Can anyone please tell me what this number on the valve mean?

  • 3
    Could it be "LL"?
    – Paul H
    Jul 23, 2019 at 16:11
  • Probably "Inspected by inspector number 77." Jul 23, 2019 at 17:10
  • 1
    Could it be "LL"? – Paul H 4 hours ago. I thought that too, as there is an LL printed in white on the tyre tube itself....I have tried to find what it means if it is 77 or if it is LL but I have been unable to find the meaning of either...if it is LL, do you know what that represents?
    – Lisa
    Jul 23, 2019 at 20:56
  • 1
    I've never seen a tube or valve with this. Is it reflective? Is it a particularly old tube from the days where some white paint was a "safety" thing? Is there any other text written on the outside of the tube ?
    – Criggie
    Jul 24, 2019 at 5:06
  • 1
    @PaulH Upside down 77 looks like: ㄥㄥ vs right side up: L L -- As you can see a 7 has a more acute angle than an L. Jul 28, 2019 at 17:50

1 Answer 1


A Schrader valve has an external width of 7.7mm per the specification. The number written on your valve refers to this fact.

Source: https://en.wikipedia.org/wiki/Schrader_valve#Dimensions

  • This is probably correct, but can you provide some proof that this is what the 77 refers to?
    – Andy P
    Jul 30, 2019 at 13:15
  • @AndyP I've searched multiple times but can't find anything. Maybe a bike store employee could look through their collection of tubes and find another one with a white stripe and number on it? Jul 30, 2019 at 15:09
  • 2
    I checked with the store guys once and he assumed its valve width
    – Ram
    Jul 31, 2019 at 11:35
  • 1
    7.7mm is the "OD" of the thread, the actual valve stem can be either 11.5mm or 16mm presuming we are just talking rubber stem Schrader Valves
    – Dan K
    Jul 31, 2019 at 12:44
  • 1
    For some reason I cant edit that comment above, but for the sake of being available, good old Sheldon Brown and a few other sites have the OD size listed as 7.7mm sheldonbrown.com/gloss_sa-o.html
    – Dan K
    Jul 31, 2019 at 13:05

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