IHxSJF: Two Denim Legends Plant their Flag at the Peak

Iron Heart Salutes Swiss Jeans Freak for 50 Years of Collecting with Fade-Friendly Collab

In the wide world of denim, there’s nobody like him. Ruedi “Swiss Jeans Freak” Karrer has been a recognizable face in the selvedge scene for as long as it has existed. Indeed, he’s been collecting denim obsessively since before many of us were born, and it all started 50 years ago.

In 1973, Ruedi was just a skinny teenager living in a small mountain village in Switzerland. He grew up in a large family that had to make do with very little, so it was a very big deal when a clothing bundle donated by a wealthy family from around Geneva arrived on his family’s doorstep.

Ruedi Karrer has been collecting denim for 50 years. The boxes behind him are full of it!

Inside were two used pairs of Levi’s jeans: a pair of 501s and a pair of 505s, both of them Big E selvedge from the ‘60s. They were probably the first pairs of Levi’s anybody had ever seen in that little corner of Switzerland.

The pairs were far too large for young Ruedi, but he inspected and admired them whenever his older brothers weren’t wearing them. His idols were James Dean and Elvis Presley, and holding that denim in his hands made him feel connected to his rebel heroes.

Jeans took on a very special meaning for Ruedi, and, as soon as he had the means to do so, he began collecting denim pieces, beginning with the first wearable pair of his own (a pair of Wranglers he purchased in 1975).

Ruedi with his Wranglers and the two pairs of Levi’s in the Jeans Museum.

These were the first steps that led him towards the foundation of the Jeans Museum in Zurich, where Ruedi has denim pieces from all over the world stacked up to the ceiling. With more than 14,000 articles, he is an unequalled documentarian of denim’s global spread in the second half of the twentieth century.

Nearly every denim brand is represented somewhere in his collection, and the museum is still growing. Each year, denimheads send Ruedi their much-loved and heavily-faded denim pieces, which he preserves and displays in his museum.

Ruedi is also a fixture of denim-related events across Europe. From denim trade shows to anniversary parties and consumer festivals, Ruedi can be relied upon to be there at all of them. His love for denim has spread across borders to encircle the world, and he leaves beaming smiles (and mouths stuffed with Swiss chocolate) everywhere he goes.

He’s not just one of the most important denim collectors in the world; he’s one of the kindest and gentlest men we’ve ever had the pleasure of meeting. We’re proud to call him a friend, and we’re honoured to have worked with Ruedi and the Iron Heart team behind the scenes to help make this collaboration a reality—a fitting tribute to a true-blue original.

This isn’t Ruedi’s first collaboration jean. Back in 2019, to celebrate his 60th birthday, he made 60 pairs of jeans together with Candiani and IMjiT35020.

You can watch the documentary (which Thomas co-directed) about the how it all came to be on the Jeans Museum website. There, you can also find information about how to donate your jeans to the museum.

A Closer Look at the IHxSJF Collaboration

Iron Heart built their reputation on the back of their signature 21 oz. selvedge—the world’s heaviest when it was first introduced two decades ago.

They’ve long been the destination brand for those who want to combine contemporary, octane-infused styling and some of the heaviest selvedges on the planet. But this isn’t all they do.

In 2016, they introduced a “lightweight” 14 oz. denim to their lineup. They perfected the recipe in 2018, when they introduced a second version of it (designated with -142) featuring their trademark double-twisted weft yarns. 

The face of the denim is smooth with little slub or nep. It feels thick and substantial, but not heavy. Soft and smooth on both sides of the denim, the pair is easy to slide in and out of. It might be the easiest-wearing pair in our collections. 

Word on the street is that the break-in period passes relatively quickly with this pair. It’s got more than enough fight in it to produce some stunning contrasts, but the whiskers and honeycombs will be sharper—still beautifully defined, but not as bold or thick as the ones you’ll see on their much heavier pairs.

At this weight, you’re much closer to the weight of the truly classic denims from Cone Mills and Canton Mills. If you’ve ever admired vintage fades, this will be a great denim to recreate them, and it will get you there quickly. Based on faded examples, we think that even those with relatively easy-going lifestyles will be able to produce beautiful fades on these within a year.

For the IHxSJF collaboration, Iron Heart has produced two fits: the IH OG and classic straight cut 634, and the more modern and slim-tapered 777. Both are sold exclusively through Iron Heart’s webshop.

