Why Do My Sandals Strap Rub? The Sunbird String Fix
By Birdies | Published: 2026-10-27
Category: How-to Guides
Discover why your sandal straps rub and how the Sunbird String's secret elastic and adjustable design can prevent blisters. Practical steps for a comfortable fit.
Quick Answer
If your Sunbird String sandals rub, the fix is usually in the secret side elastic and adjustable instep straps—tighten or loosen them to match your foot type and stop blisters before they start.
Why Straps Rub in the First Place
Most sandal rubbing happens because the foot moves inside a fixed strap, creating friction. With the Sunbird String, the soft tubular straps are designed to hold the foot without digging in, but if the elastic isn't adjusted to your arch height or foot width, you may still feel pressure points.
The secret elastic on the side of the Sunbird String is the key difference—it lets the instep straps move with your foot rather than fighting it. When the elastic is too loose, the foot slides and rubs; too tight, and the straps can pinch.
When Rubbing Signals a Fit Issue, Not a Flaw
A common mistake is assuming rubbing means the sandal is poorly made. The Sunbird String's barefoot feel and flexible front contoured sole are intentional for comfort, but they rely on the straps doing their job. If you feel rubbing on the side of the foot or across the instep, it's almost always a strap tension problem, not a design defect.
If you have a very narrow or very wide foot, the adjustable straps give you room to customize. The microsuede lining also softens over time, which can reduce friction after a few wears.
Diagnose & Fix Strap Rub in 4 Steps
- Symptom: You feel rubbing or a hot spot on the side of your foot, across the top of the instep, or along the tubular strap edge after walking for 10–15 minutes. If the rubbing is on the sole or heel, this guide may not apply—check the sole for debris or try a different sockless wear approach.
- Likely Cause: The side elastic is either too loose (foot slides and creates friction) or too tight (strap edge presses into the skin). Because the straps are tubular and soft, the elastic tension is the main variable.
- Corrective Action: Put on the sandals and locate the hidden elastic on the side of the instep. Gently pull the strap to tighten or push the elastic to loosen it. Walk a few steps and repeat until the strap sits snugly without pressure. For the crystal stone version, the microsuede lining will also soften after a few wears. If adjusting the elastic doesn't stop the rubbing after 2–3 tries, your foot shape may need a different Birdies style.
- Stop or Choose Another Option: If the rubbing continues after adjusting the elastic and wearing the sandals for 2–3 short sessions, consider trying the Sunbird Icon (which has a different strap layout) or a sandal with a heel strap for more security. The Sunbird String is designed for a barefoot feel, so it may not suit every foot type. You can also try a thin gel liner on the strap contact point, but this may affect the barefoot feel.
Product Spotlight
- The Sunbird String - Crystal Jewels: Barefoot, but held in all the right places with the softest tubular straps. Notice the secret elastic on the side making the instep straps all adjustable to fit your foot type. This adjustable elastic is the main tool for fixing strap rub—tightening or loosening it customizes the fit to your arch height and prevents the friction that causes blisters.
The Sunbird String - Crystal Jewels
