Window Repair Systems WRS Caldwell Series 50 3/8" Spiral Tube Window Balance for Tilt Windows - 29" Ye

Why I reached for this balance

A sticking, drooping tilt window is one of those small household problems that becomes a daily irritation. When a lower sash in my office stopped staying up on its own, I swapped the worn spiral balances with the WRS Series 50 spiral balance in the 29-inch, yellow-tip configuration. I chose it because it matches the common 3/8-inch spiral format found in many tilt windows and it’s calibrated for mid-weight sashes. A few weeks of everyday use later, here’s how it performed and what I learned along the way.

Build and design

The Series 50 is a classic 3/8-inch spiral tube balance: a metal tube with an internal spiral rod that stores torsion and counterbalances the sash. Construction feels solid and consistent from unit to unit, with cleanly crimped ends and a smooth spiral action. The finish resists scuffs during installation, and I didn’t encounter any burrs or rough spots that sometimes plague lower-tier balances.

The yellow tip on this version indicates a spring weight range roughly in the 24–34 lb window, which suits many mid-sized, double-pane sashes. The color coding is one of the best aspects of the system—WRS offers the same balance in multiple lengths (10 to 45 inches) and tip colors to cover lighter and heavier windows. That makes spec’ing replacements straightforward if you know your sash weight and tube length.

Fit and compatibility

If your sash uses a 3/8-inch spiral balance, this is designed as a direct replacement. The key checks before ordering:

• Diameter: Confirm 3/8-inch. If you measure the tube with calipers or a ruler, a 3/8-inch tube typically reads a bit under 1/2 inch across the flats. If yours is closer to 5/8 inch, look for a 5/8-inch series instead.
• Length: Measure the metal tube length, not including the tip or top hardware. I matched my original at 29 inches and the new balance dropped right into place.
• Tip color/weight: Choose the tip that covers your actual sash weight. If you don’t have the weight, you can estimate by measuring the sash and referencing the window manufacturer’s data or carefully weighing the sash after removing it. Picking the correct weight range is what keeps the window from creeping up or slamming shut.

One note: pivot shoes and attachment points vary. Most tilt window shoes accept the common spiral hook/clip on this balance. If your existing shoe is worn or uses an unusual connector, plan on replacing the shoes at the same time. It’s good practice anyway, as tired shoes can cause binding that feels like a spring issue.

Installation experience

This is a straightforward DIY job if you’re comfortable removing and re-installing a tilt sash. Here’s the workflow I used and would recommend:

1. Prep and safety: Wear gloves and eye protection—the spiral stores tension, and old balances can snap unexpectedly. Support the sash as you work.
2. Remove the sash: Unlock, tilt inward, and lift one side free of the jambs. Set it aside on a soft surface.
3. Release the old balances: Unhook the spiral from the pivot shoe, then back out the top screw or clip and slide the balance out.
4. Measure and compare: Before unbagging the new parts, confirm diameter, tube length, and tip color match your plan.
5. Install the new balance:
   • Secure the top of the tube in the same location as the original. Reuse the existing screw if it’s in good shape; otherwise, replace with a stainless or zinc screw of the same size.
   • Hook the spiral end into the pivot shoe.
   • Add tension. Using a balance charging tool or a pair of needle-nose pliers, rotate the spiral a small amount to pre-load it. I start conservatively—just enough to hold the shoe in place—and then fine-tune once the sash is back in.
6. Reinstall the sash: Set the top corners back into the jambs, align the pivots with the shoes, and tilt the sash upright. Test operation and balance.
7. Fine-tune: Raise the sash halfway and let go. If it drifts down, add a quarter-turn of tension to each side. If it climbs, reduce tension. The goal is neutral buoyancy at mid-travel.

I didn’t need a specialized tool, but a proper charging handle does make tensioning more controlled and reduces the chance of the spiral slipping as you twist. The entire swap for both balances on one sash took about 10 minutes, including adjustment.

Performance in daily use

With the yellow-tip balances installed and tuned, my window holds position cleanly across its range and closes without a fight. There’s no chatter in the spiral, and the sash tracks smoothly without the slight “bounce” you sometimes feel from mismatched weight ranges. After several weeks of frequent opening for ventilation, performance remains consistent—no sagging over time or change in feel.

A few smaller things I appreciated:
- Smooth retraction with low noise. No squeaks out of the box.
- The tube finish doesn’t scuff easily during install, so it still looks tidy in the jamb channel.
- Predictable tension changes. A quarter-turn actually feels like a quarter-turn in effect, which makes dialing balance easy.

Durability and maintenance

Time is the real test for balances, but the build suggests good longevity. The spiral action is well-centered, and the materials feel up to daily use. I like to add a tiny drop of light silicone-based lubricant to the spiral contact area during install and then forget about it; that tends to keep things quiet. As always, the pivot shoes and jamb channels need to be clean for any balance to do its job—grit and paint build-up cause more “balance” complaints than worn springs.

What could be better

• No accessories included. This is common, but first-time DIYers may expect screws, a charging tool, or new shoe clips in the bag. Plan on reusing your hardware or stocking replacements.
• Sizing pitfalls. Spiral balances seem simple, but mismatching diameter or tip color is the fastest way to a poor result. Clear, diagrammed guidance in the box would help ensure people order the right spec the first time.
• Upper sash access. Replacing balances on upper sashes in double-hungs is always a bit more awkward. That’s not a fault of the balance, but it’s worth noting you’ll need patience and maybe a second set of hands.

Who it’s for

• DIY homeowners with tilt windows running 3/8-inch spiral balances who want a direct, cost-effective fix for slumping sashes.
• Property managers maintaining a mix of residential and light commercial units where standardization on a proven balance saves time.
• Pros who need consistent stock across weight ranges and lengths without fussing over brand-specific oddities.

Practical tips before you order

• Confirm tube diameter with a caliper or a careful ruler measurement.
• Measure the metal tube length only; don’t include the plastic tip.
• Weigh the sash if you can, or confirm the original tip color from the old balance.
• Inspect pivot shoes; replace them if they’re cracked, wobbly, or sticky. Balances can’t compensate for bad shoes.
• Buy balances in pairs per sash and tension them equally.

The bottom line

The WRS Series 50 spiral balance does exactly what a good balance should do: disappear into the jamb and make a heavy sash feel weightless. Installation is friendly, tuning is predictable, and the yellow-tip spring range is well-suited to the mid-weight windows common in many homes. It’s offered in a comprehensive spread of lengths and tip colors, so once you know your specs, matching replacements is painless.

Recommendation: I recommend this balance for anyone replacing 3/8-inch spiral balances on tilt windows, especially DIYers who value a direct-fit, fuss-free solution. It brings tired sashes back to “set it and forget it” operation, provides consistent support across the travel range, and holds up well in daily use. Just double-check your diameter, length, and tip color before ordering, and you’ll get the result you’re after.