52x36 vs 50x34
10-21-19, 12:42 PM
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This is a very interesting thread. Found it because I think I need to go the opposite direction. I'm currently running 50/34 rings with a 11-30 cassette which I think is not enough. I think swapping out my rings for a 52/36 and keeping the 11-30 would be perfect for me. I'm constantly in a pretty high gear, and I have never shifted out of the big ring unless I am doing some steep sustained climbing. This is a typical weekly solo effort on the flat with three complete stops factored in (stop signs and lights), showing I spent most of the time in the 12. It's a steady high effort pace so I am not surging or sprinting. If I were to sprint, I would need more than 50-11 as I have been in sprints and tried to shift only to find out I was already in the 11 and there was nothing more...and I regularly spin out going downhill. My FTP is calculated by real one hour efforts on the road, not 20min tests on a trainer. I'm not a lightweight either over 50, and at 206lbs. The power pic is from a separate ride so I can turn the gear. I'm not a "spinner" when it comes to sustained power output on the flats. If I am sprinting I will be 115+.
10-21-19, 01:16 PM
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I'd just be bouncing between my 13t and 14t at around 95-100 rpm with the 39. Anything under 85 rpm sees my pedaling efficiency begin to suffer (on flat ground) which causes power loss and premature muscle fatigue.
10-24-19, 03:03 PM
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10-24-19, 03:42 PM
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On the track side, for more than a few years now, riders have been moving to bigger gears and lower cadence. Through the use of power and cadence data, rider were finding that after a certain cadence, their power started to flatten out. A lot of match sprinters aim for that 130-140 rpm sweet spot and adjust their gear accordingly. Larger people maybe more efficient at slightly lower cadences than smaller riders.
10-25-19, 08:23 AM
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Impressive stats, though I do wonder why you opt to ride the small ring? They say that the large ring is more efficient, eg. 53/19 vs. 39/14, etc.. Anything above ~17mph it looks like would be able to stay in the large ring.
10-25-19, 08:37 AM
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There's an inconvenient no-mans land around 24.5 mph on most 11t Shimano cassettes... The 53t will show a huge cadence gap between 23.5-26 mph (there's a big power difference between those speeds), and the 39t is completely crosschained when you approach 25 mph.
10-25-19, 08:47 AM
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The big ring is more efficient, but only if it has the gear you want. On an 11-28 cassette, the gaps in the lower range become more prevalent, so rather than choosing between 92 or 97 rpm in the small chainring at 21 mph, I'd have to be choosing between 89 or 103 rpm in the 53t chainring. The efficiency is buried by having to grind or spin too much.
There's an inconvenient no-mans land around 24.5 mph on most 11t Shimano cassettes... The 53t will show a huge cadence gap between 23.5-26 mph (there's a big power difference between those speeds), and the 39t is completely crosschained when you approach 25 mph.
There's an inconvenient no-mans land around 24.5 mph on most 11t Shimano cassettes... The 53t will show a huge cadence gap between 23.5-26 mph (there's a big power difference between those speeds), and the 39t is completely crosschained when you approach 25 mph.
10-25-19, 08:54 AM
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I need my 11,12, and 13. I don't think there's been a ride I've done in the past few years that hasn't had me pedaling my 53x11 at some point. It's usually for getting up to speed on downhills, getting into a tuck, then carrying that speed when existing the downhill. I'm also somewhat of a descending "specialist" (read: dense, aerodynamic, and foolish), so getting back up to speed out of corners and getting that last little push past 50 mph is absolutely necessary to get my "jollies".
