XTR M950 spider compatability

[ishaw]

I'm building up a carbon cadex frame for commuting and want to run XTR M95x groupset (i've got all the bits sitting around). My current plan is to run only one front ring (doing away with the need for a front mech and shifter) and know that I can get an XTR DH chainring and spider, but I can only find info on these fitting the M951/2 crank arms. I currently have a set of M950's that I bought here on retrobike, but can't find any info on what the difference is between these and the M951/2 cranks. Does anyone know if/why the XTR DH spider would not fit on the M950 crank arms?

Cheers

Ian

 

[letmetalktomark]

Your best option might be to buy a middleburn spider and then any choice of ring size.

The DH rings are big, 48 teeth plus IIRC.

However, the DH rings should fit all M95X series.

 

[ishaw]

Cheers for the info. I have been toying with the middleburn spider, or a retro 5 arm one, but the reason I was thinking of the DH ring was that I wanted a bigger ring for commuting, as the 44T I have on my M960 leaves me pedalling like a madman half the time, and I run out of gears.

Ian

 

[eastcoaststeve]

Be careful when you choose your spider to get a bcd with readily available rings...

I wanted to use XTR's with a single ring on my Spooky build, and grabbed a very nice set of cranks that came with an MRP guide and a big ring already attached from a former downhiller. Thinking I could pop a 36t on in place and be in business I was jazzed until I measured the bcd and came up with the Shimano oddball 112bcd...might as well be looking for needle in a haystck :evil:

If you plan on running a really "big" ring, there are a few nos downhill sprockets on Ebay at the moment.



cheers,


Steve

 

[ishaw]

Thanks for the advice Steve, will bear in mind.

Ian

 

[letmetalktomark]

TBH by the time you have bought a five arm XTR spider (if you can find one) and a suitable ring (IIRC its not compact sizing) you are most of the way to getting a middleburn spider that uses compact (I think) chainrings.

I have experimented with LX & XT spiders from the same generation as the M950 range and had some good success (LX & XT use conventional BCD).

Rory's set up uses XTR arms coupled with an LX or XT spider meaning that compact rings can be used and are easily accessible:

But again by the time you have sourced a chainset and rings you could have bought a middleburn!

 

[ishaw]

Cheers, do you know if any machining is required to fit say an LX or X spider?

 

[letmetalktomark]

Cheers, do you know if any machining is required to fit say an LX or X spider?

From my experiments nothing more than a little filling. Must be Octalink though

 

[andrewl]

Thinking I could pop a 36t on in place and be in business I was jazzed until I measured the bcd and came up with the Shimano oddball 112bcd...might as well be looking for needle in a haystck :evil:

I can get you some chainrings made up if you wish.

 

[ishaw]

Cheers for the info so far - anyone know if the STX-RC spider is compatible? For that matter, how about an AC spider?

Thanks in advance

Ian