Broken crank spider?

[Paul J]

Not sure what it's actually called but I have just taken the front sprockets off to clean and one of the lugs on the spider part of the crank has factured right through. Sprockets mount either side of it.

Does this mean a new crank and how do I know what to buy. It's not Shimano, it says Sakae and is on my Raleigh Scorpio.

 

[simon.r]

It does sound as if it's new cranks time - do you have a photo of the damage?

You'll need to know the following to replace it:

• How it fits to the BB axle (probably square taper if it's a cheap-ish OEM crank).
• Can you remove all the rings from the old crank?
• If yes and you want to re-use the rings: What the BCDs are (http://sheldonbrown.com/gloss_bo-z.html)
• If no then you'll need to buy new rings with the new cranks (a chainset)
• What the crank length is (probably 170mm or 175mm, often stamped onto the crank arm). You could consider a different length if you want to.

You'll also need a crank puller (assuming an older style square taper BB, something like this) to get the old cranks off.

It sounds more complicated than it is!

 

[biggs682]

if its cracked then replace it , following simon.r advice and pointers above

 

[Paul J]

Thanks for the advice.

I have taken the crank nut off and can see it is a square taper.
Can remove the rings from the crank easy and they are 130mm BCD
Crank length if I have measured correctly (centre of crank to centre of pedal) 170mm

I think this is suitable on chain reaction It says its suitable for 8 speed but mine is only 6 will it still be ok?

 

[Rickshaw Phil]

Thanks for the advice.

I have taken the crank nut off and can see it is a square taper.
Can remove the rings from the crank easy and they are 130mm BCD
Crank length if I have measured correctly (centre of crank to centre of pedal) 170mm

I think this is suitable on chain reaction It says its suitable for 8 speed but mine is only 6 will it still be ok?

Yes it'll be ok - 6, 7 and 8 speed are all compatible with each other

 

[Paul J]

Still haven't bought a crank yet as worried about getting one with the wrong taper. I have had a look on Sheldon Brown and Sakae are made to the Japanese standard of taper, are Shimano the same?

Will the chainline be the same with a Shimano 2300 or is this something else I need to find out.

Sorry for all the Q's but don't want to buy something that will not fit as they are quite expensive.

 

[guitarpete247]

I bought my current crankset off ebay. There are quite a few on offer including this. A question to the seller should find out the BCD. There are plenty of sellers of chainrings. I used Spa cycles. This is their Stronglight selection on offer.
I'm assuming from the age of your bike that you've got a square taper fitting.