Front Brake Advice Please

[Our Gee]

With a long trip looming I decided to change the Front Pads on our Twin Cam RT. The existing pads only had about a thousand miles left before the bottom of the "wear grooves" would be reached.
After a good clean of the calipers and pistons I fitted the new pads. (BMW Pads). Everything has gone ok and this is a job I have done many times before.
When doing a final check I notice that when looking at the Offside Caliper I can see uneven piston "protrusion". The "outer" pistons have about twice as much protrusion as the inners. I would estimate that the Inners protrude about 1.5mm and the Outers about 3mm. The nearside caliper piston protrusion looks to be equal. The old method of loosening the fork leg pinch bolt and bouncing on the forks with the brakes hard on makes no difference.
Is this a problem ?. Any advice appreciated, Thanks.

 

[Dennis the Menace]

Do you have equal wear on the pads ? or is the out side pad 1.5mm thinner than the inside pad, if they are and you cant find the problem swop the pads round every few thousand miles

How many miles do you get out of a set of pads

 

[Our Gee]

Thank's for the reply Dennis. Can't say that I have ever had equal wear on any pads although it's not the eneven pad wear that I am concerned about. If I hadn't looked so closely after fitting the new pads I would have just got on with it and rode the bike. Like I said above it's the uneven piston protrusion. Since posting this query I have had a good think and I now assume it could be down to an accumulation of the various tolerances in the front end components. In an ideal situation the caliper will be positioned "centrally" over the disc which in theory will give equal piston travel each side before the pads contact the disc. However, with the various dimension tolerances coming into play this could have an effect on the caliper position when everything is assembled up. Brake performance will not be affected it's just that I hadn't noticed this before and was curious.
Incidently I can't really say how many miles I get from pads as it does seem to vary. The pads I have just removed have done 10,000 miles and have about 0.5mm left before reaching the bottom of the "wear grooves".