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I bought a set of second hand Shimano M980 XTR shifters and some KCNC I-Spec Shifter Clamps. I have absolutely no idea how the two can work together. I would say "E" should slide into "A", but really not sure and I don’t know how to use the bolts.

shifters clamp front clamp back

I found this diagram but it did not help me to figure out how everything should fit together.

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Edit: I've had some time to review your photos more closely. Here are some observations. First, your shifters have the I Spec A version of the top cover which differs from I Spec B in a key way by the presence of that little tab above the bolt/nut hole. This tab helps secure the shifter to the brake's band clamp by fitting into a recess in the band clamp. Zooming in your bottom photo of the two KCNC clamp bands, there is evidence of a recess that that tab may fit into on the clamps. This is observed on the viewer's right side of the slotted area you've outlined as E in the photo. This also makes the pertinent section of the copied Shimano I Spec directions to be the far right column, "Conventional Type" and bottom row "A type brake lever." This makes more sense as the fixing nut is more rectangular and better suited to fit into the slot of the KCNC clamp. I'm removing references in my answer referring you to the B-type lever instructions, however, I believe the other tips in my answer should guide you to a successful connection of your shifter to the clamp band.

You'll mount the shifter onto the clamp first. A does go into E of your photo. I'm guessing the clamp bands can be used either on the right or left (each clamp can be used on either side). The band's clamp bolt will be on the rearward side of the handle bar, the mounted shifter forward of the bars. The square nut of the I Spec A system will set inside the long slot of the clamp band such that nut's square lip catches in the clamp band and it's internal threads are facing out (to accept a bolt coming thru the hole in the shifter). You'll be using the A-type clamp technique under the conventional type shifter column per your copy of the Shimano guide (bottom right square section).

So with the nut in place through the clamp, you'll then slip the shift lever's tab into the the small recess at the end of the slot of the clamp band (A) part while the shifter fastening bolt comes through (A) and into the nut. So, if we look at your photo, in the A box, the bolt threads would be coming at us. The clamp, were it there would be in the foreground, the nut in place, threads facing away from us to meet the bolt coming at us. If you happen to instead have the long cylindrical nut with the square end as featured in the bottom row, middle column of the Shimano diagram, the cylindrical part of the nut (that has been placed in the slot of the clamp band with the cylinder sticking out of the clamp) comes thru the hole of the shifter (at your designation A of your photos) then secure that with the bolt coming into the nut from the other side..

Lateral adjustment of the lever position is accomplished by loosening the shifter top cap bolt and sliding the whole shifter body.

All that said, there may be compatibility problems right off the bat. There are 4 versions of I-Spec: A, B, II, & EV. The instructions in your question regard A & B I-Spec. The KCNC clamp may be for the ISpec EV version which has a much larger, some what of a cube shaped nut that fits into the slot of the clamp and the EV shifter's top cover has a prominent long, rectangular slot that this special, cubic nut fits into and is secured similarly (to the above A/B ISpec) by a bolt coming through the slot into the nut. If you find that the either of I Spec, A/B type nuts (the squat, square one or the cylindrical one with square end) are too small to catch inside the KCNC clamp's slot--it may just go right through or have very little purchase in the slot--you may be dealing with a clamp designed for the EV I Spec version and it won't work for you without some ad lib engineering. They do make I Spec A/B compatible clamp bands that work as described above.

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  • I think I am in the [Shifting Lever B type] ⨉ [Brake Lever A type type] configuration, but I have the nut and bolts for the [Shifting Lever B type] ⨉ [Brake Lever B type] setting. I purchased the missing long square nut but there was still an issue (not the only one experiencing this according to some reviews of the KCNC clamps): the slot in the KCNC clamp is too narrow for the standard nut ! Thank you for your thorough answer. Sep 3, 2022 at 19:16

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