I have 3 pairs of Spesh mtb shoes, all sized at 45, UK11, 29cm. Went to buy road shoes the other day (Spesh Elite) and they were labelled as 45, UK10.5, 29cm. Oddly they were a touch small, so lbs ordering in some 46's - weird .......
You sure the first wasn't US11? I buy cycling shoes by euro size and find the Spesh road and MTB the same (although the flexibility of the uppers between the various models makes a difference to).
I had the same problem, been a 43 in spesh shoes for years,must have had 6 prs now. Walked into a shop this week for my a new pr of 43s..to tight,44 to big???? really struggling to find a shoe that fits now,they do half sizes in the s works top end shoe, but they come with a top end price tag.
Ihave spesh sport road and MTB shoes which are both 47s and exactly the same fit. I think they use different lasts on different models and in different years so you need to be careful to match models.
When I got my S Works road shoes earlier this year the guy in the shop told me Spesh had changed there sidings from the 2010 model year to the 2011 one. So for me a 2010 44 was just right. 2011 44 was too small and 45 too big.
this makes sense, as my other ones are 2010 or earlier. here's hoping the 46 fits....
Cheers