Best harness for Shih Tzu that won't chafe

Three harnesses and all of them rubbing behind the front legs — that's a really specific and frustrating pattern, and it tells me something useful straight away. That spot is almost always caused by the chest strap sitting too far back, or the armhole openings being too wide for a compact Shih Tzu build. Before I point you in a direction, can you tell me roughly how much your dog weighs, whether the rubbing has caused any hair loss or soreness, and what kind of walks you're doing — short local leads, or longer outings?

That's really helpful. Hair loss on both sides tells me the armhole edges are making contact every single stride — it's not a sizing issue you can fix with adjustment, it's a design issue. Step-in harnesses are almost always the culprit because the leg holes are cut to fit a generic small-dog shape, and Shih Tzus have a barrel chest with short, wide-set legs that sits very differently. The Julius-K9, while well made, has a chest plate that tends to ride too far back on short-bodied breeds. Can I ask — does she pull much on the lead, or is she fairly relaxed to walk?

Perfect — no pulling means you don't need a front-clip or anti-pull design, which opens up some better options for comfort. Given the chafing history, the escape risk, and her barrel-chested Shih Tzu build, I'd recommend the Ruffwear Web Master Harness. It has five adjustment points including a dedicated belly strap, which lets you fit it precisely around a short, round torso without the chest piece migrating backwards. Crucially, the leg loops are padded and positioned to sit at the very front of the armpit rather than behind it — which is exactly what stops that rubbing. It's more harness than most people expect to buy for a gentle plodder, but it's genuinely the construction that solves this specific problem. Available on Amazon UK and worth every penny given what you've already spent on harnesses that didn't work.

At 6kg you'd almost certainly be in the XXS. Ruffwear size by girth measurement rather than weight, so measure around the widest part of her ribcage — for most 6kg Shih Tzus that's around 33–43cm, which is the XXS range. I'd strongly suggest measuring before you order rather than going by weight alone, because Shih Tzus can vary quite a bit in chest circumference for their weight. The fit guide on the Ruffwear site is accurate and worth two minutes of your time. Once it's on and fitted snugly — you should get two fingers under any strap — you shouldn't see any bunching around the armpits at all.

Great — and if the girth measurement sits right at the top of the XXS range, size up to XS rather than squeezing her in. A slightly looser fit adjusted down is always better than a tight one for preventing chafing. I hope she gets some relief quickly — at 7, she deserves comfortable walks.