Shimano STX SE FC-MC31 chain rings

[northy]

Hello all.

Please can anyone help me keep my 1994 Bear Valley SE on the road by helping me source some new front chain rings.

I have the FC-MC31 which has the 95mm chainrings on, 5 mounting hole and the middle ring holds the outer.

I am running a 42, 34 & 24 tooth size.

Thanks very much.
northy

 

[Minifreak]

Hi mate, afraid I haven't got what your after but check eBay, item number 221949950463 . You'll need to select which ch ones may be of use.

 

[northy]

Re:

Thanks very much Minifreak - but i think mine is 95mm BCD.

 

[Egghead]

Shimano 5 arm compact triple BCDs are 94mm outer/middle and 58mm granny.
You have to be careful though, the design was not always the same - e.g. Not all 1994 STX SE rings will fit on 1994 LX cranks.
For STX MC31, the outer ring fixed to the middle ring and the granny ring connected it all to the arms.
For LX M563, the outer and middle rings fixed to the arms/each other and the granny also fixed to the arms on its own:
http://bernd.sluka.de/Fahrrad/Shimano/T ... B_1994.gif
http://bernd.sluka.de/Fahrrad/Shimano/T ... H_1994.gif

Some of the rings on that ebay listing will fit your cranks: No1 (but not 2 or 3) and Nos 10-13. They look a bit manky though.
You may have better luck finding a whole new crankset.

Cheers,
John

 

[northy]

Re:

Thank you for all your replys

I'm definatly after the 5 bolt - 95mm / 58mm chain rings. The rest of the STX range they went to 94mm / 58mm

CASH WAITING guys.

 

[Egghead]

Apologies, that was something I did not realise and I quoted the link with the 95mm dimension on it :facepalm:
There was previous thread on here about the same issue
viewtopic.php?f=1&t=51037&start=0
It seems that in 1994 only, Alivio (MC11), STX (MC30) & STX-SE (MC31-CH) used 95mm outer BCD whilst LX/XT were 94mm. After 1994 everything was 94mm.
So this means is probably going to be quite hard to find replacements.......

 

[k-rod]

Re:

perhaps it'd be worth considering replacing your crank arms as well (good used ones aren't all that expensive) ... ?

 

[Relliott6879]

I do recall STX having a peculiar chainring fitment (I think STX-RC had the 'normal' BCD of LX and XT, but I could be wrong?). I have a vague memory of Pace (I think) either making STX fitment rings or an adaptor that allowed the use of regular LX/XT pattern rings, but I imagine you'd do well to find either nowadays. On the whole, you're probably better off sourcing a period LX or XT crank, unless you're dead set on STX for catalogue-spec build purity.

EDIT: I'm not going mad, Pace RC-21! http://www.retrobike.co.uk/forum/viewto ... p;start=10

 

[cherrybomb]

Re:

The earlier STX & STX RC cranks used a unique BCD & mounting method for the outer & middle rings (Don't ask me what- I've never measured). The later STX cranks reverted to the more common 94/58, so replacement rings are much easier to source.

As has been said, the outer & middle ring on the earlier models bolt together & then the middle ring & granny bolt to the crank arm. The PCD of the granny ring (and middle ring crank mounting holes) is standard at 58mm.

I have several sets of arms, two fitted with the Pace adapters that Relliott6879 mentions, which allow you to fit standard 94mm PCD middle & outer rings.

You'll be lucky to find one now if I'm honest, and even if you get hold of one; once you've sourced new rings you could have brought a whole new crankset.

I used to have several sets of standard rings but they've all gone now I'm afraid.

 

[northy]

Thanks ever so much for the replys again.

Loving the avatar cherry bomb. I've got a period Rox sticker on my bike and had many a tshirt back in day. Nice bit of history there.

I will keep a eye out for one of these adapters, didn't know they existed.

I would happy upgrade to XT deore M737 if I can find a crankset that's NOS or barely worn.

Has anyone ever had suscess with obtaining obsole parts from Shimano spares?


Egghead: no problems, I did double check the BCD's when I first started looking. The Alivio (MC11) will be worth a look. I did check the MC33 & 34's to see if I could use the BCD of their chain rings.

I have been looking at custom chain rings today but again the elusive 95mm BCD isn't covered. Does anyone know of a custom manufacturer that can do a 5 stud 95mm outer and middle ring set for me.

Thanks Northy