Originally Posted by interested
So some real world examples shows sprocket thickness varying between 22% and 33% thicker than my cassette, even considering the ramping grooves, it really isn't that much of a difference, but for arguments sake let me say that +50% more thickness equals 50% longer wear (linear). That means that if I spread the wear on my cassette to only 3 rear sprockets I would still be significantly ahead considering wear.
I really don't think that a cheap BMX-style sprocket is made of the same grade of steel as a Shimano 105 cassette, and steel quality (hardness) plays a role in how fast things wear out.
Your argument would carry some weight if you could adjust your deraillered bike so on each of those sprockets you had a perfect chainline, but I don't believe you can. Chainline MATTERS.
Originally Posted by interested
"I choose a heavy, expensive, high friction (disadvantages) internal gear hub to gain ...(advantages)."
1) I choose a hub gear that is very slightly heavier, with a very slightly higher initial outlay, with insignificant extra friction compared to a real world derailler system because I appreciate the ease with which a single sprocket and chainring can be cleaned.
2) I choose a hub gear that is very slightly heavier, with a very slightly higher initial outlay, with insignificant extra friction compared to a real world derailler system because I can still get a comparable gear range to the gear range I commonly use on a deraillered bike for commuting and even touring but only have a single shifter and never need to double shift.
3) I choose a hub gear that is very slightly heavier, with a very slightly higher initial outlay, with insignificant extra friction compared to a real world derailler system because a dishless real wheel is stronger.
4) I choose a hub gear that is very slightly heavier, with a very slightly higher initial outlay, with insignificant extra friction compared to a real world derailler system because I have no derailler hanging precariously close to the real wheel poised to cause a great deal of damage if it takes a knock.
5) I choose a hub gear that is very slightly heavier, with a very slightly higher initial outlay, with insignificant extra friction compared to a real world derailler system because the hub I use (SRAM S7) is extremely well sealed and CAN cope with all-weather commuting with zero internal maintainence.
6) I choose a hub gear that is very slightly heavier, with a very slightly higher initial outlay, with insignificant extra friction compared to a real world derailler system because I like being able to shift gear when stationary.
Just a few real benefits.......