I've used an elliptical chainring on my Jack Taylor curved tube TT bike, I think the Durham chainring to be a bit of a silly ellipse being entirely too eccentric. I used a milder one, a thetic oval chainring from the late thirties/early forties, and steel. The ring was purchased from Hilary Stone shortly after I acquired the Taylor and was a nice 46 tooth size. Hilary's e-bay auction described it as something that was used regularly with fixed gears at the time. Someone sent me a 1938? Brown Brothers catalog file that shows the ring describing at feeling like both a 45 and 49 tooth ring.
The ellipse proved to be excellent on gently graded roads feeling very natural while climbing, and only slightly pulsing on flats. Where it sucked, literally, was downhills. When you really wound it up the chain would start to snap, and after dropping the chain three times on one hilly vintage ride, the Thetic oval went into the parts bin. Any takers? $40 plus shipping, same as I paid. The Taylor's got great character now on the drive side chain stay.
I think of the Durham ring as little more than a collectible, and would
have to be used with something like a derailleur pulley set to constantly
take up the slack. Photos of the chain and ring in and out of tension at:
http://sports.webshots.com/
Happy trails,
Dan Artley in Parkton, MD
Archive-URL: http://search.bikelist.org/
No relation to seller just interesting
Someone probably needs that for their too cool fixed gear
I am curious about all the holes.
http://ebay.com/
Howard Darr
Kinsman OH USA