You might have experienced it yourself. Getting two pairs of shoes from the same brand, in the same size, made on the same last, yet one of the pairs are more loose than the other. Usually the reason is different leathers used, which preferences affect both how the shoes can be manufactured and the feel on the foot. Learn more in this article.
For manufacturers of footwear, be it shoe factories or bespoke shoemakers, there’s numerous challenges of various types that one have to go up against. One of them is keeping the sizing consistent (yes, this goes for bespoke makers as well, once you’ve nailed the fit on a last you have to retain the same feel on all new pairs, which isn’t necessarily as given as one might think). In this article I’ve written about how different patterns may affect fit, here we go into another area that can affect it: the materials.
If we talk regular smooth calf leather, which is most common when it comes to dress shoes, it’s a leather type that has a tight fibre structure, not least with the whole part of the firmer grain area left, it has high tensile strength (meaning it can be stretched a lot), and it’s pliable. When one pull this over the last, one usually can and need to pull relatively firmly for it to shape and conform well. But depending on how this smooth leather is, if it’s thick or thin, fully chrome tanned or combination tanned, highly finished or unfinished, and so on, it may vary how it stretches and also how much it sort of “shrinks” back after the last is removed.
Then moving over to other types of materials, for example full reverse calf suede generally act relatively similar to full grain in the above regard, it’s basically the same type of leather just turned the other way around, even if usually more of the corium (the flesh side) is left on it. But split suede, which nowadays is more common, often differ a lot. Here the tight grain area isn’t there, it’s just the loose corium, and this can normally be much easier stretched and “pulled out of shape”, and has less tensile strength, meaning that one normally need to last this with less force. Then you have for example thicker cow leather which is firmer overall, and you have shell cordovan, which is rather stiff and firm, with very low tensile strength. Cordovan one need to be even more careful when one pull over the last.
Now, the manufacturers always try to accommodate for these differences, they set their machines differently for different materials or use various force if done by hand, they can use different linings or backings to make up for things, and so on. But fact is, especially since it can vary even between hides of the same type (albeit less there), that there will always be differences in various ways. For example, it’s not uncommon for split suede shoes to feel a bit more roomy and loose than calf leather shoes made on the same last and size, both due to how it’s been lasted, and due to it being a very soft material. Same with Shell cordovan, often a bit looser, but there the stiffer leather which doesn’t stretch and shape as easily affect things to often feel overall more similar to smooth calf anyway. And so on.
I can’t go into detail on all the variations here, not least since I don’t know half of it. But if you experience shoes from the same maker in the same size on the same last differently, chances are big that it’s due to reasons above (and/or if it’s different patterns, as mentioned in the beginning). But the length of the last, the so important heel to ball (widest part of the foot) length, the heel cup etc. is still the same, so it normally don’t make sense to switch sizing due to this. Better to for example insert a thin insole if a shoe is a bit roomier, since that fills up the volume which is what’s affected by how the various leathers can be lasted.
Interesting and informative, thanks!
R: Glad you think so!