Bicycle Mechanics - front derailleur wont shift to big ring

I'm building a snow bike. I bought an older Cannondale hybrid frame and moved everything from my wife's old hybrid over to the cdale. The front derailleur (20 year old Alivio) wont reach far enough to move the change to the largest ring. I tried multiple adjustments and moved the mounting - no luck. Btw, it's grip shift shifters. Ideas or should I give up and replace?

Is the big ring too far outboard for a good chain line? Depending on the crankset you've got, you may need a narrower bottom bracket.

I would try increasing the cable tension a tad and releasing tge limit screw. If it still won't work you may have hit a hard limit.

Is the big ring too far outboard for a good chain line? Depending on the crankset you've got, you may need a narrower bottom bracket.

I can move it by hand and get it to catch. Interesting, the bottom bracket is the only part I didn't move over.

different cranks require different width bottom brackets for the same chain line. different frames and rear wheels require different chain lines.

chain line is measured from the centerline of the seat tube, to the middle of the chain rings (eg, middle chain ring on a triple, or halfway between the 2 rings on a double). assuming a triple, when the chain is on the middle ring, and the middle cog in back, the chain should be 'straight' and not at an angle.

if the chain line is correct, and the derailleur isn't reaching the big ring, then you may just need to tighten up on the cable a bit (shift it into low, loosen the cable clamp at the derailleur, pull out a few mm of slack, and tighten the clamp again, and try it again).

Some BB have an asymetrical axels. If you had the BB out to clean and repack the bearings make sure it is replaced correctly. Some BB have bearings that can be adjusted for proper alignment left and right. Make sure the FD is aligned straight with the big chain ring, and is about 3mm above the large chain ring.

thanks - some good things to check. anyone had any experience with grip shift? I'm wondering if is part of the problem

I doubt that the shifters are the problem. As has already been pointed out, cranksets and bottom brackets need to match to give you the proper chainline. Since the bottom bracket wasn't part of your swap, that is more than likely the culprit.

If you can move it by hand and you moved both shifter and derailleur over it's probable that the derailleur can be adjusted correctly. Got to parktool/com/blog and go through the entire procedure for adjusting the front derailleur, including height and rotation, making sure you have well-seated cable housing in good shape. The bottom bracket could still be adding to the problem if it's causing the chainwheels to be farther outboard. If the old bike is still available you can always check how far out the spindle is out from the bottom bracket shell compared to the new one.

I can move it by hand and get it to catch. Interesting, the bottom bracket is the only part I didn't move over.

If you can move it into position by hand, your cable tension isn't tight enough. Shift to the inner ring and see if the cable is slack. It should be taut.

Check your cable housings, often they'll "explode" like Elmer fudd's shotgun with a finger in it. Sometimes this can be hard to see.

Check your cable housings, often they'll "explode" like Elmer fudd's shotgun with a finger in it. Sometimes this can be hard to see.

explode? even if I wasn't hunting wabbits? Rode to work for first time today even though front d won't shift to big ring. It's irrelevant since I never get going fast enough to use - but it bugs me that it doesn't work so planning on working on it tonight. the exploding housing reminded me that it's an old cable (and housing) which I'm sure doesn't help - think I'll replace the whole thing

Don't replace anything until you confirm that there's no slack in the cable when you're on the inner ring.

If you can move it into position by hand, your cable tension isn't tight enough. Shift to the inner ring and see if the cable is slack. It should be taut.


Don't replace anything until you confirm that there's no slack in the cable when you're on the inner ring.

My vote too.

...it's an old cable (and housing) which I'm sure doesn't help - think I'll replace the whole thing

Randomly deciding what it might be is not the best approach. If the housing had a serious enough problem that it would not allow a full shift it's very likely you would have noticed a problem when reinstalling the cable/housing, though certainly you should recheck to make sure it's . Much more likely is that you did not install the front derailleur correctly or that the tension is incorrect (which is an integral part of index derailleur adjustment. If the derailleur is mounted too high or rotated incorrectly it can prevent proper shifting, and of course too little cable tension can be a problem. Even though you can shift by hand incorrect mounting can make it difficult for the lever and cable to accomplish the shift.

Again, the best approach is to go through the entire install and adjustment procedure on the Park Tool site. It should address both problems and also show you proper procedure for the future.

I can confirm there's no slack in the cable when on the granny ring

explode? even if I wasn't hunting wabbits? Rode to work for first time today even though front d won't shift to big ring. It's irrelevant since I never get going fast enough to use - but it bugs me that it doesn't work so planning on working on it tonight. the exploding housing reminded me that it's an old cable (and housing) which I'm sure doesn't help - think I'll replace the whole thing

The linear strands that make up the outer derailer housing can also slip inside their plastic coating. This can cause all kinds of problems because the housing is no longer rigid enough. You should slip the ferrules off the housing and see if the ends are parallel. If there are any strands out of place, replace the housing.

You don't need to remove the derailer cable to inspect the housing, either. Shift the front into as high a gear as you can get it into. Then, without pedaling, downshift to the lowest gear. This will give you lots of slack in the derailer cable and you should be able to pull it out of the housing. You can check the ends for any stray strands by pulling off the ferrules. Unfortunately, you can't use this trick to check the ends at the shifter if you are using road bars and bar tape.

Derailleur height! I finally braved my unheated garage in 30 degree weather and followed the Park guide. Straight away it was clear the derailleur clamp was too high. I dropped it to the width of a penny and Viola! I went ahead and followed the whole guide and was so stoked I did the Park guide for rear too. Pretty cool when 25+ components call shift like new. Thanks for all the guidance

Thank you for this thread! I believe this will fix my new bike that I picked up online!

just a thought, oversize band for derailleur can be shimmed onto a smaller seat tube,
and so moves the derailleur it self outboard a bit..

The above thread is a great example of the reason one has to start with a known starting point before troubleshooting. Trying to solve a bike problem without first confirming all of the proper procedures for installation and adjustment have been completed is a waste of time.

just a thought, oversize band for derailleur can be shimmed onto a smaller seat tube,
and so moves the derailleur it self outboard a bit..

if its shimmed all the way around, it stays centered on the seat tube, and will have exactly the same chainline reach.

You presumed symmetrical shim , au contrare.. the RD is still a bit further to the right by the r change.

the <C> folks made a 4mm longer BB to move the crank arm in oversize seat tube frames (vs the 111)
were the FD was used. then the inboard stroke becomes an issue..

if its shimmed all the way around, it stays centered on the seat tube, and will have exactly the same chainline reach.

Not true. Most makers use the identical cage and pantograph arms on all their FDs. And most do not compensate the body of clamp-ons for the seat tube diameter. That means that the otherwise identical FD with a larger clamp will be outboard by the difference in the radius.

This was an issue with Campagnolo a number of years back. As they moved the chain line out slightly (without correcting the FDs) they had outboard reach issues with 1-1/8" clamp-on models. The larger ones and braze-on were fine, so their solution was simple --- discontinue 1-1/8" clamp-on FDs in the top models.