Rick Johnson
Scott,
I was curious about that so I modeled a couple discs in my MCAD program
, one 8" round and one with an ellipse of 7.5 x 8.5". Then I cut them in
half (representing the area a chain would contact).
In this case the measurements of the perimeter of these half
circumferences differ only a small amount, not enough to be significant
with regards to chain tension.
Round face = 26.133"
Elliptical face = 26.157"
So, with a difference of only 0.024" I can see why your chain tension
hasn't caused any issues. I'm not a single speed guy but it was still an
interesting thing to think about for a few minutes.
Rick
Rick Johnson
Bend Oregon
* * *
This news has been sanitized for your preconceptions
On 6/12/2012 3:30 PM, Dan H wrote:
> Sheldon Brown said bio pace works on fixed. Not sure about other
> designs. I guess the extra chain is taken up by the high spot so the
> tension is fairly constant.
>
> Dan Houghton
> Southwest Bicycle, LLC
> 3605 SW Multnomah Blvd
> 503-246-0333
> www.swbicycle.com
>
> On Jun 12, 2012, at 2:39 PM, "Scott Jerger" > wrote:
>
>> In response to the questions on and off list, I've had an older Rotor
>> elliptical ring on my SS cross bike for 3 years without any sort of
>> tensioner. I've never dropped the chain or felt any tension issues,
>> and I don't even feel any sort of wobble. It's magical. Granted,
>> the ring is pretty small. Maybe the problems start as the rings get
>> bigger in diameter.
>>
>> scott
>>
>> _______________________
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>> Scott Jerger
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>> FIELD JERGER LLP
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