Altura has designed the Kielder Lightweight Trail short for hotter days and it is the cheapest and lightest on test.
A big clue to being so light (under 100g in size large) is having by far the thinnest material of all the shorts here, with an almost silky, shiny fabric that’s perhaps too flimsy for the rigours of mountain biking.
The Kielder has a relaxed cut with enough hem room to fit over most trail-level knee pads, and everyone except the tallest riders will still have ample coverage to eliminate any unsightly thigh gaps.
Both colour schemes use a textured camouflage print that’s subtle rather than screaming, as well as what Altura describes as ‘predominantly’ recycled polyester – although it doesn’t specify the exact proportion. The brand also uses a PFC-free DWR coating to protect from the elements, showers, and splashes.
The Kielder lacks specially-shaped panels and a pedalling-specific cut, and being so lightweight means it is a bit shapeless. There’s a mesh-backed zipped hip pocket on each side, and they are roomy enough and decently positioned, but because the main material is so flimsy, heavier phones aren’t kept stable enough and can swing around.
The main issue we had though, was the short itself being unstable. Altura’s nailed the double front waist fastening, with a solid metal thread-through stud that can’t peel open accidentally. But for one 6ft 4in test rider, with a slim 32in waist, the short repeatedly wriggled down the hips while riding, even though the size and length seemed fine. Simply, with no way of adjusting the waist, and insufficient tension in the elastic, it would gradually creep down.
Not having a huge amount of stretch in the elastic waist also means bigger riders who aren’t as tall don’t fit in this longish size large either. Yes, there are belt loops to tune the waist, but these don’t extend around the side for some reason, so can only hold up at the front and back.
The Kielder short's fabric is too flimsy and flappy to hold its shape while pedalling, and also isn’t particularly cool or well vented. And, despite being super thin, there’s not much airflow through the fine weave, so it doesn’t even dry very quickly if soaked with sweat.