Bike-a-roni

I Just got a new crankset because I bent my old one. I put it on the bike and I found that my old derailleur doesn't have enough reach to push the chain out to the top chainring. I'm pretty sure the crank is pushed all the way onto the spindle, and I was wondering if there's any way to fix this.

If there's not a way to fix this, can anyone tell me how to find a front derailleur with a wide range of motion?

bikeman715

have you try adjusting the high (H) screw on the dérailleur ? try turning it counterclockwise until the chain move onto the chainring.

Dan Burkhart 

I would say that your new crank set requires a different length BB spindle to achieve the same chain line. Expanding the range of motion on your derailleur won't fix that. You need a new BB with a shorter spindle.

Panthers007

The best way to fix a FD (front-derailleur) is to uninstall it. Run new cable. And start over. This means putting your bike in the large-rear cog on the cassette/freewheel, and small-front chainring in the front. Then adjusting the HIGH screw (top one) so the FD's backside cage is directly over it. Then getting the chain on the small rear cog and large front - and adjusting the LOW screw.

I could explain the rest - but a video may do a better job:

https://bicycletutor.com/adjust-front-derailer/

As well as the Park Tool explanation:

https://www.parktool.com/repair/readhowto.asp?id=75

Bike-a-roni

How do I figure out what spindle length to buy?

bikeman715

you only need 5 mm clearance from the chainrings and the chainstay. so add or subtract from what you have now.

operator

Show us a picture from the rear of the bike, with the chain on the middle of the cogset in the back and middle chainring up front. You will also need to know your current bb spindle length - which means removing the cranks.

Bike-a-roni

I need 5mm of clearance between chainstay and which chainring?

operator

Ignore that. Has nothing to do with the situation. And you need only a minimum of 1.5-2mm of whichever chainring/chainstay clearance, if that's even going to be an issue. Please, just tell us which crankset you bought so you can measure your current bb and compare with what it's supposed to be spec'ed at. Or post a picture like I detailed in the last post.

Al1943

Any chainring. 2mm would not be enough because there is always some frame flex and imperfections in the crankset.
Have you torqued the bottom bracket and crankset?

Bike-a-roni

It's a Shimano m442 22/32/44. They said it was an Alivio at the bike shop when I bought it, but the number matches a deore. bb is 122 mm

DannoXYZ 

1. measure current distance between middle-ring and the centre of the seat tube.

2. optimum chain-line is around 42-45mm, let's use 45mm for a triple

3. remove cranks from BB

4. measure width of BB-spindle

5. subtract measurement #2 from #1

6. multiply by 2

7. subtract measurement #6 from #4

8. Answer #7 is the new BB-spindle length you need.


9. Double-check chainring-to-chainstay lateral clearance, do you have at least measurement #5 clearance in your current configuration?