Personally I always use black tyres because they are intended for the road and not for hospital "floors" and shopping centres.

Partly this is because they look better, and less "medical" (and they don't go all "yellow" like the grey ones do) and they really are longer lasting by miles. 

This is because the rubber used in "grey" wheelchair tyres is usually much modified, less sticky compound, so that it does not mark floors, and instead of wearing out normally, and leaving black smears on the carpets and polished floors, as black road tyres do, instead it "crumbles" away in use... So it can just be vacuumed up, or brushed away. But in use it wears out rapidly!

Also the grey tyres are generally of lower quality (cheaper) Korean or Chinese ones with fewer plies giving a weaker more puncture prone tyre.. OK so that's just the colour then!!!

Tyres with tubes are very puncture prone. In general automotive use it is estimated that tubed tyres are approx seven times more likely to suffer a puncture than a tubeless tyre is over the same mileage and conditions! Seven times! Since we all suffer from punctures due to broken glass and other rubbish at the edges of the roads this is really significant!

So since we suffer glass and other punctures in powerchairs so regularly then, why don't we (or better still - the powerchair manufacturers) all use tubeless tyres and rims? At the very least on the bigger driven wheels. They are the SAME PRICE for gods sake. Why do you suppose punctures in car tyres are so few now? Clue - TUBELESS! 

But because this is "new" (to powerchairs) technology and powerchair manufacturers are so damned slow to move forwards, we are still all using old fashioned tubed tyres...  Oh that's just great then...

<<< Except for me that is! 
As far as I know tubeless tyres are not used on powerchairs that we buy? See details on my F55s page here This is a 350 (3.5 inch) wide tyre and wheel rim, all tubeless and heavy construction so no puncture problems! And cheap...

I use these tubeless trailer tyres and wheels that are slightly bigger than the standard overpriced puncture prone tubed standard ones. Along with the trailer wheels at the same time. They are cheaper complete with the wheel than the standard ones! Also strong, (more plies) and since this change over two years ago have not had any more punctures on the rear...  And they seem everlasting too. The standard tyres are 300 x 8 inch rims. These are 350 x 8 so overall are a little wider and taller but fit easily enough.  If you wanted just to fit the tyres you can, but standard wheels are not tubeless, so you will need to keep your tubes.

The front ones are less of a problem to me because they are also black with the advantages in compound that this gives you, but theoretically these are still puncture prone, due to their tubes.  I can't find 8 inch (actually more correctly 4 inch rims with 3 inch tyres) tubeless tyres in this size and also I would need the wheels to match.  So in the interests of no more damned punctures I cut the treaded part from an old set of front tyres and stuck this with contact adhesive inside the new ones before fitting them.

Now any sharp metal or glass has to go through twice as much rubber before it sees the tube! Result? No punctures so far in the 3 years I have been doing this. Before this it was a weekly, or often daily occurrence.

Foam tyres, foam inserts, etc are all heavy, and cause the dreaded shopping trolley "wobbly wheel" syndrome at full speed - at least on my chair - so I don't use these and can't really recommend them... In addition these types of tyres absorb a lot of rolling energy compared to Pneumatic ones, meaning shorter range too.

So what to look for?

• Size, forget 12 inch, or 14 inch or 8 inch daft descriptions! These terms mean little! You need the rim size. for example my front ones are 3 inch wide rims (and tyres) and 4 inch diameter rims. So I buy 3x4 tyres that are 8 inches or 9 inches total diameter. There are plenty to choose from. As long as you don't mind black!

• Colour, if you have white carpets stick with grey tyres! They mark surfaces less if at all due to the different rubber compound, but they look horrible, and crumble away and turn yellow/brown over time. I use black!

• Tread - You don't actually need any*  Its only there to clear water at speed. Unfortunately most are designed for other purposes so we are stuck with it! Choose the ones with the least tread. *Unless you spend time off road, on wet grass etc.

• Plies. More is "stronger" less punctures, but harsher ride. You can use less air though if this really is a problem.

• Tubed or tubeless? Tubeless gives FAR less punctures. But you will need different wheels. See here for how I managed this.

• Price! Black ones are for mass market so are usually cheaper. As long as you don't buy from powerchair dealers! Then they will cost a small fortune. Trailer places, ATVs etc best places to look. Or online at trailer suppliers etc like here as an example.