HELICOIL IN REAR MECH BARREL ADJUSTER SCREW IN
TRIALNERROR
Posts: 5
I inadvertently broke the helicoil insert where the barrel adjuster enters the rear mech of a Tiagra 4601 (short cage) and I'm wondering what specs to go by in getting the replacement kit. I think the barrel adjuster bolt is M5. So do I get the M5 kit, or the M6 kit? I need to drill out and re-cut the inside of the female component, then reinsert an M5 helicoil. Naturally the thread which I cut will be bigger than the thread of the bolt in order to accommodate the helicoil, but I just can't work out exactly what size to buy. Do I go up one size, or is this allowed for in the kit whose number corresponds to the bolt size? For the record, I live in the wilds of Turkey and am sort of obliged to do a lot for myself. I went to a car garage and they only had kits for spark-plug repair, way too big, or expensive multikits for every coil ever manufactured. I only want to repair one little coil. I recoil in confusion lol.
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I can't help but think it would be cheaper to buy another rear mech than tool yourself up to helicoil the existing one. Is there even enough metal there to drill a larger hole safely?
When both pulley bolts seized in and rounded off in my 105 rear mech, by the time I'd costed replacement pulleys and bolts and screw extractors, a whole new mech was £2 cheaper...0 -
This was already a replacement. Also 640x seems to be getting harder to find as everything is going 6700. I don't want 6700 as it won't work with the brifters.0
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TRIALNERROR wrote:This was already a replacement. Also 640x seems to be getting harder to find as everything is going 6700. I don't want 6700 as it won't work with the brifters.
I'm assuming you meant 4600 vs 4700 (Tiagra)? Yes, it was annoying when they brought out 10 speed 4700 with a different pull ratio.
You could look for any older rear mech; Tiagra 4500 / 4600, 105 5600 / 5700, Ultegra 6600 / 6700.
Ebay has plenty to choose from0 -
Oops. Thumbs very fumbly today! Yes that is an option but I still curious about the helicoil question. I have lots of drill bits and tap screws anyway so it wouldn't be too much of a task. I bet I could get away with just a new helicoil if I knew precisely which to get. Certainly there is enough metal to drill and tap. Of course I might try and extract the helicoil from the old Tiagra which I reattached but I'm too scared of breaking it and being left with nothing lol0
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Buy a cheap inline cable adjuster and insert it between the shifter and downtube cable stop. Then there is no need for a barrel adjuster on the RD. You can do away with it.0
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I'd have thought an M5 Helicoil insert is designed to take an M5 threaded component when installed.
Annoyingly Shimano's EV tells you the size of the limit screws and the pinch bolt, but not the thing you're interested in. Pinch bolt is M5 so maybe the barrel adjuster is M6?0 -
What I really want to know is, does one get the recoiling kit same size as the threaded male component? You appear to believe this is so but when I check the M5 kit it says that the tap screw included is M5 and the coil is M5. This doesn't make sense if you are drilling out the.old thread. It will be too big to tap with an M5. Do you get my drift here? I suppose this is more a mechanic's area than just a cycling repair but I was just interested.0
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TRIALNERROR wrote:What I really want to know is, does one get the recoiling kit same size as the threaded male component? You appear to believe this is so but when I check the M5 kit it says that the tap screw included is M5 and the coil is M5. This doesn't make sense if you are drilling out the.old thread. It will be too big to tap with an M5. Do you get my drift here? I suppose this is more a mechanic's area than just a cycling repair but I was just interested.
This should tell you more than you ever needed to know about Helicoils
http://www.helicoil.in/pdf/HeliCoil%20Catalogue.pdf
I think it says what I thought it would., but I'm no engineer0
