ShoesBrooksGlycerin Flex

Brooks

Brooks Glycerin Flex

Brooks Glycerin Flex. 35.2mm stack, 264g. Retailer specs verified on Running Warehouse.

PR Run Verified
Soft trailsLong ultrasDaily training

PR Run scores

Grip3/5
Cushion5/5
Protection2/5
Durability3/5
Versatility3/5

PR Run derived fit scores

79Great

100-miler readiness

Will this shoe survive a hundred-mile night? 35.2 mm stack, cushion 5/5

78Great

Descent tolerance

Does it save your toenails on long descents? 25.9 mm forefoot, heel counter 2/5

100Elite

Swelling room

Room to grow when your feet swell? 25.7 mm toebox height

78Great

Grit resistance

Does dust stay outside the shoe? 4 BR breathability

23Weak

Hot-day comfort

How well does it breathe in heat? 4 BR / ?% drying

64Solid

Achilles-friendly

Kind to a cranky achilles? 9.3 mm drop, heel counter 2/5

Full specs

Drop

9.3 mm

Heel stack

35.2 mm

Forefoot stack

25.9 mm

Weight

264 g

Plate

No

Waterproof

No

Lab measurements

MeasurementValue
Traction (CoF)0.60
Breathability4 BR
Flexibility12.2 N
Torsional rigidity12.90 Nm
Heel counter2/5
Energy return49.1 %
Shock absorption143 SA
Midsole softness39.9 HA
Outsole thickness3.1 mm
Tongue padding3.6 mm
Insole removableYes
Insole thickness4.5 mm
Reflective elementsYes

Lab numbers from RunRepeat. Sources.

Fit intelligence

Toebox width

Narrow toebox (69.1 mm vs 96 mm median)

Toebox height

Category-average height (25.7 mm vs 25 mm median)

True to size.

Fit numbers from the lab. Swell guidance: foot care.

Questions before you race

Is the Brooks Glycerin Flex good for 100-mile races?

Great. 35.2 mm stack, cushion 5/5. 100-miler readiness score 79/100.

Does the Brooks Glycerin Flex fit wide feet?

No. Toebox is 69.1 mm which is narrow. Look elsewhere if you need width.

What is the drop on the Brooks Glycerin Flex?

9.3 mm, with a 35.2 mm heel stack and 25.9 mm forefoot.

Is the Brooks Glycerin Flex good on wet rock?

Traction coefficient of friction on wet lab surface: 0.60. Elite grip on wet rock.

Manufacturer specs · Retailer listing

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Image: Running Warehouse product photo

Specs: manufacturer. Verified Sep 4, 2026.

Report inaccurate data: hi@pr.run. Data sources.

Brooks Glycerin Flex Review, Specs, and Fit (2026) | PR Run