Should be ok as long as you use 9 spd chain still
I would have thought the other way so long as I use a 10sp as it will be a 10sp rear cassette, anyway I read up and I think from most of the info I read even though the chain rings from a 10sp may be a little narrow for all practicable purposes it wont make any difference as it is so small an amount, I ran 8sp cogs on a 7sp cassette, and had an 8 sp one on my 9sp cluster, but the gap between each sprocket meant I had to use the right size chain, also with the much reading, I am not sure really about the benefit of the 105 over the Tiagra regarding the gear cable, it also looks a lot more complex to set up right as well (cabling) I will probably go with 105 cassettes as apart from the three low gears they are all separate opposed to only 3 or 4 on the Tiagra ones, and since I have a 30-40-52 chainset I don't need an 11th, but I like my current set up of 13-14-15-16-17-19-21-24-28, but as the 105 onlt come as 11-28 or 12-27 I will need to get two over a couple of months then change the lower ones, just ideas firstly I need to get it up and running.
Many thanks for the input.
