This is a great shoe, tailor-made for triathletes. Yes, Zoot has had a BOA-enabled option for a few years, but now that big shoe brands are on board, BOA has made some necessary upgrades to their system. I loved the low-profile dial with a rubberized coating for wet-triathlete T2 paws, and I loved the low-seam, highly breathable upper that the BOA system allowed for. It also goes without saying that the tightening system was great at getting the laces super tight, super loose (duathletes take note!) or anything in-between. As I tightened the laces for my first run in the Fuelcore Coast 4, I noticed that the tongue was integrated into the knit upper with eyelets for the laces stitched onto the outside of the upper. With the firm ride described previously, I did not find this shoe to break in and get any softer than its first day running. Don't get bogged down, however, because a firmer shoe like this is not always a negative point. For starters, the upper material is more protective than breathable with added protective welds along with the high wear areas (i.e., lateral forefoot, toe box, eyelets) which is a big advantage for off-road use.

The Fuelcore midsole employs a combination of EVA foam densities to achieve the optimal balance between responsiveness and softness.This midsole feel works well in off-road situations where a bit more stability aids in foot control on uneven terrain. On the tarmac, however, the Dynasoft foam was not forgiving and was especially noticeable while testing on concrete floors over multiple hours. If one limits his or her use to a few hours per outing with this shoe it will wear properly. The Fuelcore Coast 4 upper is flexible, breathable, and minimizes the use of seams to keep the shoe lightweight. The upper is comprised of a pliable knit material on the outside and a smooth liner on the inside. Runners should exercise caution on wet surfaces when wearing the Fuelcore Coast 4. New Balance FuelCore Coast v4 Upper Info

All in all, the New Balance FuelCore Sonic is a great shoe and the BOA system is a huge upgrade over traditional laces. While it’s not a perfect setup yet, I think most triathletes will find the FuelCore Sonic solves a lot of big problems and leaves only a few tiny ones to iron out in later iterations.The comfort these sneakers provide is outstanding. The cushioning and support make them ideal for long walks, workouts, and all-day wear. I've experienced less fatigue and discomfort, even during extended periods of activity. Since there is no tongue, tightening the laces bunches up the fabric in between the lacing eyelets were the tongue should be. This caused initial discomfort as the crinkled fabric poked and pressed into the top of my foot. Each one of our New Balance FuelCell running shoes in the range offers subtly distinct performance characteristics, allowing you to select a model that perfectly matches your running style and goals. For a comfortable, well-cushioned ride – look no further than the New Balance rebel v2 (FuelCell), up for training runs and intense runs alike. Every piece has its iterations. Adding to the collection came with careful consideration, if it wasn’t adding to the racing experience then it had no place. Step forward the FuelCell SC Elite v3, it complements the midsole’s super springy rebounds with the dynamic energy return and stability of our Energy Arc system and a full-length carbon plate. Every aspect of its design is developed to deliver PB-busting race day speed. Meanwhile, the New Balance FuelCell Propel v3 offers exceptional day-to-day performance courtesy of lightweight uppers. If you’re after a versatile all-purpose runner that’s allows you to experience the high-rebound performance of FuellCell technology, then this is the collection for you. Upon unboxing, it’s obvious that the FuelCore Sonic is a very different-looking shoe. Without traditional laces—and the laces’ necessary accoutrements—the shoe resembles something a little more velcro-y than what we’re used to. The good news? With less “stuff”, there’s less opportunity for rubbing and chafing—super important for barefoot running and for keeping the shoe at a thrifty advertised 8.5oz weight with a small dial. The bad news? They’re not exactly fashion-forward, though to be honest, I actually did get a few compliments, so what do I know? The Fit:

Weighing in at 6.1 oz. for women and 7.2 oz. for the men’s version, they are lightweight and agile yet still provide plenty of cushion for runs lasting up to 2 hours. Heading out the door? Read this article on the new Outside+ app available now on iOS devices for members!

The Verdict:

The midsole becomes slightly more rigid in the midfoot and heel where the foot is less flexible. New Balance’s Response performance insole rests on top of the midsole to further enhance the shoe’s responsive and supple feel.