Which inner tube do I buy for this mountain bike?

Hi all 
recently had a puncture in my 5 year old Halfords mountain bike. While I was fixing the puncture I noted the markings on the inner tube. 
It says...
CST (Made in China)
26 x 1.90 / 2.125

So, seeing as Halfords are doing 4 inner tubes for £10 I thought I’d buy some. So, I go to their website and I CAN select 26” but there is no 1.90 option. Please can someone advise if I can use the ones that are 1.75 - 2.125 or do I need the exact size or a different one?

thanks all. 


  • pinkladyvenuspinkladyvenus Forumite
    361 Posts
    Tenth Anniversary 100 Posts Name Dropper
    I think the 1.75 - 2.125 should be ok as it means it will fit tyres between these measurements 
    Sealed pot challenge member 437
  • Brian_PamoBrian_Pamo Forumite
    124 Posts
    10 Posts Name Dropper First Anniversary
    Thank you 
  • moleratmolerat Forumite
    29.2K Posts
    Part of the Furniture 10,000 Posts Name Dropper Photogenic
    Just make sure you get the correct valve.
  • vacheronvacheron Forumite
    1.5K Posts
    Part of the Furniture 1,000 Posts Name Dropper Photogenic
    Agree with Molerat, if the valve looks just like that on a car tyre it is a Schrader Valve, if it is silver and more "pointy" it is a "Presta"

    Don't worry about going down a size on the tube. I have done this for decades after a tip from a bike mechanic. If I have a 2.0 tyre I buy the 1.5 or 1.75 tubes. This not only makes them a little lighter and easier to carry as a spare, but there is also less chance of pinching the tube between the rim and the tyre when you replace them.

    PS, in case you aren't aware, "26" is the diameter of the wheel in inches and "1.90 / 2.125" is the width of the tyre in inches .

    • The rich buy assets.
    • The poor only have expenses.
    • The middle class buy liabilities they think are assets.
    Robert T. Kiyosaki
Sign In or Register to comment.
Latest MSE News and Guides

Did you know there's an MSE app?

It's free & available on iOS & Android


Regifting: good idea or not?

Add your two cents to the discussion

MSE Forum

Energy Price Guarantee calculator

How much you'll likely pay from April

MSE Tools