Shifter perfomance Question? re 105 10sp compared with 9 speed

[Bigbananabike]

I've just finished building up my latest and hopefully fastest bike
Its my first 10 speed.
It has new 105 shifters, chain and rear derailleur (actually a 9 speed but who's counting?!).

The shifting performance is so much better than my two 9 speed multigeared bikes (one has basically all 105 the other has Ultegra with Tiagra shifters).
The two 9 speeders are older and have done about 20k kms each.

Is the shifting performance more likely to be wear in the older bikes or mainly that the 10 speed shifters are so much better?

 

[Peter@vecchios]

I've just finished building up my latest and hopefully fastest bike
Its my first 10 speed.
It has new 105 shifters, chain and rear derailleur (actually a 9 speed but who's counting?!).

The shifting performance is so much better than my two 9 speed multigeared bikes (one has basically all 105 the other has Ultegra with Tiagra shifters).
The two 9 speeders are older and have done about 20k kms each.

Is the shifting performance more likely to be wear in the older bikes or mainly that the 10 speed shifters are so much better?

New shifters probably mean new inner wires and housing BUT the innards of shimano 10s shifters are a derivative of their MTB shifters, which are a better, more reliable, design.