Originally Posted by
stapfam
BUT there is a problem with going to the wider range cassettes with lower gears and that is the distance between the ratios. On the 12/27 I have on the compact the spacing between the lowest 3 gears is a 3t difference. This is compared to 1 or 2t on the higher gears. To keep cadence right- I use the gears a lot and up to the 21t is fine. Then the jump is to 24 and 27. Breaks the rhythm somewhat but if I need those gears I need them and they are there to be used. Just face it-long hill with steepness built into it and I will only use one gear. This is why I got a triple fitted to the hill bike- so I can use a 12/25 cassette- still get gears low enough and not have that jump in ratios.
Your sensitivity to cadence and also wanting to spread out the range in the back to get lower climbing gear is the same problem many of us face with selecting gearing. For me it boiled down to how my body has changed and realizing I no longer (if ever) fall into the center of the bell curve where bike manufactures like to design bikes.
It wasn’t until I bought a touring bike with a triple and started thinking about adding a lot of weight on the bike and trying to climb hills that I began to see I had to somehow like a wider space between gears to get the spread I needed. I messed around making changes front and back and as I ride the bike for other uses besides touring I didn’t like the mountain gearing many put on these bikes as it was way too low for road riding and had my favorite gears split between the center and large rings.
What I ended up with was treating the two large chain rings like a road double 52, 42 the back I setup like a mountain bike with a 12-36 9 speed. That filled in the bigger steps on the center ring with half step gears on the large ring when I need them. Gave me two nice tall road gears above what the center could get and gave a purpose to the rest of the gears as not being duplication (half step). I slowly kept going lower and lower on the granny and found I could go all the way down to a 24t without issues. When loaded with touring gear I can use the 18 gear inch lowest gear but what I found is I love having a range of low gears not just that one bailout gear. I have 6 gears to select off that 24t ranging from 35 GI to 18 GI and on a long rolling climb it’s nice to drop down to that granny and select the right cog to suit the climb and do it spinning not mashing. I personally would just as soon stay in the saddle keep the cadence up and if I have to sacrifice some speed.
Like I said I think a lot of this is assessing where your strengths are and working within them. It’s not about impressing anyone with what gearing your bike has. I get around the comments by saying oh this is my touring bike that’s why I have such crazy small chain ring and such a big wide cassette.