Beginner advice needed: fixing crank arms

[FelixT]

Hi,

My bike DIY knowledge is pretty limited so asking for help replacing crank arms on an old road bike.

From the attached photos, can someone tell me what sort of crank system I have and what I’ll need to order online to replace them?

Thanks!

 

[raleighnut]

That's a Square Taper crankset.

 

[Ajax Bay]

As above: square taper. Why do you think you need to replace the chainset? From the image, maybe some of the teeth are damaged.
If the cranks are spinning OK, then the bottom bracket is OK (if not then UN-55 of the right dimensions and spindle length). The crankset is a 'double' and '5 bolt' and with rings maybe 44-34. You can replace one or both chainrings (rather than the whole chainset)- a lot easier. You will need to get a ring with 5 bolt holes and the correct BCD (bolt centre diameter) - see this Sheldon Brown link to work that out. Spa Cycles is a good source of rings.

 

[the snail]

Looks like the rh pedal is bent. Derailleur has seen better days too. If the crank is knackered rather than just the pedal, it might be best to buy a crankset and matching bottom bracket.

 

[Ajax Bay]

Easy and cheap to get a square taper chainset, and avoids the challenge of removing the BB. I considered the damaged FD 'off topic'.