shafted!
7 Attachment(s)
ran across these communal/rental bikes in nanning, china.
wondering what the weight difference would be compared to a standard chainrings/cogs/chain transmission. also wonder if they've got a 12-speed version....... http://bikeforums.net/attachment.php...hmentid=473598 http://bikeforums.net/attachment.php...hmentid=473604 http://bikeforums.net/attachment.php...hmentid=473599 http://bikeforums.net/attachment.php...hmentid=473600 http://bikeforums.net/attachment.php...hmentid=473601 http://bikeforums.net/attachment.php...hmentid=473602 http://bikeforums.net/attachment.php...hmentid=473603 |
dynamic bikes Comfort, Performance, Commuter and Folding Bicycles - Dynamic
On Bike Share - bike share and bicycle fleet solutions. I Expect the MFG is there in China. Weight? Did you use one then weigh it? |
Originally Posted by fietsbob
(Post 18114707)
dynamic bikes Comfort, Performance, Commuter and Folding Bicycles - Dynamic
On Bike Share - bike share and bicycle fleet solutions. I Expect the MFG is there in China. Weight? Did you use one then weigh it? according to the website you linked, they gots the foldie bikes and hybrids in 8-speed using shimano nexus hubs. sheldon sez: "The overall range of the Shimano 8-speed hubs is 307%, and the steps in gears are a bit uneven:" Ratio 0.527 0.644 0.748 0.851 1.000 1.223 1.419 1.615 Step 22.3% 16.0% 13.9% 17.5% 22.3% 16.0% 13.9% not sure how to calculate gear ratios without chainrings....would be an interesting setup to tour on. no more chain cleaning, no more worn chainrings/cogs..... according to the shaft drive manufacturer, "if the same bike was configured with a chain and sprockets instead of our shaft drive, our shaft drive bike would be less than 1 pound heavier than the chain bike." from the site, if my calculations are correct, the 8-speed shaft drive has a low of 28.34 inches, and a high of 87.1 for 26" wheels. http://www.sussex.com.tw/shaft-drive.html |
% + or - of 1:1 [A gear ratio] (x wheel diameter )
car/truck rear differentials have a gear ratio with similar bevel gears .. |
A friend let me try his expensive shaft driven bike. It was awfully draggy. I took it around the block and gave it back. I'd never ride a bike that inefficient even for a coffee.
It was also heavy, but I can't identify what was due the shaft and what was due to other aspects of the bike. One bad experience doesn't mean all shaft bikes have to to suck. Having said that I remain sceptical. |
Seems to me that chain drive is always going to be more efficient, lighter.
If this had real merit, it would be widespread. That's my take on it anyway. |
Read a couple of reviews of shaft bikes, they appeal to weekend bikers for simplicity, but reportedly some serious riders use 'em too, esp for harsh conditions. I figure that belt-drive is a better approach.
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Originally Posted by djb
(Post 18115701)
Seems to me that chain drive is always going to be more efficient, lighter.
If this had real merit, it would be widespread. That's my take on it anyway. also, maybe they could lubricate the shaft and gears with liquid helium! |
I should have added, "and cost effective"...
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Originally Posted by djb
(Post 18116451)
I should have added, "and cost effective"...
will last around 10K miles. unit replacement cost is $89. |
Saddlesores, I still go back to post #5 , I haven't ridden one so can't speak from experience.
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Originally Posted by DropBarFan
(Post 18116358)
Read a couple of reviews of shaft bikes, they appeal to weekend bikers for simplicity, but reportedly some serious riders use 'em too, esp for harsh conditions. I figure that belt-drive is a better approach.
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I wuz there last January 17 and 18th and took some pics also. Lots were in motion too.
I bet they ride just like a slow Pashley Princess. I had to pass on trying them with a CC. Other bikes were strangely few and pathetic. The whole city was getting torn down or rebuilding. I did get lucky at an LBS there to find a memory foam seat cover that saved my @ss the rest of the ride to Dafang. From there I had to ride the bus to Chengdu. Actually the first thing I saw in Nanning was a 50 mph blur of an e-bike. Crazy. |
If I was running a fleet of rentals that stay outdoors and are used by cyclists and non-cyclists alike, I would want them to work with minimal maintenance and have minimal chance for clothing to get snagged. Weight would be unimportant to me, and heavier might actually be beneficial in that it would likely reduce theft and reduce damage from users that abuse them. Looks to me like those goals have been met with this design.
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Originally Posted by Tourist in MSN
(Post 18117495)
If I was running a fleet of rentals that stay outdoors and are used by cyclists and non-cyclists alike, I would want them to work with minimal maintenance and have minimal chance for clothing to get snagged. Weight would be unimportant to me, and heavier might actually be beneficial in that it would likely reduce theft and reduce damage from users that abuse them. Looks to me like those goals have been met with this design.
DC's Capital Bikeshare bikes are similar, heavy 23 kg despite aluminum frame. Unique design would make it harder to steal/sell. Has 3-speed IGH/chain vs shaft-drive though. Program is amazingly popular both with locals & tourists. |
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