papajuice

Ok just picked up a really clean Trek 750 and want to switch from the straight bar and shifters to a drop bar and shifter set up. The question is do I have to change the whole group or can I just replace it with 105 handles.

Chris_W

You'll definitely need to change the front derailleur, the rear derailleur should be fine (as long as it is Shimano). If the current brakes are V-brakes then you'll need to change those to cantilevers or use a travel agent. A shorter stem may be needed so that the reach to the brake hood position on the drop bars is suitable for you, but this may be OK with the current stem. If keeping the old stem, make sure that the bar clamp diameter is the same.

FastJake

If you're willing to use bar-end shifters, you don't have to change the derailers. You just need a pair with the correct number of speeds to index on the right. If you have V-brakes you can get drop bar brake levers meant specifically for them (a few do exist), or switch to cantilevers, or use a travel agent as mentioned above.

If you want STI brifters, then you will need to change your front derailer as noted above.

papajuice

It has a Shimano STX setup on it with cantilevers, does not need ot be 105's but anything for now to convert to drop bars. Will replace later on with a full 105 set or even a Sram setup. Now it is a 7 speed which will proabably make a difference.

wrk101

Going to need to replace rear wheel to get the right spacing. 105 STI is not going to match your seven speed setup. Really need to. Either consider bar cons, or buy a second bike. Will need seven speed bar cons (obsolete). Seven speed rear is a challenge, you can find seven speed STI used, eBay, but the nice ones tend to go high.

papajuice

Sounds like I need to just save a little and go for the whole new group.

FastJake

What number of speeds were you planning with the 105 shifters? You can put 8 cogs of a 9 speed cassette on your 7 speed wheel, or 9 cogs of a 10 speed cassette. You will just have to setup the derailer so that the extra speed is locked out of your shifter.

mconlonx

Sell the bike, use the money toward a drop bar bike like you want.

papajuice

Got it cheap and the frame is a good fit for me. I want steel and even buying a new bike most off the steel ones come with a cheaper group, or you build one to get everything you want. I figured even if I have to replace everything in the long run with a whole new group I am still cheaper and have a really cool vintage feel.

HillRider

Right but 8 of 9 does require a 9-speed brifter and chain since the cog spacing remains 9-speed. Are you sure the 9 of 10 works? I've never seen it mentioned before.

To the OP: it can be done but, as you are finding out, it isn't a trivial or particularly inexpensive upgrade.

Kimmo

As mentioned, 8/9 or 9/10 will work. Or you can pick up an old 8spd cassette body for as low as $0, and re-dish the wheel.

papajuice

Thanks for all the reply's it looks like for now I will just get a set of drop down extensions to use. Then save some back and before August get me a Salsa Casserole.