I might be able to dig my Joey out later today to give you a measurement since it sounds like you are serious on wanting this info.

Too many times, someone on this forum asks for info, I spend quite a bit of time digging it out and writing a lengthy response and then they either do not comment later or they say, no longer interested but thanks anyway. I was just trying to avoid a re-iteration of wasting a lot of time again. But sounds like you really are looking for this.

My Joey, I mentioned that I have 507 tires. The Joey could be built up with either 507 or 520.

Again, mine is a decade and a half old, rim brake version, they have made changes. I once bought a set of 24X1.75 tires and the rear was too wide to fit in the frame, I think that after I bought mine that Airnimal changed the chainstays to take a wider tire but on that I am not sure. You really should check with Airnimal on tire sizes for the Joey to find out if a 24X1.75 fits, look at the photos on their website to see what tires they use, etc. A 24X1.75 is fairly common compared to a 24X1.5.

When I bought mine, Schwalbe made 24X1.5 Marathon tire that I bought, that fit, but Schwalbe stopped making that tire size soon after. Later I bought some of these in 24X1.5 to keep on the shelf, thus I have several year supply of tires.
https://veetireco.com/product/bmx-speedster/

Since most years I put less than a few hundred miles on my Joey, and I am retired I likely have a lifetime supply of tires for the Joey. (Yesterday I put 70 miles on my Lynskey, the Joey is ridden much less often.)