Renthal Duo 40mm stem review

Quality UK-made short stem

Our rating 
3.5 out of 5 star rating 3.5
GBP £79.99 RRP | AUD $139.95 | USD $99.95
Renthal Duo 40mm stem

Our review

Lightweight and as strong as it is short – a perfect partner for the modern trail bike, if a little pricey
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The new 40mm Duo stem from Renthal retains all the features that made the original 50mm option so popular, and it suits the current crop of trail bikes with longer top tubes perfectly.


Engineered to be as light as possible without sacrificing strength, it tips the scales at 123g thanks to its unique two-piece design. Adjusting or swapping bars involves a bit of extra faff, because you have to loosen six bolts rather than four, but it’s simple to assemble and the laser engraved torque settings make it easy to get it properly tightened up.

It’s not the cheapest stem in its class, and we’ve heard complaints of creaking from other riders with the 50mm version – however, with regular cleaning and greased bolts, we’ve never experienced problems. The quality of manufacturing, the distinctive black and gold anodising and the fact that the stem is made in the UK all help to justify the higher price tag.


The bolts are 4mm in diameter rather than our preferred 5mm, but at least they’re made from steel rather than easily rounded alloy.

Product Specifications


Name Duo 40mm stem (14)
Brand Renthal

Weight (g) 123
Length (mm) 40
Bike Use Mountain
Cap Bolts 6