# What does OS mean when looking at bars/stems?



## BoomingSooner (May 13, 2008)

Hey, just quick question. I notice some handlebars and stems give a size then say OS. What does the OS stand for?

Thank you.


----------



## ProStacks (Jun 19, 2008)

It stands for Over Sized. Basically they require a larger clamp on the stem, as they have a larger diameter in the middle. They offer a stiffer feel, not to mention they are stronger.


----------



## BoomingSooner (May 13, 2008)

So if the stem is OS, then the bars must be OS also?

Kind of confusing. Shouldn't a 31.8 stem fit all 31.8 bars:madman:


----------



## Rod (Oct 17, 2007)

BoomingSooner said:


> So if the stem is OS, then the bars must be OS also?
> 
> Kind of confusing. Shouldn't a 31.8 stem fit all 31.8 bars:madman:


Yes your 31.8 stem will fit the 31.8 bars. Your stem and bars are considered oversized.


----------



## BoomingSooner (May 13, 2008)

Gotcha, thanks.


----------



## sstorkel (Nov 24, 2008)

BoomingSooner said:


> So if the stem is OS, then the bars must be OS also?
> 
> Kind of confusing. Shouldn't a 31.8 stem fit all 31.8 bars:madman:


OS means OverSize, which which is the same thing as 31.8mm. The standard diameter is 25.4mm.

If you've got a stem designed to clamp 31.8mm bars and you've got a 31.8mm bar, they're both OS and you shouldn't have any problems! Some manufacturers don't use the "OS" in their labeling; they just say 31.8 or 25.4.


----------



## ProStacks (Jun 19, 2008)

BoomingSooner said:


> Shouldn't a 31.8 stem fit all 31.8 bars:madman:


Well, it does. 31.8 is the normal OS measurement(as far as I can tell). Standard is around 26 (I think, cant quite remember).

So if you have a 31.8 sized clamp on your stem, go whack some 31.8 bars in. If you have a 26, go with the same for bars :thumbsup: .


----------

