Cranks that can handle a wide range of chain rings

I have been in Colorado for much of this winter and I do not have my
own bikes with me. I have used solo Campagnolo forever (1985 anyway) on
my own bikes and I was thinking of picking up 1 or 2 compact cranksets
for use on these trips to the Colorado mountain road rides. I have used
39/53 doubles and a triple (that was geared too low) and I think a 34
to 36 with a 50 would be perfect for these trips. Now that I am getting
serious about it, I wonder if this is the best idea (swapping cranks
several times a year on a Campagnolo bottom bracket. Am I likely to run
in to problems from swapping them freguently (like wearing out the
crank's bottom bracket interface enough to cause creaking)?

I remember that at least one French manufacturer (Mavic) had a crank
that could be changed from a double to a triple. I think Stronglight
might even still make a crank that can accomplish this. Would this be a
better idea? I guess I could get a dedicated bike for doing "nothing
but" climbing and descending. The final idea is just to go with compact
and leave them there but use one that can handle a 52 big ring. I think
FSA ships at least one of its compact cranks with a 36/52. As long as I
keep the tooth difference at 16 ir fewer I should be ok. Does anyone
have any experince with these compacts swapping rings of these sizes?

Chris M wrote:

I remember that at least one French manufacturer (Mavic) had a crank
that could be changed from a double to a triple. I think Stronglight
might even still make a crank that can accomplish this. Would this be
a
better idea? I guess I could get a dedicated bike for doing "nothing
but" climbing and descending. The final idea is just to go with
compact
and leave them there but use one that can handle a 52 big ring. I
think
FSA ships at least one of its compact cranks with a 36/52. As long as
I
keep the tooth difference at 16 ir fewer I should be ok. Does anyone
have any experince with these compacts swapping rings of these sizes?

"Compact" cranks that use a 110mm bolt circle will accept chainrings
from 33 teeth on up. The largest I could find in a 10-second search is
73 teeth. A 34-52 should be fine, but the shifting may not be as good
as (for instance) a 39-53. What front derailleur and shifter are you
planning on using?

Another equipment-specific issue occurs if you use the small
chainring-smaller cog gears. You may get some rub on the larger
chainring due to the extreme angle on the chain. This will be less
apparent on bikes with longer chainstays.

Almost any triple crank can be used as a double, just by removing the
inner chainring.


Jeff

Chris M wrote:
I have been in Colorado for much of this winter and I do not have my
own bikes with me. I have used solo Campagnolo forever (1985 anyway) on
my own bikes and I was thinking of picking up 1 or 2 compact cranksets
for use on these trips to the Colorado mountain road rides. I have used
39/53 doubles and a triple (that was geared too low) and I think a 34
to 36 with a 50 would be perfect for these trips. Now that I am getting
serious about it, I wonder if this is the best idea (swapping cranks
several times a year on a Campagnolo bottom bracket. Am I likely to run
in to problems from swapping them freguently (like wearing out the
crank's bottom bracket interface enough to cause creaking)?

I remember that at least one French manufacturer (Mavic) had a crank
that could be changed from a double to a triple. I think Stronglight
might even still make a crank that can accomplish this. Would this be a
better idea? I guess I could get a dedicated bike for doing "nothing
but" climbing and descending. The final idea is just to go with compact
and leave them there but use one that can handle a 52 big ring. I think
FSA ships at least one of its compact cranks with a 36/52. As long as I
keep the tooth difference at 16 ir fewer I should be ok. Does anyone
have any experince with these compacts swapping rings of these sizes?

The 'triplizer' or 'mertz conversion' type rings are available .
Removing/remounting crank arms on your spindle twice a year
will kill them in a few seasons.

Either dedicate one bike for this or get the 'triplizer'
setup or simply go triple and just don't shift to the lower
range when you're on the prairie!

Modern triples perform very well, not at all like the
finicky stuff of the classic era!
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

On Mon, 28 Feb 2005 17:07:23 -0600, A Muzi
wrote:



Removing/remounting crank arms on your spindle twice a year
will kill them in a few seasons.


Can you say more about this? Is there a certain number of times that a
square taper crank can be remounted before it is unusable? How do you
tell?

