Linear rail question

[jdholbrook]

Thinking about using linear rail and bearings on my router.
The planned size is 36"x48".
Would 20mm rail be strong enough on the X axis (48")?
I'm sure I could devise something to support it at several places.

Thanks

Edit/
I should have explained that I'm looking at those 20mm chrome plated solid rod and bearing combo for $60 on ebay. Rod is 60" long.
Edit Off/

[wood_donkey]

Do you mean linear rails like THK? If thats the case, then 20mm will be more than enough to tackle and loads your machine will produce. If you are talking about round shafting with linear bearings, which I think you are, it should be okay but it MUST be supported.