Shower Door Towel Bars: Sizes, Back-to-Back Sets & How They Mount

By the IDEAL install crew · Frameless glass showers in Massachusetts and New Hampshire since 2014 · Updated 10-20-2026

A shower door towel bar bolts through 1/2" (12 mm) holes in the glass and is sized center to center, usually 18" or 24". Pick a single-sided bar for one side of the glass, a back-to-back bar for a towel bar on both sides, or a towel bar & handle set when the door needs a pull on the inside and a towel bar on the outside.

Can you put a towel bar on a glass shower door?

Yes. Glass-mount towel bars bolt through holes in the glass, on the door or on a fixed panel. They are made for monolithic tempered glass, and like a handle they need holes that were cut before the glass was tempered. If your glass already has holes for a towel bar, a new bar with the same spacing goes right back in. If it has no holes, you can't add a through-glass bar to that piece of glass.

Towel bar or towel bar & handle set?

• Single-sided towel bar: one bar on one side of the glass, with slim end caps on the other side (3/16" on CRL's BM Series, 1/8" on the no-washer BMNW Series). Good on a fixed panel, and the low caps make them a good fit on bypass sliding doors too. See them all in Towel Bars.
• Back-to-back towel bar: a matching bar on each side, bolted to each other through the same holes, so there is a towel bar inside and out. Most styles come both ways in Towel Bars.
• Towel bar & handle set: a pull handle on the shower side and a towel bar on the outside. One door gives you a handle to open it from inside and a place to hang a towel outside. The towel bar runs level through two holes. On the shower side, the pull hangs straight down from one of the towel bar's end posts, sharing that hole, to a third hole 6" or 8" below it. That is three holes in all: for an 8" pull with an 18" bar, two holes 18" apart and a third 8" below one of them. See all towel bar & handle sets.
• Towel bar & knob set: a towel bar on one side and a knob on the other. The knob threads into one end post of the bar through the same hole, so it needs only the bar's two holes, like CRL's 18" towel bar and traditional knob set. Also in Towel bar & handle sets.

What sizes do shower door towel bars come in?

Towel bars are sized center to center, the spacing of the two holes. These are the sizes in our Towel Bars section; you can filter it by size and type.

How do I choose the right size for my door?

The center to center size is the hole spacing, but the bar is longer than that. CRL's ladder style bars, for example, are 22" overall at 18" center to center and 28" overall at 24". So:

1. Replacing a bar? Measure from the middle of one post to the middle of the other, and order that size. The holes are already in the glass, so the spacing has to match exactly.
2. New glass? Choose the bar first, then have the holes laid out for it before the glass is tempered. Keep the bar's full overall length clear of the hinges, clamps, handle and the edges of the glass.
3. Check the swing. On a door, make sure the bar's ends and posts won't hit a wall, panel or the other hardware when the door opens.

On a typical door, 18" and 24" are the sizes CRL stocks in nearly every style, which makes them the easiest to match across a whole shower.

How does a towel bar mount through the glass?

Each post bolts through a 1/2" (12 mm) hole. CRL's BM bars use 1/4"-20 threads, and plastic washers keep the metal from touching the glass. Bars with metal washers add a 1-1/4" (32 mm) decorative washer at each post that also covers small chips around the hole; the no-washer versions (BMNW) give a sleeker, continuous look. CRL's towel bar & handle sets come with all the hardware needed to install them.

What glass thickness do I need?

Most CRL towel bars fit glass from 1/4" to 1/2" (6 to 12 mm). Ladder style bars need 5/16" to 1/2", and the premium U-style bar is made for 3/8" glass only. Here's how to measure your glass.

Matching the towel bar to your handle

Stay in the same series and finish as the handle: BM tubular with BM, square SQ with SQ, mitered MT with MT, ladder with ladder. The sets take the guesswork out of it, since the pull and the bar come together in one finish. The most common finishes are polished chrome, brushed nickel, matte black, oil rubbed bronze and polished nickel. Need a grab bar instead? A towel bar on the glass isn't one. CRL's grab bars mount to the shower wall, not the glass; they are in Pull Handles & Knobs.

Where we'd start

• CRL BM24: 24" single-sided tubular towel bar, from CRL's most popular towel bar series.
• CRL BM18X18: 18" back-to-back tubular bar, from CRL's most popular back-to-back series. Also in 24".
• CRL BM8X18: 8" pull inside, 18" towel bar outside, with metal washers.
• CRL BMNW8X18: the same set without metal washers, for a sleeker look.
• CRL SQ24X24: 24" square back-to-back bar to match square-cornered hinges.

Choosing the handle too? Read how to choose a shower door handle.