Odd sized drop handlebars

[Crepello]

ideally the sizes should match.....

Yeah but.....Sounds like the bland advice we hear from cycle shops all the time....' "Ideally" sir, you need to buy this Shimano spec'd spare - that'll be £40 please.'

Do you know what I mean? And why forums like this are such a useful source of insight - if we are honest with each other.

What is the fact on clamp size mixing? Ideally it should be the same, but IS .2 mm enough to effect a quill clamp integrity?
(Martin C suggested it is an old practise)

Personally, I don't think that I'd try anything greater than that .2mm difference.

 

[jimboalee]

ideally the sizes should match. jimbo's posts, while entertaining, should always be taken with a pinch of salt

What you are really trying to say is "I don't know if jimbo is right or wrong, so I take what he says with a pinch of salt"

 

[HJ]

hi guys, I've bought some ITM drop handlebars , the clamp area has a diameter of 25.6mm. I can't find any stems for this size, and according to sheldon this size shouldn't exist either!

http://www.sheldonbrown.com/gloss_ha-i.html#handlebar

think a 25.8 stem would be ok?

How about these you can have 0.2mm either way...

 

[snomaes]

The fit between bars and stem must always be an interference fit, NEVER clearance.

An interference fit is when the bar diameter is larger than the clamp diameter. This ensures that the clamp will ALWAYS clamp onto the bars.

If a clearance fit is achieved (i.e. the bar diameter is smaller than the clamp diameter), it will not be possible to tighten the stem clamp without using a shim of some kind (suggestions have already been made for this, aluminium can or specialist shim material).

In reality, a size-for-size fit between bar and stem clamp (i.e. the external diameter of the bars is exactly the same as the internal diameter of the stem clamp) is worse than a slight interference fit (i.e the bar should be very slightly larger than the stem clamp).

Personally, I would always ensure that the bars are slightly (no more than 0.2 mm) larger than the stem to ensure a guaranteed interference fit, which will prevent any possibility of movement once the clamp is tightened.