I swap parts around, try different setups, etc. This can include
cranks. I have an old Sugino crankset that has probably been remounted
6-8 times, moving from one frame to another and back, off for a
repaint then back on, etc. This seems like it might fall within your
'few seasons' limit of remounts (obviously time is not the factor but
number of remounts; aluminum won't 'heal' or reform if the remount
happens every six months or every six years).

On 28 Feb 2005 11:50:42 -0800, "Chris M"
wrote:

I have been in Colorado for much of this winter and I do not have my
own bikes with me. I have used solo Campagnolo forever (1985 anyway) on
my own bikes and I was thinking of picking up 1 or 2 compact cranksets
for use on these trips to the Colorado mountain road rides. I have used
39/53 doubles and a triple (that was geared too low) and I think a 34
to 36 with a 50 would be perfect for these trips. Now that I am getting
serious about it, I wonder if this is the best idea (swapping cranks
several times a year on a Campagnolo bottom bracket. Am I likely to run
in to problems from swapping them freguently (like wearing out the
crank's bottom bracket interface enough to cause creaking)?

I remember that at least one French manufacturer (Mavic) had a crank
that could be changed from a double to a triple. I think Stronglight
might even still make a crank that can accomplish this. Would this be a
better idea? I guess I could get a dedicated bike for doing "nothing
but" climbing and descending. The final idea is just to go with compact
and leave them there but use one that can handle a 52 big ring. I think
FSA ships at least one of its compact cranks with a 36/52. As long as I
keep the tooth difference at 16 ir fewer I should be ok. Does anyone
have any experince with these compacts swapping rings of these sizes?

In my personal experience, once I started with compact cranks, which
is before the boom after use in TdF, I had no need for 53/39 or
'standard ring' double cranks. You certainly can get 52/36 and swap
in a 34t ring when you need it. Yes, 52/34 will work but you'l be
using the the outer and inner cogs more. If your bottom bracket is a
Centaur or other Campy 111 or 115, you can buy a Sugino XD and just
mount the arms on your bb. If you have a Chorus or Record bb, you'll
be looking for a bb or the Campy compact cranks. I avoid removing
crankarms as much as I can.

A 110 bolt pattern is much more versatile than 135 or 130. You have a
wide choice of chainring sized from in the 50s down to 33. I run my
tandem with a 50/34 and 12/34 XT cassette. I've given up on triples.
Wanna buy a Racing-T?

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In article ,
Dan Daniel wrote:
On Mon, 28 Feb 2005 17:07:23 -0600, A Muzi
wrote:



Removing/remounting crank arms on your spindle twice a year
will kill them in a few seasons.


_ Is there something different about modern cranks? In the
era before cartridge bearing BB's it was common practice to
clean and lube the BB twice a year. This required removing
the cranks.

_ Booker C. Bense




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Dan Daniel wrote:
On Mon, 28 Feb 2005 17:07:23 -0600, A Muzi
wrote:

Removing/remounting crank arms on your spindle twice a year
will kill them in a few seasons.

Can you say more about this? Is there a certain number of times that a
square taper crank can be remounted before it is unusable? How do you
tell?

I swap parts around, try different setups, etc. This can include
cranks.

I have a folding travel bike on which I remove the cranks (Shimano 105)
every time I pack it in its suitcase. They've been removed and
reinstalled dozens of times over the last 10 years with no apparent harm.

On Mon, 28 Feb 2005 17:07:23 -0600, A Muzi
wrote:
Removing/remounting crank arms on your spindle twice a year
will kill them in a few seasons.

Dan Daniel wrote:
Can you say more about this? Is there a certain number of times that a
square taper crank can be remounted before it is unusable? How do you
tell?
I swap parts around, try different setups, etc. This can include
cranks. I have an old Sugino crankset that has probably been remounted
6-8 times, moving from one frame to another and back, off for a
repaint then back on, etc. This seems like it might fall within your
'few seasons' limit of remounts (obviously time is not the factor but
number of remounts; aluminum won't 'heal' or reform if the remount
happens every six months or every six years).

I don't know. At least as far as a hard number. And the
range is wide. If the OP can reasonably structure this such
that he won't have to remove/remount a crank arm every few
months that would be a better choice.

Various riders mount various cranks with extremely low and
some with extremely high torque. With and without lube.
(Shoot for something around 40-50 kcm. I lube everything.)
Too many variables to say "five times" or "twenty six
times" or any number as a 'rule'.

