# Stripped stem thread solution?



## Opus51569 (Jul 21, 2009)

Noticed a little bit of play in my bars. Went to tighten the bolts on the cover plate and felt the dreaded pop/free spin. I backed out the bolt and, sure enough, it had pieces of the matching thread attached to it.

If I run a bolt all the way through the stem cover plate and stem and use a washer and nut on the other side, will it compromise the strength of the stem or the clamping force?

It's a beater bike so I'm not concerned about the looks, just the strength and safety.


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## cxwrench (Nov 9, 2004)

New stem.


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## tlg (May 11, 2011)

Opus51569 said:


> If I run a bolt all the way through the stem cover plate and stem and use a washer and nut on the other side, will it compromise the strength of the stem or the clamping force?


You're not going to have a flat surface on the back side for a washer and nut to properly sit on. It may work. But there's a great chance you won't get a good clamp. 
What's the worst that could happen... faceplant?

Get a new stem. They're cheap. Maybe a torque wrench too.


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## Special Eyes (Feb 2, 2011)

tlg said:


> Get a new stem. They're cheap. Maybe a torque wrench too.



+1. Or, you could install a helicoil, for about the cost of a new stem.


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## Opus51569 (Jul 21, 2009)

Good point about the clamping surface, tlg. I hadn't thought about the fact that it isn't perpendicular to the bolt.

Thanks everyone, for the replies.

I guess I should start pricing new stems.


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## tlg (May 11, 2011)

Special Eyes said:


> +1. Or, you could install a helicoil, for about the cost of a new stem.


Most modern stems have very little material surrounding the threaded portions. I wouldn't risk taping it larger to install a helicoil. Unless maybe if it was a beefy MTB stem.


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## headloss (Mar 3, 2013)

New stem. 



> "Do not look at the handlebar on your bike as a permanent accessory. All aluminum handlebars will eventually fail. ... Some manufacturers recommend replacing stems and handlebars every four years. If you rarely ride the bike, this is overkill. If you ride hard and ride often, every four years may not be frequent enough." Lennard Zinn


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## goodboyr (Apr 19, 2006)

New stem.....or really good dental insurance.


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## MMsRepBike (Apr 1, 2014)

I've had a stem give at the faceplate before on the road. It's a terrible feeling. I was going downhill too, very lucky I didn't crash and burn.

It's very much worth it to get a new stem. 

My suggestion is to go to your local bike shop. Our shop has a whole box of unwanted stems. I'm sure we'd sell one for 5 or 10 bucks. Your local bike shop probably has a nice one that's unwanted, your size, and next to nothing in terms of cost.


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## loxx0050 (Jul 26, 2013)

If there isn't enough material to install a helicoil insert then the next best thing is to tap it to next larger sized thread and use the corresponding bolt. But, this is assuming that their is enough material left to do so which may not be the case either. 

FYI, this is a pretty common occurrence for aluminum to eventually have stripped or damaged threads because most bolts are steel. Which is a much stronger material and aluminum is actually a rather soft material. At my place of employment we build high precision machined parts out of stainless steel and aluminum (to save weight or costs where high strength is necessary). We pretty much almost always design the aluminum parts with threaded holes to have a helicoil insert. It is easier to pop out and replace a helicoil than to drill and tap a new hole (and then have to update the part drawing and assembly instructions to match).

You can buy cheap stems for $20-30 new anyways so it might not be work the hassle to fix the part (or even you see sometimes used ones on craigslist for $5-10 even).


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## Roland44 (Mar 21, 2013)

goodboyr said:


> New stem.....or really good dental insurance.


hehe true that  Just get a new stem OP..


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## BikeLayne (Apr 4, 2014)

My son-in-law has a Bianchi with an alloy stem. One of the tightening bolts stripped out and I went to the LBS to buy him a new stem but they only had Specialized. Since I do not buy Specialized products I thought I would just put a bolt and nut in there to hold it until I could get a Ritchey stem on-line. When I saw the bolt would not fit flush I took a drill and drilled the stem just enough to give a flat surface for the bolt and it allowed the bolt to sit recessed. I then tightened the bolt with my Ritchey torque tool and it tightened up very well. The nut and bolt head both fit flush and it looked ok actually. There was enough material in the stem to allow the fix. I replaced his stem with a Ritchey alloy stem since then. I keep spare parts in a bucket and had a very nice self locking nut and bolt in there and just used that. It even had an allen head.


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## Special Eyes (Feb 2, 2011)

tlg said:


> Most modern stems have very little material surrounding the threaded portions. I wouldn't risk taping it larger to install a helicoil. Unless maybe if it was a beefy MTB stem.


That's true. Treaded inserts require pilot holes that are not much larger than the original nominal diameter of the tapped hole. Stems that have those 'frog eye' bosses may not work well for inserts. Tapped holes in a more solid and beefier section of metal would. There's such a variety of stems in that regard. Still, stems are cheap on ebay!


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