Can I replace 37-622 tires with 28-622?

[Mick F]

PS.
I had a bike brand new in 1983 that came with 27 x 1 1/4 tyres.
I later fitted it with 27 x 1 tyres.

Weinmann rims, if you remember those.

[fastpedaller]

PS.
I had a bike brand new in 1983 that came with 27 x 1 1/4 tyres.
I later fitted it with 27 x 1 tyres.

Weinmann rims, if you remember those.

The very strong rims with the concave bit that corroded due to water sitting in it? I remember them well

[Chris Jeggo]

Tyre sizes is an update of a webpage originally produced by CJ for the old CTC website. Note that 26 x 1 1/4 and 26 x 1 3/8 tyres do not fit the same rim - there is a 7mm difference in bead seat diameter. My recollections of the sixties agree with this.

Tyres are round objects, and 1 inch is 25 mm (rounded to the nearest millimetre). Thus a 700mm wheel is a 28" wheel and a 650 wheel is a 26" wheel, conventionally. 700A and 650A are narrow tyres, around 32mm or 1 1/4 ins. B tyres are fatter, around 38mm or 1 1/2 ins. It is not clear to me whether size C is 1 5/8 ins (41mm) or 1 3/4 ins (44mm), but it's somewhere round there. If we add 2 times 44mm to 622mm we get 710mm, which is 28.0" (27.95 if you want to be pernickety). So labelling a 700C rim as 28 x 1 5/8 does make sense - the numbers add up, to within a few mm. And fitting to this rim a tyre which is narrower than a 'C', i.e. 37mm which is 1 3/8 to within a couple of mm, you finish up with a wheel whose diameter is less than 28". All the information provided by the OP is consistent. Also, incidentally, a 32-622 tyre will finish up pretty close to 27" diameter and a 19-622 tyre is close to 26", but nowadays we call them all 700C even though they are neither 700 nor C.

These difficulties arise because when you are designing the geometry of a bicycle the wheel diameter is paramount but when you are choosing a tyre or fitting rim brakes the bead seat diameter is critical. Both dimensions are important.

Others have answered the OP regarding tyre width suitability vs rim width. Replacing 37mm tyres with 28mm tyres will also reduce ground clearance by 9mm (3/8") which might matter when pedalling round corners or riding off-road (in a rut?).

[Mike_Ayling]

The tyres on my bike are labeled 700c x 23mm.
They also say 622 x 23.
No mention of 28, 27, or even 26.

And the sooner we switch to using ISO sizing the sooner we'll have to stop puzzling over markings, looking up what the other person meant, and converting,

Jonathan

Amen brother. The roadie and the mtb rider are on the same diameter rims, 622 only the width of the rim and tyre differs. Not many people - know that as Michael Caine used to say.

[Mike_Ayling]

The OP said his tyre said 28".

Not 27 x 1 1/4 or 26 x 1 3/8 etc.

Where can I get some of those talking tyres that say things?

Mike

[kylecycler]

I still don't quite get why they persist with such confusing sizing - when this thread was first posted I went looking for 28" x 1 3/8" x 1 5/8" tyres and this was the first one that came up:

https://www.halfords.com/cycling/bike-p ... 52004.html

Continental Tour Ride Bike Tyre - 28" x 1 3/8" x 1 5/8"

Size: 700c

(No proper explanation of the tyre width)

BIKESTER also stocks the same tyre, again listed as 28" x 1 3/8" x 1 5/8", and you have to scroll down and refer to the Specifications to see:

Tyre Size ETRTO (Width x Diameter): 37-622

https://www.bikester.co.uk/continental- ... 08248.html

Incidentally, not really relevant to this thread, but I bought a pair of these Continental Tour Ride tyres in 27.5" aka 650B aka 584mm, supposedly 42mm - ETRTO 42-584 - but they measured 38mm - undersized. Since they were meant to replace 48mm tyres (I thought I'd go narrower), they were far too small.

[Jdsk]

The tyres on my bike are labeled 700c x 23mm.
They also say 622 x 23.
No mention of 28, 27, or even 26.

And the sooner we switch to using ISO sizing the sooner we'll have to stop puzzling over markings, looking up what the other person meant, and converting,

Amen brother.

I still don't quite get why they persist with such confusing sizing...

The best way to affect their behaviour is by changing our own. It isn't easy, but the trick is to not only use ISO sizing but if you ever have to convert then to only ever convert forwards. This thread is a great illustration of what happens when you don't do it that way.

Jonathan

PS: Technical standards affect a vast amount of modern life, and they're fascinating. The history of standards can offer all sorts of insights into the technology of the time. And reveal the propensity or reluctance of people and societies to welcome or oppose change. When Cameron started talking about promoting Imperial units in schools again I realised for the first time just how deep a mess we were in.

