I’ve 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 I’m 99% in the big ring so I don’t have to worry about shifting the front in a stressful situation. It’s been a great combo for training around here and then when I go back home where it’s a bit more mountainous it’s nice to have that extra bit of easy gear.
I’m 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 doesn’t. 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.
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.
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. Haven’t had any problems.
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 can’t spring back enough to keep your chain tight. IIRC in the middle the derailleur should be vertical.
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 doesn’t mean they become the Chainrings of Death, but shifting quality will suffer.
It’s not about spinning out. It’s about chain line if you are racing. We do all kinds of things to save 1-2W from an aero or friction standpoint. Why not also optimize chain line if you’re racing especially doing something like a TT or triathlon?
If you’re just riding around town and attacking a local hill or two, 50/39 all day. But if you race, need every advantage you can get, and aren’t facing 10%+ gradients every day, go 53/39 or maybe 52/36.
