Pedal came off crank arm while riding

"Gordon" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

I would of never believed it but my left pedal came off the crank arm

<<snip..>>

Quoted message said:

bike. I know why people use loctite on pedals.

I've never seen loctite on pedals. In my experience, if you properly tighten the pedal, it is not
necessary. In fact, the opposite is true..pedals are usually difficult to remove once they've been
in there a year or two.

Quoted message said:

I looked over the bike and most of it looks okay. I am wondering though what I should do with the
pedal and left crank arm? I can force the pedal back into the first few broken threads, but that
doesn't seem too smart. Should I get the left crank arm re-threaded or maybe just get another
replacement left crank arm? Its only a Sugino VP, nothing spectacular.

Thanks.

Get a new left crank. They're generally pretty cheap if you don't have something exotic. The threads
are garbage on the old arm and it's not worth fixing, IMHO. You can try to heli-coil it but nothing
else will work. The pedal is likely fine, being much harder than the alu. crank. Make sure no thread
or alu. bits are left in the pedal threads.

Cheers,

Scott..

(Gordon) said:

I can force the pedal back into the first few broken threads, but that doesn't seem too
smart. Should I get the left crank arm re-threaded or maybe just get another replacement left
crank arm? I

your local bike shop can chase the threads for you. I've had that done and the threads
were restored.

charlie

"Gordon" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

I would of never believed it but my left pedal came off the crank arm when riding. Luckily I was
slowing down and reached the end of my destination when the accident occurred. I believe I did not
tighten the pedal enough and the pedalling motion loosened the pedal. My theory is that the pedal
came 75 % off and on my final downward power stroke the lateral force stripped off the pedal from
the crank arm. After getting up from the crash, I looked inside the threading of the left crank
arm and noticed that the last few threads were completely stripped. I was lucky and not too
seriously hurt, but it could of been more serious (even fatal) if was travelling alongside cars
and going at a higher speed. Once the pedal comes off you use control of the bike. I know why
people use loctite on pedals.

I looked over the bike and most of it looks okay. I am wondering though what I should do with the
pedal and left crank arm? I can force the pedal back into the first few broken threads, but that
doesn't seem too smart. Should I get the left crank arm re-threaded or maybe just get another
replacement left crank arm? Its only a Sugino VP, nothing spectacular.

Don't locktite them, use a grease or oil and check the right pedal after you buy a new left arm.
Sugino lefts are ubiquitous and dirt cheap. You only need to know the length which is stamped/cast
in the inside of the arm.

Lubricate the crank taper [or not*] and lubricate the fastener's thread and face.

*Illogical as it may seem, respected adherents of both persuasions seem not to experience failure.
Me, I lube everything that moves and a lot of things that don't.

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

A Muzi said:

"Gordon" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

I would of never believed it but my left pedal came off the crank arm when riding. Luckily I was
slowing down and reached the end of my destination when the accident occurred. I believe I did not
tighten the pedal enough and the pedalling motion loosened the pedal. My theory is that the pedal
came 75 % off and on my final downward power stroke the lateral force stripped off the pedal from
the crank arm. After getting up from the crash, I looked inside the threading of the left crank
arm and noticed that the last few threads were completely stripped. I was lucky and not too
seriously hurt, but it could of been more serious (even fatal) if was travelling alongside cars
and going at a higher speed. Once the pedal comes off you use control of the bike. I know why
people use loctite on pedals.

I looked over the bike and most of it looks okay. I am wondering though what I should do with the
pedal and left crank arm? I can force the pedal back into the first few broken threads, but that
doesn't seem too smart. Should I get the left crank arm re-threaded or maybe just get another
replacement left crank arm? Its only a Sugino VP, nothing spectacular.

Don't locktite them, use a grease or oil and check the right pedal after you buy a new left arm.
Sugino lefts are ubiquitous and dirt cheap. You only need to know the length which is stamped/cast
in the inside of the arm.

Lubricate the crank taper [or not*] and lubricate the fastener's thread and face.

*Illogical as it may seem, respected adherents of both persuasions seem not to experience failure.
Me, I lube everything that moves and a lot of things that don't.

And, if at all possible, use a torque wrench when you tighten it! All the pedals that I've used have
a hex key hole on the inside so that you can do this. YMMV.

David

NOT LOCTITE-Use a good grease and install tight-gordon-<< I would of never believed it but my left
pedal came off the crank arm when riding. >><BR><BR> << I know why people use loctite on pedals.

Quoted message said:

Quoted message said:

<BR><BR>

NOT LOCTITE-Use a good grease and install tight-

Gordon<< I can force the pedal back into the first few broken threads, >><BR><BR>

Take it to a decent bike shop and have them chase the threads, and check the right pedal as well...

Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St. Boulder, CO, 80302
(303)440-3535 vecchios.comvecchios.comOpen ↗ "Ruote convenzionali costruite eccezionalmente bene"

Qui si parla Campagnolo said:

Take it to a decent bike shop and have them chase the threads, and check the right pedal
as well...

