Levi’s 501 Shrink-To-Fit (STF) Denim – The Ultimate Guide

If I can summarize Shrink-To-Fit (STF) in one word it would be “personalization” – how can 501 STF be personal? Aside from the unique historical aspect of the Levis 501, the step-by-step process of getting your pair to fit specifically to your figure is personal within itself.

This guide was made to detail important segments of the STF process as a whole. We’ll start with general rundown of unsanforized denim then lead into the historical concepts of the Levis STF which in order to help readers understand  popular fits and the characteristics behind each of them.

Lastly, we’ll give a rough guide on my own personal method of shrinking your pair without the worry of overly shrinking your waist. We must note that as even Levi’s has conflicting ideologies on how a pair of STF should be wash or not washed, whether or not my method is right or wrong isn’t the real goal. Our intent is to inform those interested in picking up a pair to with enough insight to know what they will be getting into.

Sanforized vs Unsanforized

Before diving into the history of Levi’s 501, it’s critical to understand what separates a pair of Shrink-To-Fit 501 apart from any other jean in the market by exploring its technical nature.

Here’s where the sanforized vs. unsanforized conversation comes into play. Sanforization is a post-weave process patented by Sanford Lockwood Cluett in 1930 and known for its ability to shrink denim that would be otherwise shrunk down later in the consumer process after washing. The cotton is taken through a series of steps including stretching, shrinking and fixing a woven cloth in both length and width.

Or in more detail, the cotton is first moistened by water and/or steam in order to soak the cotton fibres and join them closer together as strands. Second, the cotton strands enter an endless rubber belt and belt squeeze them between a pressure roll and a rubber belt cylinder to stretch out the denim dramatically.

Next, the cotton is fed into the pressure zone and upon leaving it, the surface returns to its pre-squeezed (stretched) size. The effect of this action shortens the warp yarns, which packs the weft (filling yarns) closer together. It is at this very moment that the shrinkage occurs. After compaction, the fabric enters a dryer where the fibres are locked into their shrunken state and the moisture is removed from the fabric.


Sanforization process

Sanforization is highly praised for its ability to ensure the fabric (or in our case, denim jeans) will shrink no more than 5% after it’s washed for the first time, as opposed to a potential 10% for unsanforized fabrics. Prior to the 1930’s the sanforization process did not exist, leaving unsanforized as the only finishing method available.

As there is no pre-shrinking in respect to unsanforized denim, the first initial wash is probably the most important step for a long healthy life for denim with this quality. Without this important first wash the cotton fibres will not be reinforced and become liable to tear or rip, making it a critical initial step in the successful personalization of a pair of denim.

Understanding the sanforization process helps us identify the historical concept of the STF 501 and ultimately helps make an informed decision regarding the specific style or fit that you’re looking for.

Levi’s History 501 & 505-0252

Turning now to the historical background, we go way back to the 1860’s when Levis Strauss first started selling dry goods like denim pantaloons and duck canvas bottoms. Despite the fabric not being the most breathable, Strauss sold duck canvas bottoms since they were sturdier than denim. As such, one of the oldest items in Levi’s archive are the 1870’s Duck Canvas bottoms.

During the California Gold Rush, however, many miners complained that the pockets would tear and rip in certain pressure points. Strauss turned to Jacob Davis, a tailor from Reno, Nevada, to reinforce the pairs with rivets and extra stitching.

Since Davis didn’t have enough the means to patent his idea, he partnered with Strauss to help him patent the riveted pants. Thus, it wasn’t until the 1890’s when the first pair of 501 Shrink-to-Fit were made, and not until 1967 when Levi’s finally introduced a pre-shrunk (i.e. sanforized) pair.

Vintage 1890' 501 Calico

Vintage 1890′ 501 Calico

The modern Levis shrink-to-fit can be credited to the 1947, which has also been nicknamed the “Steve McQueen” jeans due to their slimmer fitting top block and slight taper. The 1947’s also had no extra details like crotch rivets, clinchers or suspender buttons. The 1947’s also had the famous double needle stitched arcuate that is seen on modern Levi’s.

1947 501-Steve McQueen

Vintage 1947 501XX – “Steve McQueen”

The 1954 501z (which later became the 502-0117) is probably the most influential STF pair since it’s been widely credited by denim enthusiasts for beginning the trend of sanforizing denim. Sanforization was already placed on the market with the 1950’s Levis Twill Chinos but had actually yet to make the leap to denim.

The 1954’s also had one very unique feature that was used to help sell to some of the more picky customers on the East Coast – the zipper fly. The zipper fly was a huge success with the East Coast market, but also left the pair slightly warped after washing since the jeans shrunk and the zipper fly remained unchanged.


1950’s Levis Advertisement

Levi’s began to use the same process of sanforization from their twill chinos in the denim, trying it out to counteract the wavy-zipper problem on the freshly created 505-0252 which contained the same zipper fly and a card-stock patch. Due to its popularity the 505-0252 became the leading pioneer of pre-shunk denim in Levi’s archives.

After gaining a sense of different fits under the 501 & 505 naming schemes, there’s more of a rationale behind taking a brand new pair of jeans and tossing them into the tub to reach the ultimate experience when dealing with STF 501’s.

1967 pre-shrunk ad

Vintage Levis Pre-Shrunk advertisement (left), 1967 505-0252 (right)

Washing Your 501 Shrink-To-Fit

There are multiple theories when it comes to washing or not washing your jeans. Though many recommend wearing for as long as possible before washing and it’s hard for some to soak a crisp pair of raw jeans, it’s the most important step to give your denim a long life (as you’ll lessen the chance of rips, tears, and pesky blowouts).

We’ve covered soaking raw denim in previous articles, but have re-capped below in the context of the Shrink-To-Fit.

Step 1

Fill a tub with the hottest water available. Fill it up halfway or at least enough so the pair can be fully submerged underwater.

Step 2

Next, find items that can help hold down the pair underwater since jeans tend to float. Have the pair sit in the tub submerged for at least 20 minutes, you will see a bluish tint around the edge of the water since the indigo is slightly bleeding out.

Step 3

Once the 20 minutes have passed, hang your pair over a shower or tub since it will drip. Once you feel the pants are moist (not wet) put them on to ensure that your pair doesn’t shrink past your hips. This method also tends to make a better fit since it drys up on your body.

Step 4

Wear the pair until they have fully dried. Be careful to not sit on any  furniture or walk on white carpet if your pair tends to drag at all since it will bleed and stain.

Step 5

You’ve successfully shrunk your STF pair, now wear as much as desired.

1954 shrink to fit front

1954 501z Shrink to Fit; Before (left), After (right)

1954 strink to fit back

1954 501z Shrink to Fit; Before (left), After (right)

Levi’s Vintage Clothing also made a short video on how to tub wash your jeans. It varies a bit from my personal method but different methods is what Levi’s STF is all about.

Friendly and Final Reminders

  • Most Levi’s STF do not shrink 10% as advertised, many tend to shrink between 6-8% after the first wash.
  • If you buy an anti-fit pair like the 1933’s or 1955’s 501, shrinking will not change the overall fit of the jean. It will just become smaller but the straight fit will stay a straight fit.
  • The slimmest STF pairs in the LVC collection are 1954 501z, 1947XX and the 1978 Small “e
  • The 1966 “Bob Dylan” and 1978 501 have a lighter synthetic indigo dye so it tends to fade much faster then any other 501.