Front chainrings (eggshaped)
08-30-14 | 06:13 AM
#1
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Bikes: 2015 Cannondale CAADX, 1994 Nishiki Performance Equipe
Front chainrings (eggshaped)
Hello,
I have noticed that my front chainrings are , what appears to be, more eggshaped than round. I can clearly notice it when riding and looking down at the chainrings. I am wondering if it is warped?
Cheers,
I have noticed that my front chainrings are , what appears to be, more eggshaped than round. I can clearly notice it when riding and looking down at the chainrings. I am wondering if it is warped?
Cheers,
08-30-14 | 06:29 AM
#2
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Joined: Aug 2005
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From: Pittsburgh, PA
Bikes: '96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '20 Surly Midnight Special, All are 3x10. It is hilly around here!
Shimano offered "Biopace" chainrings several years ago that were indeed "eggshaped" and were said to offer an advantage in pedaling efficiency. They never really caught on and were dropped from the product line but some are still around on older bikes or even NOS. Others have taken up the same idea recently and have found limited success. Check the engraving on your rings and I expect they will say Biopace.
08-30-14 | 07:08 AM
#3
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Joined: Nov 2004
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From: Denver, CO
Bikes: Some silver ones, a red one, a black and orange one, and a few titanium ones
It could also be a SR "Ovaltech" or Sugino "Cycloid" as well as other brands, although those are rarer. Shimano did license the technology to other manufacturers.
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Dreamin' of Bemidji Down the Mississippi (in part)
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Stuart Black
Dreamin' of Bemidji Down the Mississippi (in part)
Plan Epsilon Around Lake Michigan in the era of Covid
Gold Fever Three days of dirt in Colorado
Pokin' around the Poconos A cold ride around Lake Erie
Dinosaurs in Colorado A mountain bike guide to the Purgatory Canyon dinosaur trackway
Solo Without Pie. The search for pie in the Midwest.
Picking the Scablands. Washington and Oregon, 2005. Pie and spiders on the Columbia River!
08-30-14 | 06:35 PM
#5
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From: South Jersey near PHL
Bikes: Frequently
TdF 2013
I remember seeing last year's TdF winner Froome using a non-round chainring during at least one stage. Camera had it in close-up, and the TV hosts commented on it.
08-30-14 | 08:54 PM
#6
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From: Very N and Very W Ohio Williams Co.
Bikes: 2001 Trek Multitrack 7200, 2104 Fuji Sportif 1.5
Shimano offered "Biopace" chainrings several years ago that were indeed "eggshaped" and were said to offer an advantage in pedaling efficiency. They never really caught on and were dropped from the product line but some are still around on older bikes or even NOS. Others have taken up the same idea recently and have found limited success. Check the engraving on your rings and I expect they will say Biopace.
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