5

If you had 35mm tires (Schwalbe marathon supremes to be specific) would you get innertubes speced as 28-35mm or 35-42mm? Or whichever is cheaper?

  • Uh, you put them in the middle, not on the side. (IMO you're better off being a hair small vs a hair large. A little easier to install and less chance that the tube will get wrinkled up inside the tire. If you have to have to go really far afield in an emergency, however, better to scrunch up an oversize tube than badly stretch an undersized one.) – Daniel R Hicks Sep 15 '15 at 23:07
8

Either will work.

Use what your prefer. Smaller will weigh a bit less and be easier to install. Larger won't have the tube stretched as much, so hypothetically could survive a puncture better.

  • I just measured a Bontrager 700x23-25 tube (48 mm stem) and a Giant 700x28-32 tube (32 mm stem), both presta and they weighed 112g and 130g respectively. Both tubes were the normal versions the companies sell (not light or extra puncture protected or whatever). The weight savings between the two sizes is probably around 10 grams -- a small enough weight difference that its negligible relative to even what you ate for breakfast (or if you're feeling peckish, an average small bag of chips is around 30 grams). – Batman Sep 15 '15 at 20:46
  • Smaller tubes are not necessarily lighter. Continental makes a 35mm tube (Cross 28, 155g) which is heavier than Schwalbe’s 28-47mm tube (SV17, 150g). I weighted them once and I dimly recall that the Conti tube was also much heavier than stated. Is there a tube for 35mm tires which is lighter than the extralight Schwalbe SV18 (105g)? – Michael Sep 16 '15 at 6:30
  • Sure, though I'd think if you used the same manufacturer's tubes in the same model line the weight should be monotonic increasing. The point is that the weight of the tube isn't really worth considering. – Batman Sep 16 '15 at 6:44
2

Smaller tube is better. Even significantly smaller (eg. 20-25 mm inner tube in 40 mm tire) will work just fine. Other way around it might be hard to fit the tube inside the tire even before inflating tube.

1

It would be better to use a 28-35mm tube vs the larger. A smaller tube also makes it easier to install.

  • Welcome to Bicycles SE. We're looking for answers with more detail. Please consider clarifying if there are other reasons besides installation ease to use a smaller tube. A short, one-line answer like this is likely to get downvoted, flagged for moderator intervention, and possibly deleted. – jimchristie Sep 16 '15 at 1:01
1

It depends. If you have another bike for which one size is also suitable, get that one. If you're on the limits of your rims with these tyres and could only go one way with your next set, get the tube that would fit those. My previous tyres were 35s and I knew I would probably replace them with something a little thinner so I made sure to get the --35 size target than the 35--.

Tubes are amazingly forgiving. The bike I got recently to fix up turned out to have a 24" tube on a 26" wheel, and it held.

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