Difference between 1.5/2.125 and 1.95/2.125 inner tubes?

Question

A particular vendor on eBay has a wide range of inner tubes, all of which are branded as "Raleigh". However, there are just two types that would suit me:

• 26x1.95/2.125, Presta valve
• 26x1.5/2.125, Schrader valve

My tyres specify 26x1.95.

As I don't want Presta valves (and the Schader valve inner tubes are cheaper), I was wondering what detremental effect there would be, if any, to using the second type of inner tube which the wider range (1.5-2.125), when inflating it to the higher end of its range.

After reading Can I use an inner tube that's too narrow for the tyre?, it would appear that the more stretched an inner tube, then the more issues one may encounter.

In order words, is there any advantage (i.e. less porousity, less flats, greater mileage, etc.) when using an inner tube which has a more narrow toroidal diameter range? Why does one inner tube type have a more narrow range than the other type, and is it "better" to use a narrower ranged inner tube, than a wider ranged inner tube?

Answer 1

There is basically no detrimental effect. From a consumer/rider perspective, it really doesn't matter in almost any situation where in the printed range you are as long as you're in it. The exception that comes up most frequently is if a tire is significantly different in width than what it purports itself to be on the sidewall. That doesn't come up very frequently as an issue in the wide tire sizes.

There is a provable ability to reduce weight by going high in one range instead of low in the next one up. There is probably some none-zero difference in the porosity and rate of leakage that results from how stretched out the tube is between the two options, but it's not likely to be meaningful.

There are some deeper questions in why various tubes have the printed ranges they do that you'd probably need inside information in the inner tube production world to know. It's hard for a consumer, mechanic, retailer etc to say what minor material or construction differences are out there, particularly at the double-layered valve area where eventual failures from over stretching can occur. It's also hard to know the role played by simple difference of opinion on the manufacturing end in what range it's reasonable to print on literally the same tube and on very similar ones.

When tubes do fail from simply wearing out or being used too long, which takes a long time, it's usually around the valve area in the transition zone between the single layer construction that comprises most of the tube and the doubled-over area around the valve. The two have different abilities to expand, which causes some degree of stress riser. This is also the area that gets stressed the most from running a tube that's a little stretched. My speculation from years of handling various tubes is there's simply some discrepency in opinion in the tube labelling business about how generous the target lifespan needs to be, and that leads to some companies being willing to print wider ranges than others. There may also be examples of companies that feel their tubes have some kind of materials or construction advantage that allow them to reasonably print wider ranges than others.