Narrow Q factor 165 mm triple crankset?

[Marc Rosenbaum]

Hi All

I've ridden both an Ultegra triple and a Rotor triple on my recumbent
Bacchetta Aero. I measure the Q on the Rotors as 159 mm and the
Ultegras as 156 mm. Both of these make me feel as though my hips
angle outwards. My upright bike for many years has had a set of Sugino
AT triple cranks, which with a Phil Wood 125mm BB has a Q of 146 mm.
I'd swap these onto the Aero except that they are 170 mm cranks and I
really like the shorter 165 mm cranks. The recumbent doesn't have
chain line issues or fat chainstay issues, so the Q can be quite
narrow.

Any suggestions on how to find a set of 165 mm triple cranks with a
narrow Q (preferably under 150 mm)? Used is OK, just tell me what to
be looking for!

Thanks

Marc Rosenbaum
Meriden, NH

 

[Sheldon Brown]

Marc Rosenbaum wrote:

> I've ridden both an Ultegra triple and a Rotor triple on my recumbent
> Bacchetta Aero. I measure the Q on the Rotors as 159 mm and the
> Ultegras as 156 mm. Both of these make me feel as though my hips
> angle outwards. My upright bike for many years has had a set of Sugino
> AT triple cranks, which with a Phil Wood 125mm BB has a Q of 146 mm.
> I'd swap these onto the Aero except that they are 170 mm cranks and I
> really like the shorter 165 mm cranks. The recumbent doesn't have
> chain line issues or fat chainstay issues, so the Q can be quite
> narrow.
>
> Any suggestions on how to find a set of 165 mm triple cranks with a
> narrow Q (preferably under 150 mm)? Used is OK, just tell me what to
> be looking for!

Hi, Marc!

TA Cyclotouriste is just the ticket for your application, they've got
the narrowest tread (a.k.a. "q factor") of any cranks currently available.

http://sheldonbrown.com/harris/french-cranks

I don't generally recommend the triple version for uprights, but they're
fine for recumbents. Also the ultimate "compact double" see:
http://sheldonbrown.org/hetchins

Sheldon "Vive La France" Brown
+--------------------------------------------------------------+
| No state has an inherent right to survive through |
| conscript troops and, in the long run, no state ever has. |
| --Robert A. Heinlein |
+--------------------------------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

 

[Phil Brown]

>Any suggestions on how to find a set of 165 mm triple cranks with a
>narrow Q (preferably under 150 mm)? Used is OK, just tell me what to
>be looking for!
>
>Thanks

Why not just use a narrower BB spindle? You don't have chainstay issues.
Phil brown

 

[Jeff Wills]

[email protected]unged (Phil Brown) wrote in message news:<[email protected]>...
> >Any suggestions on how to find a set of 165 mm triple cranks with a
> >narrow Q (preferably under 150 mm)? Used is OK, just tell me what to
> >be looking for!
> >
> >Thanks
>
> Why not just use a narrower BB spindle? You don't have chainstay issues.
> Phil brown

Yes and no. I tried to put a short BB on my Lightning recumbent once.
I had no problem mounting the cranks, but the front derailleur could
not push the chain onto the granny ring- the derailleur cage ran into
the boom.

Jeff

 

[Marc Rosenbaum]

Thank you all for your responses. The first solution I tried was a
shorter spindle (double Shimano instead of triple) and the inner ring
rubs on the monotube frame. This is partially exacerbated by the
Shimano BB Octalink BB which isn't designed to allow variation of
spindle location left-right.

Sheldon, the TA set is one I rode for years on my Bob Jackson, set up
as a 48-34 with 175mm crank arms. Once I switched to a crankset with
a spider, I immediately noticed how much better the shifting was.
Also, I'm looking for a 48-36-24 set-up, and IIRC the TA only went
down to 26T.

Would you have a second recommendation that will get me a Q below
150mm and comes in 165mm crank length?

