Serios Fit Guide

Diamondback Serios Bike Fit Guide

Fit is one of the most important elements of bicycle design. An optimized position is the perfect combination of aerodynamics, power output, and sustainability. Often riders focus on just one or two elements instead of all three, leading to a less than optimized fit. The Diamondback Serios Fit Guide is designed to provide you with all the information and steps needed to determine your best fit.

Selecting a Size

Generally, we see two different types of customers purchasing a Serios bike:

  1. First time TT/Tri buyers - those that already have a road bike and are now purchasing their first TT/Tri bike
  2. Experienced TT/Tri buyers - those that already have a TT/Tri bike, and are now replacing it with a Serios

Regardless of which category you fall into, the Serios Fit Guide can help you determine the best frame size for your needs.

First-Time TT/Tri Buyers

When purchasing your first TT/Tri bike, the most general way is to base the Serios frame size on your existing road bike. Most riders tend to use the same size TT/Tri frame as their road frame. Below is chart that can help you select an appropriate size.

Diamondback Serios Bike first time buyers

Experienced TT/Tri Buyers

If you are an experienced rider and are upgrading your current TT/Tri bike, it is best to start is with your current fit. First determine the Pad Stack and Pad Reach of your current TT/Tri bike. To do this, you will need your current TT/Tri bike, a pencil, tape measure.

Diamondback Serios Bike experienced buyers

Determining your Pad Stack and Pad Reach:

  • To determine your Pad Stack (C), you will need the following measurements:
    1. Pad Height (A) - The distance from the ground to the top of the pads: ____ mm
    2. Bottom Bracket Height (B) - The distance from the center of the BB to the outer edge of rear wheel: ____ mm
    3. Pad Stack (C) = A - B = ____ mm
  • To determine your Pad Reach (F), you will need the following measurements:
    1. Pad Distance (D) - The distance from the edge of the rear wheel to the center of the pads: ____ mm
    2. Bottom Bracket Distance (E) - The distance from the edge of the rear wheel to the center of the BB: ____ mm
    3. Pad Reach (F) = ____ mm

Once you have determined your current pad stack and pad reach, refer to our fit-grid to determine the best frame size for you.

For any questions regarding your frame size and fit, please contact Diamondback Support

Diamondback Serios Bike Fit Grid

Terms You Need To Know

Bottom Bracket (BB): Connects the drive side & non-drive side cranks to each other & the frame.
Pad(s): The padded cups atop the handlebars that are designed to support the rider’s elbows while in an aerodynamic position.
Pad Stack: The vertical distance from the CENTER of bottom bracket to the top of the pads.
Pad Reach: The horizontal distance from the CENTER of the bottom bracket to the CENTER of the pads.

Achieving your Fit Coordinates

After you have calculated your Pad Stack and Pad Reach, you can achieve your fit using a combination of the provided stem spacers and/or HED aerobar risers (available from HED Cycling). The stem spacers have a total of 50mm of stack range and the HED risers have 24mm of stack range.

Pad Stack

Sample Combinations:

Size Frame Stack Low Pad High Pad
50/SM/XS 501mm 560mm 646mm
54/MD 532mm 591mm 678mm
56/LG 552mm 611mm 698mm
58/XL 572mm 632mm 718mm
Stack 0 stack 10 stack 15 stack 20
stack 25 stack 30 stack 35 stack 40
stack 45 stack 50 stack 62 stack 74

Pad Reach

Sample Combinations:

Size Frame Reach Short Pad Long Pad
50/SM/XS 395mm 431mm 496mm
54/MD 408mm 446mm 511mm
56/LG 421mm 468mm 533mm
58/XL 434mm 492mm 557mm

The Pad Reach range is 25mm and is achieved through the use of the mounting holes on the arm rest pads. Further Reach combinations can be achieved by substituting a different length stem. The mounting diameters are industry standard Ø28.6mm at the fork steerer and Ø31.8mm at the aerobar.

pad reach +12.5 pad reach 0 pad reach -12.5