My Trek fx 7.2 has been making a clicking noise when riding for some time.However, it's been getting worse; it now makes a grinding noise if I'm mashing a bit when going uphill. İ check every possibility , the problem is bottom bracket .
But which one is the right size i can't find it without opened.
And i want good qualty bb is this product good enough for daily riding ?
My bicyle L(51 cm) size ( if it necessary )
https://www.chainreactioncycles.com/M...?ModelID=34652

Need to know what kind of cranks you have, that will determine the BB you need. But you may not need a new BB. Could be a bit of grease on BB threads and torquing the cups to spec could solve the creaking.

It's a bit late now but leaving a noise until it gets worse is a recipe for greater expense.
You may have checked every possibility, but it's best to let us know what you checked, just in case you missed something. I also agree that even if it's the BB you may not need a new one.

By now the grinding noise could be anything--pedal, rear wheel, chain, or bottom bracket. If the chain has more than 2000 miles on it (3000km?), it should be replaced. More than 3000 miles, replace both the chain and cassette.

To get the right British-threaded bottom bracket you need the shell width either 68 or 73 mm, and spindle length, usually somewhere between 113 and 125 mm for triple cranksets. The shell is the frame component the bearing unit threads into and is easy enough to measure. To measure the spindle length you need to remove the cranks and measure with a caliper. Or, given the Shimano crank model number, a shop mechanic should be able to look up the correct spindle length in the Shimano dealer manual.

In my experience, squeaking/clicking noises in the bottom bracket area can't be fixed by simply replacing the BB. You should remove the cranks and BB, clean all of the threads and metal-to-metal interfaces, then reassemble. Grease all the threads and torque everything to the correct spec. (Torque values at https://www.parktool.com/blog/repair-...s-and-concepts.) If the noise goes away but then reappears after a couple weeks, do it again, but apply a couple turns of plumber's teflon tape to the BB threads.