[531colin]

Trouble is, a lot of the worlds metal tubing and sheet metal is still produced in Imperial (inch) sizes.
Thats why we have 31.8mm handlebars, 28.6mm frame tubes, and all the rest of the nonsense.....they are sensible fractional inch sizes.
Inch steerers are one inch external, the wall gauge is one sixteenth of an inch. So quill stems are seven eighths of an inch..22.2mm.
Inch and eighth steel steerers have a wall gauge of one sixteenth, so the internal diameter is one inch.....it follows that if you want to extend such a steerer, you can sleeve it internally with a bit of inch steerer and braze on an extra length of inch and eighth steerer.
If I talk about this to young people, they just look at me blankly, like I'm talking Martian or something.
Inches and fractional inches are a pain to work with, I always use metric when its sensible to do so......but all the while stuff is manufactured in imperial sizes, you might as well understand what it means.
Go to the timber merchants, see what lengths timber is sold in.....its sold in Imperial lengths....but they call it something point something metres.

[531colin]

Tyre sizes is an update of a webpage originally produced by CJ for the old CTC website. Note that 26 x 1 1/4 and 26 x 1 3/8 tyres do not fit the same rim - there is a 7mm difference in bead seat diameter. My recollections of the sixties agree with this............

Quite. You could often fit either 26 x 1 3/8 or 26 x 1 1/4 Wheels into a frame, but you couldn't fit the tyres on the wrong wheels.

[531colin]

I had a look at some actual tyres.

Vittoria Voyager Hyper, bought just as supply was getting difficult, so a year or three old?
Labelled 37- 622 , 700 x 35c and 28 x 1 5/8 x 1 3/8

Various Schwalbe, labelled stuff like 40 - 622 , 28 x 1.5 , 700 x 30c ***

EDIT.....should read 700 x 38c can't read my own handwriting!

Its my recollection (not an alternative fact) that when I was selling Raleigh Pioneers ( twenty something years ago ?) those tyres had the full 28 x 1 5/8 x 1 3/8 nonsense encrusted on them.

[iandusud]

My memories are correct,
Same rims would take 1 3/8 and 1 1/4 tyres.

This day and age are different of course, but the OP said it was an "older road bike" and said 28 was marked on the tyre.
Mine said 26 in those days, and later I had a different bike and they said 27 on them.
That's the TYRES ................ not the tubes or the cardboard labels on either of them.

These days, things are completely different, but I am talking of an "older road bike" and putting my point across.

I don't know what era your hail from but in my life time (I'm coming up to 62 and was working in the bike trade from the age of 15). I can assure you that 26 x 1 1/4 wheels would not accept 26 x 1 3/8 tyres and vice versa (or at least they weren't meant to because they use a different size rim). A 26 x 1 1/4 rim has bead seat diameter of 597mm and a 26 x 1 3/8 590mm, the difference being 7mm which roughly equals 1/4" i.e. 2 x 1/8" being the difference in section of the tyres. Imperial bike tyres have always been measured by their external diameter therefore the wider the section the smaller the rim. What caused confusion was in the 80s when someone started making narrow section tyres like 27 x 1 to fit 27 x 1 1/4 rims. This was followed by the 559 rimmed 26" wheels that we had on mountain bikes where tyres became available in all sorts of different sections but these didn't hail from Britain and therefore didn't conform to the British system of tyre sizing.

[Mick F]

I have no doubt that you are correct, but my statement was for 27" rims.
They would take 1 1/4 tyres and 1 3/8.

Dunno about 26" because mine were always 1 3/8.

My Raleigh Clubman I bought in 1983 from Dales Cycles in Glasgow came with - I can't remember the width of the tyres - but the bike was 27" wheeled.
Swapped the tyres a few times, and went down to 7/8th eventually. This is if my memory serves me correctly, but they were less than an inch, but still the same Weinmann 27" rims.

[Mick F]

This is me on the Clubman in 1986 entering Portsmouth New Hampshire (USA) after completing a 500mile ride from Niagara Falls Canada, to Portsmouth NH. Can't remember, but it was eight or nine days.

[Jdsk]

.......hence a 26 x 1 1/4 tyre requires a bigger diameter rim than a 26 x 1 3/8 tyre

No they don't.

............ or they didn't when I was on 26" rims in the 60s and 70s.
Had both those widths of tyres on the same bike over the years.

I have no doubt that you are correct, but my statement was for 27" rims.
They would take 1 1/4 tyres and 1 3/8.

Jonathan

[Mick F]

PS:
If you zoom into my photo, you can see that the tyres are much narrower than the 1 1/4 "standard" for 27" rims.

I have the original photo somewhere. The one I showed is just a scan, but the zoom-in shows how narrow the tyres were.
From my memory, there were a variety of tyre widths for various wheels.

See where the brake track is?
You can gauge the tyre height.