Do extra large chainrings exist? Will this work?
10-04-16, 09:55 PM
#26
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LitePro has rings to 58T. TA Specialites to 62T. Vuelta has large rings too.
An outside-the-box solution, one that i use on a 406 wheel is a SRAM Dual Drive hub. It turns my 47T ring into an effective 64T (and 34T) instantaneously--and I do mean instantaneously--at the shift of the trigger.
An outside-the-box solution, one that i use on a 406 wheel is a SRAM Dual Drive hub. It turns my 47T ring into an effective 64T (and 34T) instantaneously--and I do mean instantaneously--at the shift of the trigger.
I have Shimano 105 grouping compact double with an 11-28 in the back. I would like to get a replacement for the big chainring to go from my 50 to perhaps something in the 60-70 tooth range. It looks like there *might* be some dura-ace rings up to 56T -
Is that as high as I can go?
Is this a machine shop project or is there a ring I can purchase from somewhere that I can just swap out with mine?
(btw - if it *is* a machine shop project then what metal to use? What alloy?)
(dont get into the why - ;p)
Thanks.
Is that as high as I can go?
Is this a machine shop project or is there a ring I can purchase from somewhere that I can just swap out with mine?
(btw - if it *is* a machine shop project then what metal to use? What alloy?)
(dont get into the why - ;p)
Thanks.
10-05-16, 09:29 AM
#27
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They are available. My Rans Tailwind came with a large chain ring. It was a 60 or a 62, I dont remember which now.
10-05-16, 09:57 AM
#28
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Then why don't they just say so? I don't do coy. It's not a good look anyway. When someone says to me "I want to know how to do _________", but I don't feel like telling you why, so don't ask... well, sorry, that just puts me right off.
10-05-16, 10:05 AM
#29
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LitePro has rings to 58T. TA Specialites to 62T. Vuelta has large rings too.
An outside-the-box solution, one that i use on a 406 wheel is a SRAM Dual Drive hub. It turns my 47T ring into an effective 64T (and 34T) instantaneously--and I do mean instantaneously--at the shift of the trigger.
An outside-the-box solution, one that i use on a 406 wheel is a SRAM Dual Drive hub. It turns my 47T ring into an effective 64T (and 34T) instantaneously--and I do mean instantaneously--at the shift of the trigger.
10-05-16, 10:31 AM
#30
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OP must be Motor paced to even turn a huge chainring on a Bike with a 700c wheel.
Lose the Crankset and buy a Schlumpf High Speed drive ....Epicyclic overdrive and when engaged the gear will turn the chainring 2.5X the speed of the cranks.
so a 42t acts as if a 105t
the more modest speed drive is a 1.65X overdrive so same 42 acts like a 69.3t.
'/,
Lose the Crankset and buy a Schlumpf High Speed drive ....Epicyclic overdrive and when engaged the gear will turn the chainring 2.5X the speed of the cranks.
so a 42t acts as if a 105t
the more modest speed drive is a 1.65X overdrive so same 42 acts like a 69.3t.
'/,
10-05-16, 11:02 AM
#31
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If one hunts, one can often find up to about 60T through mainstream sources (used?)
Two that keep popping up are Driveline (taiwan) and Vuelta (USA)
Driveline CNC Alloy 7075 Road Bike Bicycle Cycling BCD 130mm 60T Chainring | eBay
Vuelta SE Flat 130mm BCD 5 Arm Road Chainring | eBay
This Biking Green ring is the most affordable for 70T.
Bikingreen 70T BCD130 Recumbent Chainring CNC 7075 Road Fixie Black TT Track | eBay
Bikingreen 70T BCD130 Recumbent Chainring CNC 7075 Road Fixie "Gray" TT Track | eBay
For other sizes, browse the Trike and Folding bike sites, but many are very expensive.
Here are a few links to Trisled in Australia.
80t Chainring - 110 PCD | Trisled ($180 AUD)
90t Chainring - 130 PCD | Trisled ($200 AUD)
The huge rings may not be designed for shifting.
There are also options to go smaller on the rear.
The Shimano Capreo is a 9x26, 9 speed cassette, with a few spin-offs available.
I've successfully made a 9x23, 11 speed cassette. Still a little testing, but it works quite well.
SRAM makes several MTB cassettes starting with 10T, but generally with huge low-gear sprockets.
Two that keep popping up are Driveline (taiwan) and Vuelta (USA)
Driveline CNC Alloy 7075 Road Bike Bicycle Cycling BCD 130mm 60T Chainring | eBay
Vuelta SE Flat 130mm BCD 5 Arm Road Chainring | eBay
This Biking Green ring is the most affordable for 70T.
