i bought a used Trek Multitrack 720 from a LBS that is very reputable. The bike seems low mileage and the store bike repairman told me he inspected the bike and tuned it up, and i watched him adjust the shifting after i asked him to check it. He said it is in perfect adjustment.

I am new to index shifting (I have a 1982 trek 311 road bike with friction shifters but i am out of shape so i wanted a more comfortable hybrid bike.)

I then got a used Univega via Carisma hybrid bike and i like the shifting a lot better on the Univega. THe univega has what i think are called rapid fire shifters (i dont know if they were called that when the Univega was made but they are rapid fire type.)

The Trek 720 has the grip shifters.

My complaint is that the shifting seems very clunky. It hits the right gears but there is a fairly loud clunk when i pedal after it shifts and the chain switches gears. I not only hear the clunk but i can often feel it in my knee when i am pedaling. I am concerned that it might not be good for my knees to suffer this clunk upon shifting.

I dont know exactly what year the Trek 720 was made (probably mid 90's.). It has shimano componetns for both deraillers and the bottom bracket/crankshaft thing, but the shifters say "SRAM grip shifters" so they may be SRAM brand and not OEM, I dont know (that could be the problem.)

The rear derailler says SHIMANO and sort of has an A on it. The pedal crankshaft thing says "SHIMANO DUAL SIS precision indexed shifting front and rear".

Im thinking whatever these components are and whatever the problem is maybe the best thing for me would be to switch them all out and get some good components with rapid fire shifters. Any suggestions on what components to get at the least cost and what is an esimate of the cost of the parts?

Or if that would be costly maybe i should leave it all as is and just accept it works but is clunky, and use it as a backup bike etc.

The frame seems pretty good (but might be a litlte heavy compared to other steel chromolly frames i am not sure. This bike altogether weighs about 30 pounds. The univega bike i mention above weighs about 28 pounds, i am not sure where the extra weight comes from on the Trek. It could be that either the wheels or the crankshaft or the handlebars/headset are steel and not aluminum I am not sure.

Let me put it this way-- if i want to keep the bike but switch out the front and rear derailers and the shifters, and end up with new rapid fire shifters, and my only concern is they work and shift very SMOOTHLY what is a good suggestion for parts?

Could it be the chain or the rear gears?

I am thinking maybe it is because the shifters are SRAM and not Shimano brand OEM,but they work, I just find it clunky.

Again the highly reputable local LBS bike mechanic told me it is in perfect repair and adjustment so maybe it is just cheap parts or maybe the SRAM shifters work but arent 100% compatible with the shimano parts?

Since i am new to index shifting, it is hard for me to evaluate but the Univega bike i have shifts smoother.