Originally Posted by
FBinNY
I toured for years with half step gearing and love it. If I need wider gearing I go to step and a half, but have never needed or wanted anything like the the almost standard 39/53 chainrings.
You won't need ramps because the jump is small enough for smooth changes without them. And you'll love the tight spacing this makes in your mid range gears where you do most of your riding.
I'm setting up a touring bike for next summer, for a likely trip to Norway, and will run triple with half step (or 1-1/2 step) plus a bailout granny for climbing out of the fjords.
What I have right now is 52-42-24 X 12,14,16,18,21,24,28,32,36 and I’m 99.99% happy with those gears. The 52 gives me a pretty close one and a half step range and that has been fine for the last couple years. I originally had thought about doing what Bob said and just replacing the big ring with a chain guard disc, but that seemed like a waste plus I did like one of the two larger ratios the big ring gave me. As time went on I started using the one and a half steps as it really tightens up the most common gears. If you have them you will use them is my thought.
The 10 tooth jump isn’t too bad but I got to thinking a 3 tooth jump should shift like butter up front and when I started looking at the numbers a 45t big ring split the ratio dead on half step.
It would get rid of the 117 GI top gear with 101 GI so that would be perfect for me on down hills or when riding unloaded. The two big advantages I see would be the really easy front shift 42 to 45 and the simplicity of just doing a single shift in the back to match the shift in the front.
Thanks for confirming what I felt, that ramps and pins wouldn’t be needed in doing a 3t jump. I should be able to lower my FD a little and it is doing the 24 to 42 shift where it is now fairly well with anticipation and a soft pedal shift.
Other than not looking correct will I have any issues with the FD outside guide being too far away from the chain ring?
Would adding a chain guard disc for a 52t add any security for the chain falling off the outside of the 45t with the gap?
45t seems to be an odd size outer chain ring. I have found a few but they seemed pretty expensive. Any suggestions on where to find one would be appreciated?
Thanks to all for the suggestions so far.