I have found that the threads can generally be successfully cleaned up by inserting the pedal from
the wrong side (and then putting it back as normal before riding off :-)

I've had a couple of pedals unscrew on me, before I learnt that they really did have to be done up
properly (not hugely tight, but properly snug) despite the precession effect.

James

The same thing happened to me with the right pedal. I had taken the crank off and cleaned it, and apparently just hand tightened the pedal. I was more unfortunate as I hit the pavement and came away with bruised ribs and a busted helmet. Other than the stripped pedal, the bike was all right since it landed on me.

I took the crank to the local bike shop where they chased the threads out. I reinserted the pedal, made sure it was tight (and recheck every time I ride), and haven't had any trouble since. If its just the last two or three threads that stripped, you shouldn't have any problems. The problem with buying another crank arm, in my case, was that it's awfully difficult to find a Shimano 600 right side 172.5 crank.

I tried to chase the stripped threads by threading the pedal from the backside, but the threaded part of the pedal axle wasn't long enough to go all the way through

lfdavis <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

The same thing happened to me with the right pedal. I had taken the crank off and cleaned it, and
apparently just hand tightened the pedal. I was more unfortunate as I hit the pavement and came
away with bruised ribs and a busted helmet. Other than the stripped pedal, the bike was all right
since it landed on me.

You were less fortunate than me, I only had scrapes on my left knee and arm. Even though I was
wearing wearing, its an extremely dangerous and scary situation losing control like that. Once the
pedals pops off, you lose most of your balance and control. I was really lucky that it did not pop
off on the major streets with cars zooming by me (I usually go pretty decent speeds on those
stretches).

When I was referring to using loctite on pedals I meant stores, my friend bought a Miele MTN bike
and they used loctite on most of the parts (including pedals). I guess they didn't want a rare
situation of a pedal coming off (could possibly lead to a lawsuit?). I am pretty sure that there
must be a case of some business store having a customer returning a bike with a pedal coming off.
Rare situation, but probably an unpleasent situation.

A bike store can chase the threads for me, but I would like to know more about the process how it
works? Its hard for me to visualize it repairing the threads and still being as durable originally.
Doesn't chasing make the pedal hole bigger?

I am purposely not using that crank and pedal to prevent further damage to the bike and myself. I
want to make the best and safest decision.

Thanks.

"Gordon" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

A bike store can chase the threads for me, but I would like to know more about the process how it
works? Its hard for me to visualize it repairing the threads and still being as durable
originally. Doesn't chasing make the pedal hole bigger?

I am purposely not using that crank and pedal to prevent further damage to the bike and myself. I
want to make the best and safest decision.

Thanks.

Sometimes, if you didn't take out too many threads when the pedal came out, you can clean up what's
left, put the pedal back in and there will be enough purchase left to tighten the pedal again
against the crank. I've had this both work and not work. You really can't tell until you try and see
how it tightens up. All in all, a new left crank like yours is probably $20 or so. When working in a
shop, you've got to be VERY certain that nothing catastrophic will happen once that bike leaves your
shop. As a consequence, we just generally replaced the arm and that was that. If it was someone we
knew and they understood the risks, we'd try chasing and re-installing. It's your (and your shop's)
call. Re-installing that pedal in that crank will NOT be as strong as when it was not damaged. The
question is, is it strong enough?

Cheers,

Scott..

"Gordon" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

A bike store can chase the threads for me, but I would like to know more about the process how it
works? Its hard for me to visualize it repairing the threads and still being as durable
originally. Doesn't chasing make the pedal hole bigger?

I am purposely not using that crank and pedal to prevent further damage to the bike and myself. I
want to make the best and safest decision.

Thanks.

You'll need to find someone with experience to make judicious decision. "Chase" as far as I can
tell, implies just 'run a tap through the pedal eye'. You'd think that the clear English phrase, or
even "cut" would be preferred, rather than the obfuscating "chase". Oh, well.

That process cannot add any material. Missing thread material is the actual problem and a dangerous
one at that.

You mentioned yesterday that your pedal does not fully engage the whole width of the crank thread
anyway. Cutting the occluding swarf out of the front of the thread will let you start the pedal into
the crank but it won't magically restore missing aluminum. Get an informed and experienced opinion
before standing on that pedal.

I suggested earlier that a new crank is the preferred ( under $20) course. I still think so , even
moreso now that someone has suggested "chase" as "remedy".

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

A Muzi said:

"Chase" as far as I can tell, implies just 'run a tap through the pedal eye'. You'd think that
the clear English phrase, or even "cut" would be preferred, rather than the obfuscating "chase".
Oh, well.

The phrase might make it more obvious; but to say "cut" would be very confusing. "Cut" is how you
describe the action of using a tap to make threads in a smooth hole.

Quoted message said:

That process cannot add any material. Missing thread material is the actual problem and a
dangerous one at that.

