Frame sizings

allthegearnoidea

evening all!
been looking at frames last couple of days comparing sizes geometry etc.
now the frame i had which is to be replaced due to breakage is 20", i'm on the 6ft mark and had no probs with it at all, and as far as replacement goes, i'll prolly go for a like for like (geo matches current broken one) But! something in my mind is saying go for an 18".
the main differences in the frames geo is the top tube is 30mm shorter, the question is effectively can this be counteracted by a layback post and slightly longer stem?? currently have an 80mm stem, so effectively a 100mm stem would reduce it to 10mm??
now am i thinking along the right lines here???
my current frame i'm using is a 19" full susser but have No confidence in it, its an old tech one from around 01 ish (non disc - converted using an a2z adapter) bob's for england and is very Vague when pushed hard! rode the trails i loved on the old HT and scared myself silly with just how Vague it is! the HT felt direct and quick and wo9uld change direction on the dot! frame size its fine, notice its a bit smaller but not all that and its set up as per the old bike using the old gear form it,

i know the general rule is to go and try some bikes for sizing etc, but as the frames are in taiwan/china may be a bit tricky!! i'm going to drop down the lbs during the week as they do stock one of the frames i've found and see what tyhey think as its normally a bike only option, but the one i've found only comes in 18" and i trust their opinion!


basically i'm just after finding out what you lot would consider! would you go for the larger frame or run a shorter one with a long seat post and stem?? i'm thinking that the smaller frame will be a bit more chuckable and direct?? but dont want to feel as if i'm perched ontop of it as such!! (rather than sat in it!!)
i think the ideal size would be a 19" but none of the frames ive narrowed down to attainable after christmas come in such size!

any views would be greatfully received!!

many thnaks in advance.

Timmo.

supersonic

You can replicate the same hands/feet/backside position, but the bike will be different. The longer stem will slow the handling down, thw wheelbase will be shorter, you will be further behind the bottom bracket.

allthegearnoidea

thanks Super,
i wanted to make sure i was ont he correct line of thinking!!! hopped on a mates giant which was a medium frame and felt spot on, which kinda got me thinking,
i'll try out a medium at the lbs if they have one in and get an idea,

just want to clear it up in the old noggin! you know what its like when you gte a thought stuck in there!!

supersonic

Medium, large, small.. means nowt really! Brand to brand, model to model it is just a differentiator.