How to measure presta valve length?

[I like Skol]

I'm about to order a couple of spare inner tubes for my road bike. The shop I bought the bike from gave me a spare tube as part of the purchase but the valve was far too long. The OEM ones are, funnily enough, the perfect length and also unthreaded so my pumps clamp on brilliantly.

How are the valves measured by tube suppliers?

Is it A-B, A-C or something different?

 

[jay clock]

i would say A to B

 

[I like Skol]

Perhaps I would be better asking if anyone has a boxed Michelin tube (the ones I intend to buy are Michelin A1s) with Presta valve and could they measure it and see how it compares to the stated length?

 

[youngoldbloke]

Just measured a Michelin A1 Airstop 40mm. The measurement is A-C

 

[Mo1959]

Probably a daft question knowing me but does it matter if they are too long? I know if they are too short it can cause problems with a deep rim, but wondered if it really matters if they are longer than necessary?

 

[mangid]

Probably a daft question knowing me but does it matter if they are too long? I know if they are too short it can cause problems with a deep rim, but wondered if it really matters if they are longer than necessary?

I always buy long, and use them on all of our bikes, never had an issue using 60mm on a wheel that would be fine with shorter.

 

[I like Skol]

I always buy long, and use them on all of our bikes, never had an issue using 60mm on a wheel that would be fine with shorter.

But I like perfection!!!!

 

[PeteXXX]

Think of all that extra unnecessary weight you're dragging around if its too long!!!
And thrice if both tubes and the spare are the same...

 

[Mr Haematocrit]

Zipp tubes and Specialized tubes are measured A to C