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Iron Heart 634S - Straight - 21oz Indigo
Iron Heart 634S - Straight - 21oz Indigo
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Iron Heart

634S - Straight - 21oz Indigo


Garment Measurements | Virtual Size Chart


The Iron Heart IH-634S in Indigo is an iconic cut, designed as a vintage-styled classic mid-rise Straight Tapered fit with a roomy seat, broad thigh, and a gentle tapered leg to a wide hem. This jean features the Iron Heart signature 21 oz. heavyweight, sanforized, and once-washed right-hand twill Japanese Selvedge Denim. This material is made with two twisted yarns to add bulk in a low-tension weave that will become amazingly soft with a natural drape while retaining its form. A hallmark fabric within the Iron Heart collection, this 100% cotton denim uses the vintage shuttle looming of the dual yarn method to produce a slight slub on the inside weft that softens to the body and gives this remarkable heavyweight denim an unmatched wearability. Featuring a rope-dyed indigo warp and a natural colored weft with a subtle grey cast over heavy white core yarn, this jean will evolve into a remarkable vintage blue with contrast fading patterns. Finally, it's topped with an ultra-heavy natural vegetable-tanned embossed leather patch, heavy-duty canvas twill pocket bags, embossed copper riveting on the front pockets, hidden rivets on the back, a button fly with interior selvedge detailing, and a chainstitched waist, seat and hem. This garment is sure to be a new classic using signature IH details and fabric with a contemporary yet informed high-rise tapered fit for the gent who lives his history in the present. Built for the motorcycle community and over-engineered to start, Iron Heart tests the limits of what actually can be artfully woven and sewn. The Iron Heart 634S in 21 oz. Indigo has the supreme character to rival any in its weight class, yet it will knock out and ride over the competition with championed comfort and fading potential.


  • Straight Tapered – 634 Fit
  • Mid Rise, Roomy Seat, Broad Thigh, Tapered Leg w/ Wide Hem
  • 21 oz. Japanese Low Tension Selvedge Denim
  • Proprietary Fabric - Signature Denim
  • Sanforized - One Wash
  • Red Selvedge Line
  • Double Twisted Weft Yarn
  • Indigo Dyed Warp & White Weft
  • 100% Cotton
  • Zinc Button Fly
  • Engraved Copper and Hidden Rivets
  • Heavy Duty Canvas Twill Pocket Bags
  • Fully Lined Back Pockets
  • Embossed Natural Leather Patch
  • Chainstitched Waistband, Yoke, Seat & Hem
  • Bartack Reinforced
  • Rolled & Tucked Belt Loops
  • Made in Japan


Model Measurements: 5'11" | 190 lbs. | 42" Chest | 35" Waist - Wearing Size 34

The 634S runs on the large side of Iron Heart sizing, and we suggest going down 1-2 sizes from your Actual Waist Measurement (Body). Made with a sanforized and once washed denim, most shrinkage is removed. With regular use, one can expect up to 1” of stretch in the waist over the long term.

Our Method of measuring is different than Iron Heart. We recommend consulting our Sizing Guide and using our Virtual Size Chart to reference our Method when purchasing.

Please feel free to Contact Us for additional assistance.

About Iron Heart

After 20 years of working in the Japanese garment industry, Shinichi Haraki established Works Inc., a.k.a. Iron Heart, in 2003 as a heavyweight clothing brand initially geared toward Japan’s motorcycling community. Iron Heart creates classic and timeless clothing crafted out of the finest materials and achieves the highest standards by closely working with fabric development, garment manufacturing, and the brand’s cult community. Over the years, Iron Heart has become the definition of bullet-proof garment construction. Staying true to their slogan,... View All Iron Heart Products