I am in the process of gathering parts to overhaul my drive train and need some advice about chainrings. The bike has 8500 miles on it and I am going to replace the chain, cassette, and the middle and large chainrings. Will I have any problems replacing the 42 and 52 that are currently on my TruVativ Elita Triple 30/42/52T with a 39 and 53 Ultegra?

The bike is a stock 2005 Fuji Roubaix, the cassette is a 12/26 SRAM PG-950 and a PC-971 9speed chain if it makes a difference. The derailleurs are 105.

As long as the BCD is the same, you should be fine. But with only 8500 miles, why change your chainrings? I doubt they are worn with that few miles.

That's the problem, I have no idea if the BCD is the same or how I could find out.

I'm changing them because they are starting to look like shark fins.

They should be 130 BCD for the large and middle. Shimano triple front deraileurs have a rated tooth difference of 22 teeth (52-30). 53T ring is outside the rating, but it will probably work. Just make sure the derailleur is set up so it gets as close as possible to the large ring's teeth. Otherwise, there's a possibility that the chain will hit the bottom of the cage on the inner ring.

The major thing to look out for is that 39T chainrings meant for a double setup won't be ramped or pinned on the inside to aid in upshifting from the inner to middle ring. There are 39T rings meant for triple. I have Truvativ Elita triple GXP with 52-39-30T (stock rings).

By the way, https://sheldonbrown.com/gloss_bo-z.html#bcd

Measure the center-to-center distance of two adjacent bolts on your outer & middle rings. Should be about 76.4 mm for 130 mm BCD.

Thanks. It looks like a 130 BCD and after looking around, I see that the BCD is included in product descriptions.