"Compact Double Crank" = "Touring Bike Crank"

[Robert Perkins]

This is the funniest thing to come along since oval chain rings were
"replaced" by super-duper round ones.

Finally, some company had the smarts to give the average cycling joe the
gearing he needs while wrapping it all in some "weight saving" mystique.

http://www.yellowjersey.org/cranx3.html

My '93 Cannondale touring bike came with a low-Q Ritchey triple with
50-42-30 rings. I run another Ritchey triple with 50-38-28 on my road
bike with a 7-speed 12-23 cassette.

Maybe we can now dig out our old Sugino triples and call them "vintage
racing compact"

Rob

 

[[email protected]]

Robert Perkins wrote:
> This is the funniest thing to come along since oval chain rings were
> "replaced" by super-duper round ones.
>
> Finally, some company had the smarts to give the average cycling joe the
> gearing he needs while wrapping it all in some "weight saving" mystique.
>
> http://www.yellowjersey.org/cranx3.html
>
> My '93 Cannondale touring bike came with a low-Q Ritchey triple with
> 50-42-30 rings. I run another Ritchey triple with 50-38-28 on my road
> bike with a 7-speed 12-23 cassette.
>
> Maybe we can now dig out our old Sugino triples and call them "vintage
> racing compact"
>
> Rob

Wow, why $120 for the Suntour XC-Pro long cage rear der.?
http://www.yellowjersey.org/rdxcpro.jpg

 

[A Muzi]

> Robert Perkins wrote:
>>This is the funniest thing to come along since oval chain rings were
>>"replaced" by super-duper round ones.
>>
>>Finally, some company had the smarts to give the average cycling joe the
>>gearing he needs while wrapping it all in some "weight saving" mystique.
>>
>>http://www.yellowjersey.org/cranx3.html
>>
>>My '93 Cannondale touring bike came with a low-Q Ritchey triple with
>>50-42-30 rings. I run another Ritchey triple with 50-38-28 on my road
>>bike with a 7-speed 12-23 cassette.
>>
>>Maybe we can now dig out our old Sugino triples and call them "vintage
>>racing compact"

[email protected] wrote:
> Wow, why $120 for the Suntour XC-Pro long cage rear der.?
> http://www.yellowjersey.org/rdxcpro.jpg
>
Some riders prefer "new in box", others accept used from
EBay for less. Choice is good.

Regarding your crank comment, which I'm not sure I understood-
We also sell the basic Sugino XD crank for $69.95.
Choice is good.

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

 

[John Thompson]

On 2005-06-01, Robert Perkins <[email protected]> wrote:

> This is the funniest thing to come along since oval chain rings were
> "replaced" by super-duper round ones.
>
> Finally, some company had the smarts to give the average cycling joe the
> gearing he needs while wrapping it all in some "weight saving" mystique.
>
> http://www.yellowjersey.org/cranx3.html
>
> My '93 Cannondale touring bike came with a low-Q Ritchey triple with
> 50-42-30 rings. I run another Ritchey triple with 50-38-28 on my road
> bike with a 7-speed 12-23 cassette.
>
> Maybe we can now dig out our old Sugino triples and call them "vintage
> racing compact"

This spring I decided that since I seldom used the high gears on my road
bike, I'd get rid of them. So I installed an old Stronglight 99 crank with
32-45T rings on it and paired it with a 13-21 freewheel. Now I can use all
my gears...

--

John ([email protected])

 

[[email protected]]

A Muzi wrote:
>
> Regarding your crank comment, which I'm not sure I understood-
>


I'm not sure what exact point regarding compact doubles the OP was
addressing, either. But I do wonder why anyone would pay to have the
potential utility of a crank *reduced*, as in your Sugino triple to
double conversion. I know you guys are just meeting a demand, and the
labor charge is very fair....but WHY??? Why not just put some plugs on
the 74mm mounts and ride on? Maybe one day, a triple would be handy.

 

[Paul Kopit]

On 2 Jun 2005 05:24:26 -0700, [email protected] wrote:

>I'm not sure what exact point regarding compact doubles the OP was
>addressing, either. But I do wonder why anyone would pay to have the
>potential utility of a crank *reduced*, as in your Sugino triple to
>double conversion. I know you guys are just meeting a demand, and the
>labor charge is very fair....but WHY??? Why not just put some plugs on
>the 74mm mounts and ride on? Maybe one day, a triple wo

There are little bumps where the threads for the inner ring are. When
the chain is derailled, it will lodge between the bottom bracket and
those bumps and become very difficult to get back up. Remember, when
using as a double, the crankarm is closer to the frame. Those pumps
are particularly pronounced on something like an RX 100 crank.

 

[David Huggins-Daines]

Paul Kopit wrote:
> On 2 Jun 2005 05:24:26 -0700, [email protected] wrote:
>>I'm not sure what exact point regarding compact doubles the OP was
>>addressing, either. But I do wonder why anyone would pay to have the
>>potential utility of a crank *reduced*, as in your Sugino triple to
>>double conversion.
>
> There are little bumps where the threads for the inner ring are. When
> the chain is derailled, it will lodge between the bottom bracket and
> those bumps and become very difficult to get back up. Remember, when
> using as a double, the crankarm is closer to the frame. Those pumps
> are particularly pronounced on something like an RX 100 crank.

