, and you'll see even more benefits. Reliability and durability being two very very huge ones. Only Greg mentioned the benefits of ground clearance, something that's less issue with a gearbox. He could shift more if he desired different cadence if he had a gearbox bike.
  • + 1
 I'm sure that I would love it, I just have no problems with my 1x10 derailleur setup. I want a quantitative test not a qualitative one. so things like energy loss, effects of weight and its distribution, and long term cost of it. these are claims that are thrown around by both sides but you should have data to back up the claim, especially if you are in the minority. It may be great, but it is limiting when changing frames, especially here in the US and on a budget.
  • + 3
 There's no fair test, because it's always going to be different. I can tell you that if you grab 1 out of 10 bikes with a mech from the Whistler lift line, and 1 out of 10 Zerodes. I'd be betting my $$$ that the Zerode has higher odds of running more smoothly.
You don't know any better. As I said, get used to a gearbox bike,then go back to a bike with a mech, and you'll be disappointed with the bike with the derailleur, and notice it's flaws, and feel it is inefficient at the end of the day.
Alfine gearboxes are well proven from the millions out there on commuter bikes. In a Zerode, they're not stressed like when used as a rear hub. The Rohloff in the Lahars and Nicolais are even more durable. Talking 40.000kms here. With only a squirt of oil a couple of times a year for both.
Pinion and Effigear haven't been around long enough to judge their reliability. But they'd still have all the other huge benefits a gearbox bike has. Try it, then pass comment with an informed judgement. It's unfair to judge a gearbox bike without riding it enough for it to be second nature to shift any time etc, and not have to avoid hitting your mech, or pedaling a change through without rocks being around etc.
I shift in the air and through rock gardens and corners, how cool is that.
[Reply]
  • + 4
 Well thanks for that very fact filled video from a bunch of companies who have nothing to gain by telling us a gearbox is not efficient enough.
[Reply]
  • + 2
 When riding downhill the losses in efficiency when pedaling through a gearbox are near on insignificant. The bike is pointed downhill 99% of the time and during the course of a run you will only be pedaling for short periods due to terrain being rough, steep and generally downhilly.
However, the increased efficiency of the rear suspension that is possible with a gear box equipped bike is far from insignificant. The benefits of a rearward axle path/high pivot point layout that a gear box allows (ie: Zerode) due to not being limited by a low, derailleur handicapped chain line are there for the whole course.
For downhill application the benefits of the gearbox bike far outweigh the benefits of sticking with chain and derailleur. I cannot for the life of me feel any difference between pedaling my Zerode or my Aurum (equipped with Shimano Saint derailleur and shifter, PG970 cassette, KMC X9 chain). But I can certainly feel the difference between the rear ends of the bikes, particularly in the rough stuff. The greater stability over gnarly terrain would be enough to impress, but there is also improved corner speed and a feeling of stability on landings as the suspension compresses and the wheelbase lengthens.

