[67fb]

Trek bike with 105 shifters and ultegra der. About one year old.

A week or so ago the wife said she could not shift into the big chain ring, so I put it on the bike stand and adjust cable tension and high stop. Looks ok.

Last Sunday, same complaint. So I test ride it, sure enought cant reliably get the chain on the big ring. Back to the stand, adjust the front der from scratch, reposition the height and angle, high/low stops. Looks good on the stand, shifts correctly, But.....

Test ride it and same results, sometimes it goes to the big ring, sometimes not.

When it wont shift to the big chain ring, if I leave the shifter alone and put it on the stand, first revolution of the cranks on the stand and it shifts.

Totally lost, any suggestions?

thanks

 

[Al1943]

My wife has had the same problem with her Ultegra triple, I think mostly from little use. The factory grease in the shifters gets hard and dirty causing a lot of friction. Try shooting lots of WD40 into the works to loosen up the grease and flush out the dirt. Do this with the bike right side up and upside down. Use the plastic straw that comes with the WD.
Also check for kinks in the cable and the cable routing. Clean the cable guide under the bottom bracket.

Al

 

[67fb]

Thanks, I will give the WD-40 a try, it makes sense.

She is riding her first full century on Sunday, I have to get this correct.

 

[andulong]

You might want to pull the shift cable inner wire out and take a look at it too. I had a very similar experience and found out that my cable was breaking one strand at a time where it is attached to the cable end causing very poor up shifting in the front and impossible to keep dialed in.

 

[wim]

If none of your mechanical efforts solve the problem, consider this: usually repair stand shifting is done at fairly high crank rpm and no load on the chain, so it works flawlessly. If your wife generally shifts at low crank rpms and is not swinging the lever far enough over, the front derailleur cage could go back to its original position before the chain is seated fully on the large chain wheel. Long shot, but easily checked. Perhaps when you tested the bike on the road, you did that as well.

In short: have the same no-load, high-rpm shift conditions on the road than you did on the stand and see if the thing works.

/w

 

[cyclust]

I've had the same problem with my wife's MTB, it works flawless for me, but she just can't seem to get it to shift to the big ring. Much of the problem stems from the fact that she has arthritis, and I beleive, just doesn't have the hand strength to shift with enough force. I switched from rapid fire shifters to SRAM twist shifters, and this helped some, but not much. I also used pleny of lube on the cables, used teflon cables to try to reduce friction, etc. The SRAM shifters even have a tension adjustment to adjust how much force must be used to turn the shifter, which is set to minimum. I've about come to the coinclusion that I should just run a 11-34 cassette in the back and go with a single chainring up front. Maybe for a road bike, a downtube shifter might be the answer. Another thought to keep in mind is that when a bike is on a stand, there is no vertical frame flex from the rider's weight. When a rider is aboard, the frame flexes downward a bit, thus tightening the derailleur cables a bit. It can cause it to shift slightly different on the stand versus the road. Just something to keep in mind.

 

[rochrunner]

For me with a 105 triple the trick is to make sure I move the lever all the way over when shifting and make sure the shift is complete before releasing it. If I let the lever go just as I can feel that the big ring has caught, it often falls back onto the middle ring. My upshift action just has to be more deliberate, but then it works reliably (definitely a lot better than my previous Sora triple!).

 

[67fb]

Thanks for all the suggestions.

Nothing seems to make this derailuer happy. took it off the bike to clean, blow it out with compressed air and lube the pivots. I checked the cable, lubed the housings and the cable route around the bb. All with no changes.

I'm going to replace the thing tomorrow, that or the cable...............:confused5:

Seems odd that the der would be bad in less than a year and less than 1000 miles.

 

[andulong]

I know you already tried all the adjustments but are you sure you don't have the H screw a little tight?? Backing it out just a very small amount would let the FD move out just a hair more. Might be worth a try. If the FD is moving properly, I don't see how it could be bad unless bent. Good luck.

 

[67fb]

I know you already tried all the adjustments but are you sure you don't have the H screw a little tight?? .....

Yeah, I'm worried it will be a waste of $50 to replace it and have the same behavior. Probably start with the cable.

I tried letting it move farther, eventually throwing the chain completely over the big ring. The only setting where I could reliably get to the big ring, also threw the chain off.

We have 5 bikes in the garage, two roadies, three mountain. I have never replaced a front derailuer due to a it wearing out or failing.

I have even checked the frame for cracks or problems, thinking its is flexing too much.

 

[rogerstg]

Since the problem is only when riding under tension be sure to check that the chainrings are tight to the crankarm. It could also be a sheared pin on the big ring.

 

[67fb]

Since the problem is only when riding under tension be sure to check that the chainrings are tight to the crankarm. It could also be a sheared pin on the big ring.

Ok, first glance I was looking for flat ramps, similar to my Shimano big chain ring. Turns out the Bontrager ramps are all round pins sitting in recessed parts of the ring.

So, still searching.

 

[lawrence]

You may want to consider replacing the cable and housing. If the cable is frayed it may have rubbed the inside of the housing off or normal wear and tear of the inside of the housing.

Some good ideas here such as a small crack in the frame and when you put your weight on it it flexes and moves the front derailleur just a little.

Too tight a cable?

 

[brblue]

With FD, I've seen that shifting is 50% different under load than when no load is applied to the chain / pedals. You have to work on it on the stand so that your shifts are just short of throwing the chain off the large chainring. Also, please mind that shift's aren't normally ment to be made when on the small cog in the rear.
You should check shifting up in the front, while in the back the chain is on the smallest cog usable with the current chainwheel.
i.e. i case of a double, with 53 x 39 and 12-25 cassette, from the 39x14 or so. The smaller the cog in the back, the higher the probability of an overshift while on the stand.

During a ride, if there's tension on the chain, it won;t go up on the larger chainring that easily, so the overshift probability is often lower than on the stand....

 

[67fb]

Solved

New Cable did not help.

Went to two local shops looking for a triple der with a 34.9 clamp. No Luck.

Third shop says use a braze-on der with a clamp adapter, I say "Ohh, thats what is on the bike now" . So I buy a new braze-on der. Get home, install, setup, but have the same problems.

Take the bike to a fourth shop where the main business is maintenance and parts, not bike sales. He looks at it and says, the combination of the braze-on der and clamp are allowing way too much movement. He does'nt have the part, soo..

Off I go, looking for a 34.9 diameter clamp-on der. Found it and did the setup and install and the wife now says the bike has never shifted that well. :thumbsup:

I'm guessing that 34.9 clamps were not very common on road bikes until recently, so there might be a bunch of braze-on ders attached to adapters.

Thanks for the help.