In addition, converting a triple to a double can result in a lower
Q-factor (tread) than many purpose-built doubles, which is something
that a lot of people, including me, like a lot.

Once upon a time, Sugino and others built triple cranks that used
separate spacers for the inner ring (and had no "bumps"), and bottom
brackets had interchangeable axles, so you could go back and forth from
a triple to a double as you saw fit without any grinding or filing. But
then, a lot of double cranks back then also used the 110mm BCD, too.

I wonder why the move to integrated granny spacers happened. I can't
see any benefit in it, for the consumer at least.

 

[[email protected]]

Paul Kopit wrote:
> On 2 Jun 2005 05:24:26 -0700, [email protected] wrote:
>
> >I'm not sure what exact point regarding compact doubles the OP was
> >addressing, either. But I do wonder why anyone would pay to have the
> >potential utility of a crank *reduced*, as in your Sugino triple to
> >double conversion. I know you guys are just meeting a demand, and the
> >labor charge is very fair....but WHY??? Why not just put some plugs on
> >the 74mm mounts and ride on? Maybe one day, a triple wo
>
> There are little bumps where the threads for the inner ring are. When
> the chain is derailled, it will lodge between the bottom bracket and
> those bumps and become very difficult to get back up. Remember, when
> using as a double, the crankarm is closer to the frame. Those pumps
> are particularly pronounced on something like an RX 100 crank.
>
>
I think a properly set limit screw would prevent the problem. If not, a
"third eye" type thingie surely would. I'd rather take some care
setting the limit screw or take the time to install the "third eye" and
save the money on having the crank modified, get to keep the 74mm
chainring *and* have the option to run a triple on the same crank. YMMV

 

[[email protected]]

David Huggins-Daines wrote:
> Paul Kopit wrote:
> > On 2 Jun 2005 05:24:26 -0700, [email protected] wrote:
> >>I'm not sure what exact point regarding compact doubles the OP was
> >>addressing, either. But I do wonder why anyone would pay to have the
> >>potential utility of a crank *reduced*, as in your Sugino triple to
> >>double conversion.
> >
> > There are little bumps where the threads for the inner ring are. When
> > the chain is derailled, it will lodge between the bottom bracket and
> > those bumps and become very difficult to get back up. Remember, when
> > using as a double, the crankarm is closer to the frame. Those pumps
> > are particularly pronounced on something like an RX 100 crank.
>
> In addition, converting a triple to a double can result in a lower
> Q-factor (tread) than many purpose-built doubles, which is something
> that a lot of people, including me, like a lot.
>
>
I like low Q factor cranks, too. But, IMO, you would have to set the
crankarm awfully close to the BB for the "bumps" to hit the chainstay.
>
>
> Once upon a time, Sugino and others built triple cranks that used
> separate spacers for the inner ring (and had no "bumps"), and bottom
> brackets had interchangeable axles, so you could go back and forth from
> a triple to a double as you saw fit without any grinding or filing. But
> then, a lot of double cranks back then also used the 110mm BCD, too.
>
> I wonder why the move to integrated granny spacers happened. I can't
> see any benefit in it, for the consumer at least.
>
>
No spacers probably speed up the time to assemble the crank, a factor
in production time.

 

[Paul Kopit]

On 2 Jun 2005 14:38:49 -0700, [email protected] wrote:

>I like low Q factor cranks, too. But, IMO, you would have to set the
>crankarm awfully close to the BB for the "bumps" to hit the chainstay.

No, they don't hit the chainstay. If the chain derails, it is often
difficult to get it up again. The chain lodges on the underside of
the bumps.

 

[Sheldon Brown]

David Huggins-Daines wrote:

> I wonder why the move to integrated granny spacers happened. I can't
> see any benefit in it, for the consumer at least.

There are several benefits:

Easier to change chainrings, because you don't need to deal with loose
spacers.

Better thread engagement for the mounting bolts.

You can use shorter mounting bolts.

Probably also permits the spider arms to be made thinner and lighter
since the holes don't go as far through them.

There is also a drawback; it makes it harder to customize the spacing.

For instance, my "Brown" has a nice old Sugino AP130 crank (this was, I
believe, the first 130/74 crank ever. I recall being very excited when
I got it because if finally allowed me to do a triple with full-sized
Biopace chainrings. (It is set up with 52-42-28.)

I wanted the chainline of the two big rings to be in the normal range
for a double crank, so I used much thinner than normal spacers to attach
the 28 tooth chainring.

The idea is that 99% of the time I ride it as if it were a 52-42 double,
but when I'm really up against it I have the 28 ring in reserve. For
many years I rode this with a 12-22 6-speed freewheel. The 28 tooth
chainring could only run smoothly with the 2 or 3 largest sprockets, but
there was no reason to ever use any of the other sprockets with the 28
anyway.

The skinny spacers (and a Phil Wood adjustable bottom bracket) allowed
me to get the crank in very close to the frame for usable chainline in
all combinations using the two larger rings.

This could be difficult to do now, because I'm not sure any modern front
derailer has sufficient leftward travel to shift it, but the old Sun
Tour Cyclone handles it OK.

Sheldon "Breaking The Rules" Brown
+----------------------------------------------+
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| in the 1975 Paris-Brest-Paris at: |
| http://harrietfell.com/PBP1975.html |
+----------------------------------------------+
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Phone 617-244-9772 FAX 617-244-1041
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