I found in my tools case, a can of "fix a flat for bikes only" by Pennzoil.
Just checking their site, I found "Fix-a-Flat is designed to be used in automotive highway tires (Cars, trucks, SUVs, etc.). Fix-a-Flat should not be used in tires on motorcycles, ATVs, tractors, lawnmowers, bicycles, scooters, golf carts, etc.
What is the status of this stuff? Know its like Slime

Couldn't say, but I can tell you that a bunch of people and I used to ride motorcycles. One of our group got a flat once, and I had some automotive fix-a-flat in my saddlebag. Worked fine on his flat and lasted at least the whole day. Know it lasted for at least 200 miles. Don't know if he removed the tire and fixed the flat when he got home. Now, this has been at least 40 yrs ago!

I lived in Utah in the early eighties. Thorns were a problem. I tried slime and some other fix a flat type for bicycles. I found that once you put it in a tube, the tube would not take a patch later. I found it was better to use things like Mr Tuffy or use tires with a better flat prevention casting.

I was just wondering ,cause can says ok for bikes but website states Fix-a-Flat should not be used in tires on motorcycles, ATVs, tractors, lawnmowers, bicycles. I believe it was just given to me and I forgot about it. Keeping just for emergencies

Why not look for and use bike specific solutions

here is one bike version of fix a flat https://www.biketiresdirect.com/prod...-sealant?fltr=

you can also use sealant in your tubes if you run tubes (just has a self repaired this way), but sealants work better at lower pressure i like cafelatex https://www.amazon.com/Effetto-Marip...BwE&th=1&psc=1

but in general you should be prepared for a flat for the tire technology you use

I carry 2 tubes, patch kit, tire boot, co2 and a pump for tubed

for tubular I care one or two spare tires and small bottle of sealant

I don't use tubeless yet but if i did I would carry dyna plugs, tube and good tire levers and some sealant

As a former tire guy (cars and trucks)
Fix a flat should only be used in emergencies. I hated that stuff.

I see no difference in car vs bike tires in basic chemistry so it's probably a marketing thing.

Three possible differences: 1) Imbalance issue, bike tires are more sensitive, although car tires spin faster. 2) Hazard due to propellant, possibly flammable. 3) Contents may degrade bike tubes, or inside of tire, car tire compounds may be more resistant, or just doesn't work with tubes, only for tubeless.

EDIT: 4) Volume difference, can of fix-a-flat could blow up (explode) small tires.

And yeah, I hate the stuff too, imbalance and a mess inside.

Not sure the OP can find the definitive answer here as there are so many variables such as the fluid is old and an unknown version to most/all of us here. I would just say in general that fix-a-flat fluids of any brand are iffy at best in high pressure tubed bike tires and not a permanent solution even in tubed low pressure tires IME either. Best to try it yourself if you want to find out for sure but fluids only work on very small punctures and be prepared to get sprayed with fluid on yourself and bike and make sure to carry an extra tube as the fluid filled one will be difficult/impossible to patch. For what it's worth, it may get you home if you're lucky but odds aren't great.

I do not see any of those being a real problem.

Growing up I was told by a few older wrenches of a local auto mechanic that "burned off his face" when working on a tire that had been reinflated with an aerosol. Seems that fix a flat (note the lower case) was quite flammable and when he leaned over the tire to deflate it for removal the aerosol ignited by the cigarette he had in his lips. The word "flamethrower" was used to describe the flame hitting his face. Ever since I had avoided this stuff when ever possible and have asked customers (when it seemed right) if they used an aerosol, before I did the work. Thankfully, I don't smoke either... Andy

The older stuff had flammable propellant. Whenever a customer mentioned they used fix a flat, we were extra careful.

Not sure about the modern stuff, but the boom factor is one of the reasons I'm suspicious of all canned based "solutions"
(it also makes a permanent fix require 4 times more work)

I had only asked about the product out of curiosity as I found it in a tool box.
I always carry 2 tubes/patch kit / pump and CO2 in case of really bad weather and I don't want to pump in the rain.
Pennzoil just informed me as they haven't made that type in years and to dispose of it.

I didn't say they were *actual* problems, just maybe why it is labeled the way it was. Subsequent posts have verified my vague memory of the old propellant being flammable, my very vague memory says maybe propane as the stuff was so cheap. But if so, yeah that would no longer be the case, not just for safety of use, but safety in shipping, adding huge cost for that, and propane may be a greenhouse gas like natural gas (methane) is, quite strongly.

One thing not mentioned WRT using fix-a-flat…even if it is for a bicycle application. Lots of times whatever causes the flat stays stuck, sometimes unseen, in the tire. So if you don’t get that thing out, the fix-a-flat may not work. — Dan

(above) Great point.

I suspect #4 - and the possible legal liability from same - is likely the reason for the warning.

I got curious, so I played around with this online calculator and modeled 700c x 32 and 185/75R14 tires each as a torus. For the 700c x 32, I used outer radius 350mm, and tube radius of 16mm. To approximate the auto tire (it's substantially flattened), I used 316.55mm as the outer radius, and a "tube" radius of 75mm to account for the smash. (I'd guess this is a bit of an underestimate, but I really didn't want to deal with an ellipsoid of rotation. It should be in the ballpark.)

Unless I've hosed up the math I get the auto tire as having about 16x the volume of the bicycle tire.

Assuming a can of Fix-a-Flat can inflate the auto tire to 20PSI that means it could in theory inflate the bike tire to somewhere around 15x or 16x that pressure at the same temp (same amount of gas in the can either way, though a bit more would stay in the can at higher pressures) - or over 300PSI.

I don't think I'd want to be anywhere nearby. Hence the warning IMO.