Is this size likely to survive ? There don’t seem to be any tyres available now that can be easily bought. Anyone have any thoughts ? 
Hi LoneWolf,
the 24" has not been fashionable for a while. However, it is still in active use for kids bikes and BMX meaning there is still a basic selection of tires. Nothing crazy or big on performances but that is something.
The good news is: with the plus and fat tires hitting on all bikes, including kids bikes, there are some higher volume tires coming in 24" right where we like them for muni.
Long story short: there will never be as much choice as 27.5/29 but there are still choices as long as there will be kids 
Two examples of fat tires for 24":
- Vee Tire Mission Control 24x4.0 (https://www.veetireco.com/listings/fat-tire-mission-command/)
- Specialized Ground Control Fat 24x4.0 (https://www.specialized.com/us/en/ground-control-fat/p/155312?color=228389-155312)
And some samples in the more plus-ish side:
- Specialized Big Roller, 60TPI, wire bead, 24x2.8" (https://www.specialized.com/us/en/big-roller/p/156482)
- Giant XTC Jr 24x2.8 (https://bicyclewarehouse.com/collections/24-tires/products/giant-xtc-jr-24-bike-tire)
- Kenda Slant 6 Sport 24x2.6 (https://bicyclewarehouse.com/collections/24-tires/products/kenda-slant-6-sport-24-bike-tire)
- Mongoose Fat 24x2.8 (https://www.amazon.com/Mongoose-Fat-Tire-24-2-8/dp/B071HWZVS5)
- Kenda Kaos 24x2.8 (https://www.modernbike.com/kenda-kaos-tire-24-x-2.8-l3r-pro-60tpi-wire-bead)
- Vee Crown Gem Jr 24x2.8 (https://www.modernbike.com/vee-tire-co.-crown-gem-junior-mountain-tire-24-x-2.8-120tpi-tubeless-ready-dc-compound-folding-bead-black)
- CST Fringe 24x2.8 (https://www.modernbike.com/cst-fringe-tire-24-x-2.8-wire-bead-black)
And if slightly smaller works for you (between 2.1 and 2.5) there are several references from Maxxis, Kenda…
Another would be the CHAOYANG Big Daddy 24x4.0. URC offers this as an option on their 24" Unicycles.
Another place you find 24" (507) wheels is on cargo bikes, which are increasingly popular here in Norway. While I haven’t see them with full “fat” tyres yet, they do tend to have plus size tires to help provide some level of suspension. Fat tyres seem like the next step.
Cruiser style bikes sometimes have this wheel size as well and they tend to be fairly fat. I doubt most of them would be great for muni given minimal grip but you might find something interesting if you look around.
Something else to keep in mind is the use of 24" (507) as city rental bikes in a number of locations. These are pretty unlikely to help with bigger/fatter tyres but it is another reason why 24" (507) is unlikely to totally die out.
In summary, I don’t think 24" (507) is dead yet.
Duro has a couple of 24 x 3 (muni) tyres. Either the Wildlife Leopard or the RazorBack, which looks similar.
We need the 24" for muni as a beginner/kids size, and for technical stuff, so I don’t think it will disappear.
PS: I’m not completely up to date on the 24" situation.
Wow - thanks for all the info guys. I am in the UK, and looking online to see what was available on the 24 inch which tbh didn’t seem like a lot, with most out of stock etc.
I love my 24". I suppose we can’t expect to walk into any LBS and have a choice of 24" tires. But, as others on this thread have pointed out, there are still a reasonable amount of choices. You just have to buy online.
Yesterday on the trail I chatted with a serious MTB rider riding with his son. The kid had a 24". I asked the dad if he thought there were any issues with finding good 24" tires. He told me he thought there were plenty of good choices. He installed the CST Fringe (24" x 2.8) on the front wheel of his son’s bike. He told me to try that one. He liked it and mentioned it only cost about $20.
Speaking of cheap, you can get a Chaoyang Big Daddy 24x4.0 from Amazon UK for £14.95 (≅ $18.70 / €16.70). There is only 1 left in stock but who buys two tyres?
I have no idea how good this tyre is but URC/Mad4one does offer it as an option for their 24" (507) unicycles (for a lot more money), so it can’t be that bad (I naïvely assume).
It would also depend on if LoneWolf had a frame that could accommodate this width. Obviously the URC/Mad4one frames do (since they sell it as an option) and the URC 24" unis are very reasonably priced IMHO.
Question while I am here (as I am half tempted to buy this myself). When running a 24x4.0 tyre, would a 24x3.0 inner tube be “good enough” (since I have one already) or should I pay the vast sum of £9.28 (≅ $11.60 / €10.30) to splash out on a 24 x 4.0/4.9 Chaoyang inner tube?
I presume the proper inner tube would be more reliable but with an increase in rubber, it is also going to weigh more. Thoughts?
Should be fine.
Cool, thanks
A lot of trials bikes are also 24". TartyBikes in the UK have a few 24" for trials use at https://www.tartybikes.co.uk/24_inch_tyres/c85.html . So some of these might be suitable if you don’t want a wide tyre.
A quick search for some of those listed can get them a bit cheaper, eg: