by bobones on Wed Jun 15, 2022 12:16 pm
OK, there is obviously a very narrow window for setting these up to work correctly, but I believe in the vast majority of cases it can be done by tweaking the cage alignment and limit screws. You only need a couple of hex wrenches and a bike stand, so whatever you do, forget about taking it to somebody else to fix for you.
I'll concede there may be some other factors at play which make perfect front shifting impossible in some cases, but as someone with 4 eTap groupsets, and who has set them up with bad shifting and then been able to correct it on a range of frames, I am convinced that a significant number of other users can correct their setups too.
It may sound patronising, but watch the SRAM tech videos to remind yourself of the recommended process and then start from scratch by removing the chain and realigning the FD. If you've got the FD alignment tool then there's a separate video for that.
The key aspects for me are that the cage should be low and absolutely parallel. Forget about the height adjustment guide line inside the cage (it may be in the wrong place!): just set is as low as it will go and still clear the top of the tallest teeth by 1 mm. When you tighten the FD bolt, make sure that is stays absolutely parallel to the chainrings, and is not toed in or out at all.
When the chain is on, affix the correct wedge, and set the limit screws as per the videos, i.e. chain almost touching outside cage plate in largest gear and inside plate in smallest gear.
Now, this is the bit that isn't in the videos: with the bike in the stand, test the shifting using the button on the FD over a range of cogs on the cassette. You should be able to rapidly execute front shifts all over the cassette without it throwing over the top. Do 10 or more rapidly on each cog at the back to check. If you find a cog where it tends to overthrow (usually near the middle of the cassette), turn the high limit screw to move the cage inboard by a fraction until you can execute rapid front shifts without any overthrows. Again, test the front shifting on different cogs on the stand and then go for a ride.
If you've followed the videos to the letter, done this fine tuning and still get overthrows or bad shifts, try it once more from scratch, then by all means give up, sell your SRAM gear and go buy another groupset. Just don't waste your time expecting anyone else to fix it for you.