What I’ve seen is a vertical one as you enter the shower, and a horizontal or diagonal one on the side of the shower. Basically, I think you should imagine being in there and slipping. Where would you naturally reach?
BTW, I Googled, and one site suggested making the exploratory holes in the grout, rather than the tile, as that’s more easily covered.
No expert here, but a few thoughts. I would certainly be more comfortable to install on studs.
Which is exactly how one should be installed. This allows folks of different heights to use the same rail. My MIL is 5’2", my FIL is 6’4". The angles grab bar works great for both of them.
I bought two Moen rails today, one 36" to be mounted horizontally along the back wall and a shorter one, 18", to mount vertically at the end opposite the faucet because that’s where I enter and because immediately above the faucet handles the wall is glass block. I went for the toggle style anchors because Lowe’s didn’t have any of the fancy anchors or Wall Dog screws. The anchors (Toggler brand, 1/4") I got are rated at 265 lbs in 1/2" drywall. They weren’t available in stainless so I may buy some stainless machine screws to use with the anchors just to remove the possibility that the screw heads will rust and cause rust stains under the flanges.
I’m mounting my long bar straight horizontally because I never take baths (so far) just showers and that’s where I’ll be grabbing if I lose my balance. I read somewhere that the recommended mounting height is 36" from the floor but I don’t know if that was from the bathroom floor or floor of the tub. Pretty close either way, I may go a little higher, I feel like for me roughly elbow height would be the most natural grabbing height. I just measured and my elbow is 42" from the floor. I live alone and don’t have guests that would be staying long enough to shower.
I bought the rails, a package of 10 anchors and two drill bits for tile and I spent about 128 bucks so far.
That’s exactly what I bought. Same brand even.
I was sizing it up as I was showering tonight and I’m kind of tempted to put the shorter vertical bar on the far side as opposed to on the near side as shown in all the videos I’ve watched. Or maybe mount it horizontally in the center of the short wall to the right as I enter the shower.
I’m starting to wonder if I’m over thinking all this! 
Damn, my only contribution to this thread was to plead that you PLEASE get ceramic tile drill bits. Good job!
I’m just a master carpenter that inspects and manages insurance restorations, constantly fixes other people’s bad workmanship and used to build custom homes.
I might install a towel bar partially with wall anchors in a pinch, with the knowledge it is not ideal. Anchoring a grab bar into anything but a solid structural element like a stud is just irresponsible. You may have to use some anchors because the bar’s flange is usually wider than 1 1/2", but at least one screw on each end of the bar should be into solid material.
If the bathroom wall is accessible from another room, opening drywall, installing blocking where you want it and patching is not crazy. Does require some skill.
There is a lot of sub-optimal ‘expertise’ on YouTube.
Do you know a way to tell if the tile on the wall is ceramic or porcelain? I thought I had a box of leftover tiles in the attic but the box I was thinking of is actually larger tiles from the kitchen floor. My dad did the bathroom shower tile and he would definitely have saved any leftovers so I may find them yet.
Going in from the back side may be a possibility because it is in a closet and that wall is already a mess with many small screw anchor holes from extensive shelving my brother took, leaving holes in wall. If I go that way how do I transfer the location from the back to the other side? I found my stud sensor but it’s not giving me any consistent readings (through the tile). Would spending more money and getting a better stud sensor likely give better results? If I can locate the studs in the closet wall without tearing out drywall is there an accurate way to transfer that to the shower side?
Any info appreciated!
I know how I would do it. It’s not pretty but it’s effective. I would remove a largish section of the wallboard/lathe and plaster from the closet wall. Make the opening in the wallboard the same size as the piece of pine lumber or plywood that you’re going to screw into the studs to fill the hole after you finish mounting the bar in the bathroom. It won’t be pretty but it might look better than what you have now and will provide a solid mounting point for future hanging projects in that closet.
Once you have the rectangle cut in the closet wall and have the studs exposed, use your drill to bore through the wallboard and tile on the bathroom side of the wall. Place the point of the drill bit right next to the stud and angle the drill so that when it emerges into the bathroom, the hole should be nearly centered in front of the stud. Be sure to use the correct bit and light pressure on the drill otherwise you’ll just shatter the tile or pop it straight off the wall. It may be worth getting a helper to hold a thick catalog or book you don’t mind destroying against the tile as you drill. Once this is done, go into the bathroom and drill a pilot hole straight back into the stud to provide a solid anchor for the bar.
This is going to take some guestimation and the failure rate is kind of high. Even if this first hole isn’t exactly where you want it the it will give you the vertical line on the bathroom side of the wall so you can drill again and place it more precisely. Fill any surplus “oops” holes with silicone sealer and with luck you can cover them with the mounting base of the bar.
Disclaimer: I’m not a carpenter or any kind of professional. Heed my words at your own risk.
ETA - Instead of patching the hole in the closet wall with lumber or plywood. Go to a big box store and get a big corkboard or something.
If you have access to the back side, just find the studs from there, and then just measure where the studs are and transfer that measurement to the tile side.
How 'bout this! I locate the bar exactly where I want it and drill the holes. Then I take a big piece out of the drywall in the closet and add pieces of 2x4 in between the studs to catch the screws coming in from the bathroom side. I think FluffyBob was getting at this. Then I close the closet doors and never open them again.
Actually, that won’t work. Think of the back wall of the bathroom. Beyond it is about two foot of closet space but it’s divided into two compartments. About 1/4 of this space is a closet that opens into a hallway where the bathroom door is. The other 3/4 opens into my office via two folding doors. The part that opens into my office is the part that has the messed up drywall. I just measured it and the closet that opens to the hallway goes back about 26" which takes me to roughly the center of the shower. No way I’m going in that way, it’s full of permanently mounted shelves that probably are original to the house.
Trying to hit a 1.5" stud would be pretty tricky. Not saying it couldn’t be done but it would be complicated. Would I use the wall in the hallway as my baseline? Put a straight edge along that wall and then measure back and then into the closet and hit a 1.5" stud edge?
Just measured, it’s more like 32" deep. In 26" from the hall, 32" wide.
I can’t say exactly without seeing a diagram
I appreciate you hanging with me on this thread! I’m seeing two options at this point:
(A) I half ass my way through this, down a few beers, drill some holes, use some anchors and hope for the best.
(B) Forget the grab rails and continue to rely on my shower curtain and friction fit shower curtain rod to arrest my fall if it comes to that.
Hiring someone else is not going to happen.
As much as I like drinking beer, and doing home construction work, and drinking beer while doing home construction work, please do NOT drill into ceramic tile while drinking. Have a plan for why you are drilling there.
(amateur who remodeled my kid’s bathroom, to include adding tile to the floor and walls and who procrastinated on installing the new glass shower doors because I was afraid of drilling into ceramic tile)
I’m wondering now if it’s ceramic tile or porcelain. Porcelain requires a diamond hole saw. Haven’t yet found a way to identify installed tile.
I guess, try drilling with the ceramic tile bit and if it burns up…back to Lowe’s for the diamond hole saw?
I’m quite sure they will do just that. I bought one about 9 years back when I broke my foot. It did pretty well - lasted the entire time I needed it, without needing to be repositioned. But when my husband needed to use it a couple years later, we had to reset it for every shower.
It is fine for a short-term stop-gap situation, but I would not want to rely on one if I were truly unsteady.