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Shaft drive mountain bike
I am kind of a newbie to cycling, but would like to get involved in
Mountain biking. I have been doing some research on bicycles and am considering a shaft driven mountain bike. Some of you might ask why I would even consider a shaft-driven bike when the chain driven bikes have already proven themselves. Here is a link that seems convincing to me: http://www.dynamicbicycles.com/chain...ft_v_chain.php Let me know if you can refute anything it says. I am most interested in having a bike that won't leave grease on my pants so I can take it to work. I have some concerns with shaft driven bikes though. Although, I feel confident with the Shimano brand, I'm not sure I like the looks of the gearing chart as shown on the bottom of this page: http://www.dynamicbicycles.com/chainless/gearing.php The chart makes it appear like I will be missing out on my lowest 2 and highest 3 gears. To you mountain bike pros, how will that affect my performance for trail riding? If you are interested, this is the bike I am considering, the drawbacks I am facing are the weight and the gearing. Please advise. I'd especially like to hear from anybody that has purchased a Dyanmic brand mountain bike. thanks! |
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"malandro95" wrote in message ups.com... I am kind of a newbie to cycling, but would like to get involved in Mountain biking. I have been doing some research on bicycles and am considering a shaft driven mountain bike. Some of you might ask why I would even consider a shaft-driven bike when the chain driven bikes have already proven themselves. Here is a link that seems convincing to me: http://www.dynamicbicycles.com/chain...ft_v_chain.php Let me know if you can refute anything it says. I am most interested in having a bike that won't leave grease on my pants so I can take it to work. I think they are wrong about the efficiency. A chain driven bicycle is one of the most efficient uses of energy ever invented, gears are not. Just another gimmick in my opinion. |
#3
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These bikes are aimed at people who are terrified of technology and
visible moving parts. Most of what they say on the site is blatantly self-serving and silly. (Like the claim that their bikes are particullarly good for people recovering from surgery). Internal gears have their place (not for mountain biking though) but the shaft drive is just a gimmick. Kind of reminds me of the "landrider" autoshifting bikes on the infomerical. Jeff T |
#4
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On 11 May 2005 13:49:45 -0700, "malandro95" wrote:
I am kind of a newbie to cycling, but would like to get involved in Mountain biking. I have been doing some research on bicycles and am considering a shaft driven mountain bike. Some of you might ask why I would even consider a shaft-driven bike when the chain driven bikes have already proven themselves. Here is a link that seems convincing to me: http://www.dynamicbicycles.com/chain...ft_v_chain.php Let me know if you can refute anything it says. I am most interested in having a bike that won't leave grease on my pants so I can take it to work. Their efficiency figures are not only bull****, they are egregious, ****-you and your pile of lies class bull****. This is so entirely wrong they have thrown away all credibility with it. There have been real studies done on bicycle drivetrain efficiency. The usual difficulty with chain-driven systems is discerning between the inefficiencies in the test jig and the device under test. There is nothing wrong with the Nexus hub. The range of gears is perfectly suitable for 95% of everybody. Like who ever uses the little-big combination anyway. You might miss some range if you are a highly skilled rider on difficult terrain. Go ahead and consider it, just don't believe what they say about efficiency and hope that maybe they didn't lie about anything more important. Ron I have some concerns with shaft driven bikes though. Although, I feel confident with the Shimano brand, I'm not sure I like the looks of the gearing chart as shown on the bottom of this page: http://www.dynamicbicycles.com/chainless/gearing.php The chart makes it appear like I will be missing out on my lowest 2 and highest 3 gears. To you mountain bike pros, how will that affect my performance for trail riding? If you are interested, this is the bike I am considering, the drawbacks I am facing are the weight and the gearing. Please advise. I'd especially like to hear from anybody that has purchased a Dyanmic brand mountain bike. thanks! |
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malandro95 wrote:
