Bicycle Mechanics - STI shifter movement

Just installed a new Ultegra front derailer, its a double as opposed to the Tiagra triple that was there before. The problem is now that to get to the big ring it takes a lot of force on the Tiagra shifter, to the point that I'm swerving on the road (or rollers...owwie). Is this normal or did I screw something up?

Shouldnt push that much to crash.Recheck.

Fair nuff, but what should I be checking? Everything seems normal.

You probably need to readjust the cable so the upper stop of the STI is closer to when the chain wants to jump to the bigger gear...

Set up that way and a quick push of the lever will cause the thing to shift up proper.

Is your crank still a triple? IF so then you have a problem. You need a triple front der on a triple crank and a double front der on a double crank. Yes, they are different.

-Ryan

The crank and derailler are both doubles, originals were triples

Did you change your bottom bracket to a shorter one as well? The Shimano double bottom bracket measures 109.5 mm while the triple measures 118 mm. If you still have the triple one then the crank is likely sitting too far away from the seattube for the der to shift to it.

-Ryan

yah got that too, 109.5 mm Dura Ace BB

ok. Adjustment instructions from the start.
1. Remove cable from anchor bolt. Position front der so that the cage is lined up with the chainrings and clears the big chainring by about 3 mm above it.
2. Shift the rear der into the largest cog (leftmost position).
3. Set the low limit on the front der so that the der cage plate is as close to the chain as possible without hitting it when pedaled.
4. Reattach the cable overtop of the cable anchor bolt with the cable tension pulled hand tight. Note: under the cable anchor bolt will change how much the der moves when the cable is pulled and screws things up.
5. Shift the rear der to the middle of the casssette and then shift the front der up to the largest ring. Once it is there check to see if the high limit is set properly by giving the shifter another push. If the front der moves out more then the high limit needs to be screwed in a bit, on the other hand if it does not move then you might need to unscrew the high limit a little to allow the der more movement thereby easing the shift to the big ring.
6. Shift to the smallest cog in the rear and check the clearance between the outer front der cage and chain. If it is dragging and unscrewing the high limit on the front der does not help then you need to increase the cable tension using the barrel adjuster. Make sure that your high limit is set out far enough to allow the der to move out a little when the cable tension is increased. Once drag is eliminated then run through the gears to check everything.
7. Go ride.

-Ryan