General Cycling Discussion - Right frame size? - bigger or smaller

I am buying a new Thorn Raven http://www.sjscycles.com/thornbrochure.asp.

It seems that my size gives me the option either of a 512 with a short seat post or a 487 with a long seat post. I don't fully understand the benfits to be had by going either for the larger or for the smaller frame. Anyone any ideas?

Also - any comments on Thorn's opinion that the Reynolds 853 frame may not be able to take the knocks?

Hi again marcg , I have been looking through the Thorn w/site (very good info. on their stuff!) If you click on Audax classic & scroll down to 'frame size' there they advise to get the biggest size that fits , I would personaly agree with that ,I always feel a bit uncomfortable on a small frame but for younger people who are more used to MTB type frames it could be differant, might feel more comfortable on a smaller frame , there might also be a diff. in top tube length too. See if you can trial both sizes to see which suits best . :beer:

Always get the largest frame that you can safely straddle. This will almost ALWAYS give a higher handlebar and more comfortable, stable ride.

Thanks for the advice here - I notice that in my original posy I said longer seat post.
I meant to say longer top tube.

Well actually longer seat post is correct, with a smaller
frame you use a longer seat post. This is all the rage
in pro riding and for fast amateurs now to get classic
road frames that by criteria of 10-20 yrs ago are 2-3cm
too small and compensate with high rise seat post and
long reach stems. I would go with other posters advice and get the larger frame. With the slant top tube, stand over is not a problem. In regards the tube set, I think Raven feels 853 is not appropriate for loaded touring. If you don't plan loaded touring (rear panniers, saddle pack, front bar pack and front panniers) 853 should do fine (also assuming you are less than 100Kg in weight.) Steve