As time goes on I become more and more skeptical that anyone has any real data on the durability of any given Shimano component group. The construction analysis such as Darth Lefty has attempted seems compelling, but in practice I think it takes an awful lot of miles to wear out even Claris-level components. Someone correct me if I'm wrong about this.


Claris users can be separated into three groups: (1) users who never use their Claris components enough to wear them out, (2) users who upgrade to something else long before wearing them out, and (3) users who actually stick with them long enough to legitimately wear them out. My gut feel (based on absolutely no hard data) is that the first group is the overwhelming majority and the second group is larger than the third. Also, I suspect that the percentage of users in the third group who meticulously track their mileage is fairly small. Finally, I suspect that by the time the third group have worn out their components Shimano's technology has moved on to the next generation and a direct comparison is unlikely to be made.


I'm not disputing that Tiagra is more durable than Claris. What I am disputing is that anyone really knows whether or not this difference in durability is enough to make up for the price difference.


When I bought my current commuter it came with 4600-series Tiagra components. I told myself that I was going to use those components until they were worn out before upgrading. I didn't make it. After about 5000 miles I upgraded to Ultegra-level components because the price for hydraulic disc brakes had come down enough that I wanted to make the jump and the jump. Meanwhile, a new generation of Tiagra components had been released so even if I had any real data on the durability of my Tiagra components it wouldn't be relevant.


Until I hear reports of some component group breaking down after a year or less of use, I'm going to remain skeptical.