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· Resident Curmudgeon
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You can try to chase them, but my bet is you'll have to get new ones. Try a hardware store. They'll likely have some that will fit.
 

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Just to make sure we're not misundersanding - it's the bolts themselves that are stripped, right? If so, any LBS and some harware stores (or a fastener specialty store) will have those bolts. Make sure you get the right thread.
 

· n00bsauce
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If it's the threads in the stem that are stripped I'm afraid you're SOL. I would not attempt to rethread a carbon stem for a larger bolt. The amount of material left over may not be enough to prevent cracking.
 

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hippie_rn said:
yeah, its the threads in the stem that stripped.
Since this is a composite stem, I'm assuming it uses metal threaded inserts (probably alum alloy). Is is possible the threads are actually Ok but the inserts are the problem? Specifically, maybe the inserts debonded from the carbon and are now spinning when you try to tighten the bolts. If that's the case, seems like a warranty claim could be made.

Now if the female threads are truly stripped from excessive torque, probably a write-off as others have said. If it was an alloy stem, using something like a Helicoil insert may be possible. But, doubt that will work here. The wall of the damaged inserts is probably quite thin and probably wouldn't tolerate a larger tap size.

Well, hope everything works out since that is one expensive stem!

Paul
 

· n00bsauce
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I had a carbon stem and stripped the threads in the stem. I used a torque wrench and didn't even get to the recommended torque before they stripped. No inserts and that was more than likely the problem. Even with inserts I doubt it could be fixed. How you going to get the inserts out and where you going to find replacements? You wouldn't be able to re-tap the inserts, not enough metal. I'm afraid it's likely toast.
 

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Discussion Starter · #9 ·
alright- yes there is an insert, yes the insert is stripped (not spinning or debonded). still, what i can see of the threads, they dont look too bad. ill give it a good degreasing and try a new bolt, maybe get lucky.
im still wondering though if this could be retapped if need be. the insert looks to be close to 1/8" thick

thanks for the replies guys
 

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hippie_rn said:
alright- yes there is an insert, yes the insert is stripped (not spinning or debonded). still, what i can see of the threads, they dont look too bad. ill give it a good degreasing and try a new bolt, maybe get lucky. im still wondering though if this could be retapped if need be. the insert looks to be close to 1/8" thick
Ok, that narrows it down to actual thread damage. The fact the insert has a thicker wall (~1/8") sounds encouraging. However, that may be misleading since the insert could have an end flange whereas the body is much thinner like this:



If you have nothing to lose, you might try drilling, tapping and installing a Helicoil screw thread insert. I suspect your stem bolts use either a size 4 mm or 5 mm Allen wrench. If a 4 mm hex key, the bolt/thread size is probably a M5 x 0.8 mm pitch. For a 5mm hex key, most likely a M6 x 1.0. This page has the recommended drill sizes for repairing Metric threads:

http://www.bayrivet.com/Metric_heli_products.htm

Oh yeah, the lengths of the Helicoils are based on diameter (typically 1D, 1.5D, 2D, 2.5D & 3D). This means a M5 insert would come in a 5 mm to 15 mm range in 2.5 mm increments.

Unless you have a drill press, I would definitely have a machine shop attempt the repair. They would most likely have the required special tap and insert too.

Good luck!

Paul
 

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Purchase:

1. A new stem.

2. A torque wrench.

Rules for working on carbon bikes/components:

1. Never tighten anything without using a torque wrench.

2. Never ever tighten anything without using a torque wrench.

2. Never never ever ever tighten anything without using a torque wrench.
 
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