Thorn:
"After running your dimensions through our calculations I feel that if you were to opt for a Nomad I would recommend the 540L as the bike can go rougher and will need a little more stand over clearance to ensure you will have plenty of room against the top tube.
If you opt for the Raven I would recommend 2 sizes and it will then come down to personal preference as to which one you would prefer. If you like a little more room over the top tube then go for the 530L but if you like only 20mm of clearance than you could ride a 565L but this would be tighter than recommended for rough touring."ND
If i chose a 565L Nomad
Thorn
"The 565L in the Nomad maybe just a tad too big as that bike is supposed to be able to run on much rougher terrain overall and this can cause a higher top tube to be too close to your crotch.
If you stand astride the bike with both feet flat on the ground, the stand over clearance is the distance between the top tube and your crotch. If the clearance is too small you risk slamming yourself where it hurts if you have to stop suddenly.
On modern bikes set up properly you have to slide off the saddle when you stop, putting a foot down. Riding on ordinary surfaced roads you can predict where your foot will land so you can manage with smaller clearances. However, if you are riding on rough tracks or uneven ground, you may find that your foot goes into a hollow, causing you to land on the top tube.
So it depends really on where you want to ride the bike. You should be able to make a reasonable estimate of the standover clearance for each bike. Measure your inside leg length. The size matrix for each model states the clearance near the middle and at the front of the top tube - you'll find the matrices in the brochure which I assume you already have.
my body size:
175 cm tall
BFSO: 82 cm
Arm span : 174 cm
It's the inside leg length that is important here. The tyre size matters - large tyres will raise the bike and therefore reduce the clearance. Your shoes will make a difference - if you go riding off-road in chunky boots then you will gain a little clearance.
One of the advantages of the Nomad and the Raven is their versatility - good both off-road and on-road. Thorn are recommending the smaller sizes so that you can get that versatility. If you think you will be riding only on proper roads maybe you should consider something like a Club Tour instead?
For your interest, I have a Raven Tour (the older model, now discontinued), size 497S. I am a bit smaller than you -- 167cm. I am very happy with the size as there is enough clearance for off-road riding but the reach to the drop handlebars is correct. I can ride it anywhere, both off-road and on tarmac.
I hope this helps - good luck with your purchase.
