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joseph hollinger
Joined: 12 Sep 2002
Posts: 9532
Location: United States, California, san francisco
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 Posted: Wed Feb 27, 2013 8:17 pm Post subject: |
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| Sam Zavaglia wrote: | The difference is at least 2-3lbs between steel and alloy rear sprocket, that's extra 2-3lbs that you need to rotate and stop.
You can still wear your "steel" sprockets using your standard chain to sharp needle points......think of all the HP it takes to do that. No job is done for free.  |
From measurements and calculations I did some time ago:
| Quote: | The difference between a steel 23 tooth sprocket and the same sprocket in Aluminum is .85 pounds (1.45 vs. 0.60 pounds). Both sprockets have a MOI that's approximately 32mm. If you compare that to the 137mm radius of an MG Yellow, you can prove that the effective rotational mass of the steel sprocket is slightly less that 0.2 pounds.
If you are over your class minimum weight, replacing steel with Aluminum nets you 1.05 pound improvement. If you are at the minimum or below, you get a .20 pound improvement. |
| Sam Zavaglia wrote: |
You can still wear your "steel" sprockets using your standard chain to sharp needle points......think of all the HP it takes to do that. No job is done for free. |
As I tried to point out, there's no reason you can't use your fancy chain with steel sprockets.
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A lie gets halfway around the world before the truth has a chance to get its pants on. -- Winston Churchill. |
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Sam Zavaglia
Joined: 23 Nov 2004
Posts: 1194
Location: Australia, Sydney,
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| Posted: Wed Feb 27, 2013 9:01 pm Post subject: |
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| joseph hollinger wrote: | | As I tried to point out, there's no reason you can't use your fancy chain with steel sprockets. |
This is true, however in 2 years (approx 20 race meetings) I'm yet to wear out a single alloy sprocket. I only have 2 rear sprockets that I use (23 and 24) and I'm not carrying that steel mass on my rear axle.
Some steel sprockets weigh much heavier than others and are made with much more bulk, I won't mention brands, just be aware.
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Jimmy McNeil
Joined: 12 Apr 2006
Posts: 1479
Location: United States, California, visalia
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| Posted: Wed Feb 27, 2013 9:49 pm Post subject: |
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| Quote: | | I'm yet to wear out a single alloy sprocket. |
Dido that Sam. Not sure ive ever replaced one from wear, just misalignment problems.
I could be wrong but I havent seen zero gap steel sprockets, thats reason enough not to use them. |
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joseph hollinger
Joined: 12 Sep 2002
Posts: 9532
Location: United States, California, san francisco
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| Posted: Wed Feb 27, 2013 9:52 pm Post subject: |
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| Jimmy McNeil wrote: | | Quote: | | I'm yet to wear out a single alloy sprocket. |
Dido that Sam. Not sure ive ever replaced one from wear, just misalignment problems.
I could be wrong but I havent seen zero gap steel sprockets, thats reason enough not to use them. |
Fastech has them from time to time.
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A lie gets halfway around the world before the truth has a chance to get its pants on. -- Winston Churchill. |
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