Comprehensive Opinions of the New Seismic Deltas
With the 2025 season drawing closer, I wanted to share my opinions on Seismic’s newest wheel offering – the 78.5mm Delta in G-LOC urethane. Being a Seismic team rider, and WDSC championship racer, I have spent a lot of time riding and testing these wheels, including early prototypes. I am so happy with how they turned out. They led me to a pole position at the WRG World Cup in Italy and pole position and a podium finish at the WDSC season-ender in Tennessee. I am looking forward to riding a full season on them this year.
Seismic developed the Deltas to be a thoroughbred race track wheel. Big, soft, fast, yet quick and nimble. To start with the numbers, the wheels are 78.5mm tall and 68mm wide. As for the new G-LOC urethane, you can think of it as blending the performance characteristics of Seismic’s Defcon BlackOps formulas, landing with a blend of high-rebound roll speed with the grip and consistency of a lower-rebound compound. In addition, the core is molded with an advanced new compound that enhances overall rebound and support. Seismic offers two durometers, the yellow 73.5a and green 75.5a. The masterminds at Seismic kept the Delta’s offset proportionally identical to the Alpha’s. This lets us keep a lot of the advantageous characteristics of the Alphas while simultaneously deriving the benefits of a larger wheel. A lot of the questions I’ve gotten regarding these wheels are the difference between the two. With this said, I will first describe my feelings about the wheels overall. Then, I will draw comparisons between the two.
Compared to the Seismic Alphas, my previous go-to wheel, the Deltas have more grip, more roll speed, and basically more of everything. I have found no downsides compared to the Alphas. The Delta has a thick outside lip that supports the wheel when going straight while providing a lot of feedback and consistency when gripping and sliding. The Deltas maintain the grip profile that we loved so much about the Alphas. When I say “grip profile” I am speaking of the way the wheels respond as they approach the limit of grip. The grip threshold has been significantly improved compared with the Alphas, but offer the same feedback and consistency as the Alphas. Some other large wheels have a very “binary” grip profile, – either they are gripping, or they are not. While some riders like this, as they can predict the release, I appreciate the feedback that the Deltas give me. I can also use this feedback to scrub speed, without throwing a full slide.
The Deltas have a very consistent feeling throughout the slide. Some of you may have felt wheels that get icy as you progress in a slide. It is hypothesized that this is because friction-induced heat increases slideability, especially during longer higher-speed slides. This theory has not been tested in a rigorous scientific manner, but the Deltas definitely consistent throughout the slide. This suggests that they may not be as temperature-dependent as other wheels. In the past, I have had the same set of wheels perform differently in hot versus cold conditions, but I have not felt any such difference with the Deltas.
To compare the two durometers, my preference is the yellow 73.5a. I did use the green 75.5a Deltas during a Q1 qualifying lap in Italy, and they gave me a very competitive time. There is not a big performance disparity between the two. I have spent most of my time on the yellow 73.5a Deltas. I like the grip they provide and the slow-down that lets me optimize the braking zones on my local spots. The benefits of the greens are faster straight-line speed and an easier slide initiation. The “grip profile” I mentioned earlier still applies to the greens, though the grip threshold is lower. When maxing out the grip through a corner, the yellows will give you a higher ceiling. If you want to get used to big race wheels, but are hesitant because of the aggressive characteristics synonymous with big wheels, the green Deltas would be a great place to start. The yellows are the my go-to on fast technical tracks as they offer the most braking and grip. The greens offer ample grip and will be the fastest choice on straighter, higher-speed tracks.
After they’re fully broken in, both durometers become quite playful. The yellows leave some thane, and both duros become extremely predictable fast freeride wheels. The thick lip, designed for maximum race support and grip when fresh also keeps the wheel extremely consistent and predictable as it wears. Additionally, the large core contributes to fast roll speeds and lots of support throughout the life of the wheel.
In conclusion, I have been extremely pleased with the performance of the Deltas. I am excited to have them for the entire 2025 campaign. Support your local skate shop and buy a set of Seismic Deltas, or buy them directly from Seismic Skate Technologies. Linked Here
