Seat Post Size Help Requested

[S6PNJ]

I've just bought myself a new MTB 'hack' for work and am in the process of fitting my 'good' (ie still working and not knackered) bits from my BSO onto it to make it functional. It's a weight saving on my BSO and I'm not worried about it being use for mile and n=miles as iot will only do the odd short journey every now and then. I have a good MTB and a good road bike so don't need anything else shiny at the moment.

The one issue I have is that I need a seat post.

The frame (that I bought) is a Giant Boulder Alu Lite in 6061 tubing. I've measured the seat post riser (or whatever it should be called) but I can't make out if it is 30.8 or 30.9mm ID. It appears to be 35mm OD though.



I've found Sheldon Browns seat post web page and the only one marked against the 6061 Ali is the 1998 Terrago. I've no idea how old the frame is I bought though.

I only need a cheap and cheerful seat post and clamp, nothing special, so as cheap as possible suits me fine. Any ideas as to what I actually need, whether its 30.8 or 30.9mm?

Oh, my BSO is a Halfords Apollo Slammer (2001/2 vintage) by the way so I'm not working with quality components here!

[snotrag]

30.9 is a standard size and the norm for a Giant.