I'm testing out a way to prevent duplicated gear ratios between big and small ring and give me a couple of bailout climbing ratios. The goal is to keep the ratios tight between the flatland gears.
I found that Miche makes a 55t TT ring (they are stiff) that will work with a 110bcd compact spider. When I'm fresh enough I sprint at 90-95 RPM at over 1000 watts and at 35-40mph I need the extra gear inches. This combo also gives me a fairly straight chainline with the faster speeds when riding in a fairly large pack.
I got a SRAM (now based in Chicago!) 34t inner chainring and I think the UI2 (Ultegra electronic shifting) can handle the change between 34 and 55, right now it does 39 to 56 crisply, I'll be finding out soon... I've dropped the chain and a quick shift back to the big chainring practically throws the chain back on, no grinding or slipping at all.
This setup will give me almost continuous gear ratios using a straight block 11-20 with a single shift between chainrings near the middle of the gear range. I can also change the straight block to a 11-18, 25, 29 and that gives me some very low ratio bail out climbing gears.The jump from 18-25 takes an extra bump but it works. 25 to 29 works fine.
Miche cassettes are mix and match build your own ratios, 11 speed would be nice but I made the choice to spend the extra on UI2 10 speed. Miche is not quite as clean shifting as an Ultegra cassette but I really like the ratio flexibility.
UI2 has the ability to track gear ratio usage but I need to update the firmware so I'll be doing that also to get a better picture of what ratios I'm using.
Crosschain on big big and big big-1 is not efficient and is noisy so I won't even use those (see Friction Facts for details). This is where the new DI2 would be handy where you have one button shifting that does front and rear at the same time... That will be a few years from now for me though. See my other posts on my next bike and my current chain lube choice.
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