If you're buying a built bike, it's important to consider the effect the specced components will have, especially with the likes of integrated bar/stem arrangements where a swap isn't cheap.įork offset (sometimes called rake), trail and head angle areintrinsically intertwined. A gravel bike or endurance bike that’s got disc brakes and more tyre clearance will have a longer fork to cater for that, so the head tube is going to become shorter but it doesn't increase the drop," Allen comments. Now, more bikes have different fork lengths.
"Once, a standard fork length was 370mm, and you could compare head tube lengths. When it comes to the top tube - the angle of the head tube and seat tube will have an impact – if a bike has a 55cm top tube, and a 70º angle, and another has a 73.5º angle, effectively the reach on the 73.5º bike is going to be longer." "The old school measurements like top tube length and head tube length, are a bit outdated and misleading. When I'm looking at whether a frame geometry is going to fit with what I want for a client, they’re going to be the most important measurements. "The new standard of stack and reach is the easiest way to start comparing if a bike is going to be long and low or high and short. Comparatively, the endurance ready S-Works Roubaix in the same size has a stack of 585mm and reach of 375mm. These measurements will help you determine if the bike will put you into a racer's position with a long reach and short stack (aggressive), or one which will be comfortable for long, all-day rides (endurance/relaxed) thanks to a short reach and high stack.Īs an example, a racey Specialized S-Works Venge in a size 54 has a stack of 534mm and a reach of 387mm. Reach is the horizontal distance from the centre of the bottom bracket to the middle of the head tube. Stack is the vertical distance from the centre of the bottom bracket to the mid point at the head tube.