I am kind of a newbie to cycling, but would like to get involved in Mountain biking. I have been doing some research on bicycles and am considering a shaft driven mountain bike. That's a terrible idea. I'm no fan of derailleurs, but bicycle shaft drives are not really robust enough for even gentle use. They combine the tradeoffs inherent to internal gear hubs with those of drive shafts *and* those of immature technology. Some of you might ask why I would even consider a shaft-driven bike when the chain driven bikes have already proven themselves. Here is a link that seems convincing to me: http://www.dynamicbicycles.com/chain...ft_v_chain.php Let me know if you can refute anything it says. Of the twelve points given, four are simply descriptive (numbers 1, 2, 8, and arguably 12). The others are either false or otherwise deceptive. The efficiency claim they make for their shaft drive is particularly laughable. I am most interested in having a bike that won't leave grease on my pants so I can take it to work. If you want to combine this requirement with "mountain biking" as it is generally understood, you'll need to use a Rohloff Speedhub and a chainguard or chaincase. Other gearhubs have insufficient gearing range for much off-road riding. And I wouldn't trust a bicycle drive shaft to last a satisfactory amount of time in off-road use (or any kind of riding, really). Note that off-road motorcycles use chain drive, even though shaft-drive motorcycles are common and reliable. Shaft-drive bicycles are neither common nor, to my knowledge, reliable. I have some concerns with shaft driven bikes though. Although, I feel confident with the Shimano brand, I'm not sure I like the looks of the gearing chart as shown on the bottom of this page: http://www.dynamicbicycles.com/chainless/gearing.php The chart makes it appear like I will be missing out on my lowest 2 and highest 3 gears. To you mountain bike pros, how will that affect my performance for trail riding? A normal MTB has an overall gearing range of between 5:1 and 6.5:1, while the Shimano Nexus 8 hub offers a range of slighly over 3:1. (The "chart" on the link you furnished is woefully deceptive in this regard.) This is a big difference. If you use a gearhub for off-road riding, you will give up either low (less than 1:1) gearing, which will limit your ability to climb and ride on soft surfaces; or you will give up streetworthy high gearing. For example, the Nexus 8 option with 1.5:1 ratio on the driveshaft would offer a usefully low 21 inch low gear, but would give you a high gear of 63 inches, good for a top speed of 16.5 mph at 90 pedal rpm. That's not awful, but most folks would like to be able to ride faster when conditions permit. The Nexus 8 with a 2:1 driveshaft ration would offer a top gear of 84 inches, enough to maintain 22mph at 90 pedal rpm. But the low gear of 27.4 inches could limit your off-roading options somewhat. The Rohloff Speedhub offers 5.26:1 range with 14 gears, but is incompatible with the drive shafts you have referenced because it requires a primary drive ratio of at least 2.35:1. There have been toothed belt drive coversions for the Rohloff hub, but these require special bike frames since a belt can 't be opened and reconnected like a chain. Accepting the gearing limitations imposed by a gearhub-equipped bike is a livable compromise; I have several such bikes that work well for me in city use. But I caution you that the shaft drive is not likely to be all that you hope for when it comes to reliability. If you have trouble with it, it's unlikely that you'll be able to get qualified repair and service at a bike shop. You may not even be able to buy spare parts for it. If you find it unsatisfactory, you will be stuck with a bike that can't be retrofitted with an ordinary drivetrain. The Chainless Bicycles site says: "It has been tested at over 1000 lbs./in of torque - more than 4 times the pressure exerted by an average rider under normal conditions." But a rider standing to pedal-- a very common situation in off-road riding-- places his entire weight on a 7 inch crank, and can add to this by pulling at the handlebars. What is your weight times seven? And how does that compare to the 1000 lbf-in at which Chainless Bicycles claim to have tested their drive shaft? And can you even trust that number in light of the wealth of erroneous and misleading information they provide? Chalo Colina |
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Note that off-road motorcycles use chain drive, even though shaft-drive motorcycles are common and reliable. Shaft-drive bicycles are neither common nor, to my knowledge, reliable. I saw a motorcycle the other day that used a toothed drive belt instead of a chain. That would seem to be a better option for an internal hub bike without grease than a drive shaft. Though a chain guard the separates your pants from the chain, and the chain from a lot of grit, would seem simpler still. dewatf. |
