Cottered Cranks with Fixed Gear

I have recently come into posession of a 1950's Raleigh Lenton that was
converted into a fixed gear somewhere around the early 80's. My LBS
has given it the once over, but advised me to change the original steel
cottered cranks as soon as possible, on the grounds that they would
invevitably fly apart at an intersection forthwith, especially on a
fixed gear bike.

The cotters seem to be in good condition, and the cranks are currently
secure. I'm currently using the bike on my daily commute.

Are the cottered cranks truly a ticking time bomb, or is the LBS being
unnecessarily cautious here?


Jeff 8-)

A properly installed cottered crank will be no problem with a fixed
gear. This was done for years, and there was not a rash of failures.
I had a similar set up, and it works as you would expect.

Let's see ... this bike has been a fixie for probably 20 years, with
no problem with the cottered cranks. Cottered cranks are a sturdy and
durable design. Did you ever take the cranks off of a cottered set-up?
Without a special tool, it takes alot of hammer force to pound out the
cotter -- which is held secure with a nut and washer on the narrow end.
What? Vibration is going to loosen the nut, it will fall off, and
then without warning the crank will fly off? If by some remote
possibility the nut did fall off, you would feel slop in the crank way
before anything bad happened. (Just like you feel slop in a cotterless
crank that is loosening up.) Then it would be a simple matter of
replacing and tightening the nut.

The LBS can make $100 bucks or so if they "upgrade" your bike. I wonder
what kind of experience your LBS has with cottered fixies? What is
their experience re. the failure rate of cottered fixies vs. cotterless
on fixies.

I'm a little cynical here. I asked my LBS to install a "sealed
bearing" BB on my fixie -- in part just to support them. A couple of
months later the BB loosened, IMO because of improper installation --
not tight enough. They said it was my fault, as my "back pedal for
stopping" was the cause of the problem -- and charged me for the
repair. Actually, I have front and rear brakes, and use them for most
of my slowing down. I now do pretty much all of my own repair work.

Regards,
Larry

Let's see ... this bike has been a fixie for probably 20 years, with
no problem with the cottered cranks. Cottered cranks are a sturdy and
durable design. Did you ever take the cranks off of a cottered set-up?
Without a special tool, it takes alot of hammer force to pound out the
cotter -- which is held secure with a nut and washer on the narrow end.
What? Vibration is going to loosen the nut, it will fall off, and
then without warning the crank will fly off? If by some remote
possibility the nut did fall off, you would feel slop in the crank way
before anything bad happened. (Just like you feel slop in a cotterless
crank that is loosening up.) Then it would be a simple matter of
replacing and tightening the nut.

The LBS can make $100 bucks or so if they "upgrade" your bike. I wonder
what kind of experience your LBS has with cottered fixies? What is
their experience re. the failure rate of cottered fixies vs. cotterless
on fixies.

I'm a little cynical here. I asked my LBS to install a "sealed
bearing" BB on my fixie -- in part just to support them. A couple of
months later the BB loosened, IMO because of improper installation --
not tight enough. They said it was my fault, as my "back pedal for
stopping" was the cause of the problem -- and charged me for the
repair. Actually, I have front and rear brakes, and use them for most
of my slowing down. I now do pretty much all of my own repair work.

Regards,
Larry

As they say on Car Talk, "Somebody needs to make a boat payment."

Other than being a bit heavy, cottered cranks are refreshingly durable,
handsome, and mechanically straight-forward. Keep them--and get some
slot cleated shoes and wool shorts just to spite those bike shop
jagoffs. :P

Only reason to replace would be if the chainring's worn, but
steel/chrome rings last virtually forever.

On 9 Nov 2005 21:48:17 -0800, wrote:

I have recently come into posession of a 1950's Raleigh Lenton that was
converted into a fixed gear somewhere around the early 80's. My LBS
has given it the once over, but advised me to change the original steel
cottered cranks as soon as possible, on the grounds that they would
invevitably fly apart at an intersection forthwith, especially on a
fixed gear bike.

