stripped my crank...,.

TJ? Poseno said:

I somehow managed to strip my crank, the pedal threads, on the _LEFT_ side. So I was going to re
tap the threads, but with it being a left handed thread, I needa left handed tap. Does anyone know
what Tap I need, I measered my pedal at 9/16" or are they Metric, its on a wally world bike.

A left hand 9/16 pedal tap used only in the bicycle industry. However, that probably won't help. The
pedal thread being a weak point on the bicycle anyway. A stripped thread will probably hold a pedal
cosmetically but that's not good enough to ride much. Get a new crank.

Quoted message said:

Also does anyone know where I can get left handed taps?

parktool.comTAP 6.shtmlOpen ↗

Jobst Brandt [email hidden]

In article said:

I somehow managed to strip my crank, the pedal threads, on the _LEFT_ side. So i was going to re
tap the threads, but with it being a left handed thread, I needa left handed tap. Does anyone know
what Tap I need, I measered my pedal at 9/16" or are they Metric, its on a wally world bike.

It's 9/16 x 20

Quoted message said:

Also does anyone know where I can get left handed taps?

Bicycle shop or tool supplier.

You may also need a thread repair kit to restore those threads enough to hold a pedal. The price of
a new left crank arm is often low enough for you to consider replacement, depending on what you have
and whether you care if it matches. You could also have a bike shop repair it if you don't want to
buy the thread repair kit.

--Paul

TJ Poseno said:

I somehow managed to strip my crank, the pedal threads, on the _LEFT_ side. So i was going to re
tap the threads, but with it being a left handed thread, I needa left handed tap. Does anyone know
what Tap I need, I measered my pedal at 9/16" or are they Metric, its on a wally world bike. Also
does anyone know where I can get left handed taps?

9/16 x 20tpi and at virtually all ( even little ones) LBS.

--
Andrew Muzi www.yellowjersey.org Open every day since 1 April, 1971

My LBS said they will try to re tap it. Its only the first 4 threads. But I can get one on off
another bike, but it puts one of my bikes down for the winter, so Im going to need it for spring. I
think i may have it reatapped, then use it on the bike my Mom uses, because it enver gets any high
force applied to it.

Quoted message said:

have it reatapped, then use it on the bike my Mom uses...

Now's the time to make sure all her insurance is paid up!

Just kidding, sort of...

Quoted post said:

Originally posted by TJ Poseno
I somehow managed to strip my crank, the pedal threads, on the _LEFT_ side. So i was going to re tap
the threads, but with it being a left handed thread, I needa left handed tap. Does anyone know what
Tap I need, I measered my pedal at 9/16" or are they Metric, its on a wally world bike.

Also does anyone know where I can get left handed taps?

I had a similar problem three months ago, except I tore out all the threads. Two LBS says they couldn't retap or helicoil it, a third said they could and it would be stronger. Issue became temporarily moot when a 4th had a matching used crankarm.

Issue is bound to come up again so does anyone know if heli-coiled crank arms hold up or fail?

meb said:

TJ Poseno said:

I somehow managed to strip my crank, the pedal threads, on the _LEFT_ side. So i was going to
re tap the threads, but with it being a left handed thread, I needa left handed tap. Does
anyone know what Tap I need, I measered my pedal at 9/16" or are they Metric, its on a wally
world bike. Also does anyone know where I can get left handed taps?

I had a similar problem three months ago, except I tore out all the threads. Two LBS says they
couldn't retap or helicoil it, a third said they could and it would be stronger. Issue became
temporarily moot when a 4th had a matching used crankarm.

Issue is bound to come up again so does anyone know if heli-coiled crank arms hold up or fail?

well done helicoils are fine. my campy seat post has helicoil in the clamp bolt thread - from
factory. correct, it /can/ be stronger than the original.

Quoted message said:

--

TJ Poseno said:

My LBS said they will try to re tap it. Its only the first 4 threads. But I can get one on off
another bike, but it puts one of my bikes down for the winter, so Im going to need it for spring.
I think i may have it reatapped, then use it on the bike my Mom uses, because it enver gets any
high force applied to it.

