Gravel guides
Merino in cycling jerseys: why 93% merino and when it beats synthetics
Merino beats synthetics whenever the temperature changes during a ride, when you ride several days without washing, or when you want one jersey from a cold start to a warm afternoon. Synthetics win in steady heat and for pure sweat-wicking in a race. A 93% merino / 7% elastane blend at 18 micron gives you merino's regulation and odour resistance with the stretch and recovery a cycling cut needs.
How merino regulates temperature
Merino fibres are crimped, which traps air and insulates when it is cold. The fibre also absorbs up to a third of its weight in moisture as vapour and releases it as you warm up, so the fabric cools you without feeling wet. The result is a jersey that works across a wider temperature range than any synthetic: a 5 °C morning climb and a 18 °C valley descent in the same garment.
Odour: the practical advantage
Synthetics wick sweat well but hold on to the bacteria that cause smell; after one hard ride a polyester jersey needs a wash. Merino binds odour molecules in the fibre and releases them in the wash, so a merino jersey can be worn for several days of a trip — hang it up overnight and it is fresh in the morning.
What micron means
Micron is the fibre diameter. Everyday wool is 25–30 micron and feels scratchy against the skin because thick fibres do not bend when they touch it. 18-micron merino is fine enough to wear next to the skin without a base layer; below 17 micron the fabric gets so fine it wears out quickly. 18 micron is the sweet spot for a cycling jersey.
Why not 100% merino
Pure merino stretches but is slow to recover, so a close-fitting jersey bags out at the elbows and waist and the pockets sag. A small share of elastane — 5–8% — holds the fit after hours of riding and dozens of washes without changing how the fabric feels. Tinden's jersey is 93% merino and 7% elastane for this reason.
When synthetics are better
In steady heat above 25 °C, or in a race where the only job is moving sweat off the skin as fast as possible, a light polyester jersey dries faster and weighs less. For everything else — Norwegian mountains, variable weather, multi-day trips, long days with a cold start — merino is the better fabric.
Washing and care
Machine wash cold on a wool cycle with a mild detergent, no fabric softener. Dry flat, out of direct sun. Never tumble dry. Washed this way a good merino jersey lasts for years; the elastane is usually what gives out first.
Frequently asked questions
Is merino warmer than polyester?
Merino insulates better when cold and cools better when you warm up, so it covers a wider temperature range. In steady heat a light polyester jersey is cooler.
Why do merino jerseys not smell?
Merino binds odour molecules in the fibre and releases them in the wash, while synthetics hold on to the bacteria that cause smell.
What does 18 micron mean?
The fibre diameter. 18-micron merino is fine enough to wear against the skin without itching; everyday wool is 25–30 micron.
Why is the Tinden jersey 93% merino and not 100%?
The 7% elastane keeps the close cycling fit after hours of riding and many washes; pure merino stretches but recovers slowly.