Bent Crank?

[Goggs]

Hi folks. A fortnight ago I had an accident on the bike. I damaged a pedal axle & the saddle. I replaced the pedals with another pair and took my saddle off my other bike for the time-being. I've been unable to ride the bike until yesterday & I've discovered that there's still something wrong. Although I know the pedals are good there's still a slight wonkiness to pedal revolutions.

Could it be that the pedal took such a big hit that it also bent the crank arm on that side? There's not even a scratch on the frame so I'm not thinking the frame's bent but I suppose it could be the bottom bracket. Is it possible to buy single left-side crank arms? It's an FSA crank but I'd really rather not buy a full chainset.

Any thought are more than welcome.

 

[Racing roadkill]

Hi folks. A fortnight ago I had an accident on the bike. I damaged a pedal axle & the saddle. I replaced the pedals with another pair and took my saddle off my other bike for the time-being. I've been unable to ride the bike until yesterday & I've discovered that there's still something wrong. Although I know the pedals are good there's still a slight wonkiness to pedal revolutions.

Could it be that the pedal took such a big hit that it also bent the crank arm on that side? There's not even a scratch on the frame so I'm not thinking the frame's bent but I suppose it could be the bottom bracket. Is it possible to buy single left-side crank arms? It's an FSA crank but I'd really rather not buy a full chainset.

Any thought are more than welcome.

You’ve possibly bent the axle, or knocked the B.B. cup out of true.

 

[Levo-Lon]

Remove the crankset ,if it seems extra difficult to slide out its probably bent.
I'd not expect the arm to be bent.

Put a good straight edge on the crank spindle and see if its out of true?
You may be able to re-align it with a bar " socket set extension bar etc "
The bend will be in the middle so look for a slight rock side to side with the straight edge.
A steel rule will be ideal for this

 

[Drago]

Possibly bent the crank. A picture or two might help. Crank sets aren't that expensive, and with luck you may even find a single crank on eBay.

As a point of order, its a spindle. Axles remain static and the item revolves around them. Spindles revolve with then item

 

[Cycleops]

You don’t say what type the axle is. If it’s a solid square taper it won’t bend, if it’s a hollow two piece type it may well do. Remove it and check. if the drive side took the hit and it’s the two piece type the crank could have bent the hollow spindle. If bent you’ll need a new crankset, if you try to straighten it you can’t guarantee the structural integrity of the unit.

 

[Ajax Bay]

Is it possible to buy single left-side crank arms?

Yes. Share with us what type/model of FSA crankset this is. And what type of BB? With the bike properly vertical, try putting a spirit level on the (newly installed) left pedal at the 4 'cardinal' points. If it's not level then the answers to my questions above will inform the options.

Axles remain static and the item revolves around them. Spindles revolve with then item

Or is it, since you have your pedantic hat on, a 'shaft'?
Difference-between-shaft-axial-and-spindle

 

[Goggs]

The crank is an FSA ck-745, one of their IS range, at 170mm. It's surely more likely to be the crank arm rather than the bottom bracket? I'm struggling to find a single left-hand crank arm & I think £50 seems a bit steep for two cranks. If it has to be a pair I'll have to just go for it.

 

[Goggs]

Some photos...

This one is just to let you see what the chainset looks like...

This shows the model number on the inside of the left crank...

This one shows the end-cap of the spindle. I've no idea how to remove this as I only have al old-style crank remover...

 

[Cycleops]

It looks like a self extracting crank so you just unscrew it.

Being an electric assist I wouldn’t know what’s behind the crank. You might have to take it to a Giant dealer.

 

[midlife]

It looks like it's attached to something expensive...bike shop?

 

[Goggs]

It looks like a self extracting crank so you just unscrew it.

Being an electric assist I wouldn’t know what’s behind the crank. You might have to take it to a Giant dealer.

It looks like it's attached to something expensive...bike shop?

Will the fact it's electric make a difference? Surely I just need a big allen key?

Edit* I can take the nut off but I'm unsure how to get the actual crank off.

 

[Drago]

Probably, but assumption is the Mother of all f......

 

[Cycleops]

Will the fact it's electric make a difference? Surely I just need a big allen key?

Edit* I can take the nut off but I'm unsure how to get the actual crank off.

If it’s self extracting the crank will just pull or fall off. The question is what is behind it and if that may have been damaged in some way.

 

[Levo-Lon]

Ahh now that changes things.
You have a 20+ kg bike landing on a crank arm .
Id say that is your problem

 

[Cycleops]

And a very expensive 20kg bike too!