Trek Powerfly Sport 5 Equipped Gen 4

Finding your Size

The easiest way to determine your frame size is by height, but many riders find that they are between sizes. Choosing to go up or down a size depends on your personal riding style and body proportions.

A bike with a longer reach will have a longer wheelbase. That makes it more stable, especially on high-speed descents. That’s great for riders who like to plough through rather than pop over rough stuff on the trail. If you have a relatively long torso or arms for your height, you may find that a longer reach gives you a roomier, more comfortable cockpit.

A bike with a shorter reach will have a shorter wheelbase. It’s not as stable, but it’s more nimble and easier to flick around. That’s great for riders with a more playful, active riding style who like to get off the ground and whip their wheels around. If you have a relatively short torso or arms for your height, you may find that a shorter reach makes it easier for you to hold the handlebars comfortably.

Effective top tube

Effective top tube is the horizontal distance from the centre of the head tube to the centre of the seat post. This measurement represents how a mountain bike fits while you’re sitting on the saddle. It’s important for cross country riders, who prioritise pedalling power.

Reach

Reach is the horizontal distance from the centre of the head tube to a vertical line that runs through the centre of the bottom bracket shell. This measurement represents how a mountain bike fits when you’re standing up on the pedals, like when you’re descending. Since most trail riders prioritise out-of-the-saddle riding, this tends to be the most helpful metric when comparing bike sizes from different brands.