Why not use 2 medium sized ones? likely more available and a better fit all around.

i'm still trying to get past the 'losing your clothes in the washer' portion. If you put the clothes in there, they should still be there when the cycle is done. (unless some crazy washer elf sneaks in during the spin cycle).

but, yes, 2 larger bags should work. maybe put your smaller sized items in there so they don't get 'lost'?? leave the bigger stuff outside the bags.

The clothes will not tumble freely, no matter what you do. The magnets will not work because the weight of the clothes will pull them off or slide them around. Your clothes will not come clean in a front loading machine because it relies on tumbling for its cleaning action. For the same reason, your clothes will take forever to dry. Winding something long around an agitator will make the machine become unbalanced, and stop.

Put small items like socks and underwear in a mesh bag and wash the rest unbagged. I'm sure you're not losing jeans and sweatshirts.

You could sew together four (or more) of your standard bags if you use a large front loader at the laundromat. Or try breaking down what really goes missing by counting your items for a few months. If your socks vanish, consider this gadget: https://www.amazon.com/SockDock-Laundry-Organizers-Dividers-Containers/dp/B07BXJ32Q8 

Partim is correct. You can make any size bag you want with mesh from the fabric store if you feel the need for bigger bags.

Ok, to respond to everyone:

I guess I should clarify. The idea is really more about convenience than preventing losing clothes. I know I won't lose clothes if I check thoroughly every time, but this is a hassle. Especially when you have to move a whole load between two machines that aren't necessarily right next to each other, one armful at a time. It's easy to drop them. I like the idea of loading everything into one bag, walking to the laundromat, putting it in, and then just pulling transferring the bag when it's done, rather than pulling out an armful at a time.

I have thought about two bags, which should work, but I think one large bag would work better (larger average tumbled distance), and would be more convenient.

As for magnets, I don't think they would necessarily pull loose. If the bag is close to the size of the outer diameter of the washer/dryer, the clothes should mostly be supported by the bottom of the dryer, rather than hanging from the top magnets.

Wrapping a balanced bag around the agitator wouldn't result in an imbalanced washer. However, I agree it would be harder to balance because it would be hard to adjust individual clothes after inserting. So maybe this isn't a good idea.

I like the idea of a custom bag, and will do this if I have to. Does anyone know of a larger bag though?

And any other ideas? I appreciate the feedback thus far

Does your laundromat not have these laundry carts that you can move from the washer to the dryer? When I had to use laundromats, I used a collapsible laundry basket. Placed it in front of the appliance and just scooped the load into it.

I still think laundry in a bag won't get washed and esp. dried all too well.

See the fins around the edge of the dryer? As the drum rotates, the fins lift the wet clothes to the top of the dryer and they fall to the bottom. The hot air is blowing across the dryer, so the clothes fall through the flow of hot air, which dries them. The clothes will not dry if they not free to fall, separated, through the flow of air. That's why it takes soooo long to dry when you over-fill the dryer. It's not just that there are more clothes, it's that there is no space for the clothes to fall down through the hot air stream. Your clothes will take forever to dry.

Same issue with a front load washer. The clothes move through the water when they fall. Your clothes won't get clean if they don't fall freely from the top of the "tumble".

https://www.laundrybags.com/c-73-mesh-bags-30-x-40.aspx

Seems to me the clothes would get balled up in the bags and dry that way, too, thus ending up very wrinkled. Just thinking out loud.....

Bad idea. The loads won’t balance very well, unless you have multiple bags. Use the cart or basket like Whirlpool suggested. Others have provided good reasons not to do this too.

I was looking for solutions for my wheelchair bound relative and thought that wash/dry in a mesh bag would make it so much easier for him to do his laundry.

i was looking for laundry solutions for a wheelchair bound relative and was thinking of this very thing! he has a tough time getting his laundry out of the stacked machine in his complex.

Most laundromats have those wheeled carts just for this purpose. If yours doesn't, buy a wheeled cart - there are many types. There are regular old laundry baskets, too - you put them on the floor in front of the machine and scoop everything out. Some even have handles on them to make carrying easier. Using the mesh bag for regular laundry just because you don't want do all the transferring is a bad idea - clothes will not get clean, will wrinkle and won't dry fast enough. Maybe do smaller loads, and more often. There are a ton of rolling carts and are foldable available. Just look on amazon. Even wheeled luggage will work for transporting.

This one looks like it come off and/or folds and you can carry it by those long handles

Whitewing Refresh · More Info

These are large wheeled hampers, which could be transported to the laundry

Dannyhill Residence · More Info