Some riders continually tighten their cranks, walking them
up the taper to death. Sure, you know not to do that. But
changing them every once in a while is the same thing, isn't it?

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

On Tue, 01 Mar 2005 18:00:53 -0600, A Muzi
wrote:

On Mon, 28 Feb 2005 17:07:23 -0600, A Muzi
wrote:
Removing/remounting crank arms on your spindle twice a year
will kill them in a few seasons.

Dan Daniel wrote:
Can you say more about this? Is there a certain number of times that a
square taper crank can be remounted before it is unusable? How do you
tell?
I swap parts around, try different setups, etc. This can include
cranks. I have an old Sugino crankset that has probably been remounted
6-8 times, moving from one frame to another and back, off for a
repaint then back on, etc. This seems like it might fall within your
'few seasons' limit of remounts (obviously time is not the factor but
number of remounts; aluminum won't 'heal' or reform if the remount
happens every six months or every six years).

I don't know. At least as far as a hard number. And the
range is wide. If the OP can reasonably structure this such
that he won't have to remove/remount a crank arm every few
months that would be a better choice.

Various riders mount various cranks with extremely low and
some with extremely high torque. With and without lube.
(Shoot for something around 40-50 kcm. I lube everything.)
Too many variables to say "five times" or "twenty six
times" or any number as a 'rule'.


Understood. When you said that remounting twice a year would lead to
failure in 'a few' seasons, that made me wonder if you personally *do*
have some specific number or range in your own practice.

Some riders continually tighten their cranks, walking them
up the taper to death. Sure, you know not to do that. But
changing them every once in a while is the same thing, isn't it?

I am not arguing that mounting cranks is potentially destructive
(although not to the point of failure every time, obviously). And
whatever the 'destruction' at each remounting, it will be cumulative.
The crank will not bounce back to its original shape.

I don't work in a bike shop, and even though I was working on bikes
before your shop opened, my total wrenching time over my life is
probably less than you've done in a few weeks of your business.

Is there some way to tell if a crank is in trouble? I have a very
specific reason for asking- last spring I remounted some cranks after
a repaint, and they would not work with the same bottom bracket as
before. I needed to use a longer BB- from a 122 to a 127. With the old
BB, the small chainring (Sugino triple, 10 years old or more) wouldn't
clear the chainstay. At the time, I attributed this to the alignment
work that had been done on the frame before the repaint.

There had been some serious rear alignment problems since I bought the
frame (used), and it seemed like a good time to get it looked at. The
whole rear triangle had to be twisted, shifted and realigned a couple
of millimeters (cold set by Bernie Mikkelsen, a very good frame
builder by reputation). I have had no hints of any problems since the
rebuild.

But your comments here have me wondering if the crank is in trouble.

On Tue, 01 Mar 2005 18:00:53 -0600, A Muzi
wrote:

On Mon, 28 Feb 2005 17:07:23 -0600, A Muzi
wrote:
Removing/remounting crank arms on your spindle twice a year
will kill them in a few seasons.

Dan Daniel wrote:
Can you say more about this? Is there a certain number of times that a
square taper crank can be remounted before it is unusable? How do you
tell?
I swap parts around, try different setups, etc. This can include
cranks. I have an old Sugino crankset that has probably been remounted
6-8 times, moving from one frame to another and back, off for a
repaint then back on, etc. This seems like it might fall within your
'few seasons' limit of remounts (obviously time is not the factor but
number of remounts; aluminum won't 'heal' or reform if the remount
happens every six months or every six years).

I don't know. At least as far as a hard number. And the
range is wide. If the OP can reasonably structure this such
that he won't have to remove/remount a crank arm every few
months that would be a better choice.

Various riders mount various cranks with extremely low and
some with extremely high torque. With and without lube.
(Shoot for something around 40-50 kcm. I lube everything.)
Too many variables to say "five times" or "twenty six
times" or any number as a 'rule'.

Some riders continually tighten their cranks, walking them
up the taper to death. Sure, you know not to do that. But
changing them every once in a while is the same thing, isn't it?

Searching rec.bicycles.tech for "Repeatedly mounting and removing
cranks" yielded a post that reports measurements, as well as the
following summary:

"Repeatedly mounting and removing these cranks during my test caused
them to fit farther onto the spindle each time."

