Shoe Accessories That Fix Fit: Insoles to Heel Grips
By United Nude | Official Website | Published: 2026-10-14
Category: Buying Guides
A practical buying guide to shoe accessories for fit: when insoles, heel grips, and inserts actually solve a half-size-too-big problem, and when they don't.
Quick answer
For a shoe that's a half size too big, start with a thin full-length insole if the whole foot slides, or a heel grip if only the back slips. If the shoe is more than one size too large, or the width is wrong, accessories won't fix it — return the pair. Match the accessory to the symptom, not to the shoe style.
Diagnose the symptom before you buy anything
Shoe fit accessories fail when you buy them by category instead of by problem. A heel grip won't stop your toes from sliding forward, and a full-length insole won't fix a heel that lifts because the shoe is too long at the back. Spend two minutes walking in the shoes on a hard floor and note exactly what moves: the heel, the whole foot, or just the sides. That single observation decides which accessory you need. If the shoe is a half size too big, you have a real chance of a comfortable fix. If it's a full size or more, the geometry is too far off and no insert will make it feel secure.
Insoles and inserts: what each one actually does
A full-length insole takes up volume along the entire footbed, which is the most reliable way to stop a foot from sliding forward in a loose shoe. A heel insert or heel liner only fills the back of the shoe, so it's better for a heel that lifts while the rest of the fit is fine. A tongue pad pushes the foot back toward the heel and is useful when the instep feels loose but the length is correct. Half-insoles sit under the ball of the foot and can help with a shoe that feels too deep at the front. Each of these changes fit in a different direction, so combining two that do the same job usually just makes the shoe tight in the wrong place.
When the shoe itself is the better fix
Some fit problems are design problems, and accessories only mask them. A bootie with a narrow fit and a small size run, like the Zembla Artic Mid, may feel tight across the instep even in your usual size; adding an insole there makes it worse. A style with a wider last and rounded toe, like the Fold Mid, is often the more comfortable starting point if you have a broader forefoot. Check the product's stated fit notes and heel height before you buy accessories, because a 65mm heel and a 90mm heel load your foot differently and change how much slipping you'll notice. If the catalog doesn't list a width measurement, treat that as a limitation and size up or down based on the fit note instead of guessing.
Material and care trade-offs
Accessories interact with the upper material. A knit or neoprene upper stretches with wear, so a heel grip that feels snug in week one may feel loose by week four; leather linings hold their shape better and give inserts something stable to sit against. If your shoes have a metallic finish, keep adhesives and abrasive inserts away from visible surfaces, since metallics can scuff easily with normal wear. Store shoes in a cool, dry place when you're not using them, and remove inserts periodically so the footbed can air out. None of this is complicated, but it's the difference between an accessory that lasts a season and one that peels off in a month.
Decision rules for buying fit accessories
- Heel lifts, rest of foot feels fine: Use a heel grip or heel liner. Place it at the inside back of the heel, not the sides. If it still lifts after one grip, the shoe is too long — return it.
- Whole foot slides forward: Use a thin full-length insole. Start thin; you can always add thickness but you can't remove it. If the shoe becomes tight across the instep, switch to a half-insole.
- Instep feels loose, length is right: Use a tongue pad or a self-adhesive insert under the tongue to push the foot back into the heel. Don't pair this with a heel grip; you'll double up on the same fix.
- Shoe runs small or narrow by design: Size up instead of adding accessories. Inserts take up volume you don't have to spare. Check the catalog fit note before you buy anything.
- More than one size too big: Stop. Accessories can absorb a half size, sometimes a full size, but not more. Exchange the pair; no insert will make it secure.
Fit-relevant details from the catalog
- Fold Mid: Standard fit with a slightly wider last, rounded toe, and 65mm/2.56in heel; available in neoprene or knit fabric uppers with leather lining. The wider last and rounded toe give more room up front, so this is a better starting point for broader feet than a narrow style — and the leather lining holds inserts in place more reliably than a soft knit.
- Zembla Artic Mid: Narrow fit that runs small, with a hidden 100mm/3.9in wedge and a chunky treaded platform outsole. Because it runs small and narrow, sizing up is usually the right move here rather than adding an insole — an insert would only reduce the room you just gained.
- UN Bootie Mid II: Standard fit, 65mm/2.56in heel, side zip, all-leather upper, and a metal cutout heel. A standard-fit leather bootie at a moderate heel height is the easiest candidate for a heel grip or thin insole, and the leather upper resists the stretching that makes grips loosen over time.
- Zuma Flow Hi: Normal fit with a 90mm/3.5in heel, Nappa leather and elastic side panels, and a leather-wrapped, chromed, or matte-finished heel. The higher heel shifts weight forward, so if you feel slipping here it's more likely a length issue than a heel-volume issue — check the fit before buying a grip.
Who should buy fit accessories — and who shouldn't
Best for
- Shoppers dealing with a half-size-too-big fit in an otherwise correct shoe
- Anyone with a slipping heel in a standard-fit leather bootie
- People who want to keep a favorite pair wearable after the upper has stretched
Not for
- Shoes that are a full size or more too large
- Narrow-fit styles that already run small, where sizing up is the real fix
- Anyone with a width problem rather than a length or volume problem
