Brooks Addiction GTS 15 review

We're convinced the Addiction GTS 15 from Brooks excels in specific areas that make it a top pick for certain individuals. We think its:

• Ideal for heavier runners seeking substantial support.
• Perfect for those who prefer firmer cushioning and don’t mind added weight.
• Excellent for runners concerned with pronation and outsole durability.

Despite its strengths, we do not recommend the Addiction GTS 15 for certain runners. Those who prefer lighter footwear should steer clear of this model—instead, we suggest the Hoka Gaviota 5, which offers excellent support in a more manageable weight.

We also think that runners who find firmer foams uncomfortable might struggle with the Addiction GTS 15. While firmness does typically enhance support, if you're willing to sacrifice some stability, consider the ASICS Gel Kayano 30 or the Brooks Glycerin GTS 21 as better alternatives.

The Addiction GTS 15, which we purchased and tested in our lab, might not appear breathable at first glance due to its all-black colorway, right?

However, we discovered that it actually offers excellent ventilation. After conducting our eye-catching smoke test, we rated it 4 out of 5—a highly favourable score suitable for all seasons.

Our examination with a light revealed the secret behind its optimal ventilation. The engineered mesh upper features hundreds of tiny holes that effectively allow air and moisture to pass through.

Intrigued by the abundance of ventilation holes, we next examined them under our microscope.

We observed that the mesh cleverly opens slightly every few millimetres with remarkable precision.

Concluding this section, we analysed the sliced upper and found the material to be well padded, providing a perfect balance of comfort and breathability.

We already know that the Addiction boasts good ventilation, but does this compromise its durability? Surprisingly, no.

After our Dremel test, when the sandpaper tip ceased spinning, we discovered only minor damage. This translates to a 3/5 on our durability scale—a very positive result indeed!

The good news continues with the heel padding.

We found only minimal, very reasonable damage after our tests, so we've upgraded its rating to 4 out of 5!

As we flipped the shoe, our focus turned to the hardness of the Blown Rubber outsole.

The outsole coverage is impressive. We also discovered countless cutouts that enhance the shoe's longitudinal flexibility.

We pressed our Shore C durometer and recorded a measurement of 89.4 HC, indicating its robust nature. This shoe is just built like a tank.

The high hardness of the outsole suggested promising results for our final Dremel test.

True to our expectations, after the Dremel concluded its work, we observed a minor 0.6 mm indentation, indicating an excellent potential for longevity.

We had already proven the fantastic durability of the outsole, but when we measured its thickness with our vernier callipers, we were astounded. At 6.0 mm, it's one of the thickest outsoles we've ever tested in our lab, especially notable since it's made of hard rubber, not a super-soft blend like the ASICS Cumulus 26.

This suggests that the outsole will likely last a veeeery long time. However, we also discovered that such a thick, hard outsole can mute the ride, sometimes making it feel like a brick.

When we first handled the Addiction GTS 15 in our lab, we anticipated it would tip the scales at well over 10 oz. However, at 12.5 oz or 353g, it feels like too much.

These shoes are HEAVY, and we feel they are only suitable for those willing to sacrifice lightness for durability.

We recently observed that the Addiction GTS 15 is packed with more foam than before. Now, it's essential to assess in the lab Brooks' claims by measuring its stack.

The shoe features a heel height of 36.5 mm, which offers substantial cushioning. However, it's important to note that not all of this height is due to foam—as we've previously demonstrated, much of it includes the hard rubber outsole... and the insole.

The forefoot cushioning is notably thinner than the heel, measuring just 24.4 mm. This design suggests us that the shoe is specifically tailored for heel strikers, offering a clear indication of its intended user base.

As you might guess from our previous tests, this shoe has a substantial drop. Brooks reports it as 12.0 mm, and our measurements show 12.1 mm. This minimal discrepancy is truly impressive, as we typically encounter variances of 3 or 4 mm.

With its high drop and reduced cushioning in the forefoot, it's clear that this motion control shoe is made for those who strike the ground with the rearfoot.