Here's the rest of the original post:
http://groups-beta.google.com/group/...1e1f0b34335f72

Newsgroups: rec.bicycles.tech
From: (Rinards)
Date: 1997/09/15
Subject: greased cranks slip farther up the tapers

There is much debate about whether one should grease the fit between
the crank spindle and the square tapered hole in the crank or not. I
recently found a cracked crank on my bike and became curious about the
effects of greasing the tapers. So I made some measurements of how
far a crank slips up the taper on a bottom bracket spindle when the
tapers are greased compared to when the grease is wiped off.

TEST METHOD
I measured seven cranks: the left and right arms of three crank sets,
and one loose right hand arm I had lying around. The cranks were a
pair of old, used Nuovo Record cranks, a new pair of Dura-Ace FC-7402
cranks, a new pair of Ofmega Super Competitzione arms, and an NOS
Sugino “2 GC” melt forged arm.

During the course of my test I mounted all the cranks dry, then
mounted them greased, then wiped them off and mounted them all dry
again. I measured the cranks’ position before tightening them and
after.

I used the same spindle and bolt for all cranks. I mounted the cranks
the same orientation on the spindle each time. I used a cheap torque
wrench to determine when I got to 300 in*lb. I greased the bolt’s
threads and washer.

EFFECT ON HOW FAR THE CRANK SLIPS UP THE TAPER
On average, cranks mounted on a dry spindle slide about 2.2 mm up the
taper. That’s starting from finger tight and ending at 300 inch
pounds.

However, the same cranks, when mounted on greased tapers, slide 3.1 mm
up the taper on average. That’s about 40% farther up the taper when
greased than dry. Since the crank slips farther up the taper, it must
be straining more after installation on a greased spindle.

It appears greasing the tapers of your bottom bracket spindle
increases the stress on your crank’s square tapered hole.

EFFECT ON PREDICTING CHAINLINE
Reducing the stress on the square tapered hole is one apparent benefit
of mounting the cranks dry. Another benefit is more accuracy
predicting chainline, too. As I said above, cranks mounted dry slip
2.2mm up the taper on average. Of the seven cranks I measured, some
slipped farther and some slipped less. During the first dry mounting,
the most any crank slipped up the taper was 2.7mm, and the least any
crank slipped was 1.8mm. This range is only 0.9mm. During the second
dry mounting, the range was even less: 0.7mm.

In contrast, when mounted on a greased spindle, there was a wider
range of how far the crank would slip up the taper. The farthest any
crank slipped was 3.6mm, and the least a crank slipped was 2.4mm, for
a range of 1.1mm. That’s 20 to 57% more spread than when the cranks
were mounted dry. I admit that's a pretty small difference, but one
that bothers the perfectionist in me when I am trying to choose a
spindle to give a desired chainline. It is harder to predict what
chainline you’ll get if you mount your cranks with grease on the
tapers.

EFFECT ON “STRETCHING” THE CRANK’S SQUARE HOLE
Repeatedly mounting and removing these cranks during my test caused
them to fit farther onto the spindle each time. They did not go back
to where they were the first time, even when the grease was wiped off
and the cranks were mounted dry again.

I recorded the position of each crank after mounting it the first time
(dry). Then I recorded the position of each crank after mounting it
the second time (greased). On average, the final resting place was
1.1mm farther on the spindle when mounted the second time (with
grease) compared to the first time (dry). After wiping off the grease
and re-mounting the cranks a third time (dry), they still ended up
0.6mm farther up the taper than they did the first time, though they
did recover somewhat from the greased position.

I do not know why the cranks ended up farther on the spindle after
each time. I don’t know if the cranks were stretched once by mounting
them with grease, or if the fit gets looser even from mounting them
dry. Someday I may get around to measuring the cranks’ position after
repeated dry mountings to find out. But probably I won’t.

HOW I PLAN TO MOUNT MY CRANKS IN THE FUTURE
I will wipe off the spindle and the square tapered hole in the crank
with a rag, and mount the cranks dry. I will carefully wipe off the
threads of the bolt, grease them, the bolt’s shoulder and the washer.
I will torque the bolt to 300 in*lb. I will take my cranks off as
seldom as possible.

Damon Rinard