Sounds good. I'm hearing 16, 18 and 20. 18 is in the middle so that seems safe enough.
What sort of derailleur are you contemplating? To be able to shift into 42+ tooth sprockets seems to require either something like the oneup radr cage or wolftooth goat link to modify a 10 speed derailleur, or an 11 speed mech designed for the wide range 11 speed cassettes.
What's different about what we are doing is that we don't need to access the teensy sprockets. Our starting point is halfway through a normal cluster. So my plan is to make a longer hanger that resets the starting height from an 11t to that of an 18t. The largest sprocket that we can run will be dictated by what the derailleur will shift to. I'm planning no more than 15% jumps from one gear to the next. As far as type of derailleur, just one of the long arm Shimanos made for mountain gear sets. Standard off the shelf stuff.
The main problem with a 10/11 speed that the physical spacing between the sprockets is much tighter. We don't even need seven gears. Why would we go to 10 or 11? Remember that 10 and 11 speed gear sets are a product of the pump bike world. They're trying to make the most of 250 watts and a 100 rpm power band. Thin, weak sprockets is a price they're willing to pay to get more mechanical advantage on their puny "motors". We have too much power, too many rpm, and most bicycle gear systems have too many gears, spaced too close together, that are too weak.
I know this has been gone over before, but just to recap. If you are running less than ~2,500 watts you can use normal drivetrain components. It's when you start going over 3kW that two things happen. One is parts will wear and break faster, especially with bad chain line, but secondly, you don't need the gears anymore. I'm saying that this change happens around the 2,500-3,000W mark. I understand the taller cassette to have more chain wrap and power handling, but it will take a lot of work to get decent performance. You could use junior road cassette that starts with a 15t cog, but no junior mountain gearing made. I agree that higher power eBikes don't need 8,9,10,11 gears in the back, but to have the clutch type derailleur you have to go to 10 speed. Properly used 10 speed system can handle 3,000W. If we are going to go beyond this power number than the beefing up would be best by going to single cog. @4kW, I can use 8 of my 10 gears, but 98% of riding I stay in the 17t. That's why I was curious on the Rohloff build because it had Big Block power, and then wide range, but relatively close ratios. Would also think most riding would be done in 1-3 gears on this setup?? All being said, the type of riding one does would absolutely affect the ideal drive system (flat, mountainous, off-road, cargo, high speed)
Another thought, what if we used a 10 or 11 speed, but beefed it up by having the largest diameter spacers that still allowed full chain engagement in the teeth of each sprocket? Maybe even weld it. Get it as close as possible to one solid block so the unsupported radius on each sprocket is minimized and that should significantly strengthen the sprockets as the highest bending force is going to be toward the center of each sprocket.
For mentioned maximum cog support check out SRAM OG-1090, it's the older version, expensive, but has said design feature. This is precursor to XG-1090, 1099, 1199, 1299 (10-50t!
) Who's going to be the first to test the Eagle!???
Thanks! I'll let you know.
