Hi Guys, bit stuck and need some help….

I needed to replace the middle ring which was chain sucking, and ordered an FSA 104 pcd 4 bolt ring from Wiggle.

When I came to fit it, the ring wouldn’t fit in the recesses on the spider. The holes are in the right place, and two of the hole tabs will fall into the recess, but the other two are proud? I thought I’d bought the wrong ring so ordered a genuine Shimano from Merlin with a new outer, chain and cassette.

I went to fit them tonight only to find that the Shimano ring exhibited the same issue?

If I take the old ring that came off and place over the new ring and put bolt sleeves through the 4 holes they line up perfectly? However, just like the FSA ring there is too much metal on the hole tabs to allow it to fit in the recess on the spider?

I’ve never had a problem with a chain ring not fitting before, and I’ve probably fitted a number of replacement rings to this crank in the past?

From my memory and the little marking still on the cranks, they are M751 hollowtech octalink first fitted in 2002.

Any ideas?

Thanks

You could file the tabs on the chainring a bit to make them fit.

Yes thats plan B.

Will take crank and rings to LBS tomorrow and see what they say and if they have one to fit, if not it will be down the fitting shop at work and get them ground back a touch…

If I recall, Shimano did this to stop you fitting cheaper Deore rings to XT cranks…
(Well, that was my cynical take on it anyway).
Either way, just fettle a bit off the tabs on the ring, or the spider. That’s what I did. The ring will align fine on the chainring bolts.