The insole, at 5.6 mm, is slightly more cushioned than what we typically find in running shoes. However, it's important to note that this shoe is far from being an average daily trainer.

Two words fully describe this shoe—heavy and firm. We've discussed its weight, and now it's time to evaluate its foam.

During our test runs, the BioMoGo DNA foam felt exceptionally firm, and with a measurement of 30.1 HA on our durometer, our findings confirm this. Yet, we're not taken aback by this result. A firm midsole is crucial for a motion control shoe as it provides essential support for those with severe pronation issues.

To evaluate the Addiction GTS 15's performance in extremely cold conditions, we placed it in a freezer for 20 minutes before conducting another test with the durometer. Following the freeze, it showed a change of 14.9%, which is outstanding.

The Addiction GTS 15 may resemble a brick, but its stability is unmatched. We can't recall another shoe that offers such a robust sense of stability for heel strikers.

This remarkable stability is also partly due to Brooks' GuideRails technology.

Essentially, these are two hard plastic pieces embedded into the sides of the heel, guiding the feet forward and preventing collapse—and they certainly do their job!

This shoe is geared specifically to those with severe pronation issues. Given this, it was no surprise that bending or twisting the Addiction GTS 15 proved incredibly challenging. Consequently, we awarded it a top score of 5/5 for its massive rigidity.

Naturally, a shoe built for substantial stability isn't expected to be flexible, yet this one is exceptionally rigid, akin a carbon-plated model.

We anticipated a similar result in this test, yet we were surprised. Instead of a rigid, steel-like heel counter, Brooks opted for a more balanced approach akin to daily trainers, with a moderate stiffness rating of 3/5.

This design choice enhances comfort, particularly for those with sensitive heels, and seems wise given the shoe's sufficient stability.

We confirmed the presence of reflective elements, though we found them only in the toebox and their visibility is less than impressive.

Our initial observation was thoroughly confirmed when we measured a remarkably wide 99.9 mm at the heel—providing a massive, stable landing platform that distinctly stands out from average shoes.

This expansive design offers exceptional support for rearfoot strikers!

The Addiction GTS 15, obviously lacking a plate, had a moderate performance in our 90-degree bend test with a force of 30.1N. It's essential for the shoe to maintain some flexibility longitudinally, given its extreme rigidity in torsional tests—this flexibility is key for enhancing comfort.

Remember, while it's critical for a supportive shoe to control lateral forces, having a sole that can flex longitudinally poses no issues in that regard and enhances the overall comfort for daily runs and various activities.

We repeated the test after chilling the shoe for 20 minutes, mirroring our midsole softness assessment. 

The outcome showed only a 12.5% increase in stiffness, confirming that the shoe retains considerable flexibility.

Our initial measurement in the toebox—always taken at the widest part—showed that the Addiction GTS 15 spans an accommodating 97.4 mm in our US 9 (D) pair, comfortably fitting most foot sizes.

Moreover, it's quite impressive that Brooks offers this model in a full range of widths: Narrow (B), Regular (D), Wide (2E), and Extra-Wide (4E). There are only a handful of models on the shelves offering such a variety of widths!

We took a second measurement in the big toe area, and it registered slightly lower than expected at 75.8 mm. However, for those needing extra room in the toe cap—as we mentioned earlier—this shoe is available in 2E and 4E sizes.

We shifted our focus to the tongue area and noted that the tongue is not gusseted. However, for £150, we find this acceptable, though not ideal.

The tongue is exceptionally comfortable, featuring a single thick slab of foam measuring 7.5 mm.

We've found that it's enough to protect the instep, even when tightening the laces tightly, without being excessively padded.

In line with most Brooks shoes, we didn't find a heel tab on the Addiction GTS 15.

The insole, dubbed by Brooks as Ultimate Sockliner, features a contoured design that cradles the feet, much like a bathtub, enhancing stability. We've also observed that it's removable.

We confirmed the presence of reflective elements, though we found them only in the toebox and their visibility is less than impressive.