Width of a 27 1-1/4 inch tyre

Hello :

Would anyone know the width in mm of a 27 1-1/4 inch tyre ?

Is it 1.25 inches equivalent in mm ( ie 31.75mm ) - Or some other number ?

I am trying to “compare” the ride quality of a bike I used to ride eons ago on similar road conditions that I will once again ride on with a contemporary bicycle that I will purchase shortly.

I do understand this is not an equal comparison for the different frame materials ( perhaps even tyre technology etc. ), but as I mainly have the previous experience to work with I am trying to arrive at some “base-line” in terms of ride-quality I can expect based on tyre width.

This is important as I have narrowed down my choice to 2 frames - One that can accommodate 28C & the other to 32C & hope to “match” the earlier ride experience.

I also appreciate that this is just one variable among a few others that will be considered as I make the final decision on the optimal bicycle to purchase.

Hope some of you have an answer to my above question.

Thanks in advance.



  • dj58
    dj58 Posts: 2,215
    The ISO equivalent is 32 x 630mm, from the description of the roads you will be riding, I would say go for the bike that will take a 32C or larger size tyre. As eluded to in your other post, you can go down a size if required, though difficult to increase the tyre size if you choose a bike with limited frame clearances. Your choice of tyre size will of course, be dictated by the type of brake system used, rim or disc.
  • j_vora
    j_vora Posts: 63
    Hello DJ58 :

    Your confirming that a 27 1-1/4 tyre's width being equivalent to a 32C and the discussions from previous posts where you provided valuable advice confirms and ratifies that a frame that can accommodate 32C is the way to go - This is now settled and the bike chosen


    Sound advice, as always !

    Much appreciated,