Just out of curiosity, how far can you push the FDs in your experience?
Iâve seen a 20t difference work acceptably, but not greatâŚ.anything above that is getting pretty dicey, IMO.
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Iâve been running a 52/34 for the past year or so. The shifting is pretty good. You do have to let off the gas a bit more and maybe hold the lever for a moment longer to let the chain catch on the big ring. At the same time I added a k-edge chain catcher just in case so chain drops have been relatively minimal. I get maybe one drop every 700-1000 miles.
I live in Michigan so in a race scenario Iâm 99% in the big ring so I donât have to worry about shifting the front in a stressful situation. Itâs been a great combo for training around here and then when I go back home where itâs a bit more mountainous itâs nice to have that extra bit of easy gear.
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I am far from the most powerful, but the only times I find myself spinning out the 50 is with a strong tailwind sprinting. I am in the high 30âs by then. But I do a lot of climbing, so I use the small inner ring a lot. I just did a couple races at Sea Otter and never felt like I was under geared, but occasionally wished I was lower.
Here is an example of a segment I used to attack once in a while. I am over 40 MPH, averaging 650 watts before spinning out:
Iâm liking my 53-39. Had an issue with a bent 39, switched to a 42 which I loved. UNTIL! Shimano has recommendations because of the ramping. This I learned the hard way, It works until it doesnât. Since I weigh a ton. I switch out chain ring to 50-34 for climbing events. ie. Bob Cook. My 2 cents
Thank you very much for all your answers. It was all very helpful. I decided to take an opportunity to switch to 52/36. One more question. Will I have to change the chain? As 50/34 (which is installed at the moment) I think would have shorter chain.
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Maybe yes, maybe no. You should never ride in the big-big combo, but, shift in the 52 and biggest cog in the rear, with the bike in a stand, without load, gently. and see if the chain is too short.
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It depends a bit on your frame, as the distance between rear hub and bb also plays a role. However, I switched from 50/34 to 52/36 and calculated that the chain should be half a link longer, so just left it as it was. Havenât had any problems.
Hopefully my will be the same as the chain is still ok.
but why did you now change from 50/34 to 52/36?
Because it is in between 50/34 and 53/39? 
So If I do that how will I know the chain is too short?
What do you mean by ârampingâ here and what are the reccomendations? Looking at a potential 42t to match with a 55t
With the change to bigger chainring, do I not have to move the front derailleur up???
If you have a quick link you can break the chain and quickly do the Big/Big method by Park/Sheldon. If I remember right the Park site details other ways too. Mainly when you are towards the big/big combo the deraileur is pulled to far forward and when you are in the small /small combo the derailleur canât spring back enough to keep your chain tight. IIRC in the middle the derailleur should be vertical.
Yes, unless it was too high before.
Keep it simple and ask yourself, are you the type of person who is likely to still be pedaling (to gain or maintain speed) at 40mph/64kph?
If yes get the 53, if no get a smaller chainring and enjoy have more range or smaller steps at the speeds you will actually be pedaling at.
If you look on the inside of the big chainring, you will notice an number of pins and ramps that pick up the chain and lift it onto the larger chainring - the FD just pushes the chain sideways to where it makes contact - the pins and ramps do th actual lifting. These are positioned to pick up the chain from the assumed matching inner ring. If the small and large rings are not matched (50/34, 52/36, 53/39), then the pins and ramps will not be in the right place. This doesnât mean they become the Chainrings of Death, but shifting quality will suffer.
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The correct answer is: 50/34 road bike, 58 TT bike 
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Correct answer is 46t x 11/40 - 1x drivetrain FTW 
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