Continental GP 5000 clinchers - actual width variations between sizes

I currently have a 25mm conti 5000 on the rear of one bike and a 23mm on the front. The wheels are Campagnolo Bora WTOs with 26.5 external and 19 internal widths.

With latex tubes and both tyres inflated to 85 psi, the actual width of the 25mm is about 25.7, while the 23mm is 25 bang-on.

While I've read elsewhere that the 25mm 5000s come up narrow, it strikes me as very weird that two tyres labelled as differing by 2mm actually differ by a little more than half a mm...

Have I just got a weird batch of one or the other, or is this consistent? Could it be that the 23mm is designed to the older ETRTO standard and the 25mm to the newer one, on the assumption that people still running 23mm tyres are using narrower internal rim widths?

Comments

  • N0bodyOfTheGoat
    N0bodyOfTheGoat Posts: 5,906
    edited March 2023
    I've used 23mm and 25mm... approx +1 and +2mm respectively after fitting iirc.

    32mm... Just over 30mm to begin with, just over 31mm after ~12 months.

    On 19mm(?) internal rim width Fulcrum Racing Sport 77DB.


    I've got a pair of new 30mm, probably fitting at least one to the rear of my VEL 50RL wheels (20.3mm internal rim width iirc).
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    2020 Voodoo Marasa
    2017 Cube Attain GTC Pro Disc 2016
    2016 Voodoo Wazoo
  • neeb
    neeb Posts: 4,470

    I've used 23mm, 25mm and 32mm... Only the latter sized small, just over 30mm to begin with, now just over 31mm, others approx +1/2mm respectively after fitting iirc. On 19mm(?) internal rim width Fulcrum Racing Sport 77DB.

    Did you ever measure the 23mm on those rims though? Did they measure large? (nearer 25)?


  • Yes, ran big, editted my earlier post.
    ================
    2020 Voodoo Marasa
    2017 Cube Attain GTC Pro Disc 2016
    2016 Voodoo Wazoo