How hard would it be to combine one shoe’s upper with another shoe’s midsole?

I know some quality casual and dress shoes can be resoled. The shoe can literally be taken apart and rebuilt. I am not sure how practical it would be for a running shoe. Ask a shoemaker.

Ask Phil Swift... I'm sure there's a Flex Seal product made just for this type of job.

"... I sawed this shoe in half!"

Yes, it is possible. You can look at some videos on youtube to learn how to do it:

https://www.youtube.com/watch?v=NQDMWX-0BFc

Not all that easy, really. You can't use hot water like the sneakerheads do because the glues on running shoes are insanely freaking strong. You have to bake the shoe or use chemicals to get it to release relatively cleanly. It's a slow, tedious process.

But, more so, you might not like the results as you're thinking you will. How do you plan to fasten that upper to the midsole? Layers of glue make a shoe stiff and firm, so the experience may totally change. And will the fit be right once you get it attached?

Matchmaker wrote:

I have a shoe with a great midsole but a terrible upper. If I wanted to Frankenstein a different upper onto it, is it reasonably possible?

Why not just modify the upper to your liking? Over the years, I have...

-cut off the top of the heel counter

-cut off the top of the heel collar

-removed eyelets and repunched them in a different place

-skipped the bottom eyelets

-put a vertical slit in the toebox to expand the toebox.

-cut off the outer edge of the insole to let the 5th metatarsal ride lower

-cut off the toe protector over the little toe.

-added padding to the tongue

-cut out material that created a hotspot on the side of my foot

-cut out material that created a hotspot on the joint of my big toe

I've cut off parts of the outsole to cant the shoe more to the outside to prevent pronation and done lots more to the outsole. I always modify the inserts. In fact, I routinely do this on all my shoes, except my spikes.

My point is that you can probably modify the upper enough to make it work, unless it is too small or way too narrow or too big.

I also like to modify shoes. Do you have a blog? I would enjoy reading about your work.

To answer your question: the shoe is really ugly in combination with being uncomfortable, lol.

I have a book that addresses shoe and shoe insert modifications. It's 200 Tips Every Runner Should Know, available only on Amazon.

Feet are like fingerprints or snowflakes. No two are exactly alike, so it's very difficult for some people to get a great fit. The solution is to get a shoe that's close as you can find to a good fit and then modify it to eliminate hotspots, blisters, slippage, overpronation, and so on.

There is are also a couple of chapters on performance tips... things I've added to my workouts over the years to get faster relative to my peers. You'll learn something if you read it.

Tricky. Here’s my experience with this...

It will be really hard to get them to separate undamaged. If you’re willing to destroy one upper and one sole, then your chances improve, but it’s probably going to be really hard to get a clean midsole because the kind of heat you would usually use to separate them would melt a running shoe midsole (and possibly the upper too).

Running shoe midsoles are often compression moulded. The foam is put into a mould and the lasted upper is pressed into it to shape and fuse them together. The final product yields a specifically shaped, light and springy foam which is more fragile than other materials m historically used in shoes. It’s not meant to be replaced, it’s meant to break down.

Part of what you like about the midsole may even be a part of the shoe’s upper. A strobel board can really influence the feel of it.

Even then, the midsole might be the wrong shape for the upper.

Running shoe midsoles tend to be moulded so that the upper sits inside it slightly. It improves the durability (and maybe fit), but also means that there is a high likelihood that the upper will either be too narrow or too wide at some point. That could be corrected is some cases.

Properly done with Barge or the equivalent, the bond will be as strong as any shoe, but the result still won’t be the same as just fusing the two. The sole and upper work together how both feel are a result of that. I’ve had success resoling running shoes, but the soles were made specifically for the uppers. Combining two different ones is voodoo.

Putting shoes together is simple. Taking them apart - not so much.

For all the work, you will end up with a totally new shoe which you might not like.