Bicycle Mechanics - Oh no, I stripped the bolt on my new seatpost!

HELP!!

I got a nice fi'zi:k Cyrano aluminum seatpost for Christmas.

Tonight, when I was putting it on my bike, I put my torque wrench on the 4mm bolt to tighten it to 8nm and somehow managed to strip the bolt. (It's a click style torque wrench.)

I managed to get the bolt out, but am worried about getting a new one. There's a shoulder about 10mm long that's not threaded and is slightly larger than the threads.

Any suggestions?

Oh, it's going on my Jamis Coda Sport.

Bring the bolt in to your LBS, ask them to find a replacement-it's what they do.

If you stripped out the aluminum that the thread is cut into .. in the seat post itself .. well . :notamused: too bad , seatpost May be toast.

is there aluminum on the threads when you took the bolt out?

Is this the bolt that adjusts the seat angle or the bolt that
clamps the seat in place? It is unlikely the bolt itself is
stripped, more likely the threads into which it goes are
stripped. Is 4mm the size of the allen wrench? 4mm bolt
sounds small for seatpost clamping. Bolt is a shoulder bolt,
fairly standard item, but 1 off hard to find. This site has some
info and pricing if fizik can't help. If the female threads are
stripped, a drillout, retap to next size and subbing a non-shoulder
bolt could salvage the post as the shoulder is larger as you note.
http://www.mcmaster.com/#shoulder-screws/=adibn3

I stripped out the actual "hole" the Allen key fits into. I'm assuming there's either 1.) something wrong with my torque wrench (click type) or 2.) user error.

I'm opting for the second choice!

I went to the closest bike shop today. The young man dumped a shoe box sized box out and we found a bolt to replace it.

Cost a $1.

It's been a rough month, and the seatpost thing just topped it off. I thought for sure I ruined an expensive seatpost.

If something is going to get stripped, wrecking the allen key hole is a piece of good luck.
A cloud of darkness surrounds me and I breathe lightning when something like that happens to me.
I hope everything else goes together without incident for you.

If this is a 2-bolt post, usually the front bolt sees the much higher stresses.

If there's any question about the quality of the replacement bolt, put it in front if you have that choice.

Glad you saved the new post! I was gonna suggest the oversize bolt approach by SCH if the threads were gone, been there and done that.

Just too weird that the Allen fitting would strip. Perhaps the tool didn't fit well, was poor quality/condition or maybe not in all the way?
I have been known to strip out the shallow, 3mm allen key holes on bottle cage mounts myself.

If you stripped out the aluminum that the thread is cut into .. in the seat post itself .. well . :notamused: too bad , seatpost May be toast.

is there aluminum on the threads when you took the bolt out?
Helicoil?

Just be comfortable with machine shop overhead cost,if you want someone skilled to put that helicoil in..


Update said the hex in the bolt rounded out ... whew .. that is a relief..

I have a drill and tap sent, but it's ASTM and not metric.

Thankfully, I don't need it in this case!!!

Uhmmmm....better check out the condition of your allen head wrench set. Thee tip of the wrench might be worn out and too loose (try to avoid using the ball type tips if you don't really have to, as they have less material contact with the socket on the head. I think they can strip the bolt head sockets easier because of this) when inserted into allen head bolts they do wear out after some years of use.....or you might have used a non-metric set on the bolt by mistake(??). If the wrench is OK, it might then be that the bolt manufacturing tolerances are bad and should be returned to Fizik as a defective part for exchange. Striping out allen bolt heads is not that easy unless you have a worn wrench tip or you wear out the bolt head hole from lots of use, you noted that your seatpost is an X-mas gift, so I assume it might be new so this it's kinda unusual for the bolt to strip so easily if you did not put any sort of crazy amounts of torque on it.

Chombi