Seems that CO2 is electrically attracted to the rubber in tubes and tires while O2 and N2 are repelled. This allows CO2 to go through the tube and tire more readily.
Bicycle tires are the best tire technology.
Compare bicycle tires vs car tires. Would you rather get a flat on your bike or car on your way to work?
If you get a flat on bike just change/patch the tube or boot the tire. Takes 10 minutes max. In my backpack I always ride with 4 patch kits, 4 spare tubes, 4 tires boots, and a hand pump. I also have a seatpost pump. I can fix up to 8 flat tires and repair 4 tires per commute in the worst case scenario.
If you get a car flat you only have 1 spare tire. If you get another flat you are stuck with a 2 ton pieces of metal on the side of road that you have to tow to a garage.
If a bicycle gets an unrepairable catastrophic failure like a tire blowout, you can always just run/push/carry your bike to the destination. You can’t do that with a car.
What would it take to carry enough supplies to repair 8 flat tires in a car?
Presta valves are horrible. I always use a presta-to-schrader adapter on all my presta stems.
Presta valves break so easily with a hand pump it is ridiculous. No wonder road cyclists use auto c02 pumps for flat repair. If they had to rely on using hand pumps they would never get home.
Tires ancient technology? Rubbish! Wheels, there’s an ancient technology! Where’s my hoverbike?!
There are portable pumps with hoses. This one is particularly good. I have Presta valves on every bike I use, and I have never broken one.
a short hose on a hand pump is good. also grab the pump and some spokes together to stabilize the pump.
Not the spokes. Grab the rim and curl your fingers around the pump head.
All the bike tires will be thicker than inner tubes, but they do make thicker inner tubes, that would be better than not having it, and it would be easier to cut than a tire, that is for sure. Not even sure how I will cut my tires yet when I do this, I’m thinking I’ll try a box-cutter first.
Hijack
My SIL has a problem with her back tire always going flat. She got a new tube and she filled it to 50 psi as recommended on the tire. She rode it for a few minutes and then parked it in the garage. About 5 minutes later the tube exploded. What could have caused that?
Most likely, whatever caused the first flat is still there. Possibly a sharp object embedded in the tire (thorn, glass, piece of metal, etc). Remove the tube and run your finger all along the inside surface of the tire and see if your finger catches on something. Or it could be the rim tape is worn down or pushed to the side, exposing a sharp edge of the rim or the head of a spoke. This is usually obvious by just visually inspecting the rim.
Another possibility: when a tube blows up shortly after it’s installed, it’s often because it was pinched between the rim and tire. To avoid this, I generally inflate the tube slightly, then run a tire lever or a finger all along the gap between the tire and rim (both sides) to make sure the tube isn’t caught in this gap, before fully inflating the tire.
Pneumatic tires have the feature of custom PSI. A solid tire you are basically stuck at whatever it is equivalent too which would change on how cold it is (most rubbers become less elastic as it gets colder). When I used to ride I’d adjust PSI according to the trail. Also, tubes and tires can be folded fairly flat if they are not inflated.
Another reason would be mounting the solid tire. You need tension along the bead to keep the tire on the rim and and a solid tire might be difficult and you’d have to make sure that when it was hot out that whatever material did not expand or become to elastic to allow the tire to slip off. I have seen “foam” tubes that were like a real hard sponge rubber but they rode like crap. OK for slow speed but not for anything serious.
You know, maybe you should start trying to find an alternate route to work. Just sayin’.
or a hoverbikes.
FWIW, I’ve had good results with the Specialized AirLock self-sealing inner tube. (Whereas Slime was pretty much useless.) To the extent, twice, of sealing large holes from screws which had augered into the tire. Also good with large pieces of glass which can be picked out. Not good with small pieces of embedded glass, which end up cutting the tube again and again. For those, I need to patch (and, from the location of the puncture, am able to locate and remove the offending piece of glass). Mixed results with small pieces of wire and such. For context, this is daily commute riding in San Francisco. Lots of crap in the streets.
Also a great fan of Armadillos and the Topeak air pump.
I do that, with the inner tube - actually have two cut-up dead tubes over the inflated one (I’ve only done this on my rear tyre to date as that’s where 99% of my punctures happen). I think an old tyre would make it quite hard to fit a tube in, as fitting two dead tubes is quite a squeeze.
I fitted a ‘thorn-resistant’ tube about a month ago, no punctures so far, although it will be a couple more months before I can say it’s effective.
:eek:
Wow, that’s a lot of precaution, how far are you riding? I ride 10km each way with one spare tube and a couple of patches.
It’s more complicated than that. Check out the second page of this PDF document, which shows the permeability of oxygen and nitrogen through various materials. The absolute permeabilities vary as a function of material, but more interestingly, the relative permeabilities do too. In tetra-bromo bis polycarbonate, oxygen diffuses through 7.8 times as fast as nitrogen, but in poly-wanna-cracker (or whatever that first one on the list is), oxygen diffuses through only 1.6 times as fast.
Partial pressure surely matters - diffusion rate definitely scales with it - but it’s not the only factor. Molecular mass surely matters to diffusion, according to standard gas kinematics - but it’s not the only factor either.
Nitrogen does diffuse out through tires (which are either tubed/lined with butyl rubber) more slowly than oxygen, but the difference is not all that amazing - only a factor of 1.6. That is, nitrogen leaks out about 66% as fast as air.
here’s a table comparing permeability of O2, N2, and CO2 in numerous polymers including butyl rubber. On a volume basis, CO2 escapes almost twice as fast as nitrogen. So yes, filling your tire with CO2 will get you home in a timely manner after a flat, but for minimum inconvenience, you’ll want to purge it and fill with air once you get home.
I think if they’re being sold at Walmart, we can’t really call them a fantastic vision of the future.