2

My bike uses a tire size of 700x23/25C. I understand that the 700 indicates the diameter of the rim. 23 is supposed to be the width of the tread which I believe means 23 mm, am I right? So what does the 25c mean?

4
  • 2
    Possible duplicate of What does the "c" in bicycle tire size mean?
    – ojs
    Commented Aug 29, 2017 at 17:22
  • 3
    @ojs nope - that's not a dupe because this is about two numbers for the tyre size, and not specifically about the c.
    – Criggie
    Commented Aug 30, 2017 at 8:15
  • 1
    Can you tell us what manufacturer and model your current tire is, and perhaps include a picture of the size info printed or embossed on the sidewall? Commented Aug 31, 2017 at 18:19
  • Keep in mind that 2mm is hardly measurable. You can't get a repeatable measurement more accurate than that, especially on different rims. Commented Sep 1, 2017 at 12:13

1 Answer 1

3

Some manufacturers (e.g., Specialize) offer two width measurements (e.g., 700x23/25c) to indicate that the carcass is 25 mm wide, but that the tread patch is equivalent to a 23 mm tire. I believe this is done to create a more supple tire (larger volume tires can be run at a lower pressure) while reducing rolling resistance.

Another possibility could be to indicate width/height profile differences. A tire profile that is perfectly found tire will be the same in both. I don't know if any manufacturers are doing this.

2
  • 1
    Another possibility is that the actual width of a tyre in use depends on the width of the rim it is mounted on. I haven't come across a manufacturer labelling then with a range though.
    – armb
    Commented Aug 31, 2017 at 16:41
  • @armb I think a hyphen would make more sense to indicate a range. Slashes usually indicates a duality.
    – Rider_X
    Commented Aug 31, 2017 at 22:56

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.