Border Collie harness for armpit chafing

Armpit chafing is one of the most common harness complaints, and it's almost always a fit or design problem rather than something wrong with your dog. Harnesses with narrow straps or a straight chest band tend to dig into the axilla area on active breeds like Border Collies — especially if the dog moves fast and freely. Before I point you toward something better, tell me: roughly how much does your Collie weigh, and what's the chest measurement if you have it? And is the chafing happening on both sides or just one — that can tell us a lot about whether it's the design or a sizing issue.

Both sides chafing confirms it's the design, not the fit — the harness was almost certainly cutting across the wrong part of the chest and restricting her shoulder rotation. At 19kg with a 65cm chest, she's solidly in medium territory for most brands. For hiking and longer walks with a dog that pulls moderately, I'd look at the Ruffwear Front Range Harness. It has a padded chest and belly panel specifically shaped to sit away from the armpits, and the padding is substantial enough to handle full days out without rubbing. It also has both a front and back clip, so you get some leash control without needing a separate walking harness. Has she had any skin sensitivity beyond the chafing, or is it purely a mechanical friction issue?

At 65cm chest you'd be right in the middle of their Medium, which runs from roughly 56–69cm chest. That gives you room to adjust without being at either extreme of the range — ideal. The Front Range also has two points of adjustment on the chest and belly, so you can dial it to her specific shape rather than just going by one measurement. One thing worth doing when it arrives: put it on, let her stand naturally, and check that you can slide two fingers under the chest pad without it lifting away from her body. If it's floating, it's too loose and will migrate into the armpits — which is where a lot of people go wrong even with a good harness.

The main thing is to check her movement, not just the static fit. Put the harness on, walk her around for five minutes, then look at where the front straps sit after she's been moving — they should stay clear of the point of her shoulder. If they're creeping inward, the chest strap needs to come up slightly. Also give her armpits a quick check after the first few walks, just while the harness is bedding in and she's adjusting to a different movement pattern. With the Front Range's padded panels you're very unlikely to see a repeat of what happened before, but it's worth confirming early rather than waiting weeks.

Good luck with it — the Ruffwear Front Range in Medium should be a significant step up from whatever she was in before. If the fit feels slightly off when it arrives, most retailers will exchange for a different size without a fuss, so don't feel stuck with it. Enjoy the hikes.