Our verdict

The Brooks Glycerin 20 GTS enhances the tried-and-true features of its neutral sibling with special consideration for overpronators. With substantial DNA LOFT v3 cushioning and a GuideRails system, it ensures a stable ride. While its cost may be on the steeper side and its weight could limit speedwork, we see it as a reliable companion for easy and moderate-paced runs.

Pros

  • Excellent for heel strikers
  • Provides protective cushioning
  • Offers comfort on easy running days
  • Ensures smooth transitions
  • Features a secure heel counter
  • Comes with a soft, stretchy upper
  • Good breathability
  • Effective GuideRails system

Cons

  • Midsole may feel overly firm for some runners
  • Pricier than many alternatives
  • On the heavier side

Audience verdict

90
Superb!

Who should buy

In our view, the Brooks Glycerin GTS 20 stands out as an excellent stability shoe, tailored to meet the needs of:

  • Runners looking for a versatile shoe with massive support in both the heel and midfoot areas.
  • Brooks enthusiasts aiming to add a daily stability trainer to their collection.
  • Heel strikers who want a well-cushioned stability running shoe and don't mind the £170 price tag.

Brooks Glycerin GTS 20

Who should NOT buy

If you're on the hunt for a lightweight yet stable running shoe, the Glycerin GTS 20 might not be your best bet based on our lab tests. Consider a lighter and more affordable option like the Saucony Tempus.

In our view, this shoe might also not be the best choice for midfoot or forefoot strikers due to its significant heel-to-toe drop. For runners who strike with this part of their foot, a flatter shoe with stability features, such as the Hoka Gaviota 4, is a more reasonable choice.

Brooks Glycerin GTS 20

Breathability

Even though the engineered mesh upper that Brooks incorporates doesn't offer the ultimate ventilation, we gave it a respectable 4/5 in our breathability test. 

The results show that even in warmer climates, the shoe maintains its cool. Yet an added advantage of not being overly breathable is that it can keep your feet warm during winter when paired with thick socks.

Upon testing with light, it's clear that Brooks prioritized ventilation in the toe box. This strategy is one of the most effective for maintaining good airflow and ensuring adequate ventilation.

Brooks Glycerin GTS 20 microscope

This focus on ventilation becomes even more apparent under a microscope, right? We strive to examine the ventilation holes as closely as possible, and we seem to have succeeded in that.

Brooks Glycerin GTS 20 airflow

Test results
Glycerin GTS 20 4
Average 3.8
Compared to 209 running shoes
Number of shoes
1
Breathability
5

Durability

Toebox durability

Our initial impressions of a shoe often come from the feel of it in our hands, before we even start the tests.

For the Glycerin 20 GTS, it was evident early on that the upper might not be sturdy at all. Of course, we always hold out hope that we might be surprised.

Regrettably, our concerns were confirmed once we the Dremel met the upper. The engineered mesh from Brooks couldn't withstand the pressure—it disintegrated instantly.

With such disappointing results, we had no option but to assign the Glycerin 20 GTS a score of 1/5.

Brooks Glycerin GTS 20 Toebox durability
Test results
Glycerin GTS 20 1
Average 2.3
Compared to 143 running shoes
Number of shoes
1
Toebox durability
5

Heel padding durability

The trend continues with the heel counter. When we subjected it to the same force using the Dremel, the results were equally disappointing.

Consequently, we awarded it a score of 1/5 as well.

Brooks Glycerin GTS 20 Heel padding durability
Test results
Glycerin GTS 20 1
Average 3.1
Compared to 139 running shoes
Number of shoes
1
Heel padding durability
5

Outsole hardness

Daily training shoes typically register hardness values above 75 HC, so we were genuinely surprised when we obtained a measurement of only 69.4 HC.

Softer rubber often leads to premature wear in the outsole, but could this be the case here?

Brooks Glycerin GTS 20 Outsole hardness
Test results
Glycerin GTS 20 69.4 HC
Average 80.3 HC
We use an average of four tests. The photo shows one of those tests.
Compared to 260 running shoes
Number of shoes
55.5 HC
Outsole hardness
92.8 HC

Outsole durability

Luckily, that doesn't seem to be the case. We put the Brooks rubber to the test again with the Dremel, and it held up quite well.

We were only able to create a 0.49 mm indentation in the outsole, which, by any measure, is an impressive result.

Brooks Glycerin GTS 20 Outsole durability
Test results
Glycerin GTS 20 0.5 mm
Average 0.9 mm
Compared to 121 running shoes
Number of shoes
0.0 mm
Outsole wear
2.0 mm

Outsole thickness

At a solid 3.3 mm, it appears there's sufficient rubber, which should hold up for as long as the foam maintains its cushioning.

Brooks Glycerin GTS 20 outsole

There's some exposed foam in non-important parts, yet nothing to worry about.