Thanks much

Marc

PS: If my search for the crankset bombs, I'm going to look at
modifying my Eggbeater pedals to sit closer to the crank arms and pick
up my Q reduction that way. Yet the best solution is a crankset that
doesn't have the modern design that makes the crank arms flare out so
far.

PPS: Sheldon, I hear tell you've entered the recumbent world on 3
wheels! I went to the Bentride in late August and had the chance to
ride five different trikes - woohoo!

 

[Phil Brown]

>Yes and no. I tried to put a short BB on my Lightning recumbent once.
>I had no problem mounting the cranks, but the front derailleur could
>not push the chain onto the granny ring- the derailleur cage ran into
>the boom.

Probably an FD meant for a triple chainset. You don't need one-use a regular FD
for a double chainset. Won't hit the boom.
Phil Brown

 

[Russell Seaton]

[email protected]unged (Phil Brown) wrote in message news:<[email protected]>...
> >Yes and no. I tried to put a short BB on my Lightning recumbent once.
> >I had no problem mounting the cranks, but the front derailleur could
> >not push the chain onto the granny ring- the derailleur cage ran into
> >the boom.
>
> Probably an FD meant for a triple chainset. You don't need one-use a regular FD
> for a double chainset. Won't hit the boom.
> Phil Brown

No. Even using a double front derailleur you still have the problem
of the front derailleur hitting the frame before it will allow the
chain to drop into the granny ring. Recumbent, diamond frame, does
not matter. The frame will interfere with the inward swing of the
front derailleur if you use too short of a bottom bracket spindle.

 

[Marc Rosenbaum]

This is a status report for any who may be interested. Not having
much success finding my dream crankset, I looked at all the factors
that would contribute to reducing the spacing bewteen my feet, which
includes pedals and shoes. A suggestion on another group led me to
look at the Speedplay pedals, due to shorter axle length, and I
learned that the titanium Zero pedals had the shortest length, 50mm
from crank surface to center of pedal. I
didn't really want to switch to road shoes nor did I really need to
own a set of $270 pedals So I called Crank Bros to learn if
they made a shorter pedal axles for my Eggbeaters, and learned that
they do make a Ti axle 4mm shorter than the standard, which gets the
Eggbeater down to 52mm, moving the two pedals 8mm closer together.
The Ti axle upgrade kit comes as a full rebuild kit for the
Eggbeaters for $100.

Then I did some hunting and learned that a few years ago Shimano
made XTR BBs in 112.5 and 116mm width that have the same Octalink
design that the Ultegra cranks use, so I just ordered one of each,
to see if I can replace the stock 118.5mm BB. I wasn't able to find
anyone who could answer the question of how much the spindle
protrudes past the BB cup flange on each side, so trial and error
seems to be the way I'll learn what I need to learn. One or both of
these BBs will get returned once I can measure them. I expect that
the 116mm will work and that the 112.5mm may not - if the crank
moves in too much on the right side, the inner chainring hits the
Aero main tube (recumbent monotube frame). Mounting my old Sugino AT
cranks has shown me that 45mm is not the minimum chainline that the
Ultegra front derailleur will shift, contrary to what I have been told
(Sugino chainline on the Aero is under 42mm and it looks as though
under 41mm is possible).

Anyway, I'll probably have all the pieces in my hands by the end of
next week, and I expect to drop my pedal tread dimension 10.5 to
14mm while sticking with the 165mm Ultegra crankset. I'm going to
change the c'rings to 48-38-24, not quite my perfect 48-36-24 but I
can't see buying a new crankset for 2 teeth on the middle ring. I'll
run this with an 11-26 9 speed cassette (made from a 12-34, thanks,
Sheldon, for the parts!) for a gear inch range of 22.4-106.1 on the
650c wheels. I'm looking forward to the possibility of a 11-27 or
11-28 10 speed cassette when the pieces are available, as I'd like a
28T large cog but the 9 speed 11-28 has the 18-21 jump where I don't
like it much. I'm also going to fool with an XTR M952 front derailleur
when I get the new chainrings.

Thanks for your suggestions (and to others who responded as well.)I'll
post a final follow-up when the solution is clear.