Bicycle Mechanics - Want to change shifters on my bike.

I want to change the "grip shift" style shifters on my '08 Trek 7200 to trigger style shifters. I have never done this before and figured I should ask here about component selection and any issues I might need to look out for. I searched for this information in a few different ways but didn't find anything, although perhaps I wasn't searching on the correct terms.

The bike has the 8 speed Alivio derailer on the rear and the Shimano C102 on the front.

I am not 100% sure on all of the specifics on compatibility, but I assume that something like these (http://cgi.ebay.com/Shimano-Alivio-SL-M410-Shifter-Set-3-x-8-Speed-Shifters_W0QQitemZ280244744738QQcmdZViewItemQQptZCycling_Parts_Accessories) should work.

Is the only requirement that the shifters match the 8speed (rear), 3 speed (front) of the derailers?

or is this too much of a hassle to bother with?

In short, what specs do I need to find on a trigger shifter to match the drivetrain on this bike?
What trigger (or is it thumb?) shifter do you recommend?

There are some SRAM shifters that are incompatible but if you stick with the Shimanos you linked you'll be fine. They aren't that hard to swap out. The only thing you'll need to deal with is adjusting the shifters. You shouldn't need to adjust the high and low limits on the derailers (assuming they are set properly now) so it is just a matter of adjusting the cable tension once you get everything together. Go for it. They are so much better than gripshift.

The trigger-shifters work as long as you have the right speeds on the rear and front. 8spd shifters for 8 cog cassettes. I don't know if SRAM makes the Attack shifter in 8spd, but the SRAM Attack shifter - I have a 9sp - is much nicer than the Shimano ones. Problem with Shimano many have found is it's virtually impossible to install new cables. They won't tell you how. You open it up. You find you will have to disassemble the shifter to get to the cable - and a question was asked - "Could you put it back together again?" All respondents said 'no' but one. He said he got it back together - but it took him 3 weeks! This also happened to me - so I bought the SRAM Attack shifters. Cable replacement is a snap.

I'd suggest looking into SRAM. Only purchase if it says "Shimano compatable" or similar.

Good luck. Those grip-shifters are a pain.

Then again, some of us love our grip shifters! Perhaps we're just not coordinated enough to deal with two separate levers per side... :)

Update: SRAM does have the 'Attack' available in 8spd. and Shimano compatible. I highly recommend these. At a price that's very affordable from this outfit. I found 'em elsewhere for $58:

http://www.bikesonline.com/index.php?page_URL=SRAM-Attack-8spd-rearTrigger-shifter

I did this maneuver two years ago on a TREK ZX7000. The job went flawlessly and the mechanism worked well. There was a little crowding of access between the brake lever mechanism and the shift levers which was especially noticable in cold weather while wearing gloves. In the end, it was a positive change.

I've ridden with both grip shift and rapid fire....I like the grip shift better. On my commuter I have falcon thumb shifters. Sometimes retro is good.

I have had Alivo-level 8 speed and 9 speed LX Shimano shifters and have had no problem changing the cables. Just remove the retaining screw for the cable, pull the old one, slide in the new (with some teflon lube on it), adjust the tension and you're good to go.

I had the Deore shifters which came stock on my Trek. Change the cable? HA! Change the shifter more like. Hellooooo SRAM!

Problem with Shimano many have found is it's virtually impossible to install new cables. They won't tell you how. You open it up. You find you will have to disassemble the shifter to get to the cable - and a question was asked - "Could you put it back together again?" All respondents said 'no' but one. He said he got it back together - but it took him 3 weeks!

???????

Remove one cover screw, you see the cable end, pull out the cable, put on a new one.

Most you don't even need to remove the cover, just shift to the loosest cable position and the cable pushes out the hole in the shifter body.

I tried that. It needed more of it's gut removed to get at the cable. Shimano was of no assistance. Yes - there was the cable end. Blocked in.