Brooks Glycerin GTS 20 Outsole thickness
Test results
Glycerin GTS 20 3.3 mm
Average 3.2 mm
Compared to 279 running shoes
Number of shoes
0.0 mm
Outsole thickness
6.6 mm

Weight

A significant disappointment with this shoe is its excessive weight. The scale reveals a 10.9 oz (309g) reality for a US size 9—just too much by contemporary standards.

We are eagerly looking to the next release, hoping that Brooks will take the necessary steps to bring this shoe's weight under the 10 oz benchmark.

Brooks Glycerin GTS 20 Weight
Test results
Glycerin GTS 20 10.90 oz (309g)
Average 9.35 oz (265g)
Compared to 280 running shoes
Number of shoes
5.26 oz (149g)
Weight
12.56 oz (356g)

Cushioning

Heel stack

Brooks took a conservative approach here, providing a generous amount of foam in the heel. They are aware that most overpronators are heel strikers who need extra cushioning in this area.

With 36.5 mm of nitrogen-infused DNA LOFT v3, there's no possibility of feeling the ground through this shoe.

Brooks Glycerin GTS 20 Heel stack
Test results
Glycerin GTS 20 36.5 mm
Average 33.5 mm
Compared to 279 running shoes
Number of shoes
7.6 mm
Heel stack
42.7 mm

Forefoot stack

This explains why the forefoot cushioning is fairly typical, measuring at 25.5 mm. Not many forefoot strikers are likely to single out this shoe as their top choice.

Brooks Glycerin GTS 20 Forefoot stack
Test results
Glycerin GTS 20 25.5 mm
Average 24.9 mm
Compared to 279 running shoes
Number of shoes
7.6 mm
Forefoot stack
35.8 mm

Drop

This results in an 11-mm heel-to-toe drop, which is 1 mm away from the official numbers provided by Brooks (10 mm).

This slight discrepancy is perfectly acceptable.

Brooks Glycerin GTS 20 Drop
Test results
Glycerin GTS 20 11.0 mm
Average 8.6 mm
Compared to 279 running shoes
Number of shoes
-0.8 mm
Drop
16.1 mm

Insole thickness

Brooks understands that the Glycerin line needs to epitomize comfort, and that means including a plush, thick insole.

Ours measurement came at 5 mm, which seems solid to us.

Brooks Glycerin GTS 20 Insole thickness
Test results
Glycerin GTS 20 5.0 mm
Average 4.4 mm
Compared to 275 running shoes
Number of shoes
1.5 mm
Insole thickness
7.3 mm

Midsole softness

Note: a low durometer measurement equals a soft material, whereas a high measurement means it's firm.

DNA LOFT v3 is a nitrogen-infused midsole, making it lighter and more responsive than the standard DNA LOFT.

But don't anticipate a super-plush experience like in a Nike Invincible 3. With a softness measurement of 23.4 HA, this foam delivers a balanced, comfortable feel that's well-suited for stability-focused shoes like this one.

Brooks Glycerin GTS 20 Midsole softness
Test results
Glycerin GTS 20 23.4 HA
Average 21.3 HA
We use an average of four tests. The photo shows one of those tests.
Compared to 207 running shoes
Number of shoes
8.5 HA
Midsole softness (soft to firm)
41.5 HA

Midsole softness in cold

Note: a low durometer measurement equals a soft material, whereas a high measurement means it's firm.
Brooks Glycerin GTS 20 Midsole softness in cold

Difference in midsole softness in cold

Following a 20 minutes exposure to freezing temperatures, the foam continues to strike a very balanced note—it's neither too soft nor too firm. Our subsequent round of measurements yielded a 28.9 HA value.

This represents a 23.5% increase, a result that aligns nicely with the average. It's precisely what we anticipate from a foam based on EVA. Things could indeed have been worse...

Brooks Glycerin GTS 20 Midsole softness in cold
Test results
Glycerin GTS 20 23.5%
Average 25.7%
Compared to 206 running shoes
Number of shoes
0%
Difference in midsole softness in cold
100%

Stability

Lateral stability test

Living up to its reputation, the Brooks Glycerin GTS 20 indeed proves itself as a stability shoe, and we're absolutely delighted to confirm that it truly delivers in this aspect!

Brooks Glycerin GTS 20 GuideRails

The renowned GuideRails system that Brooks deploys across a range of stability shoes is nothing short of miraculous for overpronators.

Torsional rigidity

Stability in any shoe necessitates at least a moderate level of torsional rigidity, and the GTS 20 confidently embodies this trait. Our assessment scores it a solid 4 out of 5, a rating that unquestionably surpasses the average result.

Test results
Glycerin GTS 20 4
Average 3.2
Compared to 258 running shoes
Number of shoes
1
Torsional rigidity
5

Heel counter stiffness

The rigidity of the heel counter plays an essential role too. Despite the potential discomfort some might feel with a firm heel counter, it becomes almost indispensable in stability-focused shoes. It helps prevent the shoe from lateral collapse, especially crucial for heel strikers.

In the GTS 20, we've discovered a built-like-a-tank 5/5 heel counter. While we might have preferred a bit more flexibility, we comprehend and support Brooks' whole-hearted commitment to this design, being their ultimate goal to ensure top-tier stability for heel strikers.

