Bottom bracket uneven wear

[tripletail52]

Hello peeps

Checked the pressfit BB (Shimano) on my bike yesterday after removing the chainset. Non-drive side feels perfectly smooth and well greased. Drive side is all rough and makes noises. This is after a few thousand miles and it's still turning so I'm happy to change it now, but any idea why this uneven wear happens? My guess was either due to degreaser when cleaning the chain or because I start the bike on the driveside, so every time I mount all my weight is applied to the driveside?
Cheers.

 

[Vantage]

Unless you're a lefty, your dominant most powerful leg is the right/driveside. The degrease won't have helped. The non driveside is also easier to clean than the right due to the chainset being in the way.
Few things on a bike ever wear evenly.

 

[Paulus]

Unless you're a lefty, your dominant most powerful leg is the right/driveside. The degrease won't have helped. The non driveside is also easier to clean than the right due to the chainset being in the way.
Few things on a bike ever wear evenly.

That was my first thought.

 

[rogerzilla]

Most likely to be water/dirt ingress on that side.

 

[tripletail52]

Is it a bad idea then to open the seal up on driveside and service the bearings? Obviously this one's a goner but in future? Maybe it weakens the seal gradually but regular servicing would still be better?