True diameter of a bike wheel + tyre

ggoysens
ggoysens Posts: 25
edited April 2019 in Road buying advice
Hi all,

I'm looking into some new wheels for my road bike, but I'm doubting if I can fit wheels with bigger inner rim widths.

At the moment I have wheels with 15mm inner rim width and use 25mm tyres. In order to make better use of the 25mm tyres I would like to buy some wheels with wider rims.

The thing is I can barely fit this wheel/tyre combination, I only have like a 1 or 2mm margi' between tyre and bike frame (seat tube).

So the question is, do wider rims increase or decrease the wheel+tyre diameter?

Thanks

Comments

  • cougie
    cougie Posts: 22,512
    Wider rims should decrease it as the tyre is more flattened out.

    Can't see there would be much in it though and of you get a stone chipping on your tyre it's going to stick or scratch the frame at least.
  • rwoofer
    rwoofer Posts: 222
    Completely disagree, wider rims definitely make the tyres wider. Given the already tight space, i wouldn't go any wider, unless you go down to 23mm.
  • cougie
    cougie Posts: 22,512
    We know this. Width usually isn't the issue - height is.
  • rwoofer
    rwoofer Posts: 222
    Sorry mis-read. Usually it is the width that is the problem before the height.

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