The Altra 3-Sum 1.5 is a zero-drop, natural triathlon racing shoe designed for a neutral foot motion.



The Altra 3-Sum 1.5 allows you to get the most out of your feet even with the fatigue of a swim and a bike. Designed to meet the needs of the competitive triathlete, this racing shoe features a zero drop platform to encourage an efficient stride, with enough cushion to keep your tired feet happy to the finish line. Featuring a seamless upper for sockless wear, and a quicklace system that allows you to fly through T2. An anatomical fit allows for toe splay without sacrificing security.

Model Number:

Weight: 8.2 oz (size 9)

Stack Height: Heel (13mm), Forefoot (13mm)

Available Widths: D=Medium

How It Fits (based on width D)

  • Sizing: Standard running shoe length
  • Heel: Medium to wide
  • Midfoot: Medium volume
  • Forefoot: Wide
  • Toebox Height: Low
  • Arch Structure: Medium to low
  • Shoe Shape: Semi-Straight


The 3-Sum 1.5 is a minimum featured, minimum neutral shoe intended for training and racing.


  • A-Bound is a recycled, environmentally friendly midsole compound for resilient underfoot protection.


  • EVA midsole foam for durable cushioning.
  • Natural Ride System (NRS) design includes a more natural, foot-shaped last, zero millimeter heel to toe drop, and metatarsal-specific shapes in the outsole to assist in proper foot mechanics and allow for more natural foot movement.
  • Natural Foot Design follows the natural shape of the foot for ultimate comfort.


  • Quick Dry Air Mesh wicks water away from your foot while remaining light and breathable.
  • Support Insoles are 5mm-thick removable insoles designed for runners needing more traditional support and a molded arch.
  • Seamless Upper reduces irritation and provides next-to-foot comfort.
  • Pull Tabs allows for quick entry with a single-handed pull.
  • Asymmetrical Lacing Design follows the shape of the foot for improved fit and feel.
  • Strobel Last with the upper stitched to full length fabric for a comfortable underfoot feel.


  • SpeedPod Outsole follows the natural construction of the human foot for maximum flexibility and a responsive ride.
  • Blown Rubber offers lightweight traction, flexibility, and a responsive ride.
  • Drainage Holes in the heel and forefoot allow excess water to exit the shoe.

Footwear Performance Characteristics

Pronation Control: What's This?

  • Neutral
    • Min
    • Mod
  • Support
    • Min
    • Mod
    • Max
  • Motion Control
    • Mod
    • Max

Heel-Toe Offset (mm): What's This?

  • 0
  • 1-2
  • 3-4
  • 5-6
  • 7-8
  • 9-10
  • 11+

Stack Height:

  • Barefoot
  • Minimal
  • Low
  • Medium
  • High
  • Maximal


  • Road
  • Road-Trail
  • Hard Trail
  • Varied Trail
  • Soft Trail

Shoe Type:

  • Premium
  • Standard
  • Performance
  • Racing

Customer Reviews

Comments: The lacing system in these shoes is very badly designed. When the laces are tightened, the tongue bunches up around the lace holes and causes blisters on the tops of my feet, and cuts off the circulation in my feet even with socks on. I have worn these shoes only for short runs (3-5 miles) because my feet couldn't take any more. Going back to Merrell for now.
From: Anonymous. May 4th 2015

Comments: Update from previous comment: now have two runs in these (8 miles) and love them. fit is slightly snugger the the Altra One (toebox seems a little lower), and although I have never been a fan of yankz or other elastic laces, these work ok (don't loosen too much). The shoes feel slightly more flexible than the Altra One, which is a good thing to me, but still firm ride with sufficient cushion that my feet don't feel beat up like they do with more extreme minimal shoes. These are not minimal, to be clear, but are one of the best I have used at permitting natural foot motion with some foot protection. So far so good.
From: Dogrunner. July 29th 2014

Comments: Received mine last week. I did not like the fit and feel of the Altra One2 (my main road shoe has been the Altra One), so I am hoping the 3-sum 1.5 will serve as well. I have not worn the 3-Sum 1.5 yet but wanted to confirm the sizing appears to be about the same as the original Altra One. Sole looks identical from the outside. The shoe feels good on my feet, fit is good, not squishy feeling like the One2 (if you like more cushioning you might prefer those); now waiting for an opportunity to use them!
From: Dogrunner. July 21st 2014