Help ID'ing Shimano cranks

[jimihendrix]

Was wondering what these cranks are ? and how do i measure BCD ? the way the ruler is laying in the photo comes out at 90mm centre to centre but i don't know if that's right ? only numbers i can make out on the back are MC34.

Also how would the granny ring attach ? the other spare Shimano cranks i have have got seperate bolt holes for the granny ring, these don't. Those other cranks also have a bigger diameter spider.

 

[Max P]

BCD is the diameter of the circle that makes up the bolt holes - not as you have the ruler to opposite holes. Much easier if you don't have a pattern to lay it on is to measure centre to centre adjacent holes and then check here:

http://www.sheldonbrown.com/gloss_bo-z.html#bcd

 

[Carsten]

google for shimano mc34 and you find this among other info

http://www23.brinkster.com/equipoacrobatic/tecSTX97.htm

those are the STX cranks and the granny attaches to the middle ring.

carsten

 

[jimihendrix]

Thank's for that , according to the Sheldonbrown info these have a compact drive 94mm BCD.

Are these cranks any good/worth getting new rings for ? or should i forget them and go for another pair of cranks ?

 

[kanerdog1x1]

not bad cranks these, i had a set bitd, pace did a fantastic spider so that you can run standard chainrings on them. looked top notch with different coloured middleburn rings on.....drool.

 

[jimihendrix]

Yeah, i've just been looking at middleburn rings, thinking about going for red ones, think i may
be stuck for a granny ring though, can't find anything that resembles that middle Shimano ring, not too bothered if i just run with the middle and outer rings though

 

[JeRkY]

you may find it hard pushed to find the appropriate middle ring these days.

 

[cherrybomb]

not bad cranks these, i had a set bitd, pace did a fantastic spider so that you can run standard chainrings on them.

This one......

Unfortunately, the Pace spider fits the earlier STX cranks that take a single riveted ring assembly, not the later ones you have.

 

[jimihendrix]

Thank's for the info , i think i'll get a middleburn outer for these and stick them on the GT as that's always ran a single ring anyway.
Back to the drawing board for cranks for the Orange,

might stick the fsa cranks from the gt on it for now

 

[REKIBorter]

PCD = Pitch Circle Diameter
BCD = ?