tube size confusion

[s.e.charles]

i have Panaracer Pasela tyres ('83 Raleigh mixte) marked 27 x 1.25" ----- 32 - 630

i want tubes with a minimum 40 mm presta valve stem. (adapters in the rims)

sizes i see at suppliers dance around these numbers, but not much hits the mark.

Q: what latitude do i have?

thanks

 

[Midlife]

Something like this ?

https://www.bikeparts.co.uk/products/schwalbe-sv17-700c-28-47c-27x1-1-4-40mm

 

[s.e.charles]

kind of sort of; by my word the range of sizes completely baffles me.

 

[non-fixie]

The SV17 will work, although I prefer the slightly narrower SV16, as it is a bit lighter and will stretch to 32mm as well. And anything labeled "622" will work just as well on 630 rims.

 

[s.e.charles]

if this tube is 27.5, how does it get rated 630?

the box indicates 28" - and is only adding to my confusion.

i am assuming it does Not have the weight of the "marathon" line of puncture resistant tubes - which are heavier than i need.

thanks

ps: i just ordered (2 + spare) the SV16 tubes w/ 40 presta from the Big A; so i can send them back if it's a problem.

 

[non-fixie]

27" is 630mm, except for 27 x 1 1/2, which is 609mm and 27.5", which is marketing speak for 584mm (and is called 650B in France).

Confused? You should be!

Anyway, 622, 630 and 635 are all close enough for inner tubes labeled 28". Just check that the width is somewhere near what you need.

 

[Tootyred]

Confusion between tyre outer diameter and wheel outer diameter possibly here?

 

[non-fixie]

Confusion between tyre outer diameter and wheel outer diameter possibly here?

Among other things, yes. The best resource regarding this subject I have found is St Sheldon's article on tyre sizing:

Tire Sizing

 

[s.e.charles]

thanks.

the second bike (years back) i ever worked on was a Peugeot and why didn't anyone ever tell me sizes would be different???

but i'm plugging away; appreciate the help & link.

sid