#7
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Jeff wrote: Internal gears have their place (not for mountain biking though) Really? Why not? |
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dewatf wrote:
Chalo wrote: Note that off-road motorcycles use chain drive, even though shaft-drive motorcycles are common and reliable. Shaft-drive bicycles are neither common nor, to my knowledge, reliable. I saw a motorcycle the other day that used a toothed drive belt instead of a chain. That would seem to be a better option for an internal hub bike without grease than a drive shaft. All Harley-Davidsons use belt drive. It has distinct maintenance advantages over a chain, and weight and efficiency advantages over a drive shaft. There are tradeoffs, though. One of the things I wrote in my earlier post was There have been toothed belt drive conversions for the Rohloff hub, but these require special bike frames since a belt can't be opened and reconnected like a chain. Drive belts also have the disadvantage of being a fixed length, with any change in gearing or chainstay length requiring a different size belt. Though a chain guard the separates your pants from the chain, and the chain from a lot of grit, would seem simpler still. That seems to be the preferred solution for low-maintenance bikes in European countries. Chalo Colina |
#9
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On Wed, 11 May 2005 13:49:45 -0700, malandro95 wrote:
I am kind of a newbie to cycling, but would like to get involved in Mountain biking. I have been doing some research on bicycles and am considering a shaft driven mountain bike. Some of you might ask why I would even consider a shaft-driven bike when the chain driven bikes have already proven themselves. Here is a link that seems convincing to me: http://www.dynamicbicycles.com/chain...ft_v_chain.php Let me know if you can refute anything it says. I am most interested in having a bike that won't leave grease on my pants so I can take it to work. Then protect your pants. I use a simple band that holds my pants leg near my shin, away from the chain. No problems are really solved by the shaft drive, and it causes other problems. There are definite efficiency losses from the gears -- much more so than with a chain. There is a reason chain drives have survived so long. Primarily it is the efficiency. Remember that a bike/rider is (compared to engine-driven machines) underpowered, and a 20% loss of efficiency is a serious issue. The comparison chart on the site above is, frankly, bull****. 1) Gear movement is no "rougher" with a derailleur system than with an internal gear system. I have both. 2) Maintenance: They fail to mention the difficulties you will have the first time you have to change a flat on the rear wheel. 3) There is no problem with "fully exposed" derailleurs. I have some that are 30 years old. Durable enough? 4) The alignment of a shaft drive system has to be critical. Wheels can get knocked out of alignment whether the drive system be chain or shaft. Chains are more forgiving of such misalignment than shafts. 5) The "ground clearance" issue is totally bogus. That 8" clearance is not between wheels of a car, it is from the bottom of the jockey wheels to the ground -- and this is adjacent to the rear wheel. It's not as if there were some rock that would be likely to hit the derailleur, but you would not hit with the rear wheel, or your pedals, etc. 6) Shaft drives are not anywhere near that efficient, nor are chain drives that inefficient. In addition, the SRAM internal gears have serious inefficiency of their own. 7) Why does 8-speed have the "range" of 20 gears? This is meaningless, since the range of a derailleur system can be changed easily by replacing a cassette, or chainring. Changing the range of an internal gear system is impossible. 8) Noise. Sorry, the internal gear systems are noisier than derailleur systems. 9) No grease? How do they lubricate the gears? Sure, chains are greasy, but so are the exposed ends of a shaft drive. If they are not exposed, it is because they have a cover. Chain-guards do exactly the same thing. http://www.dynamicbicycles.com/chainless/gearing.php The chart makes it appear like I will be missing out on my lowest 2 and highest 3 gears. To you mountain bike pros, how will that affect my performance for trail riding? I personally don't think most recreational riders miss much by giving up the very high gears. They do miss the very low ones. -- David L. Johnson __o | Become MicroSoft-free forever. Ask me how. _`\(,_ | (_)/ (_) | |
#10
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