Im pretty sure they don´t, but I could be wrong....

 

No

 

You are confusing mainspring with hairspring - the hairspring is paracrom. I don't beleive they replace either unless required, and then they'll charge you for it.

 

They will replace parts with the same ones that are already there. If YOU change anything, then they will put it back to how it was and charge you.

 

I have a sub date with 3135 movement manufactured in 1999. I just had it serviced by RSC Dallas and was wondering if they now replace the original mainspring with the parachrom version in this movement. Does anyone know?

A mainspring, that metal coil that stores energy that is released as the watch hairspring winds and unwinds is almost always replaced as prescribed in a full service. That part is cheap in the scheme of things and the constant tension build and release eventually takes its toll on the metal. The hairspring doesn't have the same wear and tear attributes and generally lasts the life the of the watch.

Your question implies that you feel you have a deficient movement merely because Rolex decided after your watch was made to change/upgrade the metal used in the hairspring. Nothing could be further than the truth. You have a certified chronometer 3135 movement that can be accurately adjusted for timekeeping to within a few seconds a day, and if you do the math, you'll find that tolerance to within a few hundredths of a percent per day.

The millions of 3135's (and 3035's for that matter) stuffed in the various Rolex products, giving attested, accurate timekeeping performance should be enough to calm your jittery nerves. The post service performance of your own watch should allow you to sleep well at night. To diminish the components in your watch in a futile hunt for whatever Rolex deems to be a material improvement is going to lead you to never be satisfied unless the most recent model is on your wrist. Sure, there are those with the material resources who can afford to chase the latest and greatest at the expense of their incumbent timepiece, and your challenge is to decide if you are one of those types.

 

Well said and thanks for your reply. I do appreciate the anti-magnetic properties of the parachrome but not enough to purchase a newer sub .