With a straight leg and a medium rise, the 634 was designed by Haraki-san in 2002 as a modified version of the 1960s 501 favoured by motorcycle enthusiasts. For most wearers, it fits quite snug through the top block, easing up slightly as you fall down the leg towards a generous opening. If you wear engineers or harness boots, this will definitely be the cut for you. 

If you wear less dramatic footwear (perhaps sneakers or six-inch boots), or if you prefer a more modern style, the slim-tapered 777 will be a great choice. The denim will relax considerably with wash and wear, so it’ll be best to start with a fit that hugs your thighs.

The denim has been thoroughly sanforized, and you can expect them to stretch more than they’ll shrink, so a tight fit on day one will become a comfortable slim one in time. After the first wash, the pair will snug back up, but it will quickly relax again. As always, check Iron Heart’s measurements before purchasing to avoid surprises. 

The construction, as we’ve come to expect from Iron Heart, is second to none. Polycore stitching, hidden rivets, and substantial pocket bags will help this pair go the distance. The inseam is overlocked, and the outseam features a red-line selvedge ID. Branded hardware and tucked and raised belt loops finish things off at the waist.

The tonal arcuates are hands down our favourite feature on this pair. Inspired by Ruedi’s 25 oz. Mega Beatle Buster jeans, the polycore stitching will hold its colour far better than the denim, so, as the indigo chips away, the blue arcuates will become more prominent.

Iron Heart has only featured this stitching on a handful of other releases, and, though we’re fans of Iron Heart’s classic yellow stitching, the subtler blue stitching is absolutely stunning.

The patch and printed pocket bag help to tell some of the story behind the pair. The leather patch features a drawing of the famous Swiss Alpine mountain, Matterhorn. Look closely and you’ll see Ruedi’s face worked into the contours of the mountain. You’ll find that same face smiling out at you from the inside of the jeans on the pocket bag. 

These details have been tastefully added so as not to interfere with Iron Heart’s signature design elements. The leather patch is completely sewn down, so it will probably spend most of its life concealed by a belt, and the pocket bag will likewise only be seen and appreciated by the wearer.

You’ll know what you’re wearing, but only a handful of enthusiasts will be able to recognize this pair at a glance. They’ll be a great conversation starter. 

Why Not Heavyweight? Why 14 oz.? 

Ruedi was keen to connect this pair in a tangible way to his story, and the 14 oz. denim is the closest thing that Iron Heart has to the 1960s Levi’s selvedge that so inspired him. But this hasn’t just been made for him. It’s also been made for us—for fans of well-made selvedge and practitioners of the fading arts. If it’s been a while since you’ve worn anything but heavy selvedge, this pair might be exactly what you need.

At the end of each year of the Indigo Invitational, we review hundreds and hundreds of entries from faders around the world. Last year, we were struck by how many of the pairs crossed the line nearly as dark as they were on day one. There was a common theme for many of these pairs: The fader had bitten off more than they could chew.

Left: Ruedi’s MBB 25 oz. with tonal arcs. Right: The IHxSJF-634

The heavy stuff is what attracts so many of us to the selvedge scene. It fades beautifully, and it feels incredible on our legs once it’s been fully broken in. The fades and the comfort have to be earned, though.

If we want to fade them completely inside of a year, 21 oz. and 25 oz. denims require nothing short of a herculean effort. They prove their worth when pushed to their limits, but few of us have lifestyles that can push heavy denims this far this quickly. 

Bryan’s putting his money where my mouth is; he’ll be wearing his IHxSJF-777 in Y4 of the Indigo Invitational.

“As eager as I am to slide into this pair and start coaxing some of the indigo out of them, I’m putting them on ice until January 1st.”

Ruedi will be wearing his IHxSJF-634.

If you’ve been at all disappointed with your results in previous years of the competition, we want to encourage you to lower the bar for yourself.

We’re confident that a light- to middleweight denim like this one will fade beautifully within a year, even if you spend most of that year sitting behind a desk (like us).

Fade along with us as we put this incredible denim to the test.

Support the Jeans Museum – Buy the Jeans!

When you buy a pair, you’ll be doing Ruedi and his denim institution a favour (some of the proceeds from each sale will support his Jeans Museum).

But, if you’ve been anything less than thrilled with your fading results in previous years, you’ll also be doing yourself a favour. 


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