Geez, your mother's safety for a few bucks? Ask the price of a replcement left crank - they're
seldom over $20.

If it is more than just the first thread or so, a new crank is a reasonable choice.

--
Andrew Muzi www.yellowjersey.org Open every day since 1 April, 1971

Quoted message said:

Issue is bound to come up again so does anyone know if heli-coiled crank arms hold up or fail?

Eldi makes a nice insert kit for repair. Don't use a Helicoil even if you could fine a LH
one-they're a special order. The Eldi insert is much better. But a LH crank arm is cheap at most any
LBS-just check the discard box. Phil Brown

TJ Poseno said:

Quoted message said:

I somehow managed to strip my crank, the pedal threads, on the _LEFT_ side. So i was going to
re tap the threads, but with it being a left handed thread, I needa left handed tap. Does
anyone know what Tap I need, I measered my pedal at 9/16" or are they Metric, its on a wally
world bike. Also does anyone know where I can get left handed taps?

MEB said:

I had a similar problem three months ago, except I tore out all the threads. Two LBS says they
couldn't retap or helicoil it, a third said they could and it would be stronger. Issue became
temporarily moot when a 4th had a matching used crankarm.

Issue is bound to come up again so does anyone know if heli-coiled crank arms hold up or fail?

A full insert or a helicoil, if properly installed, is not only OK, but arguably better than the
original aluminum thread. Common applications are spark plug threads in aluminum heads and the
similar sized pedal thread inserts (of which I've personally installed over a hundred over the years
without incident.) That being said, a crank extractor thread is a bottoming thread and not very deep
at that. Might be a difficult setup if there were such a special tap available (AFAIK there is not).
I can only assume that shop #3 thought you meant a pedal thread.

If someone knows of a bottoming tap for this I'm listening.

--
Andrew Muzi www.yellowjersey.org Open every day since 1 April, 1971

Quoted post said:

Originally posted by A Muzi

BTJ Poseno said:

Quoted message said:

I somehow managed to strip my crank, the pedal threads, on the _LEFT_ side. So i was going to
re tap the threads, but with it being a left handed thread, I needa left handed tap. Does
anyone know what Tap I need, I measered my pedal at 9/16" or are they Metric, its on a wally
world bike. Also does anyone know where I can get left handed taps?

MEB said:

I had a similar problem three months ago, except I tore out all the threads. Two LBS says they
couldn't retap or helicoil it, a third said they could and it would be stronger. Issue became
temporarily moot when a 4th had a matching used crankarm.

Issue is bound to come up again so does anyone know if heli-coiled crank arms hold up or fail?

A full insert or a helicoil, if properly installed, is not only OK, but arguably better than the
original aluminum thread. Common applications are spark plug threads in aluminum heads and the
similar sized pedal thread inserts (of which I've personally installed over a hundred over the years
without incident.) That being said, a crank extractor thread is a bottoming thread and not very deep
at that. Might be a difficult setup if there were such a special tap available (AFAIK there is not).
I can only assume that shop #3 thought you meant a pedal thread.

If someone knows of a bottoming tap for this I'm listening.

--
Andrew Muzi www.yellowjersey.org Open every day since 1 April, 1971 [/B]

Actually, shop #3 was talking about doing a left handed heli-coil rather than a tap of the pedal thead. That shop generally has a better knowledge of bicycles than most of the other DC area LBS-so I presumed they were right-but since they are 15 miles away I stopped at a small 1 man shop (#4) -the closest to where I work and got the part there. Guy at #4 didn't even know what a heli-coil was.

08 Dec 2003 22:53:51 -0600 A Muzi said:

That being said, a crank extractor thread is a bottoming thread and not very deep at that. Might be
a difficult setup if there were such a special tap available (AFAIK there is not). I can only
assume that shop #3 thought you meant a pedal thread.

If someone knows of a bottoming tap for this I'm listening.

Didn't VAR sell such a tap at one time? (Even if so, I've never actually seen one....)

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Jim Adney [email hidden] Madison, WI 53711 USA
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