I could use the help of some distinguished and experienced Monkeys. Some back story for those that have no clue who this Yossarian guy is. In the 90's and early 00's I rode alot, just like the rest of you monkeys. I knew what was what in the XC MTB world. DH and Freeride were a thing, but I didn't really participate in those things. Well, I did experiment in DH with Psycle-on and Tammy, but that is a different story. I stopped riding sometime in '94 - '95 or so, due to life getting in the way and other pursuits. My bikes got mothballed (thrown in the corner, still dirty from my last ride), and there they have sat for 12 - 13 years. Now I am old and fat, want and need to lose some weight, and in general improve my overall fitness. I can no longer comfortably go for a run (something I used to enjoy), because of a shattered Lower left extremity that has left me with rods and screws galore down there. The constant impact is simply way too uncomfortable. SO...that brings me back to cycling. Things have changed in that time since I last rode. Some of it I must concern myself with and other things not so much. Now, instead of XC and DH, there is Trail, All mountain, XC DH FR and who knows what other sub-genres of riding bikes. but this post isn't about those differences. This post is about the current Standards and how they compare to the standards from 2001. I have two bikes that I am trying to make ridable again. One is a 1994 Kona Killuaea Hardtail with what I believe is a 1995 Marzocchi XC-R fork on it. Ancient stuff on a steel tubed frame. I would kind of like to make this bike something I can tool around the neighborhood and get some asphalt exercise after work. Almost everything on this bike is in good working order, except the fork. The oil seals are shot and may or may not be available. Even if the seals can be found I don't know if I can find anybody with the correct tools to replace them. But again, I am digressing from my point, which will be my other bike. My other bike is a 2001 Gary Fisher Sugar 3 Disc and it needs some lovin'. The Marzocchi Z3 fork and Cane Creek rear shock both seem to work like new, which is to say probably nowhere near as good as current technology, but just fine for me at the moment. The brakes and drivetrain are a whole different story. I will make the drivetrain a whole different thread, if it is needed after I give shift systems a proper going through. I might have been a little addle brained when I was messing with shifters and derailleurs late last night. BRAKES! The Hayes HFX hydros ist kaput! I knew things wouldn't be good when the brake systems had no pressure in the lines whatsoever and there was evidence of brake fluid leakage. An attempt at bleeding the system last night revealed that the front brakes leak badly at the lever and the rear brakes leak badly at the caliper. This supports the evidence of leakage referenced earlier. I have resigned myself that I might as well just put a modern disc brake system on the bike. I have to imagine that anything modern in any price range is an improvement over 16 year old technology. This brings me to my question(s). Are the standards of fabrication the same today as they were in 2001 with regards to brake systems? Will a 160mm rotor with a 6 bolt pattern match the 6 bolt pattern on my hubs. Will the calipers mount to my frame, or have the mounting standards changed? Thanks Monkeys.