Tyre widths - out of curiosity.

[mzjo]

Putting this here rather than in the Knowledge section because it is only an observation not a question and not really linked to the other tyre width questions.

When I built up my bitza 650B tourer i used the 37-584 Schwalbe HS159 tyres that I had already for the tandem (which donated the rims). My mate Christian, 650B mecano and fanatic, remarked that they were no wider than the 30-584 tyres made for the Confrérie by Hutchinson (which are on all other counts a superior tarmac tyre). He has now supplied me with a pair of Hutchinsons and yesterday was the time to fit them, during which I took some measures. The rims are ZAC19s, which I think have an internal width of 19mm (or something very close). Having a 44-584 IRC tyre from a bicyclette in the garage I put that on and measured as well (it was a tyre that I had bought about 10 years ago in the local hyper and the synthetic gum walls have gone a bit inflexible).

The results: 37-584 Schwalbe = 34mm wide
                    30-584 Hutchinson = 32mm wide
                    44-584 IRC = 35mm wide
(which is handy to know since it means that I can source emergency spare tyres in supermarkets: they are a slightly tighter fit and may be a tiny bit higher judging by the difficulty squeezing the axle of the hub pasr the mech but they go).

Of course as a good Confrére I am keeping the Hutchinsons on. I suspect that as well as being half the weight of the Schwalbes, the the thinner sidewalls mean a bigger volume of air and a bit more comfort

[woollypigs]

Ah the old "its does NOT do what it said on the tin" thing.

I had a long moan about 20" tyres some years ago - here is the short version - read what it said on the tyres I had, ordered the same online. I could put the new ones inside the old ones even if they had the same numbers written on them. Go Figure!

I have also noticed what you have regarding width.

[mzjo]

Ah the old "its does NOT do what it said on the tin" thing.

I had a long moan about 20" tyres some years ago - here is the short version - read what it said on the tyres I had, ordered the same online. I could put the new ones inside the old ones even if they had the same numbers written on them. Go Figure!

I have also noticed what you have regarding width.

TBH and after a bit of thought the Hutchinson is made for the Confrérie with their own mould, so the maker is unlikely to concern himself overly with a couple of miilimeters. The brethren of the Confrérie are more concerned that their tyre does what they want (a fast light road tyre with a reasonable volume at a relatively low price) that the numbers on the side concern them a lot less than their other criteria (wear rate, construction integrity + those already mentioned). Of course the tyres are available on the open market so this might concern others but the Confrérie are more concerned that people don't say their tyre is rubbish!

The big surprise is the other two tyres being so much under size. My m-i-law's bicyclette is still here and might have one of the original orange Hutchinson demi-ballon on it, I ought to measure that!