Chain pulling off

[Andywinds]

I need some advice please. At slow speeds if I am in the tallest gear and apply torque the chain gets pulled off the large chainring. I think the chainring must be worn, but this does also coincide with the replacement of the BB. The bearings seem to be further inside the bottom bracket. Before I removed the bearings I did notice that they were never pushed in fully up to the C clips.

Ooops, sorry for using the wrong catagory!! Was rushing when I posted this.

 

[Andywinds]

https://drive.google.com/file/d/0B6kkPomA-k0NSHhma3I0X3dlbEU/view?usp=sharing

 

[Milkfloat]

Photo from above/behind would be better. It sounds like you just need to adjust your derailleur, but only after you are certain that your BB is in fact correctly installed.

 

[Andywinds]

Photo from above/behind would be better. It sounds like you just need to adjust your derailleur, but only after you are certain that your BB is in fact correctly installed.

Ok thanks. I will do. I pressed the BB in as far as it would go up to the C clips. I think I assumed that this was the correct way to press them?

 

[rb58]

Photo from above/behind would be better. It sounds like you just need to adjust your derailleur, but only after you are certain that your BB is in fact correctly installed.

And that it was the correct BB.

 

[Andywinds]

And that it was the correct BB.

It was like for like. It was just a case of pressing in the bearings.

 

[Andywinds]

Maybe I can use a 2.5mm space, but I guess I would have to remove the press-fit bearings first. That might be interesting!

 

[Milkfloat]

Maybe I can use a 2.5mm space, but I guess I would have to remove the press-fit bearings first. That might be interesting!

On a BB30 the spacers are on the outside of the bearing - not the frame side. I don't think it would be a spacer issue otherwise you would not be able to preload the crank arm properly. I assume that you don't have play in the cranks? Take some photos from above.

 

[Andywinds]

On a BB30 the spacers are on the outside of the bearing - not the frame side. I don't think it would be a spacer issue otherwise you would not be able to preload the crank arm properly. I assume that you don't have play in the cranks? Take some photos from above.

I've had a look at some BB30 press fit videos and mine look ok, the bearings should press into the frame by around 2mm from the looks of things. I've had a look at the teeth on the 34t and they look longer suggesting that the 50t is worn. What sort of pic would help? Something showing the crank into the frame?

 

[Andywinds]

I've got a spare chain that I can try? It was one that I took off the 53/39 setup, hardly used.

 

[Milkfloat]

I've had a look at some BB30 press fit videos and mine look ok, the bearings should press into the frame by around 2mm from the looks of things. I've had a look at the teeth on the 34t and they look longer suggesting that the 50t is worn. What sort of pic would help? Something showing the crank into the frame?

Take a photo showing the gap between the bottom bracket and shell, ideally it would have the chain on the big ring and show the position of the derailleur.

 

[MrPie]

@Fnaar is slipping (ooh-er missus)...just sayin

 

[Ticktockmy]

I need some advice please. At slow speeds if I am in the tallest gear and apply torque the chain gets pulled off the large chainring. I think the chainring must be worn, but this does also coincide with the replacement of the BB. The bearings seem to be further inside the bottom bracket. Before I removed the bearings I did notice that they were never pushed in fully up to the C clips.

Ooops, sorry for using the wrong catagory!! Was rushing when I posted this.

As I read your post it sounds like you are saying that when your chain is running both on the large Chain ring and Largest Cassette gear the chain when under torque jumps off the the chainring, Sound nothing to do with your BB, but a case of using the gears incorrectly, if you are on a large chain ring then you should keep to the smaller cassette gears, if you are using the smaller Chainring then you can use the larger Cassette gears. whilst it is possible to cross chain with your gears, it come with practice.

 

[Andywinds]

As I read your post it sounds like you are saying that when your chain is running both on the large Chain ring and Largest Cassette gear the chain when under torque jumps off the the chainring, Sound nothing to do with your BB, but a case of using the gears incorrectly, if you are on a large chain ring then you should keep to the smaller cassette gears, if you are using the smaller Chainring then you can use the larger Cassette gears. whilst it is possible to cross chain with your gears, it come with practice.

No, this was happening when in the largest chain ring 50t and in the tallest rear gear 11t. I did try another chain previously used, but that broke last night......just before I came off.

 

[Andywinds]

"Tallest gear" to me is the highest gear, ie smallest sprocket. So no cross chaining involved. (If my understanding of "tallest" is right, which I think it is, but then I am an idiot, so you never know).

You are correct :-)