On Slack, I pitched James and colleagues on doing a Shoecast. I don’t know how long the Slack post will persist, so I write here for posterity. I would like a deep dive on feet and how they fit in shoes. This is inspired because I have some difficulty finding a perfect fit. I recall a 2020 or 2021 podcast that Velonews did with the guys from Giro, and Giro said they aimed to design their shoe lasts to fit as many people as possible, and to minimize movement inside the shoe. OK, fine, but aren’t Giros shaped relatively narrow? What is a last, anyway? Here are some questions I thought about.
- First of all, how do feet even vary in shape? Everyone knows length. I assume that many of us probably more or less fit standard width shoes. If our feet are wider than average, we’d probably figure it out from foot pain. Alternatively, if you got a measurement taken on a Brannock device and the operator was competent, you’d probably get a sense of how wide your feet are. Are there more shape parameters apart from length and width?
For example, I have heard some people say they have high insteps. Is that a thing, i.e. feet vary in height along the Z-axis as well as X and Y? Do heels vary in size? When you look down at your feet, you see that your toes form a curve - does the amount of curvature vary between people? Again, are there other parameters?
- Do different genders, racial/ethnic groups, or other groups vary in average parameters? For example, many manufacturers offer women’s shoes that are narrower than a given unisex size. However, Specialized’s anthropometric review argued (based on a Retul dataset) that women’s feet are about as wide as men’s on average, as shown below. However, do note that they are measuring circumference around the ball of the foot; it’s possible this measurement might vary depending on foot volume, although it may not (high volume feet might be bigger further up, more in the instep)
As a less well-known example, Bont offer an Asian fit shoe, which they characterize as (relative to a standard fit for a given size) wider in the forefoot, narrower in the heel, and “flatter instep/arch”, which I think means lower volume.
If I’m designing a shoe, where do I get lasts? Are there a few industry standard sets? What data are they based on and how current is that data? How do you select the number of steps between sizes?
Some companies have reputations for relatively narrow shoes (e.g. Sidi, some (?) Giro models), and some for relatively wide (e.g. Bont, Lake). How do these differences originate?
Are last shapes refined as companies go along? Shimano seems to allude to doing this when they released the 902 model of the S-Phyre shoe, and James reported a perceptible difference in fit.
How can consumers reliably select a shoe? We are often advised to go to a store and try on a large number of shoes, preferably with your preferred insole brand. Are there particular things to look for? E.g. tightness around the forefoot, slop in the heel area? Most of us learned in street wear to make sure you have about a thumb’s width of excess length in front of your longest toe. Is that an accurate heuristic for cycling shoes? If you have slightly wide feet, you may have learned to size up, and in fact Shimano’s guidelines specifically recommend doing this. Is that a good heuristic? I worry that the fit elsewhere on the foot can become sloppy. Is this a good heuristic? Last, you often develop problems with a shoe fit later on, maybe after a long ride, maybe after some time. How reliably can consumers tell in the store if a shoe will work?
Somewhat related to #6. Do Brannock devices give good information to begin with? Do their measurements vary significantly if different people conduct a measurement (if you’ve ever heard the term inter-rater reliability, this is what I’m talking about)? Most Brannock devices I’ve seen output a nominal size (e.g. Euro size 40), whereas if you check, different manufacturers’ claimed last lengths may vary for a given nominal size, e.g. Fizik size 40 is listed as 257mm, Shimano is 252mm from my memory, I think Giro claimed 255mm but I can’t be 100% sure and they definitely round to the nearest 5mm which I look down upon. Anyway, are there issues like this in finding your shoe size from a Brannock device?
But related to #7: is there a standard way to measure shoe length? Most manufacturers list their last lengths, even if you have to dig (e.g. Shimano) or they’re rounded to the nearest 5mm (e.g. Giro, although they seem to have taken the length charts off their website) or they’re shown on a ruler instead of given in mm (e.g. Shimano, again, although I think the shoe boxes list the actual length). I know that Lake specifically says mark on paper the heel and the furthest toe, then measure just the Y dimension like you’d measure bike reach. However, at least a couple manufacturers I’ve seen (e.g. 45 North and Quoc Pham) have you measure the length from heel to big toe, as if you were measuring the actual TT length on a compact frame.
By now, that may be a full podcast episode. We still haven’t covered arch support. It seems that most shoe companies put a crummy stock insole that’s usually for a low arch in their shoes. There may be an unstated expectation that you replace it, but do most people? How can you select a good insole?
Insoles seem to vary somewhat in their actual height. For example, Steve Hogg contended in 2011 that Specialized’s insoles were relatively low, whereas Icebug Slim and Sofsole had considerably taller arches than any Specialized.
Moreover, some insoles offer metatarsal support (e.g. Specialized, Icebug). Some don’t (e.g. Bontrager). How beneficial is metatarsal support? Does it vary by rider? For example, some people I’ve talked to on forums don’t like Icebugs with their fairly prominent metatarsal bump, even though it doesn’t really stick in my foot when I am riding. Are there other differences between insoles apart from arch height and metatarsal support?
- How much difference does the construction of the uppers make in shoe fit? For example, I believe that I would not normally fit Giro’s lace shoe lasts, which I have heard are narrow (but I don’t know that the E70 uses the same last as the rest of the Empire line). Based on James’ review of the E70 knit and laced shoe, however, I decided to try it, and it was pretty comfortable at first, especially after I skipped a lace hole to relieve pressure. James did say that the knit uppers seemed to have more conformability, which could enhance comfort.
For the record, after 2 years on my E70s, I believe that they are slightly on the narrow side compared to what I would want if I could have a custom shoe made entirely for me. That is, they are within my fit envelope but on the narrow side. Moreover, when I tighten the laces enough to stop all foot movement during very hard pedaling, they’ll hurt my feet, especially along the outsides. Right now, even during fast group rides, I feel like my feet don’t move around so much that I want a different size or a different shoe entirely. If I were still road racing, I might feel differently.