Dynafit Ultra 100 (2023) Review: An Ultra Update

What You Need To Know

The Intro

TAYLOR: As an optimist, I don’t often find myself with low expectations. In fact, it’s quite the opposite. I know, low expectations can guard you from utter disappointment, while high expectations tend to set you up for it — I get that. Many of us here at Believe in the Run are already familiar with the searing pain of trying a new shoe for the first time, brimming with excitement, only to be destroyed by poor performance (looking at you, Saucony Endorphin Trail). Perhaps we give our running shoes just a little bit too much emotional weight.

On the other end, low expectations can also lead to unnecessary praise when those modest goals are surpassed.

A while back, the Believe crew received our first shipment of Dynafit shoes. Both the Dynafit Ultra 100 and Alpine are relatively unknown on the larger scene, but they surpassed our predictions in the performance department. Admittedly, I didn’t expect anything positive, but here’s how my runs went:

• Run 1: Surprised
• Run 2: Still a little shocked
• Run 3: This might actually be a shoe to put in the rotation

Many others have had the same experience. The biggest negatives of the shoe were the weight and some minor kinks in the ride, but overall a surprisingly good showing.

After a couple of years of feedback and testing, Dynafit has now come out with the second iteration of its most popular trail shoe. The premise of the design is to bridge the gap between comfort and performance. The update brings a more thoughtful design that stays true to Dynafit’s principles as a mountain-oriented company. What’s new? Basically everything. Dynafit went for a lighter, more nimble design with all new materials throughout.

For whatever reason, I found myself in the same boat as before. Even though I enjoyed my experience in the first edition of the Dynafit Ultra 100, I didn’t expect a lot from number two. I guess that just set me up to be surprised yet again.

Also, Dynafit didn’t change the name of the Ultra 100 at all, so we’ll be referring to it as the Dynafit Ultra 100 (2023) for clarity’s sake.

The Good

TAYLOR: Dynafit’s cyclone approach to updates works wonders for the Ultra 100 (2023)’s design. From top to bottom, this is an all-around better shoe. It’s simpler than the first version and makes strides in both comfort and performance.

One of the most notable aspects of the Ultra 100 (2023) is its fit. Even though this shoe is meant to go the distance, it can also escort you through any terrain. For a moderate/high-stack shoe (32/26 mm for a 6 mm drop), this one can ramble on technical trails at a high level. The combination of a durable engineered mesh, simple yet effective overlays, and supremely-shaped heel works together to create a comfortable and effective lockdown throughout the foot. I had no movement to speak of, even in the typical problem areas like tight corners, rocky/rooty terrain, and speedy descents.

That heel is worth coming back to talk about. Not only is it highly cushioned for comfort and fit, but it also has a nice structure and stirrup-like tech, which Dynafit coins as a Heel PreLoader. It’s a fairly simple strap around the crest of the heel bone to keep the heel strapped in. For trail shoes, this is one of the most crucial points of lockdown and Dynafit has its number. Locked and loaded, baby.

Security is also enhanced by the strategically padded lay-flat tongue. The underside is lined by a soft microfiber that helps with comfort and staying put. A traditional lacing system with a protective lacing chain guard is dually appreciated for both lacing protection and for keeping debris out.

Keep in mind that the fit is slim-ish throughout the shoe, which aids in security. The Dynafit Ultra 100 (2023) has a medium-width toe box. To the average foot, it won’t feel wide or super slim. Even though the fit is slightly more accommodating in the forefoot than the previous version, the Dynafit Ultra 100 is still fitted to have a teensy bit of wiggle room while maintaining an appropriate width for technical trail running.

This time around, the EVA-based midsole feels both lighter and more responsive. It falls into the medium firm range but feels appropriately cushioned for the long haul. Some of the closest comparisons are shoes like the La Sportiva Cyklon, Norda 001, Speedland SL:HSV, Altra Mont Blanc, Topo Athletic MTN Racer 2, and Brooks Catamount 2, where protection and comfort come first, followed by the thought that “Oh yeah, these do have a touch of responsiveness.” This falls into the range of my favorite densities of foam for true mountain romping.

As for the general shape, the midsole feels slightly rockered, giving solid foot control on the more technical stuff and a smoother ride on the gentler terrain. The base of the shoe is slightly wider than the footbed too. In combination with a firmer midfoot and heel, there’s some naturally built-in stability within the Dynafit Ultra 100.

Another component that Dynafit has no compromise on is a full-coverage Vibram Megagrip outsole. Numerous wide 4.5 mm chevron-style lugs dug into the earth nicely. On each lug are multiple tiny bumps to provide more surface area and fine-tuned grip. There’s really not much better when it comes to outsole performance across all categories of grip and durability. Recently, Megagrip outsoles have even felt a little more flexible and able to move with the midsole no matter the demand.

One last note is that even though the scale weighs my US M10.5 in at 12 oz (340 g), the Dynafit Ultra 100 feels a lot lighter on foot.

The Bad

TAYLOR: From an American’s perspective, even though the fit is more generous than the first Dynafit Ultra 100, it still isn’t in the accommodating category. It still has a fitted feel that I really enjoy for a variety of trails, but not quite enough room that I’d want it for long ultra races. For comparison, it’s close to the Hoka Challenger ATR 7, La Sportiva Karacal, and La Sportiva Cyklon. It’s simply geared more toward technical performance than comfort — which isn’t a bad thing.

The length has been an issue for Dynafit as well. It was much easier to find the optimal fit this time around because of the company’s efforts to be more consistent. My test size was a half size bigger than my typical running shoe size. This was a comfortable length for the daily runs; however, I would prefer a full size up for long runs and ultra-distance races.

Dynafit Ultra 100 (2023) Conclusion

TAYLOR: I find myself having similar feelings at the end of this review as I did with the first iteration of the Dynafit Ultra 100, but it’s important to note that performance is leagues better on all fronts. I’m positively surprised by what the new Dynafit Ultra 100 (2023) has to offer. It’s an offering that many trail runners would be happy with.

Even though you might need to try a couple of sizes to see what fits best, the Dynafit Ultra 100(2023) really is a solid go-anywhere-any-distance type of shoe. Overall, if you enjoy well-fitted and medium-firm trail shoes, this would be a great grab for anything from a daily trail grinder to a technical ultra racer

You can pick up the Dynafit Ultra 100 (2023) for $169 from Dynafit’s website using the buttons below.

Want to learn more about how our review process works? Check out this guide.