I wish to increase the cassette size on my 2016 Giant Advanced Pro. At the moment it has 11-28 but would like to go to 32 or 34 if possible. I have ordered the inner and outer derailleur plates to convert to a GS mech but am undecided about 32 or 34 max cog, would there be any problems with the 34 or is it a bit gappy for road use. I see a lot of manufacturers are going large on the rear now. Groupset is Ultegra 6800 but I will fit a 105 cassette.
I'm still using 11-32 just over two years on, as per the default spec of my Cube, but I have an 11-34 and a 105 7000 GS mech in the spares box to fit at some point.
11-12-13-14-16-18-20-22-25-28-32
11-13-15-17-19-21-23-25-27-30-34
Fractionally easier gear, but more sprockets >18T which from experience I typically use on the longer climbs, at the cost of two teeth jumps at the high end. Given I rarely use the big gears on the downhill for prolonged periods of time, the compromise suits me fine.