Test results
Glycerin GTS 20 5
Average 2.7
Compared to 242 running shoes
Number of shoes
1
Heel counter stiffness
5

Midsole width in the forefoot

An additional stability-boosting tactic often employed by brands involves expanding the shoe's landing base. Quite intuitive, isn't it?

Brooks has opted for an ultra-wide design in this case. With a forefoot width of 119.5 mm, it ranks among the widest shoes we've ever analyzed in our lab!

Brooks Glycerin GTS 20 Midsole width in the forefoot
Test results
Glycerin GTS 20 119.5 mm
Average 113.5 mm
Compared to 280 running shoes
Number of shoes
100.5 mm
Midsole width in the forefoot
126.5 mm

Midsole width in the heel

This concept extends to the heel as well. With every stride, the widened shoe naturally provides stability. Our measurement for the heel came in at 98.9 mm, surpassing the usual standards.

Brooks Glycerin GTS 20 Midsole width in the heel
Test results
Glycerin GTS 20 98.9 mm
Average 90.3 mm
Compared to 280 running shoes
Number of shoes
74.9 mm
Midsole width in the heel
106.6 mm

Flexibility

Stiffness

High torsional rigidity is almost a given for any stability shoe, but this isn't necessarily the case when it comes to stiffness. Indeed, it wouldn't make sense for a shoe designed for daily runs to be super stiff.

In alignment with this, our measurement for the 90-degree bend test came in at only 24.9N, which falls below the average result. This explains why the shoe provides such a comfortable ride during easy aerobic runs.

Test results
Glycerin GTS 20 24.9N
Average 29.4N
We use an average of four tests. The video shows one of those tests.
Compared to 262 running shoes
Number of shoes
2.2N
Stiffness
94.4N

Difference in stiffness in cold

After placing the shoe in the freezer for 20 minutes and repeating the test, we found that it became stiffer. However, this change was consistent with the results we've seen from other shoes tested under the same conditions.

The increase we measured in the lab is a substantial 41.2%, a change that you can clearly feel underfoot. Yet this is a typical outcome that we anticipate from a shoe with an EVA-based foam.

Test results
Glycerin GTS 20 41.2%
Average 37%
Compared to 262 running shoes
Number of shoes
0%
Difference in stiffness in cold
148%

Size and fit

Internal length

The shoe aligns neatly with Brooks' size charts, which indicate a US size 9 should measure 270 mm.

Our measurement came in at 270.7 mm, close enough to confidently say the shoe is true to size.

Brooks Glycerin GTS 20 Internal length
Test results
Glycerin GTS 20 270.7 mm
Average 269.0 mm
Compared to 143 running shoes
Number of shoes
259.9 mm
Internal length
277.6 mm

Toebox width at the widest part

When we shifted our attention to the toe box, we didn't find the shoe particularly spacious or restrictive—it just felt average to us.

This impression was confirmed by our measurements, which showed a maximum width of 97.9 mm, firmly in the average range.

Brooks Glycerin GTS 20 Toebox width at the widest part
Test results
Glycerin GTS 20 97.9 mm
Average 98.3 mm
Compared to 280 running shoes
Number of shoes
89.5 mm
Toebox width at the widest part
109.1 mm

Toebox width at the big toe

Nonetheless, we found our toes enjoying a touch more wiggle-room than expected. This extra space was substantiated by a 78.9 mm measurement.

Brooks Glycerin GTS 20 Toebox width at the big toe
Test results
Glycerin GTS 20 78.9 mm
Average 78.1 mm
Compared to 154 running shoes
Number of shoes
60.4 mm
Toebox width at the big toe
92.5 mm

Tongue: gusset type

The lack of a gusseted tongue in this shoe disappoints us, especially given its £170 price tag.

While this doesn't pose major problems, it could affect the perfect lockdown some of us might seek. For a more secure fit, we'd recommend considering the Hoka Arahi 6 as an alternative.

Brooks Glycerin GTS 20 Tongue: gusset type
Test results
Glycerin GTS 20 None

Comfort

Tongue padding

Brooks designers likely decided a gusset wasn't necessary for the tongue because of its massive padding. With a thickness of 9.9 mm, it's like a pillow for your instep, enhancing a snug lockdown.

Brooks Glycerin GTS 20 Tongue padding
Test results
Glycerin GTS 20 9.9 mm
Average 5.6 mm
Compared to 277 running shoes
Number of shoes
0.5 mm
Tongue padding
14.2 mm

Removable insole

The GTS 20 welcomes the use of custom orthotics or third-party insoles.

Brooks Glycerin GTS 20 Removable insole
Test results
Glycerin GTS 20 Yes

Misc

Reflective elements

Finally, it's quite disappointing that a £170 shoe like this lacks reflective elements, a trend we're seeing in many brands.

Brooks Glycerin GTS 20 Reflective elements
Test results
Glycerin GTS 20 No