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Groundwork Flyby Tight

Regular price $88 Sale price $62
Unit price  per 

Groundwork Flyby Tight

M's Groundwork Flyby Tight in Midnight

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run everywhere guarantee
free shipping over $50
free 60 day exchanges
Aron wears size M and is 5'11" Formfitting, 28.5" inseam, 
Size Chart

Durable stretch nylon, a double-lined front panel — for extra protection and modesty — and four pockets make the Flyby Tight the go-to for any distance in colder conditions. Read more

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All about the Groundwork
Breathable, moisture-wicking fabric provides light compression with an unnoticeable feel in stride

Won't sag out
Durable nylon stretches with you and retains its shape while resisting odors

Secure, unfussy fit
A minimal waistband with internal drawcord stays snug + comfortable

Extra support
Double-lined fabric in the front panel (from hip through thigh) for added protection + warmth

Pocket it
Two deep side pockets can easily accommodate the largest phone sizes plus case and minimize any movement or bounce

Keep it separated
An internal waistband pocket can stash card/cash or key

Versatile storage
Back dual-sided-entry stretch pocket can store nutrition + dual as a pass-through for a shirt

Zipperless ankle design
Articulated ankle shaping and a laser cut hem allow easy on/off + adaptable wearability to roll up the tight when warm

Stay seen
Integrated hi-vis reflective tape along the side seams along with Janji signature blue reflective logo and “watermark” on back increases visibility in low light

materials + specs

Groundwork Knit
68% nylon, 32% spandex

243g / 8.6oz (M’s Medium)

Garment made in Vietnam

Fabric Callout


High-performance, moisture-wicking stretch nylon with durable support. Explore more behind our tights and sports bra fabric.



Groundwork Knit is made using a premium grade nylon that has a significantly tighter woven filament than standard synthetics. Tighter filaments mean less microfiber shedding in the wash-cycle, plus greater durability of the garment (longer lifespan, more wearing).

Groundwork Knit fabric is also bluesign® certified meaning it is free from harmful chemicals and is fabricated in a way that meets a high environmental standard.

Learn more about our sustainable initiatives here.


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Customer Reviews

Based on 61 reviews
Rusty M
Wear it for: Running
Product Fit: Spot-on
Height: 5'10" to 6'0"
Usual Size: S
Size Purchased: S
Awesome Fit

Among the several running tights I’ve purchased from Janji the past couple years, this current model seems to be the best fitting; not too small, not too big. Pocket storage is amazing and looks like they will accommodate many items. I tend to carry a minimal amount of items but usually chapstick, a bit of nutrition, and key fobs during running races. Btw, the ‘Mountain’ color is a fun color, a definite departure from the usual blacks & grays.

Joshua Ray
Love these

Love the look of these and the fit. The only downside is the drawstring cord is super stretchy and a bit hard to get tightened and tied.

Joshua Rosen

M's Groundwork Flyby Tight in Midnight

Javier Prieto
Love these.!!

I can’t say much other than I love love these tights- I only wish I had bought a size smaller.

Paul Sailer
The pockets!!

I'm a big believer in having plenty of pockets available while on my runs and the Groundwork Flyby Tights seriously deliver! I don't think I've ever seen men's tights with more than just a back zipper pocket. The side pockets are nice and deep, so I can cram a lot in there and be certain I'm not going to lose any of it, while the rear pocket is great for gloves and would probably hold an extra layer securely too. The interior front pockets are great for keys and small gels, though I'm not sure about putting something like a wallet in there - I tested with a credit card and it seemed like it would poke my hip (fortunately, those side pockets had plenty of space!).

The fit is quite different than other tights I've had. They're definitely a bit more compressive without being too tight. Despite the compression, they are actually easier to get off than my looser fitting tights. They also sit differently on my waist - much lower on the back than I'm used to. It did initially give a sensation like others have described of sliding off my butt, which was definitely a bit awkward at first. But they stayed securely in place there and by my second run with them it felt totally normal.

The warmth is great too! They kept me cozy and comfortable on a cold day in NYC, yet were not too warm that I got uncomfortable on a warmer winter day.

I really appreciate the double-lined front panel as well. I felt comfortable running shorts-less without worrying about weirding folks out. Definitely a necessity for tights with so many pockets.

Max Zimonick
I've stopped checking

I'll let you know how I like them if the ever get here. Was supposed to be here on the 16th, has been delayed since then with no updates from usps.

Dakota Darkstar
My wife and I love them

Love them, they feel really sleek. Plus my wife loves how they look!

Husseim Sauceda

Un gran funcionamiento del producto..

Noah Shandelman
Great Product

I mean even though the size I got was too small, the tights are great. I know my brother is enjoying them a lot right now since they fit him. I’ll be able to give better feedback when I get a larger size. Looking forward to wearing more of your clothes!

Franklin Ho
Improvement over the last version!

Loved the last version of this and it looks like it's even better now. The design is less loud and the pass through pocket on the back no longer has zippers, which caught the clothing you'd loop through it. Perfect for a cold day!