Having said all that, though, with my all mountain or XC bikes I would rather stick with derailleur and cassette for tackling the ups.
  • + 1
 One other benefit of the gearbox is that you don't waste 1/2 a rotation of the cranks waiting for the chain to change gears on the cassette. That is a huge advantage when riding over terrain that only allows you 2 or 3, or even 1, crank rotations to get the power down.
[Reply]
  • + 2
 That todd guy said Gearboxes have been researched extensively? Clearly he hasn't been looking into it so much! It is worth reading www.ihpva.org/HParchive/PDF/hp52-2001.pdf which is one of the very rare actual pieces of research, rather than marketing on the subject. It would be good to see some similar results for pinion and effigear drivetrains, but I think most of us see other advantages to these systems.
  • + 1
 wow! that does actually appear to be real research! how refreshing! In any case, why do SRAM and Santa Cruz feel the need to re-market the near 100 year old derailleur (and blatantly run down gearboxes) ? are they really worried about gearbox innovators who have sold a few hundred bikes taking market share?
  • + 1
 I read that whole paper and it seems to me that an +/- 2% loss in efficiency isn't that bad considering the benefits. Especially considering they would obviously improve over time.
  • + 1
 Also just finished reading the paper, seems like good methodology and I'm also impressed that the difference in efficiency only about 2%. Fascinating.
  • + 2
 and another thing, I want my next bike built around the Sachs 3. Uphill gear, downhill gear and a flat trail gear... perfect!
[Reply]
  • + 3
 So what if i have to pedal a bit longer on a climb. It's better then dropping $100+ every 2 months replacing a derailleur that got smashed on a rock again, and again, and again...
[Reply]
  • + 3
 From my end, I've never had a catastrophic failure on my drivetrain to give a damn about gearboxes. Ride smoother, and maintain your bike properly... 'nuff said, IMO.
  • + 3
 There's many other benefits, and no need to ride or shift smoother. Like a loyal dog, a gearbox bike is always ready to go. My Zerode needs less of the attention a mech bike needs tuning and stuffin about with. and the chain alone even lasts way way longer.
[Reply]
  • + 6
 I want to try a pinion
[Reply]
  • + 2
 Didn't Greg race for the Honda Dh team about 5-10 years ago with a prototype gearbox DH bike? What happened to that bike and team?
  • + 1
 That wasn't a proper gear box. It was a derailleur and cassette in a box.
  • + 1
 Still a gearbox with most of the benefits.
[Reply]
  • + 2
 I read that chains were something like 90% efficient and then someone invented a chain with rollers on the links and they are now 99% efficient.
[Reply]
  • + 2
 I think gear box with belt drive is where we will eventually end up. how long though, who knows. progression of technology is only increasing exponentially.
  • + 2
 Belt drive introduces some pretty serious limitations, I'd be surprised if it ever goes mainstream.
  • + 1
 Belt drives have to much friction. Look at modern cars. When the government introduced minimum fuel economy standards, most switched from timing belts to chains.
[Reply]
  • + 3
 I saw a lot of shoelace flopping and slapping around at 3:57. When are we going to get some technology to combat that?
[Reply]
  • + 3
 looks like were stuck with the rear mech for a while......i have no issues anyways.......
  • + 0
 Thousands of rides have been spoiled because of rear derailleur failure, thousands more will. It's lightweight and efficient, but my praise stops there. Tulio Campagnolo invented the rear derailleur. It was simple, elegant, and appropriate for road bicycles. If he saw what these companies have resorted to these days with clutches and 42 tooth cassettes he would probably be horrified and tell them to just reinvent the wheel already.
  • + 9
 probably not, in fact he would probably be ecstatic to see how far his idea had evolved and been improved.
  • + 1
 If you don't like the rear derailleur and think you know a better solution, then go ahead and make your own system.
  • - 1
 single speed works too. as long as you don't plan on going up, down or doing anything horribly exciting with your bike...
[Reply]
  • + 3
 type 2 SUCK's tried it not sold , Shimano's is 100% better!!!
[Reply]
  • + 1
 Deraillleur NOT deraill-ee-eur WTF, he's in the business how can someone who is in the business not know that....total pet peeve for me (obviously)
[Reply]
  • + 2
 He makes it sound like it doesn't take energy or endurance to do a sport like ATV or mx racing.
  • + 3
 everybody knows MX racing is the easiest sport out there... So easy in fact even a ginger can dominate Wink
[Reply]
  • + 1
 Kudos to Minnaar for making Jake the happiest kid on the planet. Well done. Hope someone gave Jake an icepack after.
[Reply]
  • + 1
 I love you Red Bull, but you have the worst video player I've ever encountered.
[Reply]
  • + 1
 Minaar is prolly over the gear box, didn't he race on that Honda bike for a couple years?
  • + 2
 I doubt he's over it, I'm sure he wants it again.
  • + 1
 That Honda system was a derailleur and cassette in a box. Not a gear box proper. The gear box idea was just hype.
  • + 1
 Not to start with. To start with it was a CVT that I think was outlawed by the UCI, as they made a rule that a bike must have 9 gears. Not sure how that stands up now there's ten speed mechs. Mech in a box is still a gearbox, and does have nearly all the benefits of other gearboxes.
[Reply]
  • + 1
 Lets put the rear mech upside down (pointing up) and pedal backwards ;-)
[Reply]
  • + 1
 Ah there she is! If it was so f*cking good, why I haven't seen one?
[Reply]
  • - 1
 Long live derailleurs!
  • + 2
 Not as long as gearboxes ;-)
[Reply]
Below threshold threads are hidden

Post a Comment



Copyright © 2000 - 2014. Pinkbike.com. All rights reserved.
dv16 0.037154
Mobile Version of Website