Handles the extra twist of wide bars and is available right down to a 33mm length.
We’ve tested the Renthal Apex a few times over the years, and one of its unique features is the wraparound bar clamps. Normally the faceplate goes straight onto the front of the stem, with a 180º clamp, but the Apex design has a much wider 240º wrap. This means the faceplate, or in this case the two individual clamps, bolt on further round the bar, creating more overlap and contact area.
This allows Renthal to oversize the body of the stem (called the extension tube) to boost stiffness while cutting the most amount of weight possible. The two clamps also use a zero-gap design, but unlike every other stem here, the clamps close at the bottom rather than the top, leaving an ugly visible gap. You also need to slide them along the bar from the grip end, and since the edges are pretty sharp it’s easy to scrape the bar if you’re not careful.
We don’t know if it’s a consequence of the design, but the Renthal is only available in a 6º rise, and on our test bike this is just a little bit too tall. We flipped it over, but then had to add a spacer because the clamp fouled on the headset. It used to come in eight lengths, but Renthal has cut this to four, including the shortest physically possible, a 31mm.
The Apex is machined from a hard-wearing 2014-series aluminium (the clamps are 7075) and, like most Renthal parts, there’s a deep anodising that seems to last ages, even if it’s only offered in the one factory colour. The Apex is externally webbed to maximise stiffness in longer lengths.
Although the stiffness of stubby stems is mostly negligible, we did notice a little bit more give in this stem under heavy loading – but on a stiff, carbon-framed e-bike that’s not a bad thing.
The Apex 35 isn’t as sleek as the Race Face Turbine R 35, it’s fiddly to set up, and it’s more expensive, but if you want the lightest 35mm trail stem on the market, this is definitely it.