STI shifter help
 

My shifters are starting to slip a bit or not shift at all. I assume the ratchet mechanism inside is starting to wear a bit. I'm looking at a new set but am a bit overwhelmed by all the compatibility options. Right now I'm running a mix of things. 2x10 shifters tiagra 4700. 46/30 crankset with a tiagra front derailleur. I'm not attached to the front derailleur at all. The rear is a 11x40 cassette and a grx rear derailleur. I'd like to not change anything on the back end. I'd also like to keep my mechanical disc brakes. I've been looking into sram and others. Just want to make sure compatibility is right.

If you change from Shimano Tiagra to SRAM anything you will have to change the shifter because it is indexed. The pull ratio, the amount of cable pulled by each change in the index is different. It's not the front derailleur that would be the problem but the shifter so you need to replace the shift lever with a new one if it isn't a matter of adjusting the shifter mechanism. You might ask a moderator to move this to the mechanics section.

Here's a video on how to check the inside of the shifter, What's Inside a Shimano STI Shifter Look to see if what he calls "the little catches") are worn.

or a more comprehensive video on replacing the shifter if you need to.

Both front and rear shifters are failing at the same time? How many miles on those shifters? Hard to advise without knowing age/mileage.

I have the same shifters and chainrings, and had a problem with dropped shifts on rear Tiagra 4700 RD with 11/34. I started to pull the rear cable to replace it, noticed it was greased all except last inch plus inside shifter. Greased that and it's been good.

I'd look closely at condition of cables before giving up on shifters. Any fraying can cause inconsistency. To be safe on compatibility if you do replace shifters, get the same model.

Shifter are tiagra 4700 about 3 yrs old. I just had the local shop replace all the cables. We had talked and they said to try that first.