Bikingreen 70T BCD130 Recumbent Chainring CNC 7075 Road Fixie Black TT Track | eBay
Bikingreen 70T BCD130 Recumbent Chainring CNC 7075 Road Fixie "Gray" TT Track | eBay
For other sizes, browse the Trike and Folding bike sites, but many are very expensive.
Here are a few links to Trisled in Australia.
80t Chainring - 110 PCD | Trisled ($180 AUD)
90t Chainring - 130 PCD | Trisled ($200 AUD)
The huge rings may not be designed for shifting.
There are also options to go smaller on the rear.
The Shimano Capreo is a 9x26, 9 speed cassette, with a few spin-offs available.
I've successfully made a 9x23, 11 speed cassette. Still a little testing, but it works quite well.
SRAM makes several MTB cassettes starting with 10T, but generally with huge low-gear sprockets.
10-05-16, 11:32 AM
#32
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Aside from this being a zombie thread, maybe OP is the Timtak of gearing?
10-05-16, 11:37 AM
#33
Banned
There is also adding a second Bottom bracket and using another axle set of small cog on one side and then a Big chainring on the other end.. turning the wheel..with another small cog..
Its how you get up to 152 mph 152 MPH Pedal Bicycle - Intro
Its how you get up to 152 mph 152 MPH Pedal Bicycle - Intro
10-05-16, 12:24 PM
#34
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Specialty shop in UK Highpath Engineering for Cycle Products & Services make what you wish , in Ergal.
and there are big rings from TA, and Schlumpf , in France and Switzerland.
Plus, Herr Schlumpf's speed/High speed drive planetary overdrive cranks make the existing ring 1.6 or 2.5 X larger.
and there are big rings from TA, and Schlumpf , in France and Switzerland.
Plus, Herr Schlumpf's speed/High speed drive planetary overdrive cranks make the existing ring 1.6 or 2.5 X larger.
People making IHPVA recumbents will often just use a CAD program and a drill press to make their own single giant chainrings. They don't do all the shifting ramps and feed pins, but then, a normal front derailler won't shift over a very wide size range anyway. They just run a single front chainring and use a compound gear train to allow shorter starting gears.
10-05-16, 12:57 PM
#35
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Ever hear of a schlumpf bottom bracket? A planetary drive x 1.4?
10-05-16, 01:53 PM
#36
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By Now, the owner of Highpath, after health problems, shut down the business.
Schlumpf Speed Drive is 1.6 :1, not 1.4:1 a 34 upshifts to act like a 54.4t
'/,
Schlumpf Speed Drive is 1.6 :1, not 1.4:1 a 34 upshifts to act like a 54.4t
'/,
10-05-16, 02:28 PM
#37
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The highest efficiency would be with single step gearing, sprocket to cassette, and preferably with a straight chainline without derailleur.
The dual drive hub or crankset will reduce efficiency somewhat.
Likewise, an idler can be a huge gearing multiplier, but also rob a little efficiency.
The dual drive hub or crankset will reduce efficiency somewhat.
Likewise, an idler can be a huge gearing multiplier, but also rob a little efficiency.
10-05-16, 02:31 PM
#38
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10-05-16, 04:29 PM
#40
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This is the little pony with SRAM Dual Drive. Notice the single chainring, no FD in front. 18-108GI on tap without the delay or clunkiness of FD shifting. At the tap of the trigger, instantaneous upshift of 1.36x or downshift of 0.73x. At 960grams, the hub ain't light, though.
!!! Abu, you genius! Why didn't I think of that. I've spent the better part of a year trying to figure out how to put a FD on my Giant Expressway. Well not how, it looks like it would be pretty straight forward, but I would need a new crankset, probably a triple, the FD, another shifter... ... thing is I've known about the SRAM DD hubs for years. I've been planning on using one on a recumbent project. But that may never happen, and the folder is in use several times a week. Thanks buddy. I owe you.
10-05-16, 11:50 PM
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10-05-16, 11:52 PM
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10-06-16, 01:01 PM
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[QUOTE=HillRider;11317509]Yes, Bike Fridays do come with 60T large chainrings but they are mounted on standard road (130 mm bcd) cranks and the OP has a compact (110 mm bcd) so a change of cranks would also be needed. [\QUOTE]
Maybe I missed it. OP said he had a 50t ring, but didn't say he was using a 110mm bcd, aka "compact" crank. You can have a standard, 130 bcd double or triple with a 50t large ring.
Maybe I missed it. OP said he had a 50t ring, but didn't say he was using a 110mm bcd, aka "compact" crank. You can have a standard, 130 bcd double or triple with a 50t large ring.
10-09-16, 06:41 PM
#46
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six years later....
sandal, wow 88 g. i. thats a heck of a high gear. If it works for you, great...but ooooof, tall gear.
sandal, wow 88 g. i. thats a heck of a high gear. If it works for you, great...but ooooof, tall gear.
