My road bike has a Shimano 4500 Tiagra 9 speed shifter. After 6,000 miles, it's starting to show some wear and I need to replace it. All my other components are 105. Since I'm going to upgrade, I was thinking going to a ten speed. Will a 10 speed cassette fit where the 9 speed cassette was? They are Bontrager wheels.
If a 10 speed cassette will easily fit, I'll upgrade to a 10 speed shifter, cassette and chain and of coarse rear derailleur