The cotters seem to be in good condition, and the cranks are currently
secure. I'm currently using the bike on my daily commute.

Are the cottered cranks truly a ticking time bomb, or is the LBS being
unnecessarily cautious here?

Not so much unnecessarily cautious. I'd go for either maliciously lying to
get you to spend money, or dangerously incompetent wrt bikes older than
the mechanic.

There's nothing wrong with steel cranks or cottered cranks, as long as you
don't care about weight, and you don't want to take them apart,
respectively. Once you do want to take them apart, cottered cranks become
a bit of a liability, but there's certainly no reason to replace the
crankset until the BB croaks.

Jasper

They're not a PITA to take apart either, unless somebody's
over-tightened the cotters. Soak the area with penetrating lube before
trying to undo 50 y/o cotters. If you do have to drill them out, you
can buy new cotter pins.

wrote:
I have recently come into posession of a 1950's Raleigh Lenton that was
converted into a fixed gear somewhere around the early 80's. My LBS
has given it the once over, but advised me to change the original steel
cottered cranks as soon as possible, on the grounds that they would
invevitably fly apart at an intersection forthwith, especially on a
fixed gear bike.

The cotters seem to be in good condition, and the cranks are currently
secure. I'm currently using the bike on my daily commute.

Are the cottered cranks truly a ticking time bomb, or is the LBS being
unnecessarily cautious here?


Jeff 8-)


Since cottered cranks were the gold standard for track sprinting for
many years after cotterless cranks were standard on road bikes I would
say that your LBS is full of BS. Reg Harris used cottered cranks and
they worked fine for him.
Phil Brown

On 9 Nov 2005 21:48:17 -0800, wrote:

I have recently come into posession of a 1950's Raleigh Lenton that was
converted into a fixed gear somewhere around the early 80's. My LBS
has given it the once over, but advised me to change the original steel
cottered cranks as soon as possible, on the grounds that they would
invevitably fly apart at an intersection forthwith, especially on a
fixed gear bike.

The cotters seem to be in good condition, and the cranks are currently
secure. I'm currently using the bike on my daily commute.

Are the cottered cranks truly a ticking time bomb, or is the LBS being
unnecessarily cautious here?

At best, unnecessarily cautious. Any concern that such cranks are
sudden-failure-prone when there is reverse pressure involved is
unfounded in my opinion. Although cottered cranks vanished for good
reasons, it had more to do with weight and ease of assembly and
servicing than failures. The square taper allows assembly without the
need for a box of cotters and the attendant filing and fitting, and
it's easier to make a durable aluminum crank with a square taper than
with a cotter. There are lots of very old cottered-crank bikes
running aound whose BB has never been apart for anything but a little
grease (if that), and a good many are and have been in daily use by
pedicab and cargo-bike operators who spend a lot of time standing on
the pedals waiting for a break in traffic. I on't think you have
anything to worry about with your old setup; I'd just ride it. The
worst that might happen is that the crank might loosen up, which isn't
something that goes from wiggle to wobble to whoops in a hurry.
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philcycles wrote:

wrote:
I have recently come into posession of a 1950's Raleigh Lenton that was
converted into a fixed gear somewhere around the early 80's. My LBS
has given it the once over, but advised me to change the original steel
cottered cranks as soon as possible, on the grounds that they would
invevitably fly apart at an intersection forthwith, especially on a
fixed gear bike.

The cotters seem to be in good condition, and the cranks are currently
secure. I'm currently using the bike on my daily commute.

Are the cottered cranks truly a ticking time bomb, or is the LBS being
unnecessarily cautious here?


Jeff 8-)

Since cottered cranks were the gold standard for track sprinting for
many years after cotterless cranks were standard on road bikes I would
say that your LBS is full of BS. Reg Harris used cottered cranks and
they worked fine for him.
Phil Brown

no experience with fixed gear and cottered cranks, but cotters will not
last if you knock them in from the wrong side. From which can be
deduced that if your riding style involves large torque reversals you
could have trouble.
--
---
Marten Gerritsen

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