Agreed. Chasing the threads can remove garbage from inside the threads, and straighten bent threads
(which will then be weakened, most likely; see other messages here regarding metal fatigue...).

Quoted message said:

I suggested earlier that a new crank is the preferred ( under $20)

At $20, I'd not bother fooling around with anything else.

--
Rick Onanian

A Muzi said:

You'd think that the clear English phrase, or even "cut" would be preferred, rather than the
obfuscating "chase".

back in the "old" days .. lathes had a special geared shaft that was used to "chase"/create threaded
parts.... that term has just carried thru to modern times.

charlie

"Rick Onanian" <[email hidden]> wrote in message "]news:[email hidden]...

Quoted message said:

A Muzi said:

"Chase" as far as I can tell, implies just 'run a tap through the pedal eye'. You'd think that
the clear English phrase, or even "cut" would be preferred, rather than the obfuscating "chase".
Oh, well.

(ro)> The phrase might make it more obvious; but to

Quoted message said:

say "cut" would be very confusing. "Cut" is how you describe the action of using a tap to make
threads in a smooth hole.

(am)> > That process cannot add any material. Missing thread material is the

Quoted message said:

Quoted message said:

actual problem and a dangerous one at that.

(ro)> Agreed. Chasing the threads can remove garbage

Quoted message said:

from inside the threads, and straighten bent threads (which will then be weakened, most likely;
see other messages here regarding metal fatigue...).

(am)> > I suggested earlier that a new crank is the preferred ( under $20)

Quoted message said:

(ro)> At $20, I'd not bother fooling around with

Quoted message said:

anything else.

Straighten bent threads?????

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

A Muzi said:

(ro)> Agreed. Chasing the threads can remove garbage

Quoted message said:

from inside the threads, and straighten bent threads (which will then be weakened, most likely;
see other messages here regarding metal fatigue...).

Quoted message said:

Straighten bent threads?????

Yes, when a pedal is not threaded in fully and pulls out of the crankarm, not only will it strip
it's own threads, but I'll bet the threads in the crankarm will be deformed and/or stripped.

Running a tap through those deformed threads may push them back into the proper shape. Threading a
pedal in from the other side might do that better, if it has good quality threads.

Mostly, I suppose, the tap is more likely to cut the offending shape off than push it back
into place.

Of course, if the threads are actually stripped, then no tap or bolt will bring them back.

Quoted message said:

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

--
Rick Onanian

Okay here is my follow up. I brought my bike into a bike store and had the mechanic look at the
bike. I asked him about either tapping it or chasing it. He said that it was going to cost $25 CDN
for him to tap it for me (drill a new hole in the crank arm), but I was wondering how my pedal was
going to fit in properly if the hole is going to be larger than before ? He said that even if you
chase a crank arm the pedal could still come off again in the future because it is weaker. The best
solution at that time was just to buy another left crank arm. He offered me a few low end crank arms
for $10 CDN each but suggested I take an older Peugeot crank arm for $15 CDN to match the quality of
my 1985 Miele Beta Tange 900 cromoly bike. I ended up taking the latter, but I am concerned that my
pedalling motion/transfer might be affected because I now have a lighter left crank arm then my
previous one. left crank arm = older Peugot right crank arm = Sugino VP 130

At least they are both 170 mm.

I was thinking of getting another matching crankset altogether but I needed to use the bike soon so
I looked at it as possibly a short term solution, but ultimately I decided it was not worth the risk
of re-using an already damaged crank arm.

"Rick Onanian" <[email hidden]> wrote in message "]news:[email hidden]...

Quoted message said:

Quoted message said:

(ro)> Agreed. Chasing the threads can remove garbage

Quoted message said:

from inside the threads, and straighten bent threads (which will then be weakened, most likely;
see other messages here regarding metal fatigue...).

Quoted message said:

A Muzi said:

Straighten bent threads?????

(Mr Onanian continued)> Yes, when a pedal is not threaded in fully and

Quoted message said:

pulls out of the crankarm, not only will it strip it's own threads, but I'll bet the threads in
the crankarm will be deformed and/or stripped.

Running a tap through those deformed threads may push them back into the proper shape. Threading a
pedal in from the other side might do that better, if it has good quality threads.

Mostly, I suppose, the tap is more likely to cut the offending shape off than push it back
into place.

Of course, if the threads are actually stripped, then no tap or bolt will bring them back.

I think you do not use taps and dies in aluminum.very often .
--
Andrew Muzi www.yellowjersey.org Open every day since 1 April, 1971

A Muzi said:

I think you do not use taps and dies in aluminum.very often .

I stand corrected. I was thinking of how they've worked on steel for me, in non-cycling
applications.

Aluminum threads would break before they would bend back. However, if the crank isn't aluminum, it
might work; then again, if the crank isn't aluminum, it's probably cheap enough to replace for all
that effort.

Quoted message said:

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

--
Rick Onanian