Thought id do a little guide as may help others, also handy if you havent removed a crank or chain wheel etc.
Bikes a 2011 Zesty 514 but will be pretty much the same on other bikes
all parts used are Blackspire and comprises of a 38 chain ring and a 24 granny ring with a stinger chain guide, crank is Shimano SLX Hollowtech 11.
i dont recomend doing it on the lounge floor unless the Mrs is out and no chance of getting home early
parts, all nuts and retainers are included with the parts.
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A bike stand is handy if you have one
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and removing the chain will make things easier, so a good time to fit a quick link if you havent got one.
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1st remove crank starting by undoing non drive side, you will need an Allen key and a Shimano crank tool, remove Allen bolts first then undo centre cap with the Shimano tool, then simply wiggle off.
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Shimano tool
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next we need to remove the drive side, on the Hollowtech 11 its just a case of tapping out but other cranks may need the correct removal tool. With a lump of wood placed over the splined axle and a heavy Hammer give a few short sharp wacks on to the axle and the crank will be driven forward, a few wiggles by hand and it will come out..
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crank removed
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Next its time to remove old ring or rings depending on what you are wanting, you will need a star key and also a Peg tool to hold the rear of the sprocket bolts.
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Peg tool, about 3 quid from Evans.
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once removed just replace with the 2 new sprockets and fit the bash guard in place of the 3rd ring..
Now its time to fit the stinger, on my bike its the ISCG 05 version on others it may be different. simply screw in the 3 supplied screw in to the ISCG 05 fittings in the frame, set the stinger so its at least 10mm down from the chain stay on a full suss and at least 15mm on a hardtail. At this point just screw up lightly as may need to adjust on the next stage.
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Next put a bit of grease on the crank shaft and slide in the drive side (only) crank arm giving a few gentle taps to make sure its full in (this is important) as theres a measurement that is dependent on the crank being fully home.
you now need to take a measurement from the face/front of the stinger to the centre or tip of the granny ring, you are looking for a gap of between 4-6mm if gap is more than 6mm then you need to pack the rear of the stinger with the 3 supplied washers (hence why to not fully tighten up stinger yet) on mine i never needed then as the gaps 5mm.
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once gap is set its time to tighten the 3 stinger screws, so tap out crank again it will be easy now and refit once stingers done up, now refit non drive side of crank, slid onto shaft and with the Shimano tool screw in the plastic retaining screw so arm is pushed onto shaft and theres no play in the crank, now finish by doing up the 2 allen key bolts.
now you need to tighten the chain wheel on the stinger with 2 Allen keys, slide the wheel so its just touches the bash guard without putting pressure on the guard and causing resistant when turning crank.
now refit chain and set the H screw on the front mech so that the chain dosent rub against the bash guard when shifting, turn the H screw inwards (clockwise) to do this. once this is correct you wont be able to over shift by mistake as if you still had 3 chain rings, road test and adjust as needed..
and thats it..
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Untitled by
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heres a link to Blackspires instructions
http://www.blackspire.com/site_assets/w ... _guide.pdf