Sidi Guide to Shoe fit 

Fitting Yourself to SIDI Cycling Shoes
There is no substitute for perfect fit. Your shoes are the most important contact point between you and your bike, affecting power, comfort, and providing that locked-in feeling of oneness with your bicycle.

• Try shoes on at the end of the day — your feet swell by at least a half-size as the day progresses, and as much as a full size on hot days. Stand up. Feet expand under pressure — standing up will give you a better sense of how your shoes will fit under pedaling pressure.

• Bring the socks and orthotics you ride with — they have a tremendous influence on foot volume and fit.

• Be patient! Non-leather cycling shoes do not stretch over time — how they fit in the store will be how they fit, period. However, as the shoes warm up from body heat the uppers will become more pliable and conforming. Give your shoes at least 10 minutes to heat up, and readjust the closures to accurately gauge how they’ll feel mid-ride.

• Foot measuring devices typically measure length and width only, and do not account for overall shape or foot volume. It’s imperative that you try on shoes a half-size larger and smaller than your measured size, for confirmation of proper fit.





• SIDI half sizes are 3 mm longer, with slightly increased toe box volume. Full sizes are 6 mm longer, with proportionally greater volume.

• Standard-size SIDIs roughly correspond to a D width on the industry-standard Brannock sizing scale.

• Mega sizes are cut with more material throughout, and a larger-volume heelcup. Mega sizes roughly correspond to a EE/EEE width on the Brannock sizing scale.

• Narrow sizes are cut with less material throughout, and a narrower, lower-volume heelcup. Narrow sizes roughly correspond to a B/C width on the Brannock sizing scale.

• Women’s SIDIs have a more tapered shape and lower volume than standard- or narrow-width SIDIs. Women with consistently wide or narrow feet, from heel to the forefoot-may experience better fit in SIDI Std or Narrow widths.


Stand up when fastening the closures, start at the toes and work back toward the heel.

Start at the toes... ... work back towards the heel.


The Soft Instep Pad should be centered laterally, positioned so the letters “I” and “D” are over the high point of your foot

Shoes will become more conforming as they warm up—a process that can take up to 30 minutes—so be patient. You’ll want to periodically tighten straps and ratchets as this occurs, working front to back. Do not buy shoes that are too tight, thinking they’ll get bigger over time. SIDIs do NOT stretch!

When fit properly, edges of the material that fit over the shoe’s tongue should be roughly parallel. The gap should NEVER narrow toward the ankle, the straps shouldn’t bottom out, and there shouldn’t be any significant puckering of material anywhere on the shoe. If any of these conditions apply try a smaller or narrower size.

Shoe too big, foot too small. Shoe too small, foot too big.

Conversely, the uppers should never look like they’re blowing apart. There should be approximately 1 cm of ratchet strap exposed between the Caliper Buckle and the Soft instep pad, and 1 cm of hook-side High Security Velcro showing. If there’s more, try a larger or larger-volume size.


The uppers are snug, with no bunching or puckering of material, with approximately 1 cm of ratchet strap remaining above the Caliper Buckle and 1 cm of scratchy-side Velcro exposed.