Ultegra triple adjustment

Question
I have a Giant OCR carbon bike with an Ultegra triple set up.  On the rack, I can adjust it so that it shifts well, both back and front.  When I actually ride the bike, I cannot seem to shift to my the large sprocket.  Shifter feels tight and will not move to the larger sprocket, even if I play with the back gears.  The same thing happens even after taking it to a shop for adjustment.  Is this a common problem?  Is this related to the bike flexing under my weight?  What to do???

Thanks, in advance.

Darryl

Answer
Darryl,

Okay, just got back to the computer after a triathlon and taking kids to soccer games.  Shifting is always tricky, so let me make sure we are talking the same things.  "Sprocket" is usually the name for the rear gears, which are also known as gears, the "cluster" or the "cassette".  The big front drive rings on bike are called "rings" or the "chainrings" (comprised of the small, the middle and the big).  From your description, it sounds like you are having trouble with shifting to the big ring.  Also, I don't know what your weight is, but most of the modern frame are very solid through the bottom bracket and seat tube, so I doubt that is the problem.  Weight flexing the chainstays (the horizontal tubes that go back from the bottom bracket and hold the rear wheels) would affect your rear derailleur and gear cluster, but not the front derailleur.

The problem with your front derailleur could be several things.  For one, if the bike is fairly new, there will be some cable stretch within the first few hundred miles.  That's why bike shops always give you the first tune-up free: They expect the bike to come back to fix the cable stretch after its been used.  Since the cable has to pull the chain in the front up to the big ring, any stretch will keep it from doing its job.  The cure: Tighten the cable, either by turning a cable adjuster (you may or may not have one installed by the factory) or tightening the cable at the derailleur.  The latter, if you don't already know, can be a huge pain, so it might be something for the bike shop to do.  

The second possibility is that your limiter screw for the ring (you can adjust how far the chain moves so that it can't shift too far and go right off the chainring) limits the big ring too much and it can't pull up to the big ring.  Take a look at the top of the front derailleur there are two Phillips head screws labeled R and L.  Try turning the R side counter-clockwise - that should allow a little more range for the derailleur to push up the chain.

The third possibility is that your front derailleur is not parallel to the chainring.  If it has been bent or poorly installed, the two sides of the derailleur will not be parallel to the path of the chain.  Sight forward past the sides of the front derailleur to make sure the sides are on the same plane as the front chainrings.  If it is not parallel, you can release the cable, loosen the derailleur mount and change the angle.  This is another "huge pain" adjustment, so if you don't have an experienced friend who can help you, take it to the shop.

The final possibility has happened to me when I have had a bike for awhile.  I am about 185 lbs and put pretty good torque on the crankarms, so after time, my cranks loosen up and begin to move outward on the spindles.  This causes the big ring to be too far to the right to allow the derailleur to shift up to it.  The cure: Tighten the crankarm bolts.

Hopefully, your problem is one of these detailed.  If not, give me some more details and I can work through it further.

Good luck,

Graeme