Fox Defend Thermal long-sleeve jersey review

Fox’s Defend Thermal jersey is designed for cooler rides, boasting lightweight stretch-grid insulation that makes it slightly thicker than a standard top.

This, Fox claims, uses channels to help wick moisture and trap heat inside.

Made from a recycled polyester, polyamide nylon and elastane mix (72/19/9 per cent), its relaxed fit promises to have enough room for elbow guards.

Its nylon elbow sections have been durable water repellent (DWR) coated, but the rest of the garment hasn’t, according to Fox.

It features a dropped tail and is available in five sizes, from small to extra-extra-large. My size-large test sample weighed 219g.

Fox Defend Thermal long-sleeve jersey performance

True to Fox’s claims, the Defend Thermal jersey has a relaxed fit.

I preferred the slightly tighter fit of a size-medium jersey; on my frame, the large is a touch too baggy.

Despite going for a smaller size, the dropped tail was still long, amply overlapping my riding trousers and staying tucked in while on the move.

It also stayed put when untucked and protected my back from mud and water splatters.

The fit is well-tailored; the collar is tight but not restrictive, limiting airflow down your neck.

Its arms are long enough to not ride up when you extend them, but don’t swamp your hands with excess material.

Feeling soft and smooth against your skin, the gridded internal fabric makes the jersey a pleasure to wear.

Once it's soaked in sweat, that comfort continues, but the slightly baggy fit – that keeps the fabric from touching your body for the most part – means the material can feel cool when it makes contact.

However, this helps keep a thin layer of warm, insulative air between the jersey and your skin, boosting its cold-weather performance.

While not totally windproof, the material blocks some cold-air penetration, keeping you warmer than a traditional mountain bike jersey on high-speed descents.

On warmer days (between 7 and 10ºC), it’s great as a single layer, but once the temperature drops beneath 5ºC, it’s best worn with a lightweight baselayer or underneath a thin, windproof shell.

In both these layer configurations, the Defend jersey excelled, feeling comfortable and warm.

Despite the material’s light colour, it took a lot of sweat to darken or stain, fending off sweat patches impeccably.

While the elbow’s DWR coating works, I couldn’t work out how those panels repelling water would improve performance.

Finally, its looks are discreet and subtle, which will appeal to many.

Fox Defend Thermal long-sleeve jersey bottom line

Retaining body heat well while resisting sweat saturation, the Fox jersey is versatile, working well as a single layer or when matched with other technical clothing.

Although it sizes up quite large, there’s enough scope to size down for a tighter fit.

However, it’s rather expensive; some people might struggle to justify the cost.