Shimano 5 arm crank question

[uphillcursing2]

As part of the on going rebuild of my first retrobike. I have been looking at the cranks. The chainrings are completely trashed. Cant seem to find replacements in any of the online shops. All I can find is 4 arm ones.

Is it now defunct? Obsolete? Do i need to look to a new one?

I can post a pic if it helps.

Advise greatly appeciated...

Cheers

 

[Xesh]

Which model are they? Shimano usually stamp the model number in the back of the crank arm. It looks like: M7XX (in the case of an XT chainset).

The other thing you need to know is the bolt circle. Shimano made 5-bolt chainrings in both ATB and compact types.

If you want quality chainrings then Middleburn do most sizes in both patterns. Shimano are slowly phasing out their stock of 5-bolt rings and only have limited sizes available.

 

[RockiMtn]

plenty of 5-bolt options here. just a matter of if it's economical to have shipped to you.

http://www.blackspire.com/qs/category/83/5948/0/0

 

[uphillcursing2]

Cranks stamped as MC36

Pics to follow if needed.

Inner looks fine and outer looks like it might have a fair bit of life to if. its the middle that really is unuseable

 

[Xesh]

MC36 are STX iIrc. You'll be looking for compact type chainrings then. Although I seem to remember some STX chainsets had the granny ring bolted to the middle ring. If that's the case with yours I know of a shop local to me that has one of these special rings (it's a Middleburn one too iIrc).

 

[uphillcursing2]

Granny is indeed bolted to the middle ring. Bikepedia suggests that that would be the correct cranks fitted.

Is the middle ring you know of silver?

Im guessing that it might be cheaper and less hassle in the long rung to buy a new crankset? Would that be the case?

##Edit. When I say new I was thinking more of an "in keeping" than from CRC!!##

 

[legrandefromage]

certain STX chainsets have slightly smaller BCD and need specific rings - ask Fluffychicken for the sizing

 

[FluffyChicken]

MC36, a chromica colour (sort of metallic shiny bronze colouring) or silver anways ?
I think these are standard 5-arm compact drive and don't have the funny rings. I could easily be wrong as I do get lost in the hundreds (it seems) of variation of STX/STX-SE/STX-RC through the years

Anyway ChainReactionCycles sell 'em. Look for Shimano LX 5-arm compact for the middle or Middleburn maybe for a similar price (especially if you buy all 3 as a set)

About to have me tea so can look up later if you want. Pictures would help

 

[FluffyChicken]

all full now
MC36 STX-RC
BCD/PCD of 94mm (outer/middle) 58mm inner

diagram here

larger here
http://bernd.sluka.de/Fahrrad/Shimano/T ... S_1997.gif

as you can see the inner ring bolts onto the middle ring... so you're stuffed really unless a bike shop/somebody has one.

I think MC30/31/32/33/34/36 are all pretty similar in this aspect.
Get another chainset or loose the granny ring ?

(just for the info, i've looked through and MC30/31/32 used the odd 95mm BCD for outer and inner and later MC40 used the new styled and replaceable 4-arm spider setup similar 569(LX)/739(XT))

 

[uphillcursing2]

You are a good man Fluffy.
Here are the pics, i had to feed the offspring!!

Flash makes it look rougher than it really is!

Here lies the problem though: Some of the teeth are missing altogether!

So, from what you have said I ought to be looking for a "new" set of cranks. Suggestions for a '96 Klein Pulse? Im guessing something XT would not be amiss?