Adidas Adizero Prime X Strung vs New Balance SC Trainer: Which Super Stack Is Worth It?

Introduction

Some running shoes are sensible. These two are not, and that is exactly why people love them. The Adidas Adizero Prime X Strung and the New Balance SC Trainer are both super trainers with stacks well beyond what racing rules would allow, and both use carbon in one form or another. They are a little bit crazy, a lot of fun, and genuinely hard to choose between. Here is how they compare where it actually matters.

Two Illegally Tall Stacks

The Prime X Strung sits you on a massive 49.5mm of heel stack with 41mm in the forefoot, an 8.5mm drop. In practice, just call it 50mm. The SC Trainer is barely behind at 47mm in the heel and 39mm in the forefoot, with a similar 8mm drop.

The difference in feel is noticeable: on the Prime X Strung you sit right on top of the foam, while the SC Trainer cups your foot slightly as it comes into the midsole.

Uppers: Threaded vs Knit

The two uppers take very different approaches. The SC Trainer uses a stretchy knit material that hugs your foot closely. The Prime X Strung offers a lot more volume, but its threaded Strung upper is structured to give support where you need it and not where you do not.

That volume matters. The original Prime X with the less secure upper felt like standing on stilts, and rolled ankles were a real risk. The Strung version fixes that fit, which made the shoe genuinely enjoyable: one runner logged 20 miles in it during a marathon training block, including a 12 mile race in the middle, and loved the way it bounces along.

Bounce vs Cushion

If raw bounce is the priority, the Prime X Strung wins. The Lightstrike Pro foam paired with the carbon energy rods delivers an almost trampoline-like ride, and the faster you go, the more you bounce.

The SC Trainer is softer and more cushioned. It is the shoe you reach for on long runs, and your legs feel noticeably fresh when you are done. Its rocker geometry rolls you through the stride, whereas the Prime X feels more like launching upward with every step.

Weight and Geometry

The gap is roughly an ounce in women’s sizing: around 7.7 ounces for the Prime X Strung versus 8.7 ounces for the SC Trainer in a women’s 7.5. In men’s sizing it stretches to about two ounces, roughly 9.6 versus 11.4.

The lighter Prime X Strung rewards speed. The SC Trainer trades a bit of weight for that stable, rolling ride.

Stability: Bouncing on Stilts vs Surprisingly Solid

This is where the shoes genuinely split. The Prime X Strung is not a stable shoe, even with the improved upper. It is a shoe you have to balance on while running, and that is part of its character.

The SC Trainer, remarkably, is stable for how tall it is. The Energy Arc setup plays a big role here, keeping the ride controlled despite the enormous stack. If stability matters to you, this is a clear advantage.

Price and Verdict

Then there is the deal breaker for many people: price. The Prime X Strung costs $300, while the SC Trainer comes in at $180, which almost feels cheap by comparison.

On pure race-day performance or maximum bounce, the Prime X Strung takes it. But for the majority of runs, training days, and everything in between, the SC Trainer is simply more usable, and it does not require a second mortgage. If you could only own one, the SC Trainer is the easier answer. At $300, the Prime X Strung is hard to justify as an everyday shoe, though your ankles would certainly get strong.

Conclusion

Both of these super trainers are fun, bouncy, and unapologetically excessive. The Adidas Adizero Prime X Strung is the race-day rocket with unmatched bounce, while the New Balance SC Trainer is the more stable, more affordable, more versatile option for everyday training. For most runners, the SC Trainer earns the win on usability and value.