Hi all,
I'm new to the site and this is my 1st post so be kind :-)

I've just bought a GT Agressor XC3 from Halfords which seemed like an exceptionally god spec for the price, I've got it home and ridden it though and I hate it !!!
I have a very old Free Spirit which was falling apart but the new one it feels as though my legs are coming up to my chest and the only way to stop it is by raising the seat so high it's then uncomfortable on your hands and I can't touch the ground whilst seated.
I measured how far the middle of the crankshaft is from the ground and the XC3 is a good two inches higher than my old bike.
My query is does frame size affect how far the centre of the crank is from the ground or does it only affect the distance from the bottom of the cranck to the top of the seat tube ???
Not quite sure what I can do with this, I'm not damning the bike it's a great bike BUT it just doesn't seem to be the right size for me.
I'm 5"7 and my inseam / inside leg is 29" and it's a 18" frame.
Do you know if I have any right to change it, I've taken it our for about 5 miles of cycling, does that mean I have to live with it ???
Any help / advice appreciated and thanks in advance!