Fit

Ensuring that your new bike is properly fit to you is an important step in preparing for your first ride.  Your Authorized Specialized Retailer will be able to provide a basic fit, ensuring that you are able to ride your bike comfortably and efficiently. Specialized also offers Retül Fit, a data-driven bicycle fitting tool designed to improve comfort, prevent injury, and increase performance.

Frame Geometry

The Aethos features identical fit and handling geometry as the Tarmac SL7. Detailed measurements can be found in the geometry chart:

Image of geometry table -click to enlarge

Adjust the saddle height

The correct saddle height is crucial for pedaling efficiency and comfort. Retül can help you estimate your Aethos bike size and saddle height here


A new Alpinist seatpost has been developed for the Aethos. The minimum seatpost insertion from the top of the seatpost collar is 75mm.  The maximum insertion is 215mm.  If the supplied seatpost does not meet these requirements for your appropriate saddle height, you may need a shorter or longer seatpost.

Image of seatpost insertion -click to enlarge


Adjust the reach

If your bike is the correct size, you should be able to comfortably reach the handlebars with your elbows slightly bent. Your bike saddle can move back and forth on the rails–start with it centered and fine tune as needed. A professional bike fitter will set this position to line up your knee with the pedal axle. You can also adjust your reach by raising or lowering your handlebar height, and by increasing or decreasing the length of your bike stem.


A maximum of 35mm of spacers may be placed beneath the stem.  The lightweight scalloped spacers may be used below the stem only.  A maximum of 5mm of solid spacers may be installed above the stem.

Image of headset spacers -click to enlarge


Tire Pressure

Running the correct tire pressure is crucial for a controlled and enjoyable ride.What you see below is a recommendation of a starting point or a "ballpark" tire pressure based on rider weight and tire size. Your preferred tire pressure may vary according to load, terrain, conditions, and ride style. Front tires can be inflated with less pressure than rear tires. You'll also see a decal on your wheels indicating maximum inflation pressure--never exceed the maximum inflation pressure of your tires or rims. Enjoy your ride! 

The Aethos complete bike is equipped with 26mm tires. The frame will accommodate a tire width up to 32mm on 21mm rims with a clearance of 4mm.

Image of road bike tire pressure graph -click to enlarge

Tubeless conversion

Many riders choose to convert to tubeless tires to prevent pinch flats. Tubeless tires allow riders to use lower inflation pressure without the risk of damaging a tube from impacts.  Please ensure that both your rims and